DESIGNING THE CIRCULAR METABOLIC BUILDING The case of Biotope in the Sunrise Campus Master Thesis
Wageningen University Environmental Technology Group Urban Environmental Management
MASTER THESIS
DESIGNING THE CIRCULAR METABOLIC BUILDING The case of Biotope in the Sunrise Campus Author: Léa Gejer Struchiner Supervisor: Ingo Leusbrock Examiner: Huub Rijnaarts August 08 2011
Contents SUMMARY ................................................................................................................................................. 1 1. INTRODUCTION .................................................................................................................................. 3 1.1.
RESEARCH PURPOSE ................................................................................................................... 4
1.2.
RESEARCH QUESTIONS ............................................................................................................... 5
1.3.
OUTLINE OF THE THESIS ............................................................................................................. 5
2. THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN ............................................................................. 6 2.1.
CRITERIA 1: WASTE EQUALS FOOD, CIRCULAR METABOLISM ........................................................ 7
2.2.
CRITERIA 2: CELEBRATE DIVERSITY, BIODIVERSITY ....................................................................... 8
2.3.
CRITERIA 3: USE CURRENT SOLAR INCOME, USE ONLY RENEWABLE SOURCES ............................... 9
3. EVALUATION CRITERIA ...................................................................................................................... 10 3.1.
URBAN HARVEST APPROACH (UHA): CIRCULAR METABOLISM AND USE OF RENEWABLE SOURCES . 10
3.2.
BIODIVERSITY CRITERIA ............................................................................................................ 12
4. CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE ........................................................................ 15 4.1.
STAKEHOLDERS ........................................................................................................................ 16
4.2.
THE MASTER PLAN AND THE BUSINESS AS USUAL (BAU) SCENARIO ........................................... 19
5. SCENARIOS: METHODOLOGY ...................................................................................................... 21 5.1.
ENERGY FLOW ......................................................................................................................... 22
5.2.
HYDROLOGICAL FLOW .............................................................................................................. 23
5.3.
BIODIVERSITY .......................................................................................................................... 25
6. SCENARIOS ...................................................................................................................................... 26 6.1.
SCENARIO 1 – BUSINESS AS USUAL (BAU) ................................................................................ 29
6.1.1.
ENERGY FLOW ................................................................................................................. 31
6.1.2.
WATER FLOW .................................................................................................................. 32
6.1.3.
BIODIVERSITY .................................................................................................................. 33
6.1.4.
BUSINESS AS USUAL: ASSESSMENT ................................................................................... 34
6.2.
SCENARIO 2 – EFFICIENT .......................................................................................................... 35
6.2.1.
ENERGY FLOW ................................................................................................................. 37
6.2.2.
ENERGY DEMAND MINIMIZATION ...................................................................................... 37
6.2.3.
ENERGY PRODUCTION ...................................................................................................... 44
6.2.4.
WATER FLOW .................................................................................................................. 45
6.2.5.
WATER DEMAND MINIMIZATION ....................................................................................... 46
6.2.6.
MULTISOURCE AND RUNOFF MANAGEMENT....................................................................... 46
6.2.7.
BIODIVERSITY .................................................................................................................. 48
6.2.8.
‘EFFICIENT SCENARIO’: ASSESSMENT ................................................................................. 48
6.3.
SCENARIO 3 – BIO‐DIVERSE ...................................................................................................... 50
6.3.1.
ENERGY FLOW ................................................................................................................. 51
6.3.2.
ENERGY DEMAND MINIMIZATION ...................................................................................... 52
6.3.3.
ENERGY PRODUCTION ...................................................................................................... 57
6.3.4.
WATER FLOW .................................................................................................................. 59
6.3.5.
WATER DEMAND MINIMIZATION ....................................................................................... 60
6.3.6.
MULTISOURCE AND RUNOFF MANAGEMENT....................................................................... 61
6.3.7.
BIODIVERSITY .................................................................................................................. 63
6.3.8.
‘BIO‐DIVERSE SCENARIO’: ASSESSMENT ............................................................................ 64
6.4.
SCENARIO 4 – PRODUCER ......................................................................................................... 66
6.4.1.
ENERGY FLOW ................................................................................................................. 68
6.4.2.
ENERGY DEMAND MINIMIZATION ...................................................................................... 69
6.4.3.
ENERGY PRODUCTION ...................................................................................................... 72
6.4.4.
WATER FLOW .................................................................................................................. 77
6.4.5.
WATER DEMAND MINIMIZATION ....................................................................................... 79
6.4.6.
MULTISOURCE AND RUNOFF MANAGEMENT....................................................................... 79
6.4.7.
BIODIVERSITY .................................................................................................................. 80
6.4.8.
‘PRODUCER SCENARIO’: ASSESSMENT ............................................................................... 81
6.5.
SCENARIO 5 – HYBRID.............................................................................................................. 83
6.5.1.
ENERGY FLOW ................................................................................................................. 85
6.5.2.
ENERGY DEMAND MINIMIZATION ...................................................................................... 86
6.5.3.
ENERGY PRODUCTION ...................................................................................................... 88
6.5.4.
WATER FLOW .................................................................................................................. 92
6.5.5.
WATER DEMAND MINIMIZATION ....................................................................................... 93
6.5.6.
MULTISOURCE AND RUNOFF MANAGEMENT....................................................................... 93
6.5.7.
BIODIVERSITY .................................................................................................................. 93
6.5.8.
‘HYBRID SCENARIO’: ASSESSMENT .................................................................................... 94
7. DISCUSSION ..................................................................................................................................... 96 8. CONCLUSION .................................................................................................................................. 102 References .......................................................................................................................................... 103 Annex 1 – Technology index ............................................................................................................... 108
SUMMARY Annex 2 – Potential Water Applications (Asano, 2006) ...................................................................... 109 Annex 3 – Water application qualities and volumes in Sunrise Campus Buildings ............................ 110 Annex 4 – Water Consumption in Working Environments in the Netherlands. ................................. 111
SUMMARY
SUMMARY The present thesis deals with the role of the built up environment in relation to the resources it relies on. It reflects and designs urban systems towards closed cycles of energy and water, through the use of renewable resources. Moreover, it takes into account the buildings integration to its local biodiversity. All these issues, when planned for an urban area, will bring up an effective design through a strategic management of resources. To create such effective design, the ‘Cradle to Cradle’ (C2C) (McDonough et al., 2002) theory is embraced as the theoretical background for the design criteria. The three tenets of the book are used to generate and evaluate scenarios for the study area. The first tenet, ‘waste equals food’, is represented by the search of a circular metabolism of energy and water in the building’s design. The second, ‘celebrate diversity’, is represented by the biodiversity that can be enhanced depending on each scenario’s design features. Finally, the third tenet, ‘use current solar income’, is represented by the effort of using renewable and local energy and water. For the first and third criteria, the Urban Harvest Approach (UHA) (Agudelo et al., 2009) is applied, whereas for the second, indices of quantity and quality of green areas are assessed. The study area is the Sunrise Campus, an industrial site located in Venlo, the Netherlands. This campus serves as an open innovation place for companies and institutes that have their main focus on glass and energy. There, a building called Biotope is to be built, and this building will serve as a meeting place for all workers of the companies. The Biotope is to create an identity in the campus while it stimulates the working environment. A Master Plan of the Sunrise Campus is being developed, where the C2C theory is strongly emphasized. According to the theoretical background, five different scenarios for the Biotope and Sunrise Campus were developed and assessed according to the three criteria mentioned above. The first is the ‘Business as Usual’ (BAU) Scenario, which is designed according to information of the energy and water flows, and biodiversity of the buildings that are currently placed in the study area. It is the basis for comparison with other scenarios. The second is the ‘Efficient Scenario’, where the building efficiency is seen as a tool that intends overall positive effects towards a more sustainable design. The third scenario is the ‘Bio‐diverse’, which prioritizes the biodiversity through the implementation of green areas rather than other technologies that make possible the production of clean water and energy. The fourth scenario is the ‘Producer’, which in turn, prioritizes the production of renewable
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SUMMARY energy and water rather than biodiversity. The last is the ‘Hybrid Scenario’, which intends to give the same priority level to the production of renewable water and energy, and the biodiversity. These scenarios are designed managing different technologies that are seen as a connection between the human functions of the Biotope and the renewable sources such as the Sun and the rain water. Different technologies that reduce the water and energy demand, and others that enhance their multisource are implemented. At the same time, green areas are also added to the program with the intension of increasing the biodiversity in the Biotope and in the campus. According to each building design and chosen technologies, their demand, their self‐sufficiency and output of energy and water vary. Furthermore, the amount of green area in each design, as well as the local species that would live there, will differ. Finally, these scenarios were assessed and evaluated according to the above mentioned criteria. They are analyzed and compared in order to achieve the most effective solution for the case study.
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INTRODUCTION 1. INTRODUCTION The Industrial Revolution has given humans unprecedented power over nature through new technologies and the use of non‐renewable sources of energy (McDonough et al., 2002). The mass industry has allowed and incentivized high consummation standards and consequently massive use of resources. In search of comfort, convenience, and material wealth, the modern society has scarified not only human health, but also the health of all species. We are starting to exhaust the capacity of the very systems that sustain us, and now we must deal with the consequences (Ryn et al., 2007). Thus, modern industrial life is based on an unsustainable level of use of natural systems. The root cause of human imbalance with the natural ecosystem and biochemical cycles, on which all life depends, is the decision to expand the use of resources without reflecting on the consequences. Many of the current environmental problems derive from the fact that the sinks, on which the human society depends, cannot make use of their wastes1. The excess waste then disrupts the functioning of its sinks. The cities are forced to concentrate the wastes, producing huge landfills, polluted air and water bodies (White, 2006). According to Keen et al., the urbanization processes within the modern industrial society are characterized first of all by the use of fossil fuels consumption associated to greenhouse gases and pollutant emissions (Keen, 2002). Second, it is characterized by the increased production of synthetic chemicals used to create products. Those products such as pesticides and plastic are not easily broken down by natural ecological processes. Third, new forms of human organization, which are not directly engaged with food production and associated ecosystem functions, have developed. Finally, it is characterized by exponential growth of human population. Within the nowadays consummation patterns, the human society rarely thought about the impacts of their wastes. Yet, as the use of resources has increased, so has the production of wastes of all kinds (White, 2006). Therefore, the idea of unlimited economic growth with unlimited use of resources is becoming outdated and it is necessary to review the old values initiated during the Industrial Revolution. Hence, it is crucial to discuss the role of the built environment in such analysis, since the cities’ areas are increasing and represent most of the populations’ settlements. Already in 1996, according to Girardet, although the urban areas occupied only 2% of the world’s land surface, they used 75% of the world’s resources and released a similar percentage of global wastes (Girardet, 1996). Moreover, half of the world’s population has been living in urban areas since 2008; whereas in Europe, North and Latin America more than 70% of the population is by now living in urban environments (UN‐ HABITAT , 2008).
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Wastes are defined as all the materials left over from production or consumption. They can be solid, liquid or gaseous (White, 2006).
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INTRODUCTION 1.1. RESEARCH PURPOSE In the present thesis, the built environment is conceived as a dynamic and complex ecosystem, where the social, economic and cultural systems cannot escape the rules of abiotic and biotic nature. Therefore, like any ecosystem the built environment has inputs and outputs of energy and materials. According to Newman, the main environmental problems are related to the growth of these inputs and managing the increasing outputs (Newman, 1999). Consequently, while contemporary urban life covers our biological origins, people still depend on ecological systems to meet basic needs such as food, oxygen and water (Keen, 2002). This thesis will study urban ecology as complex systems of relationships and interactions between people and resource use within the urban environment. The challenge is to create fewer wastes and at the same time, develop market for those wastes that are still produced. The main objective of this research is to identify a viable model for urban building in relation to all resources upon which urban regions depend, but currently tend to deplete or destroy. Most of the time, the technologies in use in the business as usual situation need inordinate amounts of chemicals, materials and energy, often with harmful environmental consequences. In contrast, according to Todd, it is possible to design living technologies that have the same capability as natural systems do, such as self‐design, self‐repair, reproduction and self‐organization in relation to changes (Todd, 1996). Therefore, this thesis seeks to evaluate different designs of building settlements when concerned with metabolic cycles of energy and water of a built environment. It takes the case of study of the Sunrise Campus, an industrial region located in Venlo, the Netherlands, which is in its design phase. The municipality of Venlo, which is the client of the Sunrise Campus Master Plan, aims at reducing CO2 emissions and at increasing the use of renewable resources. The campus is an open innovation site for companies and institutes which have their main focus on glass and energy (Studio Marco Vermeulen, 2009). Hence, the idea is to compare different solutions for the case study assessing the flows of energy and water in and out of the site in study. These flows should stretch renewable resources close to their ability to replenish supplies. At the same time, the waste generated is to be reused within the campus ecosystem. In addition, this thesis aims to explore the relationships between energy/materials and site use activities that will set the boundaries and conditions for the design proposal. Furthermore, the Biotope, a building that will be set as the heart for the campus will be studied. The Biotope will be understood as an example that could irradiate to the campus and to the city of Venlo. It will mimic the consumer‐producer ecosystem, in order to mix urban activities with the natural world. The residues will be reduced to their minimum and the circularity of physical processes will be set. This process will make use of renewable resources that will bring up a diverse, clean, safe and healthy environment. Consequently, the site will be addressed as a potential place to provide habitat for plants and animal species. 4
INTRODUCTION 1.2. RESEARCH QUESTIONS Hence, this thesis aims to create a discussion of the different ways to design a building, with a strategic resource management and spatial planning, towards the human integration with the surrounding environment. Therefore, it aims to connect the existent knowledge gaps, by answering the following questions: Main Research Questions RQ.1. How can a new building be designed in the most effective way to avoid the damage caused to the surrounding environment, without depleting the ecosystems and bio‐chemical cycles on which it depends, and being a part of a sustainable urban environment? RQ.2. Why is the introduction of such buildings crucial for the continuous development of the current society? Sub‐Research Questions RQ.3. What will the social and technological functions of the Biotope building be? RQ.4. What are the current technologies available and how can they be combined in this case? RQ.5. What will the quantities of inflows of energy and water of the Sunrise Campus and the Biotope be according to its new functions? RQ.6. What are the design options for the Biotope – which are dependent on the buildings’ architectural design, spatial orientation, construction materials and used technologies – such that they will prevent the destruction and depletion of the surrounding environment even though the building will depend on resources such as energy, water and materials for its functioning? 1.3. OUTLINE OF THE THESIS The thesis starts by grounding a theoretical framework that is supported by three main principles established according to the understanding of an effective design. After that, an evaluation criterion is set, with the purpose of assessing different possibilities for the case study. The case study, which is a building called Biotope that is located in an industrial campus, the Sunrise Campus, is described in its current situation and its Master Plan is studied. As a baseline for the comparison of scenarios, the first scenario, which is the Business as Usual (BAU) situation is designed, according to the main characteristics of the existing buildings in the campus. After that, four other scenarios are developed. They are assessed according to the theoretical framework criteria and compared.
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THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN 2. THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN The task of righting the balance between society and nature requires the application of the knowledge of the functioning of ecosystems to a fundamental redesign of human support technologies. Todd argues that such redesign according to applied ecology can reduce the negative footprint on the Earth by up to 90% (Tood et al., 2003). Therefore, designs produced with regard for, and taking advantage of, the characteristic behavior of natural systems will be the most successful (Bergen et al., 2001). The Biotope project aims to better integrate society with its supporting environment. Therefore, in this thesis, it is recognized that human society is inseparable from and dependent on natural systems. Bergen et al. argue that sustaining human society requires engineering design practices that protect and enhance the ability of ecosystems to perpetuate themselves while continuing to support humanity (Bergen et al., 2001). Mitsch defines ecological engineering as the design of sustainable ecosystems that integrate human society with its natural environment for the benefit of both (Mitsch, 1996). Therefore, following ecological principles, the Biotope design recognizes the relationship of organisms (including humans) with their environment. It works on the difficulties of design imposed by the complexity, variability and uncertainty inherent to natural systems; while it aims at the integration of society and ecosystems in built environments. In the book ‘‘Cradle to Cradle’’, McDonough and Braungart argue that the conflict between industry and the environment is not an indictment of commerce but an outgrowth of purely opportunistic design. The design of products and manufacturing systems growing out of the Industrial Revolution reflected the spirit of the day and yielded a host of unintended yet tragic consequences (McDonough et al., 2003). Today, with our growing knowledge of the living earth, design can reflect a new spirit. In fact, it is argued by the authors that, when designers employ the intelligence of natural systems—the effectiveness of nutrient cycling, the abundance of the sun's energy—they can create products, industrial systems, buildings, even regional plans that allow nature and commerce to fruitfully co‐ exist (McDonough et al., 2002). In this thesis, the ‘Cradle to Cradle’ (C2C) theory will be used as the base for the theoretical framework for the analysis of the Biotope / Sunrise Campus design options. C2C is underpinned by three tenets: waste equals food; use current solar income; and celebrate diversity (McDonough et al., 2002). These principles are taken into consideration when exploring design options for the study area and they are explained in the following Section. Furthermore, they are taken as the three different criteria to evaluate the design proposals, and are described further in Section 3.
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THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN 2.1. CRITERIA 1: WASTE EQUALS FOOD, CIRCULAR METABOLISM The design will be mostly concerned with the idea of circular urban metabolism. This means, following Keen, that the area will be developed by mimicking a natural system, while ensuring that waste products are re‐integrated into wider ecosystems. In this model, it is possible to specify the physical and biological processes of converting resources into useful products and wastes like the metabolic processes of human bodies or ecosystems. The amount of waste depends on the amount of resources required (Keen, 2002). In this project, the human society is seen as a part of the biosphere that we are transforming. We are seen as just another ‘producer‐consumer ecosystem’, as described by Howard Odum (Figure 1). In this model, waste is not a natural concept, because, in natural systems, the outputs from one activity are the inputs for other activities. Although the objective is to produce less waste and reuse them within the site, these wastes continue to exist elsewhere. They take up spaces that are referred to as ‘sinks’. Some of the materials lying on sinks are inert and may be ignored. However, other materials continue to play an important role in the environment, such as contaminants in the food chain or greenhouse gases in the atmosphere. Only humans have managed to create unusable wastes, and these are the ones that are disturbing the natural cycles on which we depend (White, 2006).
Figure 1. Howard Odum’s model of typical producer‐consumer ecosystem. Source: White, 2006.
According to Nederlof et al., the urban metabolism concept facilitates the integration of different cycles (water, energy and nutrients) in the built environment. Therefore, planners must consider water, energy, and nutrient flows together rather than separately, and will have to design with flexibility for future changes (Nederlof et al., 2010). However, the present thesis will mainly focus on 7
THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN the assessment of energy and water flows. Even though the nutrient flow will also be seen as a part of the system, the only data of this flow that will be assessed are those that are related to the other two flows. 2.2. CRITERIA 2: CELEBRATE DIVERSITY, BIODIVERSITY Tzoulkas et al. state that the concept of biological diversity was initially defined as the total number of species within a given area. It was further complemented with the concepts of genetic diversity, habitat diversity and cultural diversity. Therefore, biodiversity comprehends genes, species, habitats, associated interactions and socio‐economic, aesthetic and ethical values (Tzoulas et al., 2010). However, the multi‐scale aspects of the concept of biodiversity have led the present thesis to focus on the concept of biodiversity defined by Bergen et al. This definition states that biodiversity can manifest itself in terms of the number of species, genetic variation within species and functional diversity (when different species can perform similar functions) (Bergen et al., 2001). When natural structures and processes are included and mimicked, nature is treated as a partner of design, and not an obstacle to overcome and dominate. Life causes local decrease in entropy by producing order out of chaos (even though the energy expended to produce order results in more entropy overall). The practical implication is that although ecosystems are complex, they have the capacity to self‐organize. The design serves only as the choice generator and as a facilitator for matching environments with ecosystems, but nature does the rest (Bergen et al., 2001). According to Bergen et al., ecosystems are heterogeneous, displaying patchy and discontinuous textures at all scales. Moreover, they are complex because they do not function around a single stable equilibrium. Therefore, the structure and diversity produced by the functional space occupied by ecosystems is what allows them to remain healthy or to persist (Bergen et al., 2001). Furthermore, diversity systems are more ecologically resilient and able to persist and evolve (Bergen et al., 2001). Moreover, the complexity and diversity of natural systems cause high degree of spatial variability. Every system and location is different and solutions should be site‐specific and small‐ scaled. Therefore, the vegetation chosen for the building and its surrounding should be local and appropriate for the climate and soil. This will minimize disruption to existent ecosystems and at the same time avoid irrigation and active maintenance (Snep et al., 2009). Traditional and mono‐functional business sites are usually seen as colossal urban developments that destroy historical landscapes and biodiversity values. Biotic aspects of this land use environment, that is, fauna and flora and the landscape they inhabit, are not fully addressed in the business as usual site concepts. Therefore, sustainable development of business sites is increasingly being called for (Snep et al., 2009). For that reason, the Sunrise Campus and the Biotope are assumed to be potential sites to provide habitat for plants and animal species (please refer to Section 4 for more details of the case study).
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THEORETICAL FRAMEWORK: THE EFFECTIVE DESIGN 2.3. CRITERIA 3: USE CURRENT SOLAR INCOME, USE ONLY RENEWABLE SOURCES Bergen et al. claim that to let nature self‐organize, it is necessary to make maximum use of the free flow of energy into the system from natural sources, primarily the Sun (Bergen et al., 2001). Hence, the building should be positioned and built in the most effective way of using solar energy and natural ventilation. The use of natural energy brings up complexity and diversity of fauna and flora, at the same time, it allows self‐organization of the ecosystem. Trees and plants use sunlight to produce food (McDonough et al., 2003). Mimicking this system, the Biotope will directly collect solar energy or tap into passive solar processes, such as day lighting, where natural light can be “piped” into indoor spaces. Other technologies such as combined heat and power, bio‐digester, or photovoltaic cells, where energy flows are fueled by sunlight, will be also explored as options. Moreover, like in the Figure 2, the Biotope will nourish its surrounding, by making more than is necessary for its own metabolism. It should produce more energy than it consumes and purify materials such as water and air. Finally, the Biotope will create in the Sunrise Campus a dynamic interdependence, where it will support different buildings inside the campus in multiple ways.
Figure 2. Biotope and its relationships with the surrounding buildings in the Sunrise Campus.
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EVALUATION CRITERIA 3. EVALUATION CRITERIA Two different methodologies are used to evaluate the scenarios, according to the above theoretical framework. The first copes with the first and third design criteria, (waste equals food and use solar income). This evaluation criterion is the urban harvest approach (UHA), developed by Agudelo‐Vera et al. (Agudelo‐Vera et al., 2011). This method assesses energy and water balance flows through three different indices: demand minimization, self‐sufficiency and waste output. The second methodology copes with the design criteria of celebrate diversity. It is focused on biodiversity in the built environment. Its assessment comprehends two different calculations: green area and local species indexes. 3.1. URBAN HARVEST APPROACH (UHA): CIRCULAR METABOLISM AND USE OF RENEWABLE SOURCES Urban metabolism quantifies the overall fluxes of resources of an urban area. To evaluate the circular metabolism, the Urban Harvest Approach method developed by Agudelo et al. has been used. The UHA aims for improved resources management by closing cycles, through the use of innovative technologies and harvesting natural resources (Agudelo‐Vera et al., 2011). The UHA always starts with a baseline assessment, followed by the evaluation of strategies to harvest resources. According to Agudelo et al., it consists of three bases for calculations. First, the demand is minimized. Second, it is necessary to reduce waste outputs by cascading and recycling. Last, renewable and local sources are used for the remaining demand (Agudelo‐Vera et al., 2011). In what follows, these strategies are explained. Baseline Assessment The baseline assessment, the starting point of the UHA, is a mass flow analysis for the Business as Usual (BAU) Scenario. The aim is to identify all the external inputs and outputs of a defined urban system and to understand the situation of the development of the area in the case of absence of any concern to urban harvest and biodiversity issues. A demand and an output inventory are covered in this analysis. The demand inventory quantifies the activities that consume resources and studies the qualities required for their uses. The output inventory describes the outgoing resources of flows, their quantity and quality. Demand (input) Minimization After the baseline assessment, minimization of demand is achieved by modifying human behavior or by harvesting resources through the implementation of technologies and through designing an optimum spatial distribution of the scenario. The UHA focuses on technology implementation to reduce resource demand. After the baseline assessment, the activities of the buildings are to be identified and technologies are to be selected in order to contribute in the reduction to those resource demands. Output Minimization The output minimization is achieved through recovery, cascading and recycling. Recovery refers to direct reuse of outputs that have kept the same quality during the use of resource. In this case, the quality of a resource has remained the same. Cascading also refers to direct reuse of outputs, however with a deteriorated quality. Finally, recycling refers to reuse of a particular resource flow after quality upgrading. 10
EVALUATION CRITERIA Multisource After demand and output minimization, there can still be a remaining demand. According to the UHA, this is supplied by using local and renewable resources, such as solar energy and rain water. Urban Metabolic Profile According to the UHA, urban systems have two different impacts on the environment. The first is the extraction of resources, and the second is due to release of wastes. The Urban Metabolic Profile provides information regarding the demand of resources and production of wastes or secondary resources. They are used to evaluate the possible UHA combined strategies. Therefore, a building unit is assessed according to the following variables: Conventional Demand (Do) that represents the demand when conventional technologies are implemented, which is the case of the Business as Usual Scenario demand. Minimized Demand (D) is the new demand after different technologies are applied. Cascade (C) refers to resources that are directly reused within the building. Recycle (R) is the flow of resources that is treated and reintroduced in the building unit Consumption (Co) is the part of demand that is being consumed, converted to one or more different components, or diminished, e.g. by decay. Multisource (M) refers to local sources used in the building. To relate these variables it is possible to achieve the following definitions: Waste Exported (We) refers to the wastes produced by the building unit and exported. It can be described as the following formula: . Resources harvested (Rh) are the sum of resources cascaded (C), recycled (R), and multisource (M); i.e. For water and energy assessment, the urban metabolic profile can be described by the Demand Minimization Index (DMI), the Self‐Sufficient Index (SSI) and the Waste Output Index (WOI). Together, the three indices evaluate the criterion 1 and 3 of the theoretical framework explained in Section 2: waste equals food and use of current solar income. These indices are given by: Demand Minimization Index DMI The DMI represents the percentage of change in the demand taking as reference the conventional demand, according to the chosen technologies in each scenario.
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EVALUATION CRITERIA Self‐Sufficient Index SSI
The SSI shows the relation of the resources harvested and the new demand. If the SSI=1, the area is self‐sufficient, by harvesting, recycling and cascading local and renewable sources. If SSI=0, there is no multisource, cascading, or recycling. In this case, waste is produced and all the resources are imported to the system. If SSI > 1, the production of renewable sources is more than the demand, and the extra production is to be exported. Waste Output Index WOI
The waste output index represents the relation between the waste that is exported (We) and the demand. Therefore, WOI=‐1 represents the conventional linear metabolism, where there is no reuse of resources within the system. However, WOI=0 means that there is no waste being exported, which characterizes a circular metabolic system. For the energy assessment, the Consumption (Co) has to be defined for each appliance used within the building. It is only possible to obtain the exact appliances after a more detailed building project, where the function needs of the Biotope are further defined. Therefore, the Co is considered zero for all the scenarios, and it does not interfere in the energy assessment. For the water assessment, the Co is also neglected, because the water losses are considered to be a minimum fraction of the total demand. 3.2. BIODIVERSITY CRITERIA According to Snep et al., the Dutch guidelines for biodiversity conservation are: to improve the quality of existing habitats, to enlarge the size of existing habitat patches, and to connect different habitat patches to create a sustainable habitat network (Snep et al., 2009). Detailed biodiversity studies would be necessary for the evaluation of the development of biodiversity in the comparison of the present situation and future scenarios. Although detailed studies are crucial for a precise description of urban habitats, they can be time and resource intensive and are not possible in the present thesis. According to Snep et al., there are five principles that are capable to enhance biodiversity in business sites (Snep et al., 2009). These principles are: a. Make use of the potential of flat roofs for habitat b. Enhance the green areas c. Enhance the ecological quality of existing green, making use of local species d. Make better use of vacant lots e. Implement habitat corridors in the design
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EVALUATION CRITERIA For the evaluation of the biodiversity criteria, the three first principles are going to be measured and compared among the design options. The use of the potential of flat roofs for habitat and the enhancement of green areas will be evaluated according to the total area of green roofs and green areas within the buildings. The third principle will be evaluated according to whether these green areas have potential to become habitat of local species or do not. The biodiversity criterion is based on two variables: the amount of green areas, the total implantation area in the Sunrise Campus and in the Biotope, and the amount of each type of green area. The types of green areas assessed in this study are green roofs, green walls, gardens ponds, constructed wetlands and greenhouses. They are classified as controlled (CG) and not controlled (NCG), as it is shown in Table 1. The total green area (TG) is the sum of the controlled and not controlled areas . Not controlled areas are green roofs and walls, gardens and ponds, where local species will take place. Controlled green areas are constructed wetlands and greenhouses, where human beings control the species that are going to be planted. In the case of greenhouses, the temperature and humidity will be also modified, and local species will have fewer chances to develop. The implantation areas (A) are the Biotope and Sunrise Campus project areas. They are further explained in Section 6. Table 1. Controlled and not controlled areas.
green roof Not controlled green areas (NCG) garden pond Total Green Area (TG) constructed wetland Controlled green areas (CG) greenhouse
For the evaluation of biodiversity in each scenario, two indices are to be assessed, the Green Area Index and the Local Species Index. These indices are given by: Green Area Index (GAI) GAI
The Green Area Index (GAI) represents the relation of the total green area and the implantation area. If GAI=1, the total amount of green areas is equal to the implantation area. If GAI=0, there is no green area at all. Note that GAI can be greater than 1, which means that the total green area is larger than the implantation area. This can occur if there is more than one level of green in the study area (Figure 3).
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EVALUATION CRITERIA
Figure 3. Green area index (GAI) shows the relation of total green and implantation area.
Local Species Index (LSI) LSI
The LSI is the percentage of the total green areas, which are not controlled. LSI=0 means that the green areas are totally controlled and there is no space for the development of local species in the green areas. On the other hand, LSI=1 means that there is no greenhouses or constructed wetlands and that the total amount of green areas have potential to become habitat of local species.
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CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE 4. CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE This thesis discusses the metabolic cycles in the built environment, its importance and possibilities. It takes the case study of the Sunrise Campus located in Venlo (the Netherlands), a city that aims at reducing CO2 emissions and the use of non‐renewable resources. In this campus, the industrial area in the direct vicinity of the company Scheuten Solar Glass will be developed, and different stakeholders are taking part in the project (please refer to Section 4.1). In this area, other industries focusing on glass and energy production will be located (Studio Marco Vermeulen, 2009). Therefore, the land use of the Sunrise Campus is classified as a business site, that is, according to Snep et al., “areas designated by local, regional and in some cases national governments to accommodate multiple companies that produce, transfer or store goods or provide services” (Snep et al., 2009). The Sunrise Campus will be set as an example of urban enterprise that will be designed to provide its own energy, wastewater treatment, and water supply. This campus will be developed in an area of approximately 30ha, located in the Southern part of Trade Port West between the A67 highway and Eindhovensesweg (Figure 4). The operational area of the Sunrise Campus consists of two thirds of the total area (approximately 19,8ha). Within this area, an industrial site of 130.000m² is planned and is designated to consist of 37% of production, 30% of research and development (R&D), 27% of offices and 6% of facilities (Municipality of Venlo, 2010).
A67 Sunrise Campus Eindhovensesweg
Figure 4. Sunrise Campus location. Source: Municipality of Venlo, 2010.
The draft Master Plan is already projected. According to the Municipality of Venlo, it is the structural basis for the construction of the Sunrise Campus. The area will serve as an open innovation campus for companies and institutes that have their main focus on glass and energy. The Master Plan strongly emphasizes the ‘Cradle to Cradle’ (C2C) philosophy in the whole area of the campus. Moreover, it aims to create an identity in the campus while it stimulates the working environment (Gemeente Venlo, 2010). Thus, through the main values such as “innovation, openness, encounter, knowledge, comfort and sustainability” (Studio Marco Vermeulen, 2009), the Sunrise Campus intends to be an attractive working environment.
15
CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE In the center of the area and in the green heart of the campus, a multifunctional building called Biotope will be located (Figure 5). It is designated to serve as a meeting place for all employees of the campus. Moreover, it will bring the companies together and it will set for a place of exchange of knowledge and cooperation (Studio Marco Vermeulen, 2009). The Biotope will hold facilities such as restaurants, day‐care, fitness, meeting room, conference center, laboratories, glass museum, and C2C information center, within a building area of 12.500m². Therefore, the Figure 5. Schematic drawing of the Sunrise Campus program and zoning. In the center is represented the Biotope, which Biotope will become an icon for the campus, will be the connection between all the other buildings in the like the campus itself will become an icon for Sunrise Campus. Source: Master Plan Sunrise Campus, 2009. the city of Venlo (Vermeulen, 2010). Hence, the main proposal of this thesis is to develop and evaluate different design options for the Biotope building in order for it to be a prototype installation for the whole campus. As such, each design option for the Biotope will result in a different scenario for the whole Sunrise Campus. The design will be concerned with the Biotope’s function as a human and technical link between the offices, industries and people. 4.1. STAKEHOLDERS Three different groups of stakeholders were identified in the Sunrise Campus project: local government/Municipality of Venlo, Scheuten Company, and employees of the Sunrise Campus. Firstly, the local government of the province of Limburg aims to reduce drastically CO2 emissions in the region. Moreover, the Municipality owns the land in study; thus, it has asked for the Master Plan studies and is responsible for the development of the industrial region where the Sunrise Campus is located. Therefore, the Municipality aims to develop a sustainable region based on C2C principles. (Gemeente Venlo, 2010). Secondly, although according to the Master Plan different companies focused on glass and energy production will be located in the campus, Scheuten is the only one that is already placed in the area. This company presented itself very closed when asked for contacts and interviews for the present thesis. In email exchange, the person responsible doubted that the Sunrise Campus is really interesting for the thesis case study. Moreover, although the fact that this company produces photovoltaic cells, it does not show itself willing to close energy or materials cycles or even to become self‐sufficient in energy production. When asked if they aim to cover the energy demand from the industries with photovoltaic cells, the answer was: “I don’t think so, in time a few percent of the total demand”2. Scheuten does not have the assessment of the quantity of rain water
2
A few emails were exchanged directly with Scheuten. The technical data was sent by Tim Verstegen the Engineer Coordinator of Quality, Arbo and Environment in Scheuten Glas Nederland.
16
CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE collected, used and discharged; the real quality of the discharged water (the contact person stated the water was “clean to lightly polluted” with “dust and non‐toxic paint”). Moreover, the temperature of the waste‐heat, i.e. the heat that is produced during glass production and processing and is released to the environments without being reused, was not available either. Finally, the third group of stakeholders is the workers of the Sunrise Campus. Although they do not have power for decision making, they are those who will experience the actual business site and the Biotope after their development. As it was already mentioned, it is not yet known which companies will be placed in the area (except for Scheuten), but they will be focused on knowledge intensive companies according to the Master Plan. Nowadays, the Sunrise Campus consists of five buildings that belong to the Scheuten company. Three of them (M16, M6, M10) are used for production and processing of glass. The other two buildings are used for office activities (H30) and research and development (R&D) (H9). In between the buildings, there are ponds and vegetation. Through the existing fishing activities, it can be deduced that the level of pollution of the water in the pond is low (Figure 6). The current inputs of water, energy (electricity and heat) and workers in the current situation of the Sunrise Campus are described in Tables 2 and 3. The data from production halls and offices was provided by the municipality of Venlo (total area, volume, electricity demand, gas demand water demand and number of workers), as well as the number of workers in the R&D. The averages of energy, water, gas were calculated by dividing the total demand by the area (in the case of gas, by the volume). In addition, the data from R&D were accessed considering that these places are used half as production halls and half as offices. Table 2. Current situation: energy demand in the Sunrise Campus. Source: Bas van de Westerlo, 2010.
TOTAL AREA (m²)
TOTAL VOLUME (m³)
TOTAL ELECTRICITY DEMAND (MWh/year)
AVERAGE ELECTRICITY DEMAND/m² (MWh/year/ m²)
TOTAL GAS DEMAND (Nm³/year)
AVERAGE GAS DEMAND/m³ (Nm³/year/m³)
PRODUCTION 34.350 R&D 4.600 OFFICES 3.060 TOTAL 42.010
258.000 34.500 14.076 306.576
13.051 1.288 552 14.339
0,38 0,28 0,18
573.989 80.040 34.000 688.029
2,22 2,32 2,42
Table 3. Current situation: water demand and number of workers in the Sunrise Campus. Source: Bas van de Westerlo, 2010.
TOTAL AREA (m²)
PRODUCTION R&D OFFICES
34.350 4.600 3.060
TOTAL WATER DEMAND 37.199 5.120 1.401
TOTAL
42.010
43.720
AVERAGE WATER DEMAND /m² (m³/year/m²) 1,08 0,77 0,46
TOTAL NUMBER OF WORKERS 207 48 235
AVERAGE NUMBER OF WORKERS/m² 0,006 ‐ 0,077
490
17
18
Figure 6. Current situation of Sunrise Campus. Map adapted from Google Earth.
CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE
CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE 4.2.
THE MASTER PLAN AND THE BUSINESS AS USUAL (BAU) SCENARIO
The Master Plan for the area was designed in 2010, by the Studio Marco Vermeulen and GroupA, that were hired by the Municipality of Venlo (Studio Marco Vermeulen, 2009). This Master Plan is still in debate with the main stakeholders and financial issues are also being discussed. Therefore, there is no timeline for its construction yet. According to the Master Plan, in the existing open area in the two blocks adjacent to the James Cookweg street, new buildings that will work as production hall, research and development, and office will be constructed (Gemeente Venlo, 2010)(Figure 7). This new area of 209.000m² represents the study area of this thesis.
M6 M10 James Cookweg
H30
Figure 7. Future situation of Sunrise Campus and study area. Source: Master Plan 2010 and Google Earth.
Table 4 shows the results of the calculation of the inputs of this new development, if the buildings are to be conceived in the business as usual (BAU) scenario. For the energy, water and number of workers in the area, the average numbers of the current situation were used and multiplied by the new area according to its function (production, research and development (R&D), and offices). According to the Master Plan, the Biotope area is 12.500m² (Studio Marco Vermeulen, 2009). For the assessment of energy, water and number of workers, the Biotope was considered an office building. The total built up area to be developed in the Sunrise Campus is 133.000m², and the Biotope’s expected built up area is 12.500m². In the Biotope, 960 people are expected to work and consume annually 5.723m³ of water, 2.255MWh of electricity and 138.889m³ of gas in a business as usual situation.
19
CASE STUDY: THE SUNRISE CAMPUS AND THE BIOTOPE Table 4. Sunrise Campus new energy and gas demand for each activity sector in the BAU situation.
NEW TOTAL AREA (m²)
NEW TOTAL VOLUME (m³)
NEW TOTAL AVERAGE NEW TOTAL AVERAGE GAS ELECTRICITY ELECTRICITY GAS DEMAND /m³ DEMAND DEMAND /m² DEMAND (Nm³/year/m³) (MWh/year) (MWh/year/m²) (Nm³/year)
PRODUCTION R&D OFFICES
50.000 39.300 31.500
375.546 294.750 144.900
18.997 11.011 5.682
0,38 0,28 0,18
835.501 683.853 350.000
2,22 2,32 2,42
BIOTOPE
12.500
57.500
2.255
0,18
138.889
2,42
TOTAL
133.300
872.696
37.945
2.008.242
Table 5. Sunrise Campus water demand and number of workers for each activity sector in the BAU situation.
NEW TOTAL WATER DEMAND (m³/year)
AVERAGE WATER DEMAND /m² (m³/year/m²)
TOTALNUMBER OF WORKERS
AVERAGE NUMBER OF WORKERS/m²
PRODUCTION R&D OFFICES
54.146 30.276 14.422
1,08 0,77 0,46
301 1.627 2.419
0,006 0,041 0,077
BIOTOPE
5.723
0,46
960
5.308
TOTAL
104.567
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SCENARIOS: METHODOLOGY 5. SCENARIOS: METHODOLOGY Aiming at discussing different solutions for buildings designs, five scenarios were projected and afterwards evaluated according to the criteria explained in Section 3. The scenarios vary in the building’s shape, spatial distribution, technologies used, and resources harvested in relation to energy, water, and biodiversity in the area. They were worked out to reduce the energy and water demand together with producing energy and water by the use of multisource. Green areas are also added to the program with the intension of increasing the biodiversity in the Biotope and in the campus. The demand, self‐sufficiency and output of energy and water will differ according to each building design and chosen technologies. Moreover, the amount of green area in each design will vary, and the local species index will alter according to each use of green spaces. All the areas were calculated according to the referent drawings of each scenario. They were made and calculated using the AutoCad software. The first scenario is the ‘Business as Usual’ (BAU), which does not have any concern to minimize energy and water demand, to make use of renewable resources, or to enhance the quantity and quality of green areas. The second scenario is the ‘Efficient’, which looks towards a better energy and water performance, and starts to incorporate green areas, although still in a small scale. The third scenario is the ‘Bio‐diverse’, which has the priority of increasing the green areas as well as their quality. Minimizing demand and using renewable sources are also important features of this scenario, but they are combined with the implementation of biodiversity in the study area. The fourth scenario is the ‘Producer’, which focuses on reducing and producing the maximum of renewable energy and water that is possible in the limited area, with the combination of a great amount of different technologies. It aims at not only being self‐sufficient, but also at being an exporter of renewable energy and water. Finally, the last scenario, the ‘Hybrid’, mixes the different characteristics of the above scenarios, in the search of a balance between the three criteria explained in Section 2 that are needed to achieve an ‘effective design’. The scenarios were developed according to different technologies of water and energy reduction demand and multisource, and the implementation of green areas. The technologies used and their assessments are explained in each scenario when they are applied. Annex 1 – contains a list of the technologies applied along with the pages in which their explanations are given. These methods were studied and different combinations of them were developed resulting in the design options. In what follows, the methodology of the choices of the energy, water technologies and biodiversity design is explained.
21
SCENARIOS: METHODOLOGY 5.1.
ENERGY FLOW
According to the main features of each scenario explained in the Section below, a range of technologies were first selected from the ones that have commercial accessibility, available technical knowledge and that have been already tested. After that, they were categorized according to different energy demand minimization and multisource technology. These strategies are listed in Table 6. The demand minimization technologies are: passive lighting and diming control, use of LED lamps, solar tubes, CPU management, building insulation materials and green roofs. The multisource technologies are: photovoltaic (PV) cells on roofs and windows, aquifer thermal energy storage systems (ATES), waste bio‐digestion, wind turbines and ‘greenhouse village’ system. The functioning of each technology is explained in the Section 6, at the same time that the energy flow of each scenario is described. Please refer to the Technology Index (Annex 1 – Table 6. Energy variants for the scenarios design. The technologies are classified as those that minimize the energy demand and multisource technologies.
‘greenhouse village’
wind turbines
Anaerobic digester
ATES
PV windows
PV cells
no multisource
MULTISOURCE TECHNOLOGY
green roofs
insulation materials
CPU management
solar tubes
DEMAND MINIMIZATION use of LED lamps
SCENARIO
no demand minimization passive lighting and diming control
1. BAU
2. EFFICIENT
3. BIO‐DIVERSE
4. PRODUCER
5. HYBRID
Except for the ‘BAU Scenario’, all the other scenarios implement energy demand minimization in its design with passive lighting and diming control, use of LED lamps, solar tubes, CPU management, building insulation materials. Besides all these measures, in the ‘Bio‐diverse’ and ‘Hybrid’ scenarios, green roofs are added. Furthermore, in the ‘BAU Scenario’, there is no harvesting and production of renewable energy, whereas in all the other scenarios, multi‐sourcing guarantees the production of a portion, or in some cases the total amount, of the Biotope’s demand. In the ‘Efficient Scenario’, PV cells are combined with PV windows and ATES systems. In the ‘Bio‐diverse Scenario’, PV cells are not to be placed on the Biotope’s roof, because it is to be covered by green roofs. On the other hand, the increase in the amount of green areas in this scenario generates a growth in the production of green waste. Therefore, an anaerobic digester is implemented, generating energy from the green waste. In the ‘Producer Scenario’, PV cells are to be placed on the roofs of the human function areas of the building. In addition, PV windows are to be installed in the South façade and on the roof of the greenhouse areas. Moreover, greenhouses are to be applied in this scenario. They produce heat, food and clean water for the human functions of the Biotope. Besides that, an anaeric digester and 22
SCENARIOS: METHODOLOGY ATES systems are to be implemented in this scenario. The implementation of small scale wind turbines on the roof is studied. Lastly, the multisource in the Biotope building of the ‘Hybrid Scenario’ is equal to the ‘Producer Scenario’, with the difference of not implementing wind turbines. 5.2. HYDROLOGICAL FLOW In the Sunrise Campus, the industries can re‐circulate their water using on‐site technologies in order to recycle it. However, the metabolism of the water used for industrial purposes is not going to be studied in this report. This report will focus on the human water use of the Biotope. According to Asano, before choosing the technology that can be used for water reclamation and reuse, it is necessary to consider the range of potential reuse application, and a general discussion of water quality and quality for each application. Seven general categories of water reuse application can be seen in the Annex 2. Also, it is important to take into account the use of multiple technologies for producing multiple qualities of water (Asano, 2006). Therefore, in water reclamation and reuse, the treatment needed and the degree of water quality will depend on the reuse application. Three different categories according to the quality needed in each function are considered for the case study. Quality 1 (Q1) is referred as drinking water quality, that can be used for food preparation and wash basin. Quality 2 (Q2) is related to uses such as irrigation and industrial water (industrial water is not assessed in this study). Quality 3 (Q3) refers to toilet flush water quality (Annex 3 – Water application qualities and volumes in Sunrise Campus Buildings). In this sense, multi‐sourcing is the key to guarantee a stable offer for the existing demand (Agudelo, et al., 2009 and Han, et al., 2008). It refers to the use of different water sources to obtain water with different qualities that could match directly with the demand. The multi‐sourcing makes use of hidden flows and secondary resources that comes from cascading and recycling activities (Agudelo, et al., 2009). In the Sunrise Campus, not only reservoirs are water sources, but one building can be the main source for other buildings. Moreover, within each building, the outflow of a determined use can be the inflow for another use. Furthermore, the liquid wastes of the Biotope consists of urine, toilet flush water (included water to clean toilets), faeces, kitchen wastewater, water used for personal hygiene (washing basin). The waste streams in the Biotope can be categorized into three different types of water: rain water (RW), grey water (GW), and black water (BW). The grey water is the mixed water from kitchen and washing basin. The black water is the wastewater from the toilets, which conveys urine, faeces and flushing water. Each quality of water has different needs of treatments. There are a number of variations of technologies that can be used for each type of water quality. In the ‘BAU Scenario’, the wastewater streams are combined and transported to the public wastewater treatment plant. However, in order to keep different wastewater streams separate, to use different treatment techniques, and to close water and nutrients cycles, the decentralized sanitation methods is to be considered in other scenarios. To make it possible, a community‐based method of sanitation is to be used. According to Kujawa‐Roeleveld, this method provides off‐site
23
SCENARIOS: METHODOLOGY wastewater treatment at level of community in contrast to central treatment that covers an entire city or catchment area (Kujawa‐Roeleveld et al., 2010). Hence, these scenarios are to explore separated collection in one, two (rain water and black water) or three streams (rain water, black water and grey water). These separated streams can be then treated with the most suitable technology for each stream. A selection of these treatments was chosen, and their technical needs were specified. They were selected from technologies that have commercial accessibility, available technical knowledge and that have been already tested. In Table 7, the choices of water discharge demand minimization, multisource and water reuse for each scenario is shown. The functioning of each technology is explained in the Section 6, at the same time that the water flow of each scenario is described (please refer to Annex 1). Therefore, the ‘Efficient’ and ‘Bio‐diverse’ scenarios work with the separation of the water collection into two water streams, the rain water (RW) and wastewater (WW). The wastewater is the combination of grey and black water. In both scenarios, the rain water is harvested and used for flushing toilets. In addition, in both scenarios, the demand is minimized by using efficient faucets and low flush toilets. However, in the first mentioned scenario, the rain water is used directly from the ponds and the wastewater is discharged into the public sewage system without being treated locally. In the ‘Bio‐diverse Scenario’, there is the implementation of constructed wetlands and ‘Living Machine’ system. According to White, this system uses only natural biological processes, mostly con‐ sisting of plants, through which the influent flows (White, 2006). The wastewater is treated and reused for flushing toilets. Moreover, if there is more treated water than it is used, it is re‐directed to a local watercourse. Table 7. Water variants for the scenarios design.
Anaerobic digestion
‘greenhouse village’
‘Living Machine’
constructed wetlands
water retention ponds
rain water harvest and use
MULTISOURCE AND REUSE no rain water harvest
vacuum toilets
low flush toilets
efficient faucets
no demand minimization
3 streams: RW, GW, BW
WATER DISCHARGE DEMAND MINIMIZATION 2 streams: WW and RW
SCENARIO
1 stream: public sewage system
1. BAU 2. EFFICIENT 3. BIO‐DIVERSE 4. PRODUCER 5. HYBRID
The ‘Producer’ and ‘Hybrid’ scenarios have the same water treatment system. In these cases, the wastewater collection is separated into three different streams, the rain, grey and black water. The demand is minimized by the use of vacuum toilets and efficient faucets. Black water is collected by means of vacuum toilets and stored and treated in an anaerobic digester, where energy is produced. The system yields a clean grey water effluent, which is directed to the constructed wetland. There the water receives a secondary treatment and is stored in ponds until its next use. In these scenarios 24
SCENARIOS: METHODOLOGY drinking water is also produced from rain water, by implementing a greenhouse. In this system, rain water and the water pre‐treated by wetlands are used for irrigating the greenhouses. The irrigation water evaporates and is collected. After an activated carbon filtration, re‐hardening and quality monitoring, it is used as drinking water. 5.3. BIODIVERSITY The types of green areas are described in Section 3.2 and are classified as controlled and not controlled. For more details in the biodiversity design, please refer to Section 6. The green areas types were chosen according to energy and water technologies applied and/or the scenarios main characteristics (please refer to Section 5). They are shown in Table 8. In the ‘BAU Scenario’, the ponds only retain the water that naturally runs to its surface. In the ‘Efficient Scenario’, the ponds work as a retention and settlement structure which enables the use of rain water in the Biotope. In the ‘Bio‐diverse Scenario’, the rain water is to be treated in constructed wetlands and the wastewater is to be treated in a ‘Living Machine’. Besides that, in this scenario, the green areas are to be enhanced and green roofs and walls are also to be implemented, as well as gardens within the building. In the ‘Producer Scenario’, all the green area is implemented aiming at the local production of energy and cleansed water, resulting in only controlled green areas. Greenhouses are there to produce food, heat and clean water, whereas the constructed wetlands are to treat the rain and grey water. The ‘Hybrid Scenario’ is very similar to the Producer in its biodiversity design; however green roofs are also partially added to the top of the Biotope. Table 8. Green areas variants for the scenarios design.
greenhouse
garden
CONTROLLED constructed wetland and retention pond
NOT CONTROLLED
pond
SCENARIO
green roof/ wall
1. BAU
2. EFFICIENT
3. BIO‐DIVERSE
4. PRODUCER
5. HYBRID
25
SCENARIOS
6. SCENARIOS The following scenarios represent the search for solutions that create a connection between the Biotope and external sources of energy and water, and biodiversity according to the criteria established in Section 3. For that, a variety of technologies (please refer to Section 5) and different spatial organization of the study area are considered. Each scenario represents the use of a collection of these technologies in a different spatial situation. The human functions of the Biotope remains as suggested in the Master Plan, i.e., the building will function as a meeting place for the campus, and its program covers functions such as conference center, study center, restaurants, fitness center, glass and energy museum, and C2C museum. Other auxiliary functions are annexed to the main program of the building such as kitchen and restrooms. The total area reserved for the human function is the same for all scenarios, namely 12.500m² which will hold a total of 960 workers. The Biotope implantation area is 60.500m² (Figure 8). This area is the total area where the Biotope is emplaced, counting the ground floor area of the Biotope together with its vicinity area, which can be used as green or paved areas, parking lots or greenhouses. This area can be open or closed, depending on technological or biodiversity needs of each scenario. The Sunrise Campus implantation area covers 202.900m² and 5.308 workers (including the Biotope’s implantation area and workers).
Figure 8. Biotope and Sunrise Campus Implantation Areas. Biotope Implantation area is 60.500m², whereas the Sunrise Campus implantation area is 202.900m².
In some scenarios, besides the technological and human functions, food production is added to the main program. The food is produced in greenhouses in the Biotope implantation area. The amount of food produced is not assessed, but the heat, green waste and clean water are assessed as outputs that are to be used for the human function. In the Sunrise Campus implantation area, not only the Biotope is implemented, but other fifteen buildings are to be located, and their function will vary among offices, industrial hall and R&D (Figure 8). However, because the Master Plan is still in the development phase, there is no data about the 26
SCENARIOS exact function of each building, such as the kind of industry that will be set in each plot. Consequently, the information of different demands in relation to water, energy and materials, and the external outputs of these buildings are missing.
Figure 9. Building roofs in the Sunrise Campus that is managed in the scenarios development. This is done to intensify the main characteristics of each scenario.
For this reason, the present thesis focuses only on the assessment and design of the Biotope implantation area described in Figure 8. However, there are two exceptions in relation to the boundaries in the assessment exercise: (1) Other buildings roofs The Biotope assessment represents a scenario; i.e. an outline or model of an expected sequence of similar characteristics. The other buildings roofs in its surrounding are added as a part of the scenarios to intensify their main characteristics. Table 9 describes the roof management in the other buildings of the Sunrise Campus. The roofs are either not to be used, or they are to be covered with PV cells and/or green roofs. In the ‘BAU Scenario’ they are not to be used, whereas in the ‘Efficient’, ‘Producer’ and ‘Hybrid’ Scenarios, PV cells are suggested to be placed on the roofs. On the one hand, when PV cells are to be placed on the roofs, they are not assessed in the Biotope’s scenario evaluation. In these cases, the energy produced in each roof is to be used within the respective building and does not interfere in the Biotope’s energy flow. On the other hand, when green roofs are placed on these building, as in the ‘Bio‐diverse’ and ‘Hybrid Scenario’s, they are to be taken into account in the scenario evaluation. The green area (GAI) and local species indices (LSI) are assessed for both, the Biotope and the Sunrise Campus (please refer to Section 3.2). This happens because the biodiversity cannot be assessed only as a local issue. The surrounding area of the Biotope is important to enhance the resilience of the biodiversity within the building. According to Snep et al., the larger the urban green area, the greater the species richness that may be expected (Snep et al., 2009).Therefore, enhancing the green area in the surroundings of 27
SCENARIOS the Biotope, creates an increase in the amount of the not controlled green area of the campus, and consequently, the green area of the Biotope itself becomes more diverse, more resilient, and able to persist and evolve. Table 9. Other buildings roofs variants for the scenarios design.
no roof management
1. BAU
2. EFFICIENT 3. BIO‐DIVERSE
PV cells
green roofs
ROOF MANAGEMENT
SCENARIO
4. PRODUCER
5. HYBRID
(2) Other buildings wastes In the ‘Bio‐diverse’, ‘Producer’ and ‘Hybrid’ scenarios, the wastes of other buildings of the Sunrise Campus are to be used in the Biotope (Table 10). These wastes are black water, grey water and organic waste, which are used to produce either energy or clean water. In this case, these wastes and the outputs of the production generated from them are assessed. This happens because of the first and third theoretical criteria explained in Section 2.1 and 2.3. This waste is not assessed as external input, because the clean water and energy produced from the waste output of the other buildings becomes food for the Biotope and for the Sunrise Campus. At the same time, the Biotope is nourishing its surrounding area by producing clean water and energy back to those buildings. Finally, these wastes are not considered as imported because they are part of the study area and they are to be returned to these buildings, although it is in another form. Table 10. Other buildings variants for the scenarios design.
black water
organic waste
WASTE USE grey water
SCENARIO no waste use
1. BAU
2. EFFICIENT
3. BIO‐DIVERSE
4. PRODUCER
5. HYBRID
28
SCENARIOS 6.1.
SCENARIO 1 – BUSINESS AS USUAL (BAU)
The first scenario is the Business as Usual Scenario, which is the basis for comparison with other scenarios according to the different application of technologies and designs. It is also the baseline assessment for the indicators of the urban harvest approach and biodiversity (please refer to Section 3). This scenario shows the energy and water flows of the Biotope and the Sunrise Campus in the BAU situation. The building orientation will be in a North‐South axis, following the streets design (Figure 10). Figure 11 shows the main Section of this scenario schematically. The electricity and heat are exclusively supplied by the conventional public companies. Also from a public utility, water enters the building as drinking water and after use, it is directly discharged as wastewater. The rain is not harvested and is also discharged in the public sewage. In this case, there are no efforts in the building design to reduce the consumption of energy and water, whereas the energy production is null. N
Figure 10. Scenario 1: Business as Usual plan view.
29
SCENARIOS
Figure 11. Business as Usual Scenario schematic Section. Water, heat (H) and electricity (E) flows. Legend: 1 and 2. Electricity and gas for heating are supplied by the conventional public companies. 3. Also from a public utility, water enters the building as drinking water quality (Q1). 4. The wastewater is directly discharged into the public sewage system. 5. The rain is not harvested and is also discharged together with the wastewater. 6. The sun energy is lost.
The main design characteristics of the ‘BAU Scenario’ are:
Biotope area: 12.500m² (three story building) Biotope roof area: 4.000m² Biotope implantation site: 60.500m² Sunrise Campus implantation site: 202.900m² Number of workers: 960 Sunrise Campus: no flows exchange Building orientation: North‐South axis
30
SCENARIOS 6.1.1. ENERGY FLOW The main design characteristics of energy consumption and production of the ‘BAU Scenario’ are:
Conventional heat and electricity from public supply Cooling system: conventional air‐conditioning system Heating system: central heating fueled with natural gas No reduction in demand No production of energy
In Table 11. Energy demand in Biotope and Sunrise Campus in the ‘BAU Scenario’ per year., the outline of the total energy demand in the ‘BAU Scenario’ is expressed. The energy consumption covers the electricity and heat that are assessed separately proportional to the current situation demand (please refer to Section 4.3 or more details in this calculation). The total electricity demand is 2.255MWh/yr, and the heat is 138.889Nm³/yr or 1.335MWh/yr (using a conversion factor of 0,00961 from 1m³ of natural gas to MWh (Graaff et al., 2010)). This results that the total amount energy consumed is 3.590MWh/yr. Table 11. Energy demand in Biotope and Sunrise Campus in the ‘BAU Scenario’ per year.
Biotope
Electricty Heat (natural gas) Energy
2.255 1.335 3.590
Sunrise Campus
MWh MWh MWh
37.945 19.299
MWh MWh
In Figure 12, the different uses of the electricity are shown according to their percentages. These percentages 26,5% in Biotope are assumed to be the same as in office 26,0% buildings. According to the United Nations Environment 25,5% 25,0% Programme, in the average of the European office 24,5% building energy demand, 25,6% of the electricity is 24,0% consumed for lighting demand; 26% for cooling demand; 23,5% and 24,2% for office equipment such as appliances like 23,0% computers, printers, etc., and the same amount (24,2%) for other buildings uses such as elevators, automatic doors and building maintenance (United Nations Environment Programme, 2007). Therefore, the lighting demand in the ‘BAU Scenario’ is 577MWh/yr, the cooling Figure 12. Biotope ’s electricity demand in the demand is 586MWh/yr, the office equipment is ‘BAU Scenario’. 546MWh/yr, and the other uses demand is 546MWh/yr (Table 12 and Figure 12). Table 12. Electricity use in Biotope in the ‘BAU Scenario’ per year.
lighting cooling office equipment others
25,60% 26,00% 24,20% 24,20%
577 586 546 546
MWh MWh MWh MWh
31
SCENARIOS 6.1.2. WATER FLOW The main design characteristics of water consumption and production of the ‘BAU Scenario’ are:
No reduction measures in relation to water demand Rain water management: traditional storm drainage system Wastewater management: combined sewer system: 1 stream outflow public discharge (grey water, black water and rain water) The total water demand in this scenario is 5.723m³/yr (see detailed calculation in Section 4.3). Like the energy, the water is imported from the public utilities as drinking water (Q1) (please refer to Section 5.2), while the rain water is not harvested. The traditional storm drainage system is used. According to Burkhard et al., it consists of inlet structures and drainage pipes that transport water to the nearest outfall (Burkhard et al., 2000) (Lazarus, 2009), which removes water from its natural course (Lazarus, 2009). The ponds only retain the water that naturally runs to its surface. Moreover, there is not any technique to reuse the water. The different uses of water in the building are assessed in Table 13 and shown in Figure 13. It was considered that the water used for human purposes during working hours in the Sunrise Campus was proportional to the domestic Dutch water use behavior per person per day (see detailed data in Annex 4 – Water Consumption in Working Environments in the Netherlands.). The total water demand of the Sunrise Campus in the ‘BAU Scenario’ is 101.459m³/year (see Section 4.2), of which 26.574m³ represents the human use (according to proportion of human water demand in the Netherlands), while the difference represents industrial use (please refer to Annex 3). It results that, in the Biotope the water demand is 4.992m³/year for this scenario. The activities assessed are food preparation, drinking water, wash basin, dishwasher, and toilet flush. Table 13. Water demand in the Biotope in the ‘BAU Scenario’ per year.
WATER DEMAND BIOTOPE USE PERCENTAGE drinking water faucets toilet flush dishwasher food processing
184 541 3.788 306 174
m³ m³ m³ m³ m³
4% 11% 76% 6% 3%
TOTAL
4.992
m³
100%
The drainage system consists of the combined sewer system (CSS), transporting both wastewater (domestic use) and storm water to the centralized conventional sewage treatment from the local public utility. To assess the outputs, the input water demand was multiplied by the discharge coefficient 0,8 (according to Kujawa‐Roeleveld et al., a typical value of the discharge factor is 80% of the drinking water used) (Kujawa‐Roeleveld et al., 2010). Toilet flush represents the biggest amount of water use (76%), whereas the second most used water is represented by the use washing basins for hygiene use (11%)(Figure 13).
32
SCENARIOS 80% 70% 60% 50% 40% 30% 20% 10% 0%
Figure 13. Biotope ’s water demand in the ‘BAU Scenario’.
6.1.3. BIODIVERSITY The biodiversity area in this scenario is considered to be only the pond area, which can serve as habitat for different ecosystems. The other open areas in the vicinity of the Biotope are considered to be paved, and they are not assessed in this scenario. The total pond area is 12.682m². It was calculated through Autocad software according to the design shown in Figure 10. Table 14 shows the green area amounts and its total in the ‘BAU Scenario’. Moreover, it displays the assessment of controlled and not controlled green areas in the Biotope and Sunrise Campus. Table 14. Biodiversity assessment in the ‘BAU Scenario’.
green roof Not controlled garden pond constructed wetland Controlled greenhouse Total
SUNRISE CAMPUS 0 0 12.682 0 0 12.682
m² m² m² m² m² m²
BIOTOPE 0 0 12.682 0 0 12.682
m² m² m² m² m² m²
33
SCENARIOS 6.1.4. BUSINESS AS USUAL: ASSESSMENT This Section gives an overview of the assessment of the ‘BAU Scenario’. For more details about the following indices calculation and methods, please refer to Section 3. The results of the energy and water demand are expressed in Table 15, whereas the biodiversity assessment is shown in Table 16. There is no use of technologies for reducing the energy demand. The demand is not minimized and the DMI is zero. The SSI is also zero for this scenario. This means that the Biotope relies totally on external input demand, and consequently, it is dependent on non‐local and non‐renewable energy. Moreover, there are no strategies to minimize the outputs such as cascading and recycling in this scenario. As a result the WOI for energy and for water is ‐1. The ‘BAU Scenario’ is an example of a building linear metabolism. Table 15. Energy and water assessment for the ‘BAU Scenario’.
BAU ENERGY
Conventional Demand (Do) New Demand (D) Cascade (C) Recycle(R) Consumption (Co) Waste exported (D‐C‐R‐Co) Multisource (M) DMI= (Do‐D)/Do WOI=‐(D‐C‐R‐Co)/D=‐We/D SSI=(C+R+M)/D
3.590 3.590 0 0 0 0 0 Indices
BAU WATER
MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr
4.992 4.992 0 0 0 4992 0
m³/yr m³/yr m³/yr m³/yr m³/yr m³/yr m³/yr
0
0
‐1
‐1
0
0
The biodiversity area in this scenario is considered to be only the pond area, which is a not controlled area and different ecosystems can inhabit. The others open areas in the vicinity of the Biotope are considered to be paved and they are not assessed in this scenario. The total ponds area and consequently, the total green area is 12.682m², according to Figure 10 and calculated by using Autocad software. Table 16. Biodiversity assessment for the ‘BAU Scenario’.
Implantation area (A) Not controlled green (NCG) Controlled green (CG) Total green (T) GAI = T/A LSI = T‐CG/T
SUNRISE CAMPUS 202.900 12.682 0 12.682 0,06 1
m² m² m² m²
BIOTOPE 60.500 12682 0 12.682 0,21 1
m² m² m² m²
As a result, the GAI in the Sunrise Campus is 0,21 and in the Biotope is 0,06 , i.e. the total green area corresponds to 6% of the Biotope ’s implantation area (Table 16), whereas it also indicates 21% of the Sunrise Campus area. Without the existence of greenhouses and constructed wetlands, the LSI is 1. This means that local species can make use of the total amount of the green areas. Note however that even though LSI=1, the total amount of green area (GAI) is very low. 34
SCENARIOS 6.2.
SCENARIO 2 – EFFICIENT
In this scenario, the efficiency is seen as a tool that intends to have overall positive effects on a wide range of issues. According to McDonough et al., it is valuable when conceived as a transitional strategy to help current systems slow down and turn around (McDonoug et al., 2002). It brings up a Biotope that is able to reduce its energy and water consumption, and at the same time, to produce renewable energy and water. The energy production is focused on photovoltaic systems, which are produced by the industries located in the Sunrise Campus (Figure 14). However, the renewable energy production based on photovoltaic systems is not enough to make the building autarkic in relation to energy and water cycles. Consequently, the Biotope cannot make more than it is necessary for the building consumption, but it will achieve reduced quantities of energy and water that are imported to the building. N
Figure 14. ‘Efficient Scenario’ plan view.
35
SCENARIOS The main design characteristics of the ‘Efficient Scenario’ are:
Biotope area: 12.500m² Biotope roof area: 4.335m² Number of workers: 960 Building orientation: 3 blocks in the east‐west axis. The distance between the blocks (34,5m) is 3 times their height (11,5m), for the optimum use of direct sunlight and heat (Figure 15). Sunrise Campus buildings: use of PV cells on all roofs (this is not going to be assessed because each building uses its own energy production)
m
100m
Figure 15. ‘Efficient Scenario’: Transversal Schematic Section AA (h=11,5m and d=34,5m). These blocks are connected through passages. PV windows are to be installed on the South façade, whereas PV cells are to be installed on the roofs.
36
SCENARIOS 6.2.1. ENERGY FLOW The management of the energy flow in this scenario consists of two steps. First, the energy demand is minimized through the implementation of passive lighting and heating, insulation materials, use of LED lamps, solar tubes and CPU management. After that, the building will produce energy through the implementation of PV cells on the roof and in the southern façades. Moreover, ATES system will be used for harvesting the heat and cold within the building throughout the year (Figure 16). These techniques are to be explained in details in what follows.
W
Figure 16. ‘Efficient Scenario’ Energy management. Block Schematic Section BB. Legend: 1. 2. 3. 4. 5. 6.
Passive lighting and heating Insulation materials; use of led lamps, CPU management ATES system PV cells on roof and windows Solar Tubes Extra energy from ‘green companies’
6.2.2. ENERGY DEMAND MINIMIZATION In this Section, the technologies that were taken into consideration in the ‘Efficient Scenario’ and their implementation are explained. They are listed in Table 17 and in what follows, they are explained. For the assessment, it was first taken into account lighting reductions with passive lighting and dimming control. Second, the use of LED lamps instead of regular incandescent bulbs was considered. Third, the cooling and heating demand were minimized, by the implementation of passive ventilation and insulation materials in the buildings envelope. Lastly, the ATES system was assessed, reducing the remaining heating and cooling demand. Table 17. Implemented technologies to energy demand minimization in the ‘Efficient Scenario’.
TECHNOLOGY
(1) LIGHTING
(2) OFFICE EQUIPMENT (3) COOLING
REDUCTION Literature Source
passive lighting and diming control use of LED lamps instead of regular incandescent bulb
40,00%
(Bodart et al., 2002)
90,00%
(MacKay, 2008)
CPU management and standby and active mode power reductions for computers passive ventilation
40,00%
(Waide et al., 2007)
10,00%
(Kolokotroni et al., 2006)
37
SCENARIOS
(4) HEATING
(1)
ATES
70,00%
insulation materials: floors, walls, windows and roofs
40,00%
ATES
46,00%
(Bridger et al., 2005); (Nieuwenhuize, 2011) (MacKay, 2008) (Bridger et al., 2005); (Nieuwenhuize, 2011)
Lighting demand minimization
In what follows the lighting demand minimization is described according to two technologies used: passive lighting and dimming control, and use of LED bulbs instead of incandescent bulbs (Table 17).
Passive lighting and diming control
The passive lighting method is understood as glazing luminous transmission coefficient, façade configuration, opening orientation and rooms width (Bodart et al., 2002). Therefore, the Biotope has been oriented on an east‐west axis to maximize the Southern solar potential for day lighting, passive solar and photovoltaic applications (Figure 14). The other features described above are expected to be detailed in a further architectural design and are out of the scope of this thesis. For the increase of the windows area and the optimum passive lighting effect, the Biotope can be divided in three connected blocks. These blocks should be separated by a distance such that one block will not shade the others during business hours. This distance is set to be three times the buildings height, in the case of this building orientation in the Netherlands (Scheuten Solar, 2011).
Figure 17. Solar tube. Source: Solartube International, 2011.
Moreover, solar tubes (Figure 17) are to be implemented on the roof of the building, to complement the passive lighting effect. A solar tube is a way of using passive sunlight as lighting for a building. It is a tubular skylight that captures sunlight on the top roof. Sunlight is redirected down to a highly reflective shaft and diffused throughout the interior space (Solartube International, 2011). Other forms of indirect lighting such as light shelves and zenithal illumination are to be used in this 38
SCENARIOS scenario for the optimization of the passive lighting, but they are to be detailed in a future architectural design. Together with the passive lighting, diming control devices are to be used in this scenario. With the implementation of this system, one light is automatically turned off when there is already enough light in the room. It works also through occupancy sensors, and the lights are automatically turned off when there is no one in the room. These measures regulate lighting within the rooms, reducing considerable amount of internal energy loads.
Use of LED bulbs instead of incandescent bulbs The regular incandescent bulbs that are used in the ‘BAU Scenario’ deliver 10lumens/W. In the ‘Efficient Scenario’, these lamps are to be replaced for LED (light‐emitting diode) bulbs, which deliver 100 lumens/W (MacKay, 2008). Thus, with the use of these lamps, the lighting demand is reduced by 90% (Table 18 and Figure 18).
Figure 18. Energy Saving LED bulb. Source: Direct, 2011.
Therefore, through passive lighting, diming control and use of LED lamps, the annual lighting demand of 577MWh in the ‘BAU Scenario’ is reduced to 23MWh. This represents a reduction of 96% in the lighting consumption (Table 18). Table 18. Yearly lighting Demand Minimization in the ‘Efficient Scenario’.
LIGHTING ‘BAU SCENARIO’ TECHNOLOGY
577 REDUCTION
passive lighting and diming control
40,00%
use of led lamps instead of regular incandescent bulb LIGHTING ‘EFFICIENT SCENARIO’ DEMAND
90,00%
MWh
NEW DEMAND 346 MWh 35
MWh
35
MWh
LITERATURE SOURCE (Bodart et al., 2002) (MacKay, 2008)
(2) Office Equipment energy demand minimization On average, desktop computers require 125 to 150 kWh per unit per year, depending on the capacity of the system, the efficiency of the power supply and the number of hours the machine is left in active, sleep, or standby mode. In most offices, 64% of desktop computers are left on after work‐hours. Moreover, desktop‐derived servers are now commonplace in office spaces for network management. Because these units have large capacities and are often left on 24 hours a day, they can consume 3 to 5 times the energy of desktop computers (Waide et al., 2007). Since many electronic appliances spend a majority of their time idle, until recently, efforts to control the energy consumption of office equipment have focused on standby power usage. But as use increases and most office appliances now easily comply with current energy use specifications, active mode power specifications are also important for a decrease in energy demand. Qualified
39
SCENARIOS products such as Energy Star specify minimum power supply efficiency for desktop computers, servers, and monitors (Waide et al., 2007). Moreover, computer networks in commercial office buildings usually use considerably more energy than necessary, because the network software being used may not support low‐power modes, even when computers are on standby (Waide et al., 2007). While many tools are available to control the power used by networked computer monitors, software that helps manage central processor unit (CPU) energy use is to be adopted in the ‘Efficient Scenario’. According to Waide et al., standby and active mode power reductions for computers and CPU management generate energy savings in the range of 40% to 60% (Waide et al., 2007). In the ‘Efficient Scenario’, this yields a reduction of 327MWh in the total energy demand (Table 19). Table 19. Yearly office Equipment Demand Minimizatiuon in the ‘Efficient Scenario’.
OFFICE EQUIPMENT ‘BAU SCENARIO’ DEMAND TECHNOLOGY REDUCTION CPU management and standby and 40,00% active mode power reductions for computers OFFICE EQUIPMENT ‘EFFICIENT SCENARIO’ DEMAND
546
MWh
NEW DEMAND 327
MWh
LITERATURE SOURCE (Waide et al., 2007)
327
MWh
(3)
Heat and cold demand minimization
In what follows the heat and cold demand minimization is described according to two technologies that were used. For the assessment, it was first applied passive ventilation and insulation materials. After that, the ATES system was implemented (Table 17).
Passive Ventilation
In the Biotope, natural ventilation strategy is a combination of cross ventilation, warm air rising and wind passing over the terminals causing suction (Figure 19). Use of passive high capacity measures provide effective night cooling as internal and external temperatures have a higher variance, and consequently convection is increased at night. These strategies are to be detailed in further architectural design of the Biotope. Natural or passive ventilation is intended to maintain the purity, temperature, humidity and movement of the indoor air within a certain comfort range. It has a hygienic and energetic function. Through passive cooling with night ventilation, the required indoor temperature can almost always be maintained when coupled with a consequent reduction of the solar load and of internal thermal loads as well as usage of the building’s storage capacity. According to Kolokotroni et al., night ventilation strategies in office buildings reduce the cooling demand by 10% (Kolokotroni et al., 2006).
40
SCENARIOS
Figure 19. Combination of cross ventilation, warm air rising and the wind passing over the terminals causing suction. Source: Twinn, 2003.
Insulation materials
Aiming at the optimization of the heating and cooling systems, the ‘Efficient Scenario’ is concerned with the thermal proprieties of the Biotope’s outer shell. According to Waide et al., improvements applied to windows, walls, ceilings and roofs of a commercial building reduce energy cost, and at the same time reduce mold and other moisture problems, equipment breakdown, and discomfort (Waide et al., 2007). The thermal conductivity and air filtration through walls account for 21% for the total heat losses from commercial buildings during heating months. Windows are responsible for 22% of a building’s total heat losses in winter and 32% of cooling loads in the summer. Finally, the roofs account for only 1% of the total heat gains during the summer months and for 12% of the total heating load. Cool roofs can reduce peak cooling demand in 10% to 15% (Waide et al., 2007). This is the case of green roofs that will be implemented in the ‘Bio‐diverse Scenario’ (please refer to Section 6.3.2) In order to minimize these conductivity rates, insulation materials such as fiberglass, mineral wool and cellulose are to be used on the floors, walls and ceilings of the Biotope. Double glass and spectrally selective glass are to be used in windows. Sandwich walls are to be used for the increase in thermal insulation. According to Lindström, they consist of two concrete panels separated by a layer of thermal insulation of a thickness selected as required due to location and climate. The internal panel is normally load‐bearing with a thickness in the range of 120mm to 150mm (Lindström, 2011). With the implementation of all the above measures, the use of insulation materials in the building envelope will avoid significant thermal losses. It is assessed that the use of insulation materials can achieve a 40% reduction in the heating and cooling demand of a building (MacKay, 2008).
41
SCENARIOS
ATES system
In this scenario, a system using aquifers for energy storage, referred to as Aquifer Thermal Energy Storage (ATES), is used. The ATES is an open loop system in which groundwater is used to carry the thermal energy in and out of the aquifer (Figure 20). The system consists of two water wells, one with cold and the other with warm water. When a building needs to be cooled, cold water is pumped into the system. Groundwater of approximately 7°C can be directly used for cooling. During its circulation through the building, this water is heated up and will be stored in the warm well with a temperature of about 15 to 25°C. When heating is needed, warm water is pumped into the system after passing the heat exchanger. This water is cooled down after circulating through the building and will be stored in the cold well. Pipes are needed in a range of 20 to 250 meters below ground level. The minimal scale of operation is about 50 houses or a building with a minimum floor area of 2,000 square meters (Nieuwenhuize, 2011; Andersson, 2007). According to Bridger et al., ATES systems can reach 70% to 100% of efficiency. Moreover, the author also states that the ATES system can deliver the entire heat load for an office building (Dickinson et al., 2009). According to Nieuwenhuize, it generates energy savings of about 50 to 80% for cooling and up to 50% for heating. The heat and cold efficiency is assessed to create a balance between the energy exchanged in the two wells. For the scenarios energy assessments, the same amount of energy that is saved for the cooling reduction is also reduced from the heating demand. The coefficient of performance (COP) of the ATES’ system considered is 40 for heat pumps and 4 for other pumps (one for the hot and another for the cold wells) (Nieuwenhuize, 2011). The groundwater retains a temperature higher or lower than the undisturbed ground temperature. Therefore, during periods of high heating or cooling demand, water is pumped from the aquifers and used as an energy source or sink (Bridger et al., 2005). The main components of an ATES system are a suitable storage aquifer, a production well or wells (which may act as pumping or injection wells), a low cost or free source or sink of thermal energy (such as waste industrial process heat or solar heat for heating or cold outside air temperatures for cooling), a heat exchanger, and a demand for the energy transfer (Bridger et al., 2005).
Figure 20. ATES system. Source: Dickinson et. al., 2009.
42
SCENARIOS Table 20 expresses the results of the implementation of the technologies explained above for heating and cooling demand minimization. The remaining demand of cooling is to be fulfilled with conventional air conditioned systems, fueled by electricity. The heating demand will be completed through central heating systems powered by natural gas, which has to be imported to the system. For the cooling demand assessment, first the demand was reduced by the use of passive night ventilation, whereas, for the heating demand, insulation materials were first considered. The remaining demand was minimized by the using the ATES system. For that, it was first considered that ATES system minimizes 70% of the cooling total demand (Nieuwenhuize, 2011), which corresponds to a reduction of 351MWh. The same load of energy (351MWh) was reduced from the heating demand, which represents 46% out of the total heating demand. After that, the energy spent by the pumps needed for the system was added to the calculation. The heating pump has a COP of 40, whereas the other pumps (including the cold pumps) have a COP of 4 (Nieuwenhuize, 2011). The demand of each pump is the ratio between the energy minimized by the ATES system and the COP: heat pump demand
ATES demand minimization
The pumps have a total demand of 110MWh/yr, in the form of electricity. Therefore, this amount of energy is added to the ‘others demand’. In the ‘BAU Scenario’, the ‘others demand’ is 546MWh/yr (Table 12), and in the Efficient Scenario is 656MWh/yr. Table 20. Yearly heat and cold minimization assessment for the ‘Efficient Scenario’.
COOLING ‘BAU SCENARIO’ DEMAND TECHNOLOGY passive night ventilation ATES COOLING ‘EFFICIENT SCENARIO’ DEMAND HEATING ‘BAU SCENARIO’ DEMAND TECHNOLOGY insulation materials ATES HEATING ‘EFFICIENT SCENARIO’ DEMAND PUMP DEMAND (ELECTRICITY) ATES cooling pumps (COP 4) ATES heat pump (COP 40) ATES other pumps (COP 4) PUMP DEMAND (ELECTRICITY)
REDUCTION 10% 70%
REDUCTION 40% 46%
‐ 5% ‐21% ‐2%
586 MWh NEW DEMAND LITERATURE SOURCE 528 MWh (Kolokotroni et al., 2006) 176 MWh (Bridger et al., 2005) (Nieuwenhuize, 2011) 176 MWh 1.335 MWh NEW DEMAND LITERATURE SOURCE 801 MWh (MacKay, 2008) 431 MWh (Bridger et al., 2005) (Nieuwenhuize, 2011) 431 MWh 9 MWh (Nieuwenhuize, 2011) 92 MWh (Nieuwenhuize, 2011) 9 MWh (Nieuwenhuize, 2011) 110 MWh
As a result of bringing together all the above mentioned strategies for electricity and heat demand minimizations, the total energy demand dropped from 3.590MWh (please refer to Section 6.1) to 43
SCENARIOS 1.625MWh in the ‘Efficient Scenario’. The electricity used for lighting, office equipment, and others is responsible for 908MWh whereas the heat and cold are responsible for 718MWh of the energy demand (Table 21). Table 21. Energy demand in the ‘Efficient Scenario’ for each use and the total demand per year.
‘EFFICIENT SCENARIO’ ENERGY DEMAND Lighting Office Equipment Cooling Heating Others TOTAL ELECTRICITY DEMAND TOTAL HEAT/COLD DEMAND TOTAL ENERGY DEMAND
35 328 176 431 656 908 718
MWh MWh MWh MWh MWh MWh MWh
1.625
MWh
6.2.3. ENERGY PRODUCTION Photovoltaic (PV) panels are able to directly convert light into electricity. Some materials exhibit a property known as the photoelectric effect that causes them to absorb photons and release electrons. These free electrons are captured, resulting in an electric current that can be used as electricity (Gil, 2002). In the ‘Efficient Scenario’, PV cells are used both on the roof of the building (with a 20o inclination) and in the South, east and west façades. According to MacKay, the average raw power of sunshine per square meter of South‐facing roof in Britain is roughly 110W/m2. Moreover, mass produced solar panels are available and with cheap prices at an efficiency rate of 10% (MacKay, 2008). In adittion, there is currently available in the market, a semi‐transparent vertical window that produces 35 to 40kWh/m2/yr (Schueco, 2011). This represents an average power delivered of 4,6W/m². The main issues described in the table below were taken into considerations in this scenario design for the energy production. All the areas were calculated according to the plan view and Section figures (Figures 14 to 16) through the Autocad software. Table 22. Implemented technologies and yearly energy production in the ‘Efficient Scenario’.
TECHNOLOGY PV cells PV window
TOTAL
AVERAGE POWER DELIVERED 11W/m2
4.335 m2
417
MWh
Figure 12 (Autocad)
(MacKay, 2008)
4,6W/m2
1.242 m2
50
MWh
Figure 12 and 13 (Autocad)
(Schueco, 2011)
467
MWh
AREA
ENERGY PRODUCTION
LITERATURE SOURCE
SOURCE
In the ‘Efficient Scenario’, the total area of the roof of the Biotope is 4.335m². The PV cells are to be installed on it, producing 417MWh per year. The PV windows are to be installed in the South façades 44
SCENARIOS and together they have a total area of 1.242m², which are able to produce 50MWh per year (Table 22). As a result, on the one hand, through the implementation of the photovoltaic systems explained above, the Biotope is able to produce 467MWh per year. On the other hand, its new demand for electricity is 1625MWh per year (Table 18). The Biotope becomes a significant producer of its own energy, being responsible of 59% of the new energy demand. The extra energy is to be imported from companies that produce energy from renewable sources. 6.2.4. WATER FLOW In the ‘Efficient Scenario’, there are three main objectives related to the water management. First, it aims to reduce human water consumption in the Biotope, by installing water efficient appliances. Second, in this scenario, the surface water runoff is managed minimizing local hydrological impact. Third, it incorporates high ecological value ponds landscaping into the site. This issue is incorporated in Section 6.2.7. Figure 21 represents the water flow in the Biotope for the ‘Efficient Scenario’. The rain water is collected from roofs and permeable pavements and stored in the ponds. It is used for flushing toilets and irrigation. The rain water that is not used within the building is returned to the groundwater via soakways, preventing flooding. For other activities that require a better water quality, drinking water is supplied to the building by the local public water company. The Biotope’s wastewater is discharged into the sewage system and treated by the local public utility.
Figure 21. ‘Efficient Scenario’ water management. Legend: 1. The rain water is collected from roofs and permeable pavements. 2. It is stored in the ponds that work as a retention and settlement structure. 3. It will be used in the Biotope for flushing toilets (Q3). 4. Drinking water (Q1) is imported to the system to supply the other human uses. The water demand is minimized by the use of efficient faucets and low flush toilets. 5. Biotope’s wastewater is discharged into the sewage system and treated by the local public utility, in a separated stream from the rain water. 6. Rain water overflow is returned to the groundwater via soakaways.
45
SCENARIOS 6.2.5. WATER DEMAND MINIMIZATION In the ‘BAU Scenario’, toilet flush accounts for more than 75% of the total water demand, whereas the faucets used for hygiene accounts for more than 10% (please refer to Section 6.1). Together they represent more than 85% of the total water demand. In the ‘Efficient Scenario’, the minimization of water demand is focused on these two uses of water. Low flush toilet A typical toilet uses 7.5 to 9 liters per flush, while dual low flush toilets use 2 to 4 liters (Lazarus, 2009). For the following calculation, the lowest typical consumption (7,5L) and the highest dual low flush (4L) are considered. Efficient Faucets Self‐regulating flow restrictors to faucets reduce pressure and flow rates and minimize wastage. They reduce water consumption by approximately two thirds (Lazarus, 2009). These two technologies are capable of minimizing the water demand in toilet flush and hygiene faucets from an annual average of 4.328m³ in the ‘BAU Scenario’ to 2.200m³ in the ‘Efficient Scenario’. The total demand is reduced from 4.992m³ per year in the ‘BAU Scenario’ to 2.864m³ per year in the ‘Efficient Scenario’ (Tables 23 and 24). Table 23. Implemented technologies to water demand minimization in the ‘Efficient Scenario’.
BAU DEMAND
NEW DEMAND
toilet flush
3.787 m³/yr
180 m³/yr 2.020 m³/yr
TOTAL
4.328 m³/yr
2.200
Hygiene/faucets
541 m³/yr
m³/yr
REDUCTION
LITERATURE SOURCE
64%
(Lazarus, 2009)
47%
(Lazarus, 2009)
49%
Table 24. Yearly water demand in the ‘Efficient Scenario’ for each use and the total demand.
EFFICIENT DEMAND
drinking water, coffee and tea
184
m³
hygiene
180
m³
toilet flush
2.020
m³
dishwasher
306
m³
food processing
174
m³
TOTAL DEMAND
2.864
m³
6.2.6. MULTISOURCE AND RUNOFF MANAGEMENT The rain water is collected from roofs, paved and pond areas of the entire Sunrise Campus. The rain water from the roofs is harvested and stored in the ponds (Figure 21). Moreover, an infiltration and a collection system are used, limiting peak runoff in sewer system and reducing overflow from combined system. For this to happen, permeable pavements are used in parking lots and roads. This type of pavement consists of three layers. A base layer of 300mm of coarse gravel (3,5‐5,0cm), a top layer of 100mm of fine graded gravel (0,3‐2cm), and a pavement made of modular blocks (Burkhard et al., 2000).
46
SCENARIOS Drainage pipes will collect the infiltrated water that will be already clean of oil and petrol contamination from the roads by the pavements. Together with the storm water collected from all of the Sunrise Campus roofs, it will be discharged into the ponds. The ponds work as a retention and settlement structure. Outflows from the ponds are directed via an outlet structure, into a receiving watercourse. Then, in each building of the campus, including the Biotope, the rain water from the ponds passes through a sand filter in the down pipe before entering to the main tank, according to each building’s need. In the Biotope, submersible pumps then deliver it, not without passing through a regular water filter, and it is used for toilet flush (Q3). To assess the water harvested and used, the input water consumption of toilet flush was multiplied by the discharge coefficient 0,8 (Kujawa‐Roeleveld et al., 2010). Therefore, it is expected that new water (rain water) is added to the system in every cycle. The multisource assessment is therefore 20% of the water used for toilet flush, resulting in 403m³/yr. In the Sunrise Campus, the total amount of potential water harvest is 155.219m³/year, considering the roof, paving and ponds as surfaces capable of water harvest (Table 25). For this calculation, the average of annual rainfall in the Netherlands was considered 76,5cm/year (Royal Dutch Meteorological Institute, 2007). However, the portion that is harvested in the Biotope implantation area is 46.283m³. This amount of water is able to fulfill the Biotope’s yearly water demand. Table 25. Potential water harvest according to the Dutch rain fall.
SUNRISE CAMPUS BIOTOPE
IMPLANTATION AREA (A) 202.900 60.500
RAINFALL NL m² m²
0,765 0,765
m/yr m/yr
POTENTIAL RAIN HARVEST 155.219 m³ 46.283 m³
In the ‘BAU Scenario’, the total water demand of the Sunrise Campus is 104.567m³/yr (please refer to Section 4.3). Considering that in the Netherlands and in the region of Venlo the average rainfall is nearly constant (Figure 22), it is sufficient to harvest water for the maximum of three months. The volume of the ponds is designed to have space for 26.142m³, which is sufficient to harvest water for three months of use. According to Burkhard et al., the ideal depth of the pond for it to act as retention and settlement structure is from 0,6 to 1,8m (Burkhard et al., 2000). Thus, the depth of the ponds is considered to be 1,8m. The total area of the ponds needed for the BAU situation is 14.523m². In the ‘Efficient Scenario’ the ponds design represents 15.113m² (Figure 14) (the area was calculated using Autocad software). If there is an overflow from the pond, it is directed via a soakaway into a receiving water course. The soakaway are underground structures, which normally are circular shafts. They are filled with medium gravel, into which runoff can be discharged (Burkhard et al., 2000). Finally, the wastewater is not treated onsite, but it is discharged into the sewage system where it will be treated by the public utilities.
47
SCENARIOS
Figure 22. Average rainfall in the region of Eindhoven. Venlo is located 60km of Eindhoven and thus it is assumed that they have a similar rainfall. Source: Weather and Climate, 2009.
6.2.7. BIODIVERSITY In the ‘Efficient Scenario’, the roofs are managed for the use of photovoltaic panels; therefore, these roofs are not to be used to increment the amount of green areas. However, the ponds are potential places for habitats of different species. Besides the fact that they function as retention structures, they also integrate the area with the surrounding landscape, serving as habitat for wildlife. The surrounding areas of the ponds are considered to be gardens. All the green areas are located within the Biotope s implantation site. The total area that is able to promote biodiversity in the Sunrise Campus and in the Biotope is 31.000m² (Table 26). Table 26. Biodiversity variations in the Biotope and Sunrise Campus implantation areas in the ‘Efficient Scenario’.
green roof not controlled garden pond constructed wetland controlled greenhouse Total
SUNRISE CAMPUS 0 16.300 14.700 0 0 31.000
m² m² m² m² m² m²
BIOTOPE 0 16.300 14.700 0 0 31.000
m² m² m² m² m² m²
6.2.8. ‘EFFICIENT SCENARIO’: ASSESSMENT The energy and water are resumed into three different evaluation indices that are explained in Section 3.1. These indices are the demand minimization (DMI), the waste output (WOI) and the self‐ sufficiency (SSI) indices. They are expressed in Table 27 for the ‘Efficient Scenario’. Furthermore, biodiversity is evaluated according to two different indices: green area (GAI) and local species (LSI), for the Biotope ’s and Sunrise Campus’ implantation areas (please refer to Section 3.2). These indices are also shown in Table 28 for the ‘Efficient Scenario’. Energy The DMI for energy is 0,55, i.e. the ‘Efficient Scenario’ is able to reduce its energy demand in 55% when compared to the ‘BAU Scenario’. The WOI is the same as in the BAU (‐1) scenario, because strategies such as energy cascading or recycling are absent, and the output is not minimized. Finally, with the application of PV cells on the roof and PV windows, the SSI achieves 0,29, and the Biotope is able to produce 29% of its total demand, with renewable and local energy. 48
SCENARIOS Consequently, the building has a moderate improvement towards self‐sufficiency when comparing to its energy demand. The remaining demand is to be imported to the building from public companies. Water By reducing the water demand with low flush toilets and by using efficient faucets, it was possible to reduce the water demand in 57% (DMI=0,43). Moreover, when using rain water to flush the toilets, the multisource increases, although in a small scale, and the self‐sufficiency index becomes 0,14. However, like in the energy system, cascading and recycling are not being used and the WOI remains the same as in the ‘BAU Scenario’ (‐1,00). Table 27. Energy and water assessment for the ‘‘Efficient Scenario’’.
EFFICIENT ENERGY
Conventional Demand (Do) New Demand (D) Cascade (C) Recycle(R) Consumption (Co) Multisource (M) DMI= (Do‐D)/Do WOI=‐(D‐C‐R‐Co)/D SSI=(C+R+M)/D
3.590 1.625 0 0 0 467 INDICES 0,55 ‐1 0,29
EFFICIENT WATER
MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr
4.992 2.864 0 0 0 403
m³/yr m³/yr m³/yr m³/yr m³/yr m³/yr
0,43 ‐1 0,14
Biodiversity The biodiversity area in this scenario is considered to be the pond and its surrounding area (Figure 13), which is a not controlled area and different ecosystems can take place. The others open areas in the Sunrise Campus are considered to be paved and they are not assessed in this scenario. As a result, the GAI in the Biotope is 0,51 and for the Sunrise Campus is 0,15, i.e. the total green area corresponds to 51% of the Biotope’s implantation area, whereas it also indicates 15% of the Sunrise Campus area. Without the existence of greenhouses and constructed wetlands, the LSI is 1. This means that local species can make use of the total amount of the green areas (Table 28). Table 28. Biodiversity assessment for the ‘Efficient Scenario’.
SUNRISE CAMPUS
Implantation area (A) Not controlled green (NCG) Controlled green (CG) Total green (T) GAI = T/A LSI = T‐CG/T
202.900 31.000 0 31.000 0,15 1
BIOTOPE m² m² m² m²
60.500 31.000 0 31.000 0,51 1
m² m² m² m²
49
SCENARIOS 6.3.
SCENARIO 3 – BIO‐DIVERSE
In this scenario, the biodiversity guides an energetic and material engagement of the Sunrise Campus and the Biotope. As a consequence, the built up and green areas will become interdependent. In its design, priority is given to the amount of green areas inside and outside the building. According to McDonough et al., the vitality of ecosystems depends on the relationships between the species, their uses, and exchanges of materials and energy in a given place (McDonough et al., 2003). The design of the Biotope in this scenario mimics a natural landscape, and the three blocks of the building create a parody of three small hills. These hills are covered with green roofs, of which nature will take control (Figures 23 and 24). Furthermore, due to the new shape of the buildings, its area is 10% bigger than in the first and second scenarios. However, the human function area will remain the same as in the previous scenarios. The extra area will be occupied by green spaces and consequently, the water demand will increase. Moreover, the blocks have four floors instead of three, and the distance between them will follow the same proportions as in the ‘Efficient Scenario’ (Figure 14), in order to enhance the natural lighting in the Biotope. N
Figure 23. ‘Bio‐diverse Scenario’ plan view.
50
SCENARIOS Furthermore, the vegetation is also seen as an energy source in this scenario. The garden waste, together with the kitchen waste, will be digested through anaerobic digestion, producing methane that will be used within the Biotope as electricity and heat. The wastewater from all the buildings of the Sunrise Campus will be cleansed in a ‘Living Machine’ (Todd, 1996) and recycled, creating a step towards a building’s circular metabolism. Moreover, the green waste of the other buildings will be used for energy production of the Biotope. This waste is not assessed as external input, because the clean water and energy produced from the waste output of the other buildings becomes food for the Biotope and for the Sunrise Campus. The main design characteristics of the ‘Bio‐diverse Scenario’ are:
Biotope area: 13.750m²/ Human functions area:12.500m² Biotope roof area: 7.980m² Number of workers: 960 Building orientation: 3 blocks in the east‐west axis. The distance between the blocks (45m) is 3 times their height (15m) (please refer to Figure 14, Section 6.2). Sunrise Campus buildings: green roofs in all roofs (the organic waste of the green roofs are added in the bio‐digestion process)
W
Figure 24. ‘Bio‐diverse Scenario’: Block Schematic Section AA.
6.3.1. ENERGY FLOW The energy flow for this scenario follows some of the parameters of the ‘Efficient Scenario’, with a few modifications. The most important is the addition of green roofs, and consequently, the subtraction of PV cells that were in the roof in the previous scenario. The production of energy is now dependent on anaerobic digestion of organic solid waste and PV windows (Figure 25). The implementation of green roofs provides strong insulation in warm days (75%), whereas in cold days this efficiency is reduced to 15% (Liu et al., 2003). This causes an imbalance between heating and cooling demand in the building throughout the year and as a consequence, it influences the ATES system. In this case, the ATES system should be tested and its installation effectiveness should be evaluated. In what follows, two alternatives were studied for the energy of the ‘Bio‐diverse Scenario’. One includes an ATES system (a), and the other excludes it (b). After that, a comparison between them is made and one of the sub‐scenarios is chosen to represent the ‘Bio‐diverse Scenario’.
51
SCENARIOS
W
Figure 25. ‘Bio‐diverse Scenario’ Energy management. The ATES system is included in the Sub‐scenario (a), and it is not in sub‐scenario (b). Schematic Section AA. Figure 25 – Legend: 1. Passive lighting and heating 2. Solar tubes 3. Insulation materials, use of led lamps, CPU management 4. Green roof 5. Organic waste from Biotope and green roofs of other buildings are added to the anaerobic digester 6. Anaerobic digester 7. Energy is produced in the anaerobic digester is used in the Biotope 8. ATES system (only in Sub‐Scenario (a)) 9. Extra energy from ‘green companies’
6.3.2. ENERGY DEMAND MINIMIZATION a. ‘Bio‐diverse Scenario’ (a) ‐ without ATES ‐ energy demand minimization In this Section, the technologies that were taken into consideration in the ‘Bio‐diverse Scenario’ (a), and their implementation are explained. They are listed in the following table after which they are explained. First, lighting reductions with passive lighting and dimming control were taken into accountl. Second, the use of LED lamps instead of regular incandescent bulbs was considered. Third, the cooling and heating demand were minimized, by the implementation of passive ventilation and implementation of insulation materials in the buildings envelope, and green roofs. Lastly, the ATES system was assessed, reducing the remaining heating and cooling demand. The lighting demand and office equipment minimization are to be the same as in the ‘Efficient Scenario’ and they are not to be assessed in this Section (please refer to Section 6.2.2 for the referred assessment). In this Section, heat and cold demand will be assessed for the two alternatives in the different sub‐scenarios.
52
SCENARIOS Table 29. Implemented technologies to energy demand minimization in the ‘Bio‐diverse Scenario’ (a).
TECHNIQUE
(1) LIGHTING
(2) OFFICE EQUIPMENT
(3) COOLING
(3) HEATING
REDUCTION
Literature Source
passive lighting + diming control
40.00%
(Bodart et al., 2002)
use of led lamps instead of regular incandescent bulb
90.00%
(MacKay, 2008)
CPU management and standby and active mode power reductions for computers passive ventilation
40.00%
(Waide et al., 2007)
10.00%
(Kolokotroni et al., 2006)
green roof ATES
75.00% 70.00%
insulation materials: floors, walls, windows and roofs green roof ATES
40.00%
(Liu et al., 2003) (Bridger et al., 2005) (Nieuwenhuize, 2011) (MacKay, 2008)
15.00% 13.75%
(Liu et al., 2003) (Bridger et al., 2005) (Nieuwenhuize, 2011)
(1)
Lighting demand minimization (please refer to ‘Efficient Scenario’ for detailed data) (2) Office Equipment energy demand minimization (please refer to ‘Efficient Scenario’ for detailed data) (3) Heat and cold demand minimization Passive Ventilation (please refer to ‘Efficient Scenario’ for detailed data) Insulation materials (please refer to ‘Efficient Scenario’ for detailed data) Green roof and ATES system Green roofs not only add aesthetic appeal to the unused roof space that is available in most urban areas; they also provide many benefits. Green roofs can protect the roofing membrane from exposure to ultra violet radiation and storm damage. Furthermore, they can reduce energy demand for air conditioning, through direct shading of the roof, evapotranspiration and improved insulation values. Moreover, if widely adopted, green roofs could reduce the urban heat island (an elevation of temperature relative to the surrounding rural or natural areas due to the high concentration of heat absorbing dark surfaces such as rooftops and pavements), which would further lower energy consumption in the urban areas (Liu et al., 2003). According to Liu et al., green roofs are more effective in reducing heat gain than heat loss. The green roof also significantly moderates the heat flow through the roofing system and reduces the average of daily energy demand for air conditioning systems by more than 75%. However, in the opposite situation, its effectiveness is only 15% (Liu et al., 2003). Therefore, the green roof implementation generates an eminent imbalance in the annual heat and cold demand. The ATES system does not produce heat, but it balances the heat and cold within a building throughout the year. The great difference in insulation in different seasons creates a misbalance in the ATES system. As a result of the considerable reduction of the cooling demand, the 53
SCENARIOS heating efficiency of the ATES system becomes very low (Table 30). For more detailed information in the ATES calculation, please refer to the ‘Efficient Scenario’. Table 30 expresses the results of the implementation of the technologies explained above for heating and cooling demand minimization. The remaining demand of cooling is to be fulfilled with conventional air conditioned systems, fueled with electricity. The heating demand will be completed through central heating systems powered with natural gas, which has to be imported to the system. The table below expresses the results of the implementation of the technologies explained above for heating and cooling demand minimization. With the implementation of the green roof, the heating efficiency of the ATES system drops significantly. For the cooling demand assessment, first the demand was reduced by the use of passive night ventilation, whereas, for the heating demand, insulation materials were first considered. After that, the implementation of green roofs is assessed. It is considered an efficiency of 75% for the cooling, whereas 15% for the heating demand minimization. The remaining demand was minimized by the use of the ATES system. For that, it was first considered that an ATES system minimizes 70% of the cooling total demand, which corresponds to a reduction of 93MWh. The same load of energy (93MWh) was reduced from the heating demand, which represents only 13,6% out of the total heating demand. After that, the energy spent by the pumps needed for the system was added to the calculation. Please refer to Section 6.2.2 for more details of this calculation. Table 30. Yearly heat and cold minimization assessment for the ‘Bio‐diverse Scenario’ (a).
COOLING ‘BAU SCENARIO’ DEMAND
586
TECHNOLOGY
MWh
REDUCTION
NEW DEMAND
passive night ventilation
10%
528
MWh
green roof
75%
132
MWh
ATES
70%
40
MWh
40
MWh
(Bridger et al., 2005) (Nieuwenhuize, 2011)
1335
MWh
COOLING ‘Bio‐diverse Scenario’ (a) DEMAND
LITERATURE SOURCE (Kolokotroni et al., 2006) (Liu et al., 2003)
HEATING ‘BAU SCENARIO’ DEMAND TECHNOLOGY
REDUCTION
NEW DEMAND
insulation materials
40%
801
MWh
(MacKay, 2008)
green roof
15%
681
MWh
(Liu et al., 2003)
13,6%
588
MWh
588
MWh
(Bridger et al., 2005) (Nieuwenhuize, 2011)
ATES HEATING ‘Bio‐diverse Scenario’ (a) DEMAND
LITERATURE SOURCE
PUMP DEMAND (ELECTRICITY)
ATES cooling pumps (COP 4)
‐ 35%
14
MWh
(Nieuwenhuize, 2011)
ATES heating pump (COP 40)
‐4%
23
MWh
(Nieuwenhuize, 2011)
ATES other pumps (COP 4)
0%
TOTAL PUMP DEMAND (ELECTRICITY)
2
MWh
(Nieuwenhuize, 2011)
39
MWh
54
SCENARIOS The pumps have a total demand of 39MWh/yr, in the form of electricity. Therefore, this amount of energy is added to the ‘others demand’. In the ‘BAU Scenario’, the ‘others demand’ is 546MWh/yr (Table 12), and in the Efficient Scenario is 585MWh/yr. b. ‘Bio‐diverse Scenario’ (b) energy demand minimization The energy demand minimization for this sub‐scenario, ‘Bio‐diverse Scenario’ (b), follows the same parameters as the above sub‐scenario (a), described above, but the ATES system is excluded. The tables below show the technologies used and the assessment of demand reduction. Table 31. Implemented technologies to energy demand minimization in the ‘Bio‐diverse Scenario’ (b).
TECHNIQUE
LIGHTING
OFFICE EQUIPMENT
REDUCTION
Literature Source
passive lighting + diming control
40.00%
(Bodart et al., 2002)
use of led lamps instead of regular incandescent bulb
90.00%
(MacKay, 2008)
CPU management and standby and active mode power reductions for computers passive ventilation
40.00%
(Waide et al., 2007)
10.00%
(Kolokotroni et al., 2006)
green roof insulation materials: floors, walls, windows and roofs green roof
75.00% 40.00%
(Liu et al., 2003) (MacKay, 2008)
15.00%
(Liu et al., 2003)
COOLING
HEATING
Table 32. Heat and cold assessment in ‘Bio‐diverse Scenario’ (b).
COOLING ‘BAU SCENARIO’ DEMAND TECHNOLOGY passive night ventilation green roof COOLING ‘Bio‐diverse Scenario’ (b) DEMAND HEATING ‘BAU SCENARIO’ DEMAND insulation materials green roof HEATING ‘Bio‐diverse Scenario’ (b) DEMAND
REDUCTION 10,00% 75,00%
40,00% 15,00%
586 NEW DEMAND 528 132 132
MWh
MWh MWh MWh
1335 801 681 681
MWh MWh MWh MWh
LITERATURE SOURCE (Kolokotroni et al., 2006) (Liu et al., 2003)
(MacKay, 2008) (Liu et al., 2003)
c. Comparison of the Bio‐diverse sub‐scenarios (a) and (b) The table below compares the sum of heating and cooling demand in each Bio‐diverse sub‐scenario and in the ‘Efficient Scenario’, where there is no place for green roofs. In addition, it compares the demand minimization that ATES system provided in three situations. In the ‘Bio‐diverse Scenario’ (a), the combinations of the ATES system with green roof reduces the heating and cooling energy demand in 161MWh/year, when compared to the ‘Bio‐diverse Scenario’ (b), where only green roofs are implemented. This means that in the sub‐scenario (b), there is an augmentation of 25% in the energy demand. 55
SCENARIOS Table 33. Comparison of the yearly heating and cooling assessment for the ‘Bio‐diverse Scenario’s (a) and (b) and ‘Efficient Scenario’.
‘EFFICIENT SCENARIO’ ‘Bio‐diverse Scenario’ (A) ‘Bio‐diverse Scenario’ (B)
HEATING AND COOLING TECHNOLOGIES ATES green roof and ATES green roof
HEATING AND COOLING DEMAND 718 MWh 667 MWh 813 MWh
ATES DEMAND MINIMIZATION 722 MWh 133 MWh 0 MWh
However, when comparing the demand minimization of the ‘Efficient Scenario’ and ‘Bio‐diverse Scenario’ (a), the heating efficiency of the ATES system drops from 54% in the ‘Efficient Scenario’ to 16% in the ‘Bio‐diverse Scenario’ (a), due to the implementation of the green roof. Moreover, the total amount of energy minimized in the ‘Efficient Scenario’ through this system is 722MWh, whereas in the ‘Bio‐diverse Scenario’ (a), it decreases to 133MWh. This means a reduction of 81% in the heating and cooling minimization generated by the referred technology. Concluding, it is possible to state that the ATES system, when combined to green roofs, does not function as efficiently as it is expected. Therefore, the ‘Efficient Scenario’ (b) is taken into consideration in the following assessment of energy. (4) Others demand In this scenario, the wastewater will be treated through the ‘Living Machine’ system, instead of simply being discharged into the sewer system as in the ‘BAU’ and ‘Efficient Scenario’. In the previous scenarios, the energy spent by the water treatment system is not accounted because the process is realized outside the study area. According to Albion Water Ltda., the ‘Living Machine’ licensed water company, this system’s power consumption is 178kWh/day for a system designed to treat 1000m³/day (Worell Water Technologies, 2007). The ‘Living Machine’ cleanses all the water used by human function in the Sunrise Campus. According to Kujawa, the average quantity of wastewater is 80% of the water demand in a building (Kujawa‐Roeleveld et al., 2010). In the Sunrise Campus, the demand of water is 104.567m³/year (Annex 3), and therefore, the wastewater is 83.654m³/year, and consequently, 321m³/day. This results in an extra energy demand of 0,057MWh/year. This value is very low when compared to the total energy demand (1.720MWh/yr) (Table 34) and will not be considered for the energy assessment. d. ‘Bio‐diverse Scenario’ (b) demand minimization The total energy demand for the ‘Bio‐diverse Scenario’ (b) is 1.720MWh. The electricity use is responsible for 908MWh whereas the heat and cold are responsible for 813MWh of the energy use (Table 34).
56
SCENARIOS Table 34. Energy demand in the ‘Bio‐diverse Scenario’ for each use and the total demand per year.
Energy
Total energy demand
Lighting Office Equipment Cooling Heating Others NEW ELECTRICITY DEMAND HEAT/COLD DEMAND NEW ENERGY DEMAND
35 327 132 681 546 908 813 1.720
MWh MWh MWh MWh MWh MWh MWh MWh
6.3.3. ENERGY PRODUCTION In the ‘Bio‐diverse Scenario’ (b), the Biotope produces energy through bio‐digestion and through the implementation of solar PV windows on the South façades. In what follows, these strategies are explained. (1)
Anaerobic digestion of food waste and green waste
In this Scenario, anaerobic digestion that operates with high solids reactors (up to 30%) is to be implemented, for the treatment of food and garden waste. According to Kujawa‐Roeleveld et al., this type of digestion has grown in use in the past decade, and it can be described as (Kujawa‐Roeleveld et al., 2010): Anaerobic bacteria Organic matter + H2O new cells + CO 2 + CH4 + NH3 + H2S The beneficial end product is methane (CH4). Other products are sludge water, carbon dioxide and traces of ammonia and hydrogen sulphide. The sludge water can be dewatered to produce a supernatant and a filter cake. The filter cake and the filtrate are to be used as a suitable fertilizer, because they have soil conditioning effects (Kujawa‐Roeleveld et al., 2010). However, it is not going to be assessed in the further results, because it is considered to be part of the nutrients flow which is out of the scope of the present thesis. The process of anaerobic digestion consists of three phases: hydrolysis, acidogenis and methanogens. In these phases, different bacteria are active and are called the hydrolyzing bacteria, non‐methanogenic and methanogenic respectively. The maintenance of an environment that keeps the acidogenes and methanogens in dynamic equilibrium is (Kujawa‐Roeleveld et al., 2010):
Be oxygen free Not contain inhibiting salts Have a 6,5 < pH < 7,5 Be of adequate alkalinity, 1.500 to 7.500mg/L Have sufficient nutrients, phosphorus and nitrogen Be temperature steady at either mesophilic or termophilic conditions Have a constant solids loading rate
57
SCENARIOS The high solids anaerobic digestion is an aerobic process where the solids content in the reactor are 25 to 35%. Many processes of this type are in existence internationally. The Dry Anaerobic Composting (DRANCO) process of organic waste uses a solid concentration of 30 to 35% (Kujawa‐ Roeleveld et al., 2010; De Baer, Luc, 2010) and can be used as a model for the Sunrise Campus. The cycle time is 16 to 21 days and the biogas production is 5 to 8m³ for each cubic meter of reactor. The gas content is 55% methane and the energy production is 140 to 200m³ of biogas per tonne of raw organic waste at 40 to 60% dry solids (Kujawa‐Roeleveld et al., 2010). According to Lundie et al., one person in household produces 86,66kg of wet food waste in a yearly base (Lundie et al., 2005). To assess the total wet food of the Biotope, this production was proportional to the working days in a year (260) and working hours a day (8). This amount is reduced to 20,4kg per person per year. The total amount of workers in the Biotope is 960. Therefore, the total waste food production in the Biotope is 19.754kg (Table 35). Table 35. Food waste in the ‘Bio‐diverse Scenario’ per year.
Waste production/ person‐yr
Food waste
20,4 kg
Workers in Biotope 960
Total waste produced 19.754
kg
LITERATURE SOURCE (Lundie et al., 2005)
The total amount of green areas from green roofs in the Sunrise Campus (including the Biotope green roof), green wall gardens in the Biotope and ponds sum 136.318m² (see Section 6.3.7). According to Gaston et al., a square meter of urban garden produces 0,34kg of green waste (Gaston et al., 2005). Therefore, the total amount of green waste produced annually in the Sunrise Campus in the ‘Bio‐diverse Scenario’ is 46.416kg (Table 36). Table 36. Green waste in the ‘Bio‐diverse Scenario’ per year.
Garden waste
Waste production
Green area
0,34kg/m² 81.725 m²
Total waste produced 46.416kg
LITERATURE SOURCE (Lundie et al., 2005); Section 3.6.7 (green areas)
It follows that the total amount of the garden and food waste produced by the Biotope and Sunrise Campus in this scenario is 66.170kg/year that are to be digested through anaerobic treatment. The energy production of anaerobic digestion is 200m³ per ton (Kujawa‐Roeleveld et al., 2010), which is equal to 1,92MWh/ton of waste (conversion factor of 0,00961 (Graaff et al., 2010)). When the full amount of organic waste produced in the Biotope is treated though anaerobic digestion, it yields 127MWh of potential energy. Combined heat and power (CHP) generation systems can be used to produce heat and electricity at an efficiency of 85% (of which 40% electricity and 60% heat) (Graaff et al., 2010). This would result in a production of 65MWh of electricity and 43MWh of heat on an annual base (Table 37).
58
SCENARIOS Table 37. Combined heat and power from organic waste bio‐digestion per year.
Total organic waste
energy production rate Total Energy potential
66.170 kg 1,92MWh/ton
127MWh
Total energy available for CHP 108MWh
Total Total heat electricity produced produced 65MWh
43MWh
LITERATURE SOURCE
(Kujawa‐Roeleveld et al., 2010); (Graaff et al., 2010)
(2) PV windows In the proposed design, the South façade of the three blocks sum a total area of 2.317m² (calculated through the Autocad software, according to Figures 23 and 24). Considering the PV window avaragee power of 4,6W/m² (refer to Efficiency Scenario for more details), it yields a total electricity production of 93MWh per year. The total energy produced in this scenario through anaerobic digestion and PV window is 201MWh per year. The electricity produced is 136MWh/yr, whereas the heat produced is 65MWh per year (Table 38). The total energy demand is 1.720MWh/yr (Table 34). In this scenario the Biotope still needs to import a great amount of its energy demand. The extra energy is to be imported from companies that produce energy from renewable sources. Table 38. Implemented technologies and yearly energy production in the ‘Bio‐diverse Scenario’.
TECHNOLOGY
HEAT
ELECTRICITY
Literature Source
ANAEROBIC DIGESTION
65 MWh
43
MWh
(Kujawa‐Roeleveld et al., 2010); (Graaff et al., 2010)
PV WINDOW TOTAL 201MWh
0 MWh 65 MWh
93 136
MWh MWh
(Schueco, 2011)
6.3.4. WATER FLOW The water management in the ‘Bio‐diverse Scenario’ is similar to the ‘Efficient Scenario’, because it aims to reduce human water consumption in the Biotope, by installing water efficient appliances. Moreover, in both scenarios, the surface water runoff is managed by minimizing the local hydrological impact. However, different from the ‘Efficient Scenario’, constructed wetlands are implemented as a part of the wastewater management that will work together with the retention ponds. Furthermore, a ‘Living Machine’ (Todd, 1996) is added to the program of the building. This ‘Living Machine’ will clean all the human wastewater of the Sunrise Campus, and the Biotope will be able to export back the same water in Q3 (please refer to Section 5.2), promoting recycling. In addition, the water demand is going to be higher than in the ‘Efficient Scenario’, because of the implementation of gardens within the building area. Figure 26. Water flow in the ‘Bio‐diverse Scenario’. represents the water flow in the Biotope for the ‘Bio‐diverse Scenario’. The rain water is collected from roofs and permeable pavements and treated in constructed wetlands and stored in the ponds. It is used for flushing toilets and irrigation. The Sunrise Campus’ wastewater (black water and grey water) is treated in the ‘Living Machine’ (Todd,
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SCENARIOS 1996). The treated water will be reused for toilet flush and irrigation, creating a loop in the water flow.
The extra water that is not used within the building is returned to the groundwater via soakways, preventing flooding. For other activities that require a better water quality, drinking water is supplied to the building by the local public water company.
Figure 26. Water flow in the ‘Bio‐diverse Scenario’. Legend: 1. 2. 3. 4. 5.
The rain water is collected from roofs and permeable pavements. It is stored treated in constructed wetlands and stored in ponds (Q3). The water is used in the Biotope for flushing toilets and irrigation (Q3). Drinking water is imported to the system (Q1) The Sunrise Campus’ wastewater (black water and grey water) is treated in the Living Machine. The treated water will be reused for toilet flush and irrigation (Q3), creating a loop in water flow. 6. After treated in a Living Machine (Q3), extra water will be discharged into a local watercourse, to prevent flooding.
6.3.5. WATER DEMAND MINIMIZATION Within the Biotope there will be 1.250m² of gardens, which corresponds to 10% of the human function area. On the one hand, it increases the biodiversity in the area. On the other hand, it increases the water demand of the building. It was assumed that the garden water demand for irrigation is half of the greenhouse irrigation demand in the Netherlands, which according to Stanghellini is 0,75m³ of irrigation water per square meter (Stanghellini, 2009). This results in an extra demand of 469m³ per year (Table 40). The irrigation water is also recycled in the ‘Living Machine’. The water demand minimization in this scenario follows in the same way as in the ‘Efficient Scenario’. The demand is reduced through low flush toilets and use of efficient faucets (please, refer to the ‘Efficient Scenario’ for more detailed data about those reductions). Like in the previous scenario, the technologies applied are capable of minimizing the water demand in toilet flush and hygiene faucets from an annual average of 4.328m³ to 2.200m³. This means a reduction of 49% in the described uses. Although the water demand is higher than in the ‘Efficient 60
SCENARIOS Scenario’, because of the garden area, it is still reduced if compared to the BAU situation. The total demand is 3.332m³/yr (Table 40), whereas in the ‘BAU Scenario’ is 4.992m³/yr (Table 13). Table 39. Implemented technologies to water demand minimization in the ‘Bio‐diverse Scenario’.
BAU DEMAND
faucets toilet flush
541 m³/yr 3.787 m³/yr
TOTAL
4.328 m³/yr
REDUCTION 64% 47%
LITERATURE SOURCE (Lazarus, 2009) (Lazarus, 2009)
NEW DEMAND 180 m³/yr 2.019 m³/yr 2.200 m³/yr
Table 40. Water demand in the ‘Bio‐diverse Scenario’ for each use and the total demand per year.
BIO‐DIVERSE DEMAND
drinking water, coffee and tea
184
m³
hygiene
180
m³
toilet flush
2.020
m³
dishwasher
306
m³
food processing
174
m³
garden irrigation
469
m³
TOTAL DEMAND
3.332
m³
6.3.6. MULTISOURCE AND RUNOFF MANAGEMENT The rain water is collected from roofs and permeable pavements (please refer to ‘Efficient Scenario’ for detailed data). In this scenario, green roofs are used as part of the storm water management strategy. According to Liu et al., green roofs delay runoff into the sewage system; hence, they help to reduce the frequency of combined sewage overflow (CSO) events, which is a significant environmental problem in urban areas. Moreover, the plants and the growing medium can also remove airborne pollutants picked up by the rain, thus improving the quality of the runoff (Liu et al., 2003). The rain water is stored in constructed wetlands. According to Asano, constructed wetlands are artificial wetlands, designed to utilize natural aquatic plants and organisms to improve water quality, retain rain water for flood control during heavy rain events, and provide wildlife habitat. A constructed wetland can also serve as habitat for wildlife, and potentially as a recreational site if it is designed to maintain its principal functions while safeguarding public health (Asano, 2006). The wetlands have two functions in this scenario. First, they have the same functions of ponds, which is to retain the rain water. Second, they also act as purification ponds, because they can be used for preliminary rain water treatment consisting of a screen and sand removal tank before the water is to be used in the Biotope in quality 3 (please refer to Section 5.2). According to Burkhard et al., the wetlands consist of a watertight pool, filled with a medium and planted with aquatic plants (macrophytes), which are able to grow in a water saturated root zone. At the upstream end of the wetland, an inlet structure distributes the inflow. At the downstream end, an outlet structure collects the treated wastewater (Burkhard et al., 2000).
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SCENARIOS After the wastewater is used within the building, it is to be treated in a Tidal Wetland Living Machine (TWLM) or ‘Living Machine’. This system was chosen for the ‘Bio‐diverse Scenario’ because of its low energy demand, and the combination of water treatment with wetland plants and animals, which enhances biodiversity in the campus. This system cleanses sewage and industrially contaminated water using natural biological processes, mostly consisting of higher plants, such as reeds, through which the influent flows (White, 2006) (Todd, 1999). A Tidal Wetland Living Machine (TWLM) uses mainly bacteria, but also employs other living organisms such as plants and gastropods to aid in the mineralization and removal of contaminants from the water. The system comprises multiple flood and drain (tidal) wetland cells (Figure 27). Tidal wetland cells flood and drain in a serial fashion. A recycle loop passes water several times through the treatment system (Austin et al., 2005; Worell Water Technologies, 2007). The TWLM consists of four or six tidal wetland cells. It includes a first lagoon that has an inlet for receiving wastewater to be treated and a first vertical flow marsh cell that has an outlet on the bottom. A second lagoon has an inlet for receiving water from the first marsh cell and a second vertical flow marsh cell that has an outlet on the bottom. The first and second lagoons are adapted to function essentially aerobically and to contain plants having roots positioned to contact water that is flowing into them. Each lagoon is adapted to maintain a population of grazing aquatic invertebrates. The first and second marsh cells are adapted to contain plants having roots positioned to contact water that is flowing into them (Austin et al., 2005).
Figure 27. Tidal wetland Living Machine. Source: Worell Water Technologies, 2007.
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SCENARIOS The system is particular for alternating marsh cells and lagoons. The overall hydraulic regime in this system preferably involves fill and drain cycles wherein wastewater is alternately pumped between cells and lagoons. The vertical flux of water in and out of the marsh cells is designed to cycle over a predetermined period, and is therefore referred to as tidal (Austin et al., 2005). The TWLM achieves advanced biochemical oxygen demand (BOD), total suspended solids (TSS), and total nitrogen removal at a fraction of the energy cost of conventional technologies. Simultaneous nitrification and denitrification is a key feature of the TWLM system. Nitrification occurs in drained wetland cells while denitrification occurs in flooded wetland cells (Austin et al., 2005; Worell Water Technologies, 2007). The ‘Living Machine’ achieves an advanced tertiary treatment suitable for reuse systems (Austin et al., 2005; Worell Water Technologies, 2007). In the Sunrise Campus, the water treated in the ‘Living Machine’ is reused for toilet flush within the buildings. The extra cleansed water is discharged into a receiving water course like in the ‘Efficient Scenario’ (Figure 26) (please refer to Section 6.2). To assess the outputs, the input water demand was multiplied by the discharge coefficient 0,8 (Kujawa‐Roeleveld et al., 2010). Therefore, it is expected that new water (rain water) is added to the system in every cycle. The multisource assessment is therefore 20% of the water used for toilet flush, resulting in 403m³/yr. 6.3.7. BIODIVERSITY In this scenario, a large amount of green areas emerges. Biotic aspects of the business site environment, that is, flora, fauna, and the landscape they inhabit are addressed. This characteristic is developed in three different areas of the Biotope and Sunrise Campus. First, the green areas within the building are about 10% of the constructed area. Second, the wastewater treatment system, the ‘Living Machine’, besides purifying the water, enhances the quantity of species in the building. Third, green roofs and the ponds, which are seen as potential habitats for many plants and animals species, are extensively used in the Sunrise Campus. As a result, the total area that is able to promote biodiversity in the Sunrise Campus and in the Biotope is 136.318m² and 65.328m² respectively (Table 41). As described previously, the flow rate of reclaimed water possibly will need to be adjusted to accommodate natural seasonal changes that affect the growth and life cycle of some species. For instance, some wetland plants are not able to sustain extended periods of inundation or may require an annual dry period. Thus, if the proper conditions are not created, adapted or invasive plant communities will replace these plant species and the specific habitat that they support. Inlet and outlet structures should be designed so that water levels and flow rates can be adjusted as necessary. Bypass or transfer structures should also be provided to transfer water to different areas of the wetland as needed (Asano, 2006). The total area for the wetlands and ponds is 16.000m2 (Figure 23). It was assessed that half of this area is constructed wetland, and work as a part for the water treatment system and is classified as a controlled green area. The other half is the retention pond that works as a water storage and is a not controlled area. As a result, the total not controlled green area in the Sunrise Campus and Biotope is 128.318m² and 57.328m² respectively. The controlled green area is 8.200m² for the Sunrise Campus and the Biotope. 63
SCENARIOS Table 41. Biodiversity variations in the Biotope and Sunrise Campus implantation areas in the ‘Bio‐diverse Scenario’.
SUNRISE CAMPUS BIOTOPE
green roof not controlled garden pond constructed wetland and ‘Living Machine’ controlled greenhouse Total
78.970 41.348 8.000 8.200 0 136.318
m² m² m² m² m² m²
7.980 41.348 8.000 8.200 0 65.328
m² m² m² m² m² m²
6.3.8. ‘BIO‐DIVERSE SCENARIO’: ASSESSMENT The energy and water are resumed into three different indices that are explained in Section 3.1: demand minimization (DMI), waste output (WOI) and self‐sufficiency (SSI). For the ‘Bio‐diverse Scenario’, they are expressed in Table 42. Furthermore, biodiversity is evaluated according to two different indices: green area (GAI) and local species (LSI), for the Biotope’s and Sunrise Campus’ implantation areas. These indices are also explained in Section 3.2 and the results of the ‘Bio‐diverse Scenario’ are expressed in Table 43. Table 42. Energy and water assessment for the ‘Bio‐diverse Scenario’.
BIO‐DIVERSE ENERGY
Conventional Demand (Do) New Demand (D) Cascade (C) Recycle(R) Consumption (Co) Multisource (M) DMI= (Do‐D)/Do WOI=‐(D‐C‐R‐Co)/D SSI=(C+R+M)/D
3.590 1.720 0 0 0 201 INDICES 0,52 ‐1,00 0,12
MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr
BIO‐DIVERSE WATER 4.992 3.332 0 1.991 0 498
m³/yr m³/yr m³/yr m³/yr m³/yr m³/yr
0,33 ‐0,40 0,75
Energy The ‘Bio‐diverse Scenario’ has considerably minimized its energy demand, achieving a DMI of 0,52. However, its own multisource (anaerobic digestion of solid waste and PV windows) is able to produce only 12% of the scenario demand (SSI=0,12), representing low grades of self‐sufficiency. The external demand is provided by the local public utility. It is expected that in this scenario the electricity is imported from energy companies that produce renewable energy. Analogously, for the heating demand, conventional gas should be imported to the campus. The WOI is the same as in the ‘BAU’ and ‘Efficient’ scenarios (‐1,00), because strategies such as energy cascading or recycling are absent and the output is not minimized.
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SCENARIOS Water The water demand is increased when compared to the ‘Efficient Scenario’ due to the implementation of gardens inside the Biotope. Consequently, the DMI decreases to 0,33. Rain water is harvested and used for irrigation and low flush toilets. It is recycled by a ‘Living Machine’ and re‐ used within the building. To assess the recycled water, the toilet and irrigation water input (Table 40) was multiplied by the discharge coefficient 0,8 (Kujawa‐Roeleveld et al., 2010). Therefore, 80% of the water demand of toilet flush and irrigation water is recycled water, treated by the ‘Living Machine’. The multisource (rain water) is the other 20% that is to be harvested. Drinking water is imported to the system from the local public utility. As a result, the wastewater output is minimized and the WOI is ‐0,40. This represents that 60% of the wastewater is re‐introduced to the system. Finally, the SSI is 0,75, and it is represents the use of rain water that is harvested in the Biotope. Biodiversity The biodiversity area in this scenario is considered to be the constructed wetland/ pond, its surrounding area and green roofs throughout the campus (Figure 23). Table 43. Biodiversity assessment for the ‘Bio‐diverse Scenario’.
SUNRISE CAMPUS
Implantation area (A) Not controlled green (NCG) Controlled green (CG) Total green (T) GAI = T/A LSI = T‐CG/T
202.900 128.318 8.200 136.518 0,67 0,94
m² m² m² m²
BIOTOPE 60.500 57.328 8.200 65.528 1,08 0,87
m² m² m² m²
As a result, the GAI for the Sunrise Campus is 0,67 and for the Biotope is 1,08, i.e. the total green area corresponds to 67% of the Sunrise Campus implantation area, whereas it also indicates 108% of the Biotope ’s area. The biodiversity area in the Biotope’s is bigger than the implantation area of the Biotope itself due to the design of internal gardens in the buildings on different floors. Because of the great amount of gardens and green roofs in this scenario, the Biotope’s the Sunrise Campus’ local species index are 0,94 and 0,87 respectively. This means that local species can make use of almost all the green areas.
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SCENARIOS 6.4.
SCENARIO 4 – PRODUCER
In this scenario, the production of clean energy, water and food are the main concerns. The technical design is based on the ‘‘greenhouse village neighborhood’ (Mels et al., 2010), a neighborhood designed together with greenhouses where they exchange heat, nutrients and water in different qualities. N
Figure 28. ‘‘Producer Scenario’’: plan view.
The design results from the necessity of coupling 2 hectares of greenhouse to the 12.500m² of human functions in the Biotope, in order to cope with the heating demand in the Biotope. The Producer Biotope is divided into three blocks, and has two floors. The distance between the blocks (24m) is 3 times their height (8m), to achieve the optimum passive lighting effect (please refer to Figure 15 and Section 6.2.2). The greenhouses are to be placed in the East and West sides of the building blocks. They are covered with PV windows on their South façades as well as on their roofs. Natural lighting and ventilation will be provided through solar tubes and ventilation tubes. In this scenario, two alternative technologies are applied to the human function’s roof, generating two sub‐ scenarios. In the sub‐scenario (a), the roofs are covered with PV cells, whereas in the sub‐scenario
66
SCENARIOS (b), wind turbines are to be placed on the roofs. They are compared and the most efficient technology is chosen for further calculations (Figures 28 and 29). In order to produce more energy than what is necessary to fulfill the Biotope’s demand, the ‘greenhouse village’ (Mels et al., 2010) works together with Fine Heat Wired Heat Exchangers (FiWiHEx) ATES system (Mels et al., 2010; Kristinsson, et al., 2008); two anaerobic digesters, one for solid waste (please refer to Section 6.3.3), and a UASB (Upflow Anaerobic Sludge Balnket) reactor (Graaff et al., 2010; Kujawa‐Roeleveld et al., 2010) that will treat the wastewater; and PV windows. In the ‘Producer Scenario (a)’, PV cells are to be installed on the human functions roof, and in the ‘Producer Scenario (b)’, wind turbines will be placed. The water system works with greenhouses coupled with constructed wetlands and the UASB reactor, which will produce energy by the digestion of the wastewater. In this scenario the UASB links the energy and water system. The main design characteristics of the ‘Bio‐diverse Scenario’ are:
Biotope area: 12.500m² (human functions) Greenhouse area: 20.000m² Number of workers: 960 Building orientation: 3 blocks in the east‐west axis. The distance between the blocks (24m) is 3 times their height (8m), for the optimum use of direct sunlight and heat (Figure 15). Sunrise Campus buildings: use of PV cells in all roofs (it is not going to be assessed because each building uses its produced energy)
Figure 29. ‘‘Producer Scenario’’: Building Schematic Section AA. In the ‘Producer Scenario (a)’ PV cells will be installed in the human’s function block, whereas in the ‘Producer Scenario (b)’, wind turbines will be placed.
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SCENARIOS 6.4.1. ENERGY FLOW Figure 30 represents the energy flow in the Biotope in the ‘Producer Scenario’. The energy system comprises of a closed greenhouse (a greenhouse that does not release excess heat through ventilation); heat exchangers in the greenhouse; a FiWiHEx ATES system, which consists of a piped heat distribution system to greenhouses and the human function area of the Biotope; a heating and cooling system consisting of floor and ceiling pipes in the human function area of the Biotope, and a cooling tower. The South façades of the three blocks and the roofs of the greenhouses are covered with PV windows. Moreover, the human functions blocks are roofed with PV cells (in the ‘Producer Scenario (a)’ and wind turbines ‘Producer Scenario (b)’. The kitchen waste and black water are digested, producing heat and electricity. Vacuum toilets are used in the building to keep the stream of black water in concentrated state, which is used in the anaerobic process to produce energy.
Figure 30. ‘Producer Scenario (a)’: energy flow. Legend: 1. PV windows 2. Roof: solar tubes, PV cells (sub‐scenario (a)), wind‐turbines (sub‐scenario (b)). 3. Insulation materials; use of led lamps, CPU management 4. Greenhouse: heat produced is used in human functions of the Biotope 5. ATES FiWiHEx System: responsible for heat exchange between the greenhouse and human functions 6. Use of vacuum toilets for separation of the water streams. The organic waste (black water, food and greenhouse waste) from Biotope is added to two anaerobic digesters (one for solid waste and the other for black water) 7. Anaerobic digesters 8. Energy (heat and electricity) produced in the anaerobic digester is used in the Biotope 9. Extra heat and electricity production is exported to other buildings
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SCENARIOS 6.4.2. ENERGY DEMAND MINIMIZATION The energy demand minimization follows the same issues for lighting, office equipment, and passive ventilation and insulation materials as the ‘Efficient Scenario’ and they are not to be assessed in this Section (for more detailed data please refer to Section 6.2). However, the heating and cooling system is connected to an energy producing greenhouse. All the technologies mentioned are listed in the table below. Next, they are described and the new heat and cold demand is calculated. For the assessment, it was first taken into account lighting reductions with passive lighting and dimming control. Second, the use of LED lamps instead of regular incandescent bulbs was considered. Third, the cooling and heating demand were minimized, by the implementation of insulation materials in the buildings envelope. Lastly, the ATES FiWiHEx system was assessed, reducing the remaining heating and cooling demand. Table 44. Implemented technologies to energy demand minimization in the ‘Producer Scenario’.
TECHNOLOGY
LIGHTING
OFFICE EQUIPMENT COOLING
HEATING
(1) (2)
(3) a. b.
REDUCTION Literature Source
passive lighting and diming control use of led lamps instead of regular incandescent bulb
40,00%
(Bodart et al., 2002)
90,00%
(MacKay, 2008)
CPU management and standby and active mode power reductions for computers insulation materials ATES FiWiHEx
40,00%
(Waide et al., 2007)
10,00% 100,00%
insulation materials: floors, walls, windows and roofs
40,00%
ATES FiWiHEx
65,89%
(MacKay, 2008) (Bridger et al., 2005); (Nieuwenhuize, 2011); (Mels et al., 2010) (MacKay, 2008) (Bridger et al., 2005); (Nieuwenhuize, 2011); (Mels et al., 2010)
Lighting demand minimization (please refer to ‘Efficient Scenario’ for detailed data) Office Equipment energy demand minimization (please refer to ‘Efficient Scenario’ for detailed data) Heat and cold demand minimization Insulation materials (please refer to ‘Efficient Scenario’ for detailed data) ATES FiWiHEx and ‘greenhouse village’ system
The ‘greenhouse village’ is a design for a neighborhood that provides its own wastewater treatment, water supply and greenhouse products. The basic elements of the design are an energy‐producing greenhouse, houses and an anaerobic digester (Mels et al., 2010). In the present study, the houses are replaced by the human functions’ area of the Biotope. The basics elements of the energy system for climate control in the greenhouse connected to a building block are (Figure 31) (Mels et al., 2010): A closed greenhouse that does not use windows to release excess heat 69
SCENARIOS Heat exchangers in the greenhouse An aquifer that stores hot and cold water (ATES system), and its management systems with pumps and flow control A heating and cooling system that consists of floor and ceiling pipes A cooling tower
Figure 31. Energy system in a greenhouse connected to a building block. Source: Mels et al., 2010.
The ‘Energy Producing Greenhouse’ or ‘greenhouse village’ system concept is attributed to the high‐ quality and innovative Dutch glasshouse horticulture in the moderate West European climate and the thick sand/clay layers in the Rhine delta, which works as a substrate for seasonal heat storage. The glasshouse horticulture becomes a source of energy without being an energy consumer. The term ‘closed’ relates to maintenance and control of the inside climate of the greenhouse, which means that no ventilation of the greenhouse by means of windows is performed. Moreover, such a concept allows low‐impact urban food production (Amosov, 2010). According to Mels et al., the basic concept of the energy producing greenhouse is to harvest the excess heat produced by the greenhouse in the summer. Moreover, the FiWiHEx (Fine Heat Wired Heat Exchangers) are used in these systems. They increase the groundwater temperature from 8oC to 25‐27oC while maintaining the air temperature of a greenhouse at a maximum of 30oC. The heated groundwater is stored in the aquifer. At night or during the winter, the stored heat can be used to warm up the greenhouse and the building block. The Biotope is equipped with a heating and cooling system consisting of floor, wall and possibly ceiling pipes. Moreover, a cooling tower has to be added to the system to keep the balance of the aquifer and to ensure that its temperature does not exceed 25oC, avoiding heating and cooling of the soil (Mels et al., 2010).
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SCENARIOS As a result, Kristinsson and Timmeren state that by using FiWiHEx system, the energy consumption in a greenhouse is reduced from 50m³ of natural gas/m2 of plantation to zero (Kristinsson et al., 2008), and therefore, the cooling reduction in this ATES system is 100% (Table 45). The greenhouses do not need to be cooled either, since they are already cooled by the cooling tower. The heat produced by the greenhouse is stored in the ATES system. For the cooling system, the same model as in the ‘Efficient Scenario’ is used for calculations. For the cooling and heating demand assessment, it was first reduced the demand by the use of insulation materials. The remaining demand was minimized by the use of the ATES system. For that, it was first considered that the cooling reduction in the FiWiHEx ATES system is 100% (Kristinsson et al., 2008). This corresponds to a reduction of 528MWh. The same load of energy (528MWh) was reduced from the heating demand, which represents 66% out of the total heating demand. After that, the energy spent by the pumps needed for the system was added to the calculation. Please refer to Section 6.2.2 for more details of this calculation. The table below expresses the results of the implementation of the technologies explained above for heating and cooling demand minimization. Table 45. Heat and cold minimization assessment for the ‘Producer Scenario’ per year.
COOLING ‘BAU SCENARIO’ DEMAND
586
TECHNOLOGY
MWh
REDUCTION
NEW DEMAND
10%
528
MWh
(MacKay, 2008)
100%
0
MWh
(Mels et al., 2010)
0
MWh
1335
MWh
Insulation materials ATES FiWiHEx COOLING ‘PRODUCER SCENARIO’ DEMAND
LITERATURE SOURCE
HEATING ‘BAU SCENARIO’ DEMAND TECHNOLOGY
REDUCTION
NEW DEMAND
insulation materials
40%
801
MWh
(MacKay, 2008)
ATES FiWiHEx
66%
273
MWh
(Mels et al., 2010)
273
MWh
HEATING ‘PRODUCER SCENARIO’ DEMAND
LITERATURE SOURCE
PUMP DEMAND (ELECTRICITY)
ATES FiWiHEx cooling pumps (COP 4)
‐2,5%
14
MWh
ATES FiWiHEx heat pump (COP 40)
‐10%
132
MWh
ATES FiWiHEx pumps (COP 4)
‐5%
13
MWh
159
MWh
TOTAL PUMP DEMAND (ELECTRICITY)
(Bridger et al., 2005) (Nieuwenhuize, 2011)
(4) Others demand minimization The others demand in the ‘Producer Scenario’ is not minimized and it is assessed like in the ‘Efficient Scenario’. Please refer to Section 6.2 for more detailed information. In addition, the pumps energy demand of the ATES FiWiHEx system is added to it. The pumps have a total demand of 159MWh/yr, in the form of electricity. Therefore, this amount of energy is added to the ‘others demand’. In the
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SCENARIOS ‘BAU Scenario’, the ‘others demand’ is 546MWh/yr (Table 12), and in the ‘Producer Scenario’ it is 705MWh/yr. (5) Total ‘Producer Scenario’ demand The total annual energy demand for the ‘Producer Scenario’ is 1.339MWh. The electricity use is responsible for 1.066MWh whereas the heat and cold are responsible for 273MWh of the energy use (Table 46). Table 46. Yearly energy demand in the ‘Efficient Scenario’ for each use and the total demand.
Energy Lighting Office Equipment Cooling Heating Others NEW ELECTRICITY DEMAND HEAT/COLD DEMAND NEW ENERGY DEMAND
Total energy demand/yr 35 327 0 273 705 1.066 273 1.339
MWh MWh MWh MWh MWh MWh MWh MWh
6.4.3. ENERGY PRODUCTION In the ‘Producer Scenario’, producing energy is the most important feature. Energy is produced through all possible technologies on site. Electricity is produced by PV windows, PV cells (sub‐ scenario (a)), and wind turbines (sub‐scenario (b)). Anaerobic digestion of green waste and wastewater generates heat and power (CHP). Finally, the greenhouses, besides producing food and organic matter for bio‐digestion, also generate heat for the human functions of the Biotope. In what follows, two alternatives were studied for the energy ‘Producer Scenario’. One includes PV cell on the human function roofs ‘Producer Scenario (a)’, and the other applies wind turbines on these roofs ‘Producer Scenario (b)’. After that, a comparison between them is made and one of the sub‐scenarios is chosen to represent the ‘Producer Scenario’. a. ‘Producer Scenario’ (a) – PV cells on human function’s roof (1) Anaerobic digestion In the ‘Producer Scenario’ the anaerobic digestion works with three different streams: garden waste, kitchen waste and black water. For that, two different digesters are to be used. For the treatment of food and garden waste an anaerobic digestion that operates with high solids reactors (up to 30%) is to be implemented (please refer to Section 6.3.3). At the same time, another reactor (a UASB reactor) that is suitable for diluted and concentrated wastewater is to be used.
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SCENARIOS a. Food and garden waste The kitchen waste follows the same calculation as in the ‘Bio‐diverse Scenario’ (please refer to Section 6.3.3 for more detailed data). The total waste food production in the Biotope is 19.754kg (Table 35). The total amount of green areas in the Sunrise Campus and in the Biotope is 32.000m² (see Section 6.4.7). Therefore, the total amount of green waste produced annually in the Sunrise Campus in the ‘Producer Scenario’ is 10.880kg (Table 47) (please refer to Section 6.3.3 for more detailed data). Table 47. Green waste in the ‘Bio‐diverse Scenario’ per year.
Waste production
Garden waste
Green area
Total waste produced 10.880kg
0,34kg/m² 32.000 m²
LITERATURE SOURCE (Lundie et al., 2005); Section 3.6.7 (green areas)
Table 48. Combined heat and power from organic waste bio‐digestion per year.
Total organic waste 30.634 kg
energy Total production rate Energy potential 1,92MWh/ton 59MWh
Total energy Total heat Total available for produced electricity CHP produced 50MWh 30MWh 20MWh
LITERATURE SOURCE (Kujawa‐Roeleveld et al., 2010); (Graaff et al., 2010)
It follows that the total amount of the garden and food waste produced by the Biotope and Sunrise Campus in this scenario is 30.634kg/year, which are to be digested through anaerobic treatment. It is assumed that the energy production of anaerobic digestion is 200m³ per ton (Kujawa‐Roeleveld et al., 2010), which is equal to 1,92MWh/ton of waste (conversion factor of 0,00961 (Graaff et al., 2010)). When the full amount of organic waste produced in the Biotope is treated though anaerobic digestion, it yields 59MWh of potential energy per year. Combined heat and power (CHP) generation systems can be used to produce heat and electricity at an efficiency of 85% (of which 40% electricity and 60% heat) (Graaff et al., 2010). This would result in a production of 20MWh of electricity and 30MWh of heat on an annual base (Table 48). b. Wastewater In this scenario, the black water from the toilet (urine and faeces) is separated from the grey water (please refer to Section 6.4.4) in all the buildings in the Sunrise Campus. Vacuum toilets are to be used for its collection and the energy is recovered by anaerobic treatment. Vacuum toilets operate with a pump generated vacuum using small volumes of water to flush. Water is used only for rinsing the toilet bowl. The vacuum system operates pneumatically (vacuum pumps, ejectors or compressors) and needs a water connection to the toilet and electricity for the vacuum units. The transport can be both in the vertical direction for limited distances and horizontal directions for long distances (Kujawa‐Roeleveld et al., 2010). 73
SCENARIOS According to Graaff et al., anaerobic treatment is regarded as the core technology for energy and nutrient recovery from source separated black water because it converts organic matter to methane, which can be used to produce electricity and heat, while at the same time anaerobic treatment yields low amounts of excess sludge. Moreover, the nutrients are largely conserved in the liquid phase and can be subsequently recovered with physical‐chemical processes such as precipitation and ion‐exchange or removed biologically (Graaff et al., 2010). They are to be used as fertilizers in the greenhouse. However, it is not going to be assessed in the further results, because it is considered to be part of the nutrients flow, which is out of the scope of the present thesis. The anaerobic treatment of wastewater, like in the organic solid waste, is based on the biological degradation of organic material in which methane gas and carbon dioxide and water are produced. The complete biological degradation proceeds in four stages: hydrolisis, acidification, acetogenesis and methanogenesis. In the anaerobic treatment, different bacteria capable of these four stages are to be present (Kujawa‐Roeleveld et al., 2010). Various types of anaerobic reactors have been developed for the treatment of wastewater. In the present scenario the UASB (Upflow Anaerobic Sludge Balnket) is used, because, according to Kujawa‐ Roeleveld et al., it is the most well‐known UASB reactor. This system is unfit for the digestion of concentrated slurries but suitable for diluted and concentrated wastewater and can be part of a multi‐stage system (Kujawa‐Roeleveld et al., 2010). The influent enters the reactor through a distribution box in which the flow is divided into a number of sub‐streams. These streams flow through pipes to the bottom of the reactor and come into contact with the active anaerobic sludge blanket. The degradation of organic matter occurs mainly in this sludge blanket. Therefore, in the upper part of the reactor, three‐phase separator is installed, which separates sludge, water and biogas (Kujawa‐Roeleveld et al., 2010). Graaf et al. state that with a methanisation level of 60%, 12,5L of CH4/cap/d can be produced from black water (Standard Temperature and Pressure (STP)). It yields an average of 335MJ/cap/year (Graaff et al., 2010). The efficiency of combined heat and power (CHP) is 85% (Graaff et al., 2010), resulting in a capacity 67,7MJ/cap/year, which is equal to 0,019MWh/cap/year. Table 49. Energy production from anaerobic treatment in the ‘Producer Scenario’ per year.
Type of waste Kitchen and garden waste wastewater
Total energy Total electricity Total heat
Energy production Energy production Sunrise Biotope (MWh/yr) Campus (MWh/yr) 50 0 18
82
68
82
Total (MWh/yr)
150 60 90
literature source (Graaff et al., 2010), (Kujawa‐ Roeleveld et al., 2010), (Liu et al., 2003)
Vacuum toilets are to be installed in all the buildings of the Sunrise Campus, where 5.308 people are expected to work. To assess the total wastewater in the Sunrise Campus, this production is calculated proportionally to the working days in a year (260) and working hours a day (8). The total 74
SCENARIOS Biotope energy production from anaerobic digestion of black water is 18MWh/yr, and in the Sunrise Campus it is 82MWh/yr, from which 40% is electricity and 60% is heat (Table 49). In the ‘Producer Scenario’, the yearly total energy production of kitchen and garden waste, and black water is 150MWh, from which 60MWh/yr is electricity and 90MWh/yr is heat. (2) Greenhouse Village’ Besides being a food producer, each hectare of greenhouse, according to Mels et al., is able to produce heat for 100 houses in the Netherlands weather conditions (Mels et al., 2010). According to SenterNovem, a household in the Netherland consumes 184Nm³ of natural gas annually (SenterNovem, 2007), which is equal to 1,76MWh/yr (conversion factor 0,0096 (Graaff et al., 2010)). It is assumed that a standard house in the Netherlands has 100m² of area. Therefore, one hectare of greenhouse produces 177MWh/yr and consequently, 2ha of greenhouse produces 354MWh/yr (Table 50). In the ‘Producer Scenario’, the Biotope demand for heat is 273MWh/yr (Table 46). The extra heat will be exported to the others building in the Sunrise Campus. Table 50. ‘greenhouse village’ energy production in the ‘Producer Scenario’ per year.
TECHNOLOGY ‘GREENHOUSE VILLAGE’
GREENHOUSE AREA 2 ha
AVERAGE HEAT PRODUCTION 177 MWh/ha
HEAT PRODUCTION 354 MWh
LITERATURE SOURCE (Mels et al., 2010) (SenterNovem, 2007)
(3) PV window The area of the South façades of the three blocks and the roof of the greenhouses sum a total of 11.400m² (Figure 28 and 29). The assessment of the energy production of PV windows follows the same as in the other scenarios. Please refer to ‘Efficient Scenario’ for more detailed data. The total electricity produced by PV windows is 456MWh/year. Table 51. PV windows energy production in the ‘Producer Scenario’ per year.
TECHNOLOGY PV window
AVERAGE POWER AREA DELIVERED (figures 28 and 29) 4,6 W/m2 11.400 m2
ENERGY PRODUCTION 456 MWh
LITERATURE SOURCE (Schueco, 2011)
(4) PV cells The area of the roofs that cover the human function zones of the Biotope is 6.250m² (Figure 28). The energy production of such technology follows the same as in the other scenarios. Please refer to ‘Efficient Scenario’ for more detailed data. The total electricity produced by PV cells is 602MWh/year. Table 52. PV cells energy production in the ‘Producer Scenario’ per year.
TECHNOLOGY PV cells
AVERAGE POWER DELIVERED 11 W/m2
AREA (figures 28 and 29) 6.250 m2
ENERGY PRODUCTION 602 MWh
LITERATURE SOURCE (MacKay, 2008)
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SCENARIOS (5) Total energy production ‐ ‘Producer Scenario (a)’ The following table expresses the main technologies used for the production of energy in the ‘Producer Scenario (a)’. The total energy produced by the Biotope is 1.562MWh per year, from which 1.118MWh/yr is in the form of electricity and 444MWh/yr as heat. Table 53. Total energy production in the ‘Producer Scenario (a)’ per year.
TECHNOLOGY
HEAT
ELECTRICITY
Literature Source
ANAEROBIC DIGESTION
90
MWh
60
MWh
‘GREENHOUSE VILLAGE’ PV WINDOW
354 0
MWh MWh
0 456
MWh MWh
602
MWh
1.118
MWh
PV CELLS TOTAL ENERGY 1.562MWh
444
MWh
(Graaff et al., 2010), , (Kujawa‐Roeleveld et al., 2010),(Liu et al., 2003) (Mels et al., 2010) (Schueco, 2011) (Urban Green Energy Inc., 2010)
b. ‘Producer Scenario’ (b) – Wind turbines on human building’s blocks roof (1) Anaerobic digestion (please refer to ‘Producer Scenario (a) for detail data) (2) ‘greenhouse village’ (please refer to ‘Producer Scenario (a) for detail data) (3) PV window (please refer to ‘Producer Scenario (a) for detail data) (4) Wind turbines According to MacKay, the power of the wind, for an area A is: 1 2
Where, ρ is the air density and it is equal to 1,3kg/m³ (MacKay, 2008); and v is the wind speed. The wind speed in the region of Eindhoven is 8,83knots (Windfinder, 2010). One knot is equal to 0,514m/s, therefore, the wind speed in the Sunrise Campus is 4,5m/s.
Figure 32. Wind mill Eddy. Source: Urban Green Energy Inc., 2010.
The wind turbine selected for the Biotope is a small‐scale wind turbine called Eddy (Figure 32). This turbine is chosen as an example of the small scale wind turbines that is available in the market. It is produced by Urban Green Energy and has an area (A) is 2,1m² (Urban Green Energy Inc., 2010). This turbine is dual‐axis design, which utilizes both horizontal and vertical forces along the length of the axis. 76
SCENARIOS Therefore, the total power from the Eddy turbine is 124W. However, according to MacKay, the wind turbine efficiency is 50% (MacKay, 2008). Therefore, the power that is available for direct use in the Biotope through the use of a wind turbine is 62W, which is equivalent to a total energy of 0,54MWh/year. MacKay also states that the wind turbines should be spaced at a distance of at least 5 times their diameter (MacKay, 2008). In this case, the diameter is 1,5m (Urban Green Energy Inc., 2010); therefore, they should be spaced each 7,5m. On the roof surface of each building of the human function blocks of the Biotope (dimensions: 30x70m), it is possible to implement four rows of nine wind turbines each. On the roof of the three blocks that compose the Biotope the 108 wind turbines are to be placed. Together, they produce 58MWh/year (Figure 28 and Table 54). Table 54. Windmills energy production in the ‘Producer Scenario’ per year.
TECHNOLOGY
ENERGY PRODUCTION/ WINDMILL/YEAR 0,54 MWh
108 WINDMILLS
ENERGY PRODUCTION
LITERATURE SOURCE
58
(Urban Green Energy Inc., 2010)
MWh
(5) Total energy production ‐ ‘Producer Scenario (b)’ The following table expresses the main technologies used for the production of energy in the ‘Producer Scenario (b)’. The total energy produced by the Biotope is 1.018MWh per year, from which 574MWh is in the form of electricity and 444MWh as heat. Table 55. Total energy production in the ‘Producer Scenario’ per year.
TECHNOLOGY
HEAT
ELECTRICITY
ANAEROBIC DIGESTION
90
MWh
60
MWh
PV WINDOW ‘GREENHOUSE VILLAGE’ WIND TURBINES
0 354
MWh MWh
456 0 58
MWh MWh MWh
TOTAL ENERGY 1.018 MWh
444
MWh
574
MWh
Literature Source (Graaff et al., 2010) (Anaerobic Digestion, 2011) (Schueco, 2011) (Mels et al., 2010) (Urban Green Energy Inc., 2010)
c. Comparison of ‘Producer Scenario (a)’ and Producer Scenario (b)’ In the ‘Producer Scenario (b)’, wind turbines are to be placed on the roof of the human function zones. They generate 58MWh/yr and the total Biotope energy production is 981MWh/yr. However, if PV cells are to be installed in their place, they will generate 602MWh per year and the total energy production of the Biotope is to be 1.562MWh/yr. The PV cells produce more than ten times energy than the wind turbines. Therefore, the ‘Producer Scenario (a)’ (Table 53) is taken into consideration in the following assessment of energy. 6.4.4. WATER FLOW The water management in the ‘Producer Scenario’ also aims at reducing human water consumption in the Biotope by installing water efficient appliances. Moreover, the surface water runoff is managed by minimizing local hydrological impact. However, differently from the previous scenarios, the ‘greenhouse village’ system will be implemented. This system is able to treat the wastewater and to produce drinking water. It is done through the collection and treatment of the condensation 77
SCENARIOS of the irrigation water that evaporates. The drinking water is to be used by the human functions of the Biotope. Figure 33 represents the water flow in the Biotope for the ‘Producer Scenario’. The rain water is collected from roofs and permeable pavements, treated in constructed wetlands and stored in the ponds. Then, it is used as irrigation water (Q2) in the greenhouses in the Biotope. The water is condensed and collected. After another filtration it is to be used for human uses in the Biotope (Q1). The wastewater is separated into three water streams by the use of vacuum toilets. The black water is to be used for anaerobic digestion in a UASB reactor, whereas the grey water returns to the constructed wetland, and starts another cycle. The extra water that is not used within the building is returned to the groundwater via soakways, preventing flooding.
Figure 33. ‘Producer Scenario’: water flow 1. The rain water is collected from roofs and permeable pavements. 2. It is pre‐treated in constructed wetlands and stored in retention ponds (Q2). 3. The grey water from the human functions in the Biotope is treated in a bioreactor (Q2). 4. Water irrigation tank (Q2). 5. Greenhouse irrigation (Q2), water condensation, collection and reuse (Q2). 6. 15% of the water is discharged into the public sewage system. 7. Filtration activated carbon, re‐hardening and quality monitoring (Q1). 8. Drinking water tank (Q1). 9. Drinking water is distributed to Sunrise Campus buildings. 10. Within each building, water is consumed. 11. Grey water collection and discharge into open wetlands. The water starts another cycle. 12. Vacuum toilets are used in the buildings and the black water is collected and sent to a UASB reactor, where it is digested and energy is produced. 13. UASB reactor.
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SCENARIOS 6.4.5. WATER DEMAND MINIMIZATION Within the Biotope in the ‘Producer Scenario’, there is 2ha of greenhouses which produce vegetables that are to be consumed by the workers of the Biotope (Figure 31 and 32). Moreover, these greenhouses produce heat, and are part of the water treatment of the system. According to Stanghellini, the water demand of a greenhouse in the Netherlands is 0,75m³ per square meter per year (Stanghellini, 2009). This results in an extra water demand of 1.500m³ per year. The water demand minimization in this scenario follows by the use of efficient faucets and vacuum toilets. The water consumption for the faucets are assessed as in the ‘Efficient Scenario’ (please refer to Section 6.3 for more details). According to Agudelo et al., a vacuum toilet consumes 0,8 to 2l per flush (Agudelo‐Vera, et al., 2011). It is considered in this report that a typical (BAU) toilet consumes 7.5l per flush (Lazarus, 2009) and that a vacuum toilet consumes 2l. As a result, the choice of using the vacuum toilet generates a reduction of 73,3% in water consumed for toilets, when compared to the ‘BAU Scenario’ (Table 56). The new water demand is 3.354m³ and the different demands are expressed in Table 57. Table 56. Implemented technologies to water demand minimization in the ‘Producer Scenario’.
faucets toilet flush TOTAL
BAU DEMAND 541 m³/yr 3.787 m³/yr 4.328 m³/yr
REDUCTION 26% 73% 72%
NEW DEMAND 180 m³/yr 1.010 m³/yr 1.190 m³/yr
LITERATURE SOURCE (Agudelo‐Vera et al., 2011) (Lazarus, 2009)
Table 57. Water demand in the ‘Producer Scenario’ for each use and the total demand per year.
PRODUCER DEMAND
drinking water, coffee and tea
184
m³
hygiene
180
m³
toilet flush
1.010
m³
dishwasher
306
m³
food processing
174
m³
greenhouse
1.500
m³
TOTAL DEMAND
3.354
m³
6.4.6. MULTISOURCE AND RUNOFF MANAGEMENT The rain water is collected from roofs and permeable pavements (please refer to Section 6.2 for detailed data) (Figure 33). It is stored in constructed wetlands, that work as a secondary treatment for domestic sewage and as retention ponds (please refer to Section 6.3.2 for more details). It is used as irrigation water (Q2). The grey water from the human uses of the Biotope, after being treated in an aerobic bioreactor, is combined to the rain water for the irrigation. The grey water of the Biotope is purified in an aerobic bioreactor. Before treatment the liquid fraction of the anaerobic digester (UASB) (please refer to Section 6.4.3), which contains the nutrients, is mixed with the grey water. According to Mels, the treatment purposes in this aerobic bioreactor are: removal of oxygen consuming organic pollutants, conversion of ammonium into 79
SCENARIOS nitrate (nitrification), partial denitrification, i.e. transformation of nitrate into gaseous nitrogen. By partial denitrification the nitrate concentrations in the irrigation water can be tailored for the specific demands of the greenhouse plants. After treatment, this water is used for irrigating the greenhouse. The excess sludge of the aerobic bioreactor is brought into the UASB digester (Mels, et al., 2010). Greenhouse plants will evaporate the irrigation water. The vapor condenses and is collected. The collected water is of high quality. It can be used as drinking water (Q1) after being filtrated through activated carbon and re‐hardened, and quality monitored, because pure distilled water is too low in salts for human consumption (Mels et al., 2010). Moreover, small volumes of drained irrigation water (approximately 15%) will have to be discharged (into the public sewage system) to keep the salt concentrations at a low level. As a result, small volumes of external water (rain water) are still needed for the water cycle (Mels et al., 2010). The rain water stored in the wetland is to be use. The wastewater will be separated into grey and black water with the use of vacuum toilets. According to Graaff et.al, separation of domestic wastewater at the source results in black water from the toilet (faeces and urine) and less polluted grey water from showers, laundry and kitchen. The main benefits of such approach include the possibility of recovering energy and nutrients and the efficient removal of micro‐pollutants. Grey water has a high potential of reuse because it is the major fraction (70%) of domestic wastewater and has a relatively low level of pollution. Black water contains half of the load of organic material in domestic wastewater, the major fraction of the nutrients such as nitrogen and phosphorus, and can be collected with a small amount of water when vacuum toilets are used (Graaff et al., 2010). The grey water will be collected and discharged into the constructed wetland, and this water will start another cycle. The black water will be treated through anaerobic treatment in a UASB reactor, which by converting organic matter into methane, produces electricity and heat (please refer to Setion 6.4.3). The UASB reactor connects the energy and water flows. The excess of sludge will be treated and used as a fertilizerin the greenhouse (it is not going to be assessed in the present thesis, because it is part of the nutrient cycle that is out of the scope). 6.4.7. BIODIVERSITY In this scenario, the biodiversity area is composed of greenhouses and constructed wetlands. Both have a stipulated function related to human functions in the Biotope. Therefore, both are controlled green areas, with the implementation of specific species that are able to cope with the determined functions (Table 58). Table 58. Biodiversity variations in the Biotope and Sunrise Campus implantation areas in the ‘Producer Scenario’.
green roof not controlled garden pond constructed wetland controlled greenhouse Total
SUNRISE CAMPUS 0 0 6.000 6.000 20.000 32.000
m² m² m² m² m² m²
BIOTOPE 0 0 6.000 6.000 20.000 32.000
m² m² m² m² m² m²
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SCENARIOS The total area for the wetlands and ponds is 12.000m2 (Figure 28). It was assessed that half of this area is constructed wetland, and work as a part for the water treatment system and is classified as a controlled green area. The other half is the retention pond that works as a water storage and is a not controlled area. The total greenhouse area is 20.000m². 6.4.8. ‘PRODUCER SCENARIO’: ASSESSMENT Like in the previous scenarios, the energy and water are resumed into three different indices that are explained in Section 3.1: demand minimization (DMI), waste output (WOI) and self‐sufficiency (SSI). For the ‘Producer Scenario’, they are expressed in Table 59. Furthermore, biodiversity is evaluated according to two different indices: green area (GAI) and local species (LSI), for the Biotope’s and Sunrise Campus implantation areas. These indices are also explained in Section 3.2 and are expressed in Table 60. Energy The ‘Producer Scenario’ has considerably minimized its energy demand, achieving a DMI of 0,63. Producing energy is a crucial feature in this scenario. The total energy produced by the greenhouse, PV windows, PV cells and anaerobic digestion is assessed as multisource. There are no cascading and recycling strategies for the energy system in this scenario. Like in the previous scenarios, the WOI is ‐1, because strategies such as energy cascading or recycling are absent and the output and consumption are not minimized. The SSI becomes 1,17, which means that this scenario is able to produce more energy than is needed, and it becomes an energy exporter. The heat and electricity consumption is smaller than their demand. In both cases the Biotope becomes an exporter. Water The water demand is increased when compared to the ‘Efficient Scenario’, due to the greenhouses inside the buildings, and the DMI becomes 0,33. The rain water is harvested and used for irrigation in the greenhouses. After treated, it becomes drinking water and is reused in the Biotope. From there, the grey water is treated and enters back to the cycle. To assess the recycled water, the total water demand was multiplied by the discharge coefficient 0,8 (Kujawa‐Roeleveld et al., 2010). The multisource (rain water) is the other 20% that is to be harvested. Table 59. Energy and water assessment for the ‘Producer Scenario’.
Conventional Demand (Do) New Demand (D) Cascade (C) Recycle(R) Consumption (Co) Multisource (M) DMI= (Do‐D)/Do WOI=‐(D‐C‐R‐Co)/D SSI=(C+R+M)/D
PRODUCER ENERGY 3.590 1.339 0 0 0 1.562 INDICES 0,63 ‐1,00 1,17
MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr MWh/yr
PRODUCER WATER 4.992 3.354 0 2.682 0 671
m³/yr m³/yr m³/yr m³/yr m³/yr m³/yr
0,33 ‐0,20 1,00
81
SCENARIOS Although the water demand increases due to irrigation water, recycling is also enhanced by the use of the ‘greenhouse village’. As a result, the WOI is ‐0,33. This represents that 66% of the wastewater is re‐introduced to the system. Finally, the SSI is 1,00, indicating that the water flow in this scenario has a circular metabolism. Biodiversity The biodiversity area in this scenario is considered to be the greenhouses and constructed wetlands which are considered to be controlled, and ponds that are not controlled. This results in the LSI of 0,19 for both Biotope and Sunrise Campus. On the other hand, the GAI in the Sunrise Campus is 0,16 and in the Biotope is 0,53, i.e. the total green area corresponds to 16% of the Sunrise Campus implantation area, whereas it also corresponds to 53% of the Biotope ’s area. Table 60. Biodiversity assessment for the ‘Producer Scenario’.
SUNRISE CAMPUS
Implantation area (A) Not controlled green (NCG) Controlled green (CG) Total green (T) GAI = T/A LSI = T‐CG/T
202.900 6.000 26.000 32.000 0,16 0,19
m² m² m² m²
BIOTOPE 60.500 6.000 26.000 32.000 0,53 0,19
m² m² m² m²
82
SCENARIOS 6.5.
SCENARIO 5 – HYBRID
The ‘Hybrid Scenario’ brings together all the other scenarios’ features: efficiency, biodiversity and productivity. This scenario is able to balance these three characteristics. It joins the best results from the previous scenarios, at the same time that it connects the different flows in the Sunrise Campus. The implementation of green roofs, green walls and internal gardens in its design makes it similar to the ‘Bio‐diverse Scenario’. Moreover, this scenario is also seen as a producer of energy and water that it is done by the implementation of the ‘greenhouse village’, PV windows, PV cells, anaerobic digestion and ATES system. Indeed, food production in greenhouses is also present in this situation. Moreover, the Hybrid Biotope is a producer of drinking and irrigation water that will satisfy all of the Biotope’s water demand. N
Figure 34. 'Hybrid Scenario’: plan view
83
SCENARIOS The Hybrid Biotope is a block divided into seven sub‐blocks (Figure 34 and 35). Their functions are intertwined by human functions, internal gardens and greenhouses. Each sub‐block has a footprint of 2.817,5m². The design was solved with the purpose of achieving the maximum sunlight in the greenhouses and human functions sub‐blocks. Based on the ‘Efficient Scenario’, the length of each sub‐block (35m) is more than three times the height of the building (11,5) (please refer to Section 6.1 for detailed information). The human function and greenhouses sub‐blocks contain three stories, whereas the garden halls are located only on the ground floor (Figure 35). They are located in between the other sub‐blocks, and the sun rays are not obstructed. The two human function blocks are covered with green roofs and green external wall (East and West walls) and are located in the center of the building. In the extremity of the Biotope, greenhouses are implemented and they will produce food and heat for the human function blocks. The greenhouses and garden blocks will be covered with PV windows on their roofs, as well as the South façades. The main design characteristics of the ‘Hybrid Scenario’ are:
Biotope area: 31.250m²; human function area: 12.500m²; Greenhouse area: 12.500m²; Garden area: 6.250m² Biotope roof area: 14.577,5m² Number of workers: 960 Building orientation: East‐West axis. The building is divided in 7 blocks: 2 human function (3 stores); 2 greenhouse (3 stores); 3 gardens (1store) The length of the blocks (34,5m) is 3 times their height (11,5m) (Figure 35). Sunrise Campus buildings: mix of the use of the roofs between PV cells (this is not going to be assessed because each building uses its produced energy) and green roofs.
Figure 35. ‘Hybrid Scenario’: Schematic Section AA. L (length)> 3 x h (height), to allow passive heating and sunlight.
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SCENARIOS 6.5.1. ENERGY FLOW The energy system is very similar to the ‘Producer Scenario’. It comprises of a closed greenhouse (a greenhouse that does not release excess heat through ventilation); heat exchangers in the greenhouse, an ATES system, a piped heat distribution system to greenhouses and human functions sub‐blocks, a heating and cooling system consisting of floor and ceiling pipes in the human functions sub‐blocks, and a cooling tower. Moreover, PV windows are to be implemented in the South façade and on the roof of the blocks of greenhouses. PV cells are also to be implemented, but they will be placed on the green roofs, enabling the production of energy and enhancement of biodiversity at the same time. Finally, anaerobic digestion of kitchen, garden and black water are to generate heat and electricity (Figure 36). The choice of adding green roofs in the human function blocks will create a different scenario for the energy flow when compared to the ‘Producer Scenario’ (please refer to Section 6.3.2 for the comparison between the implementation of the ATES system combined with green roofs and its implementation when not combined with green roofs). Although the efficiency of the ATES system is reduced, it still is an important factor for the reduction of the demand in this scenario. Moreover, the implementation of green roofs is crucial for the enhancement of the biodiversity in this scenario (please refer to Section 6.5.7).
Figure 36. ‘Hybrid Scenario’: energy flow. 1. 2. 3. 4. 5. 6.
PV windows Green roof and PV cells Insulation materials, use of LED lamps, CPU management (in the human function blocks) Green house: heat produced is used in human functions of the Biotope. Green waste production. Internal gardens: heat produced is used in human functions of the Biotope. Green waste production. ATES FiWiHEx System: responsible for heat exchanges between the greenhouse, gardens and human function blocks 7. Use of vacuum toilets for separation of the water streams. The organic waste (black water, food and greenhouse waste) from Biotope is added to two anaerobic digesters (one for solid waste and the other for black water) 8. Anaerobic digesters 9. Energy (heat and electricity) produced in the anaerobic digester is used in the Biotope 10. Extra electricity production is exported to other buildings
85
SCENARIOS 6.5.2. ENERGY DEMAND MINIMIZATION In this Section, the technologies that were taken into consideration in the ‘Hybrid Scenario’ and their implementation are explained. They are listed in Table 61 after which they are explained. The energy demand minimization follows the same issues for lighting, office equipment, passive ventilation, and insulation materials as the ‘Efficient Scenario’ (for more detailed date please refer to Section 6.2). Besides that, green roofs are added in the human function blocks, and the energy demand minimization that they generate is assessed like in the ‘Bio‐diverse Scenario’ (a). The heating and cooling system is connected to an energy producing greenhouse and their calculation follows as in the ‘Producer Scenario’. However, in this scenario, the green roofs are combined with ATES system, which reduces its efficiency (please refer to Section 6.3.2). For the assessment, it was first taken into account lighting reductions with passive lighting and dimming control. Second, the use of LED lamps instead of regular incandescent bulbs was considered. Third, the cooling and heating demand were minimized, by the implementation of passive ventilation and insulation materials in the buildings envelope, and green roofs. Lastly, the ATES system was assessed, reducing the remaining heating and cooling demand. Table 61. Implemented technologies to energy demand minimization in the ‘Producer Scenario’.
TECHNOLOGY
LIGHTING
OFFICE EQUIPMENT
COOLING
HEATING
REDUCTION Literature Source
passive lighting and diming control use of led lamps instead of regular incandescent bulb
40,00%
(Bodart et al., 2002)
90,00%
(MacKay, 2008)
CPU management and standby and active mode power reductions for computers insulation materials green roof ATESFiWiHEx
40,00%
(Waide et al., 2007)
10,00% 75.00% 100,00%
insulation materials: floors, walls, windows and roofs
40,00%
(MacKay, 2008) (Liu et al., 2003) (Bridger et al., 2005); (Nieuwenhuize, 2011); (Mels et al., 2010) (MacKay, 2008)
green roof
15.00%
(Liu et al., 2003)
ATESFiWiHEx
16,47%
(Bridger et al., 2005); (Nieuwenhuize, 2011); (Mels et al., 2010)
(1) Lighting demand minimization (please refer to ‘Efficient Scenario’ for detailed data) (2) Office Equipment energy demand minimization (please refer to ‘Efficient Scenario’ for detailed data) (3) Heat and cold demand minimization a. Insulation materials (please refer to ‘Efficient Scenario’ for detailed data) b. Green roof (please refer to ‘Bio‐diverse Scenario’ for detailed data) c. ATES FiWiHEx (please refer to ‘Producer Scenario’ for detailed data)
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SCENARIOS The lighting demand, office equipment and others demand minimization are to be the same as in the ‘Efficient Scenario’ and they are not to be assessed in this Section (please refer to Section 6.2 for the referred assessment). In this section, heat and cold demand will be assessed. For the cooling and heating demand assessment, it was first reduced the demand by the implementation of insulation materials. The remaining demand was minimized by the use of the ATES FiWiHEx system. Then, the green roof implementation was considered, which was able to reduce 396MWh of the yearly demand. After that, it was considered that the cooling reduction in the ATES FiWiHEx system is 100% (Kristinsson, et al., 2008). This corresponds to a reduction of 132MWh. The same load of energy (132MWh) was reduced from the heating demand, which represents 16,47% out of the total heating demand. The total cooling demand per year is zero, whereas the heating demand is 549MWh/yr. Table 62 expresses the results of the implementation of the technologies explained above for heating and cooling demand minimization. After that, the energy spent by the pumps needed for the system was added to the calculation. Please refer to Section 6.2.2 for more details of this calculation. Table 62. Yearly heat and cold minimization assessment for the ‘Hybrid Scenario’.
COOLING ‘BAU SCENARIO’ DEMAND TECHNOLOGY
586
MWh
REDUCTION
NEW DEMAND
passive night ventilation
10%
528
MWh
(Kolokotroni et al., 2006)
Green roof
75%
132
MWh
(Liu et al., 2003)
100%
0
MWh
(Mels et al., 2010)
0
MWh
1335
MWh
ATES FiWiHEx COOLING ‘HYBRID SCENARIO’ DEMAND
LITERATURE SOURCE
HEATING ‘BAU SCENARIO’ DEMAND TECHNOLOGY
REDUCTION
NEW DEMAND
insulation materials
40,00%
801
MWh
(MacKay, 2008)
Green roof
15,00%
681
MWh
(Liu et al., 2003)
ATES FiWiHEx
16,47%
549
MWh
(Mels et al., 2010)
549
MWh
HEATING ‘HYBRID SCENARIO’ DEMAND
LITERATURE SOURCE
PUMPS DEMAND
ATES FiWiHEx cooling pumps (COP 4)
2,5%
13
MWh
ATES FiWiHEx heat pump (COP 40)
2,47%
33
MWh
ATES FiWiHEx pumps (COP 4)
0,25%
3
MWh
TOTAL PUMPS DEMAND
49
MWh
(Bridger et al., 2005) (Nieuwenhuize, 2011)
(4) Others demand minimization The others demand in the ‘Hybrid Scenario’ is not minimized and it is assessed like in the ‘Efficient Scenario’. Please refer to Section 6.2 for more detailed information. In addition, the pumps energy demand of the ATES FiWiHEx system is added to it. The pumps have a total demand of 49MWh/yr, in the form of electricity. Therefore, this amount of energy is added to the ‘others demand’. In the 87
SCENARIOS ‘BAU Scenario’, the ‘others demand’ is 546MWh/yr (Table 12), and in the ‘Hybrid Scenario’ it is 595MWh/yr. (5) Total ‘Hybrid Scenario’ demand The total energy demand for the ‘Hybrid Scenario’ is 1.506MWh. The electricity use is responsible for 908MWh whereas the heat and cold are responsible for 549MWh of the energy use (Table 63). Table 63. Energy demand per year in the ‘Hybrid Scenario’ for each use and the total demand.
Energy Lighting Office Equipment Cooling Heating Others NEW ELECTRICITY DEMAND HEAT/COLD DEMAND NEW ENERGY DEMAND
Total energy demand/yr 35 327 0 549 595 908 598 1.506
MWh MWh MWh MWh MWh MWh MWh MWh
6.5.3. ENERGY PRODUCTION In the ‘Hybrid Scenario’, energy is produced through all possible technologies on site. Electricity is produced by using PV windows. Organic waste bio‐digestion produces heat and power (CHP). In this scenario, black water from all the buildings in Sunrise Campus and organic waste from food production are added to the bio‐digestion process. Finally, besides producing food and organic matter for bio‐digestion, the greenhouses also generate heat for the human functions of the Biotope. (1) PV windows The area of the South façade in the ‘Hybrid Scenario’ has 684m². PV windows are also added to the roofs of the gardens and greenhouses sub‐blocks, which has the footprint of 10.412m². The assessment of the energy production of PV windows follows the same as in the other scenarios Please refer to ‘Efficient Scenario’ for more detailed data. The total electricity produced by PV windows is 447MWh/year (Table 64). Table 64. PV windows energy production in the ‘Hybrid Scenario’ per year.
TECHNOLOGY AREA (roofs of gardens and greenhouses, and South façade) PV WINDOW 11.096 m²
AVERAGE POWER DELIVERED 4,6 W/m²
ELECTRICITY PRODUCTION 447 MWh
LITERATURE SOURCE (Schueco, 2011)
(2) PV cells PV cells will be placed on the green roofs. This enables the production of energy, and the enhancement of biodiversity at the same time (Figure 37). It was considered that the PV cell area is half of the green roof area. Thus, the total green roof area is 4.000m² and the PV cells area is
88
SCENARIOS 2.000m². The total electricity produced in one year by PV cells in the ‘Hybrid Scenario’ is 193MWh (Table 65). Table 65. PV cells energy production in the ‘Hybrid Scenario’ per year.
TECHNOLOGY PV cells
AVERAGE POWER DELIVERED 11 W/m2
AREA (figures 28 and 29) 2.000 m2
ENERGY PRODUCTION 193 MWh
LITERATURE SOURCE (MacKay, 2008)
Figure 37. PV cells installed on green roofs. Source: Swale Borough Council, 2011.
(3) Anaerobic digestion In the ‘Producer Scenario’ the anaerobic digestion works with three different streams: garden waste, kitchen waste and black water. For that, two different digesters are to be used. For the treatment of food and garden waste an anaerobic digestion that operates with high solids reactors (up to 30%) is to be implemented (please refer to Section 6.3.3). At the same time, another reactor, a UASB reactor, that is suitable for diluted and concentrated wastewater, is to be used. a. Food and garden waste The kitchen waste follows the same calculation as in the ‘Bio‐diverse Scenario’ (please refer to Section 6.3.3 for more detailed data). The total waste food production in the Biotope is 19.754kg (Table 35). The total amount of green areas from green roofs in the Sunrise Campus is 82.875m² (see Section 6.5.7). Therefore, the total amount of green waste produced annually in the Sunrise Campus in the ‘Hybrid Scenario’ is 28.178kg (Table 66) (please refer to Section 6.3.3 for more detailed data of the calculation). Table 66. Green waste produced yearly in the ‘Bio‐diverse Scenario’.
Garden waste
Waste production
Green area
0,34 kg/m² 28.178 m²
Total waste produced 28.178 kg
LITERATURE SOURCE (Lundie et al., 2005); Section 3.5.7 (green areas)
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SCENARIOS Table 67. Yearly combined heat and power from anaerobic digestion of organic waste.
Total organic waste 47.932 kg
energy Total production rate Energy potential 1,92MWh/ton 92MWh
Total energy Total heat Total available for produced electricity CHP produced 78MWh 47MWh 31MWh
LITERATURE SOURCE (Kujawa‐Roeleveld et al., 2010); (Graaff et al., 2010)
It follows that the total amount of the garden and food waste produced by the Biotope and Sunrise Campus in this scenario is 47.932kg/year, which are to be digested through anaerobic treatment. It is assumed that the energy production of anaerobic digestion is 200m³ per ton (Kujawa‐Roeleveld et al., 2010), which is equal to 1,92MWh/ton of waste (conversion factor of 0,00961 (Graaff et al., 2010)). When the full amount of organic waste produced in the Biotope is treated though anaerobic digestion, it yields 92MWh of potential energy per year. Combined heat and power (CHP) generation systems can be used to produce heat and electricity at an efficiency of 85% (of which 40% electricity and 60% heat) (Graaff et al., 2010). This would result in a production of 47MWh of electricity and 31MWh of heat on an annual base (Table 67). b. Wastewater The black water is assessed as in the ‘Producer Scenario’ (please refer to Section 6.4.3). The total Biotope energy production from anaerobic digestion of black water is 18MWh/year, and in the Sunrise Campus is 82MWh/year, from which 40% is electricity and 60% is heat (please refer to Section 6.3.3 for detailed calculation) (Table 68). Table 68. Yearly energy production from anaerobic treatment in the ‘Hybrid Scenario’.
Type of waste Kitchen and garden waste Black water Total energy Total electricity Total heat
Energy production Energy production Sunrise Biotope (MWh/yr) Campus (MWh/yr) 78 0 18
82
96
82
Total (MWh/yr)
178 71 107
literature source (Graaff et al., 2010) (Anaerobic Digestion, 2011) (Liu et al., 2003)
In the Producer Scenario, the total energy production, in one year, of kitchen and garden waste, and black water is 178MWh, from which 71MWh is electricity and 107MWh is heat.
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SCENARIOS (4) ‘Greenhouse Village’ The greenhouse production of energy is assessed in the same way as in the ‘Producer Scenario’ (please refer to Section 6.4.3). The greenhouse and internal garden areas are seen as heat producers. Together they have a total area of 18.750m² (please refer to Section 6.5.7). As a result, this system provides a total of 332MWh of heat per year (Table 69). Table 69. ‘Greenhouse village’ energy production in the ‘Hybrid Scenario’ per year.
TECHNOLOGY ‘GREENHOUSE VILLAGE’
GREENHOUSE AREA 1,87 ha
EFFICIENCY 176,82
MWh/ha
HEAT PRODUCTION 332 MWh/yr
LITERATURE SOURCE (Mels et al., 2010) (SenterNovem, 2007)
The following table expresses the main technologies used for the production of energy in the ‘Hybrid Scenario’. The total energy produced by the Biotope is 1.150MWh per year, from which 711MWh is in the form of electricity and 439MWh as heat. Table 70. Total yearly energy production on the ‘Hybrid Scenario’.
TECHNOLOGY
HEAT
ELECTRICITY
ANAEROBIC DIGESTION
107
MWh
71
MWh
PV WINDOW PV CELL ‘GREENHOUSE VILLAGE’ TOTAL 1.150MWh
0 0 332 439
MWh MWh MWh MWh
447 193 0 711
MWh MWh MWh MWh
Literature Source (Graaff et al., 2010), (Anaerobic Digestion, 2011) (Schueco, 2011) (MacKay, 2008) (Mels et al., 2010)
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SCENARIOS 6.5.4. WATER FLOW The water management in the ‘Hybrid Scenario’ is similar to the ‘Producer Scenario’. The demand is reduced through the installation of water efficient appliances. Moreover, the surface water runoff is managed minimizing local hydrological impact. Like in the ‘Producer Scenario’, the ‘greenhouse village’ system will be implemented. This system is able to treat the wastewater and to produce drinking water. It is done through the collection and treatment of the condensation of the irrigation water that evaporates. The drinking water is to be used by the human functions of the Biotope. Figure 38 represents the water flow in the Biotope for the ‘Hybrid Scenario’. Please refer to the ‘Producer Scenario’ for more details of the ‘greenhouse village’ system. In the ‘Hybrid Scenario’, the demand of the water flow differs from the ‘Producer Scenario’, because of difference in green areas within the Biotope.
Figure 38. ‘Hybrid Scenario’: water flow 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
The rain water is collected from roofs and permeable pavements. It is pre‐treated in constructed wetlands and stored in retention ponds (Q2). The grey water from the human functions in the Biotope is treated in a bioreactor (Q2). Water irrigation tank (Q2). Greenhouse irrigation (Q2), water condensation, collection and reuse (Q2). 15% of the water is discharged into the public sewage system. Filtration activated carbon, re‐hardening and quality monitoring (Q1). Drinking water tank (Q1). Drinking water is distributed to Sunrise Campus buildings. Within each building, water is consumed. Grey water collection and discharge into open wetlands. The water starts another cycle. Vacuum toilets are used in the buildings and the black water is collected and sent to a UASB reactor, where it is digested and energy is produced. 13. UASB reactor.
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SCENARIOS 6.5.5. WATER DEMAND MINIMIZATION The greenhouses water consumption is added to the new demand (Table 71). The water demand minimization in this scenario follows by the use of efficient faucets and vacuum toilets. The water consumption for the faucets are assessed as in the ‘Efficient Scenario’ (please refer to Section 6.2.5 for more details). In addition, vacuum toilets are used and are assessed as in the ‘Producer Scenario’ (please refer to Section 6.4.5 for details in the calculation).The tables below show the results of the use of the mentioned technologies in the ‘Hybrid Scenario’ and the new water demand and uses respectively. Table 71. Implemented technologies to water demand minimization in the ‘Hybrid Scenario’.
faucets toilet flush TOTAL
BAU DEMAND 541 m³/yr 3.787 m³/yr 4.328 m³/yr
REDUCTION 26% 73% 72%
NEW DEMAND 180 m³/yr 1.010 m³/yr 1.190 m³/yr
LITERATURE SOURCE (Agudelo‐Vera et al., 2011) (Lazarus, 2009)
Table 72. Water demand in the ‘Hybrid Scenario’ for each use and the total demand per year
BIO‐DIVERSE DEMAND
drinking water, coffee and tea
184
m³
hygiene
180
m³
toilet flush
2.020
m³
dishwasher
306
m³
food processing
174
m³
greenhouse
937
m³
2.791
m³
TOTAL DEMAND
6.5.6. MULTISOURCE AND RUNOFF MANAGEMENT Multisource and runoff management follows the same as in the ‘Producer Scenario’. Please refer to this scenario for detailed information. 6.5.7. BIODIVERSITY The ‘Hybrid Scenario’ is at the same time a producer of clean energy and water and a place where biodiversity is generated. The green areas are given high importance. Not controlled areas are present in this scenario in the form of green roofs (in the Biotope and other buildings in Sunrise Campus), green walls and internal gardens. The wetlands and greenhouses are considered controlled green areas. The total amount of green areas in the Sunrise Campus is 82.875m² and 34.100m² in the Biotope implantation area (Table 73). Table 73. Biodiversity variations in the ‘Hybrid Scenario’.
green roof/wall not controlled garden pond constructed wetland controlled greenhouse Total
SUNRISE CAMPUS 42.525 6.250 10.800 10.800 12.500 82.875
m² m² m² m² m² m²
BIOTOPE 5.775 6.250 10.800 10.800 12.500 46.125
m² m² m² m² m² m²
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SCENARIOS 6.5.8. ‘HYBRID SCENARIO’: ASSESSMENT Like in the previous scenarios, the energy and water are resumed into three different indices that are explained in Section 3.1: demand minimization (DMI), waste output (WOI) and self‐sufficiency (SSI). For the ‘Hybrid Scenario’, they are expressed in Table 74. Furthermore, biodiversity is evaluated according to two different indices: green area (GAI) and local species (LSI), for the Biotope’s and Sunrise Campus’ implantation areas. These indices are also explained in Section 3.2 and are expressed in Table 75. Energy The ‘Hybrid Scenario’ has considerably minimized its energy demand, achieving a DMI of 0,58. The total energy produced by the greenhouses, PV windows, PV cells and anaerobic digestion is assessed as multisource. Like in the previous scenarios, the WOI is ‐1, because strategies such as energy cascading or recycling are absent. Moreover, the output and consumption factors are not minimized. The SSI becomes 0,76, which means that this scenario is almost able to produce 76% of its demand. However, it still needs to import electricity and heat. Water The water demand has decreased when compared to the ‘Producer Scenario’. This happens because the green area within the Biotope is smaller in the ‘Hybrid Scenario’. With the implementation of efficient faucets and vacuum toilets, the DMI is 0,44. The rain water is harvested and used for irrigation in the greenhouses. After treated, it becomes drinking water and is reused in the Biotope. From there, the grey water is treated and enters back to the cycle. To assess the recycled water, the toilet and irrigation water are summed. The multisource (rain water) is the difference between the new demand and the recycled water. The rain water is harvested and used for irrigation in the greenhouses. After treated, it becomes drinking water and is reused in the Biotope. From there, the grey water is treated and enters back to the cycle. To assess the recycled water, the total water demand was multiplied by the discharge coefficient 0,8 (Kujawa‐Roeleveld et al., 2010). The multisource (rain water) is the other 20% that is to be harvested. Moreover, the WOI is ‐0,20. This represents that 80% of the wastewater is re‐ introduced to the system. Finally, the SSI is 1,00 representing that the Biotope is totally self‐ sufficient in relation to its water demand. Table 74. Energy and water assessment for the ‘Hybrid Scenario’ per year.
Conventional Demand (Do) New Demand (D) Cascade (C) Recycle(R) Consumption (Co) Multisource (M) DMI= (Do‐D)/Do WOI=‐(D‐C‐R‐Co)/D SSI=(C+R+M)/D
HYBRID ENERGY 3.590 1.506 0 0 0 1.150 INDICES 0,58 ‐1,00 0,76
HYBRID WATER MWh MWh MWh MWh MWh MWh
4.992 2.791 0 2.233 0 558
m³ m³ m³ m³ m³ m³
0,44 ‐0,20 1,00
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SCENARIOS Biodiversity In the ‘Hybrid Scenario’, not controlled green areas are present in this scenario in the form of green roofs (in the Biotope and other buildings in Sunrise Campus), green walls and internal gardens. The wetlands and greenhouses are considered controlled green areas. As a result, the GAI for the Sunrise Campus and for the Biotope are 0,41 and 0,76 respectively, i.e. the total green area corresponds to 41% of the Sunrise Campus implantation area, whereas it also indicates 76% of the Biotope ’s area. The local species index in the Sunrise Campus is 0,72 and 0,49 in the Biotope . These numbers show the balance between controlled and not controlled green areas in both the campus and the building. Table 75. Biodiversity assessment for the ‘Hybrid Scenario’.
SUNRISE CAMPUS
Implantation area (A) Not controlled green (NCG) Controlled green (CG) Total green (T) GAI = T/A LSI = T‐CG/T
202.900 59.575 23.300 82.875 0,41 0,72
m² m² m² m²
BIOTOPE 60.500 22.825 23.300 46.125 0,76 0,49
m² m² m² m²
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DISCUSSION 7. DISCUSSION Aiming at understanding an effective way of designing a building that avoids possible damages that it can cause to the surrounding environment, such as depleting ecosystems and bio‐chemical cycles on which it depends, four scenarios were developed and compared to the ‘BAU Scenario’. They were evaluated according to the three tenets of the ‘Cradle to Cradle’ theory (waste equals food, celebrate diversity, and use Solar income). These criteria are summarized in three indices for energy and water, and two for biodiversity (please refer to Section 3). The results of the assessment of all the scenarios are described in Table 76 and Figures 39 to 41. For the energy assessment, the demand minimization index is similar for the ‘Efficient’, ‘Bio‐diverse’, and ‘Hybrid’ scenarios. They achieve more than 50% of demand minimization by using the chosen technologies. The ‘Producer Scenario’ has achieved a higher DMI than the other scenarios. This happens because of the implementation of the ATES FiWiHEx in combination with greenhouses which allowed it to achieve a 100% reduction of the energy used for cooling in the building. Although the ‘Hybrid Scenario’ uses the same system, its DMI is lower. This is because the fact that the minimization of the heating demand drops significantly with the implementation of green roofs (from 66% in the ‘Producer Scenario’ to 16% in the ‘Hybrid Scenario’). This happens because the green roof implementation generates an eminent imbalance in the annual heat and cold demand. At the same time, the ATES system does not produce heat, but it balances the heat and cold within a building throughout the year. The great difference in insulation in different seasons creates a misbalance in the ATES system. As a result of considerable reduction of the cooling demand, the heating efficiency of the ATES system becomes very low. Table 76. Results of energy, water and biodiversity assessment. Demand Minimization (DMI), Waste Output (WOI), Self‐ sufficiency (SSI), Garden Areas (GAI) and Local Species (LSI) indices.
BAU
EFFICIENT
BIO‐DIVERSE
PRODUCER
HYBRID
0,52
0,63
0,58
DMI= (Do‐D)/Do
0,00
energy 0,55
WOI=‐(D‐C‐R‐Co)/D
‐1,00
‐1,00
‐1,00
‐1,00
‐1,00
SSI=(C+R+M)/D
0,00
0,29
0,12
1,17
0,76
DMI= (Do‐D)/Do
0,00
water 0,43
0,33
0,33
0,44
WOI=‐(D‐C‐R‐Co)/D
‐1,00
‐1,00
‐0,40
‐0,20
‐0,20
SSI=(C+R+M)/D
0,00
0,14
0,75
1,00
1,00
GAI = T/A
biodiversity‐ Sunrise Campus 0,06 0,15 0,67
0,16
0,41
LSI = T‐CG/T
1,00
0,94
0,19
0,72
GAI = T/A
0,21
biodiversity‐ Biotope 0,51 1,08
0,53
0,76
LSI = T‐CG/T
1,00
0,19
0,49
1,00
1,00
0,87
96
DISCUSSION 1,20 1,00 0,80 DMI
0,60
SSI 0,40 0,20 0,00 BAU
EFFICIENT BIO‐DIVERSE PRODUCER
HYBRID
Figure 39. Energy results: DMI and SSI. The WOI is not represented because it has the same value (‐1,00) for all scenarios.
In all scenarios, including the BAU, the waste output indices for energy have the same value. This happens because energy cascading and recycling are not used in any of the scenarios. Cascading energy is possible by using high quality energy only for purposes that require it, and lower quality energy where this will suffice. By linking various energy producing and consuming functions, a cascade can be formed (Dobbelsteen et al., 2010). In the functions Biotope of the different scenarios, it was not possible to create such a link. However, for further studies, cascading energy should be re‐ evaluated, however, in a bigger scale than the Biotope scale. There, it would be possible to link industrial and human functions by energy cascading. Furthermore, the losses of electrical and heating appliances are neglected (please refer to Section 3.1). Consequently, their consumption remains the same. For further analysis, a more detailed study of each electrical/heating appliance should be done, in order to establish different consumptions for each scenario (Figure 39). The self‐sufficiency indices represent the use of renewable resources in relation to the demand of each scenario. The ‘Efficient Scenario’ achieves a moderate self‐sufficiency (0,29) in energy which represents its intention towards overall positive effects in the building’s design. However, the ‘Bio‐ diverse Scenario’ shows a shy result for its self‐sufficiency in energy (0,12). This scenario opts for bringing as much as biodiversity as possible in detriment of energy production. The energy is only produced from digestion of solid organic waste and PV windows that are to be installed in the South facades. The energy production of the digestion of solid waste was very low, representing only 6% of the total energy demand in this scenario. This explains why the result of the SSI for the ‘Bio‐diverse Scenario’ is not as pleasing as in the other scenarios. Still, the energy production can be augmented by importing organic waste from the outside of the boundaries of the study area. At the same time, the ‘Producer Scenario’ achieves a very high index for self‐sufficiency (1,17), and it becomes an energy exporter. PV cells in the sub‐scenario (a) showed themselves very efficient when compared to the wind turbines in the sub‐scenario (b). The PV cells produce more than ten times energy than the wind turbines. Therefore, because of their low‐efficiency, wind turbines were not considered in any scenario.
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DISCUSSION Finally, the ‘Hybrid Scenario’ achieves a very high grade of self‐sufficiency (0,76), although it still needs to import electricity and heat to meet its demand. In all the assessments, the efficiency of the PV cells considered was 10%. This is, according to Mackay, the efficiency of “very cheap” and “lower‐ efficiency panels” (MacKay, 2008, pp. 41). He also states that “typical solar panels have an efficiency of about 10%; expensive ones perform at 20%” (MacKay, 2008, pp. 47). The “cheap” technology was chosen because it is more accessible. However, if the PV cells were to produce twice the electricity assessed in the Section 6.5.3, the electricity produced would suppress the demand. It is up to the stakeholders to define the budget that they want to spend on the buildings construction. However, if the cheapest PV cells are to be implemented, another solution for this scenario to become totally self‐sufficient would be to import organic waste to produce the needed electricity and heat.
1,00 0,75 0,50 0,25
DMI SSI
0,00
WOI
‐0,25 ‐0,50 ‐0,75 ‐1,00
BAU EFFICIENT BIO‐DIVERSE PRODUCER HYBRID
Figure 40. Water results: DMI, SSI and WOI for each scenario.
The water demand is also minimized in all scenarios by using efficient faucets and dual flush or vacuum toilets. However, the larger the green area within the Biotope, the higher is the water demand. The implementation of greenhouses and gardens diminish the DMI for the water (Figure 40). Moreover, in the ‘Producer’ and ‘Hybrid’ scenarios, where the ‘greenhouse village’ is implemented, obtain 100% of self‐sufficiency in water demand is obtained, representing that the total amount of water used is provided by the rain water harvest. Therefore, if on the one hand the implementation of the ‘greenhouse village’ increases the demand in water, on the other hand, the scenarios become more self‐sufficient and the waste output is minimized, bringing an overall positive effects. The water waste output index is not minimized in the ‘Efficient Scenario’. Nevertheless, with the implementation of recycling water strategies in the ‘Bio‐diverse’, ‘Producer’ and ‘Hybrid’ scenarios, the output is minimized. In the ‘Producer’ and ‘Hybrid’ scenarios, it achieves its peak, when the irrigation and toilet water are recycled by the ‘greenhouse village’ system. The ‘Producer Scenario’ achieves a better index (‐0,20), because it has a higher percentage of irrigation water in its demand. The self‐sufficiency is the ratio between resources harvested and the minimized demand (please refer to Section 3.1). Thus, if the SSI is less than 1, there is the necessity of importing external 98
DISCUSSION resources, generating a cost. On the other hand, if the SSI is greater than 1, there is a surplus in the production of energy which can be sold, generating profit. The resources that are not harvested by multisource, recycling and cascading are the external demand, which is imported to the system. The external demand and yearly expenses with energy and water demand are assessed in the following table for each scenario. The price of electricity for industrial consumption in 2011 in the Netherlands is considered €0,0975 per kWh of electricity and €0,0336 per kWh of natural gas (Europe's Energy Portal, 2011). The water is considered to cost €1,51 per cubic meter (Geuden, 2007). Table 77. Yearly expenses of external demand.
electricity (MWh) heat (MWh) water (m³) electricity (€) heat (€) water (€) Total (€)
1.BAU
2.Efficient
3.Bio‐diverse
4.Producer 5.Hybrid
EXTERNAL DEMAND 2.255 1.335 4.992
467 431 2.124
903 616 844 COST
‐52 ‐616 0
246 110 0
219.863 44.847 7.538 272.247
45.533 14.482 3.207 63.221
88.043 20.698 1.274 110.014
‐5.070 ‐20.698 0 ‐25.768
23.985 3.696 0 27.681
The total yearly expenses of the ‘BAU Scenario’ for electricity, heat and water that is imported from the system is €272.247. These expenses decrease 60% in the ‘Bio‐diverse Scenario’, 77% in the ‘Efficient Scenario’, and 56% in the ‘Hybrid Scenario’. In the ‘Producer Scenario’, the total demand of energy, water, and heat is smaller than the building’s demand. The excess is exported. Therefore, the expenses decrease 109%. However, to make a comprehensive cost analysis of the enterprise, different information should be added to this sheet. The buildings construction costs is extremely significant, as well as its maintenance expenses. For instance, the ‘Producer’ and ‘Hybrid’ scenarios, which have the cheapest annual expenses, have greenhouses and constructed wetlands in their design. The greenhouses need a great amount of constructed area, and both greenhouses and wetlands require workers to maintain them. Moreover, these scenarios are those that contain a higher number of technologies implemented, which will result in higher costs when compared to other scenarios. Thus, this estimate of expenses only represents the external demand of the Biotope, and a more detailed analysis should be done in a further step in order to evaluate the profitability of each scenario. Finally, the bio‐diversity indices express the amount and quality of the green areas in the Biotope and in the campus. As it is expected, the ‘Bio‐diverse Scenario’ achieves a better performance, accounting for more biodiversity area than the implementation area of the Biotope. Its LSI is also very high when compared to the others, promoting habitat for local species in the campus. This is due to the existence of internal gardens on different floors of the building and to the implementation of green roofs throughout the campus. In the ‘Producer Scenario’, in spite of the great amount of green areas in the Biotope, they are planned to produce food or clean water, and the local species index is decreased. The ‘Hybrid Scenario’ is able to mix a significant amount of
99
DISCUSSION green area with more than half of them being exclusively used to generate biodiversity in the Campus and in the Biotope (Figure 41). 1,2 1 0,8 0,6 0,4
GAI (Biotpe) LSI (Biotpe)
0,2 0
Figure 41. Biodiversity indicators (LSI and GAI) for the Biotope.
The energy and water cycle, and biodiversity were chosen to represent the scenarios evaluation. An analysis of the nutrient cycles should be also explored in further studies to create a more complete assessment. Moreover, the materials that will be used for the construction of the buildings play an important role in further evaluation. The materials should use as less energy as possible, avoid dioxide carbon emissions, discharge the least amount of waste production as possible, and use the least amount of land use as possible (for excavation and disposal). During the development of this thesis, the main difficulty was to find out how different technologies would work together, as for instance in the case of the green roofs and the ATES system. More studies should be made to understand the coexistence of these technologies. Moreover, although there was an effort for using consolidated technologies that are available in the market, some of the used technologies are still in study phase. This is the case of the ‘greenhouse village’. This system was only implemented partially and there are still some missing data of this technology. These cases should be re‐evaluated if they are to be applied in the future development of the Biotope and the Sunrise Campus. Furthermore, a range of technologies were selected from the ones that have commercial accessibility, available technical knowledge and that have been already tested. When these technologies were designated, others were excluded. Thus, there are still other technologies, that can always be joined to the current study, and improve the designs of the scenarios. In addition, the Biotope and the Sunrise Campus are interdependent (please refer to Section 2.3), and therefore another difficulty was to define the boundaries of the buildings’ design and assessment. Because of this relationship, and because the biodiversity cannot be measured only locally, the roof of other buildings were assessed for the biodiversity indices. Moreover, in the scenarios where the digestion of waste is present, the other buildings waste (within the Sunrise Campus) is used and they are not considered to be imported. When using the other buildings waste
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DISCUSSION to producing energy and clean water, this waste becomes “food” for the Biotope and for the Sunrise Campus. Finally, the approach used in this thesis managed to join two different evaluation methods. It takes the UHA method, and complements it with the biodiversity study of each design, bringing a comparison of the scenarios. If the two methods were to be done separately, the results would be different. On the one hand, according only to the UHA, the best overall results would be of the ‘Producer Scenario’, where the DMI, WOI and SSI for energy and water. On the other hand, if only the biodiversity is assessed, the ‘Bio‐diverse Scenario’ would be the best option, with the highest indices of green area and local species. The ‘Hybrid Scenario’ shows that a balance of these different characteristics is possible. Thus, it shows itself as a very suitable option. Hence, the approach suggested induces different solutions when managing the combination of different technologies that can be applied in such situations. It results on a consistent comparison between the scenarios. However, the scenarios and their calculation are still in a representative scale. The present thesis managed to bring an overall idea for decision making by handling different technologies and biodiversity in the campus and the building. Therefore, once the stakeholders define the most suitable scenario for them, the technical possibilities should be checked, and calculations of the determined scenario should be further detailed in every technology used. After that, the architecture project would be able to be developed and it will meet the desirable design results.
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CONCLUSION
8. CONCLUSION Urban systems are the world’s most significant users of resources and play a key role towards a sustainable development. To guarantee global sustainability, urban areas must be planned to manage their resources strategically (Agudelo et al., 2009). In this thesis, this strategic way of thinking was related to the three tenets of the ‘Cradle to Cradle’ theory, where a balance between the management of resources and the enhancement of the biodiversity in the study area was pursued. This equilibrium would be the most effective way for the Biotope to integrate society with its supporting environment. Therefore, aiming at understanding this balance in a building’s design, four scenarios were developed for the case study and compared to the ‘BAU’ situation. They were evaluated according to their capability of mimicking ecosystems, and they were designed towards a circular metabolic profile. Moreover, they were designed and evaluated according to their capability of harvesting and using the most renewable and local resources as possible. Finally, they were also planned to increase the diversity within the Sunrise Campus and the Biotope. All the scenarios aim at bringing feasible options for the Biotope, and vary in their design, spatial orientation, and multisource technologies. All of them intent to prevent the destruction and depletion of the surrounding environment, even though they still depend on resources such as energy, water and materials for their functioning. The human functions of all the developed scenarios remain as described in the Master Plan. However, different technologies were chosen and combined in different ways, according to the main objective of each scenario. The use of different technological functions brought out different results for energy, water and biodiversity assessments. Moreover, although the scenarios developed have different characteristics, all of them represent a step towards a more efficient design according to the three criteria stipulated. The four scenarios bring up possible solutions that balance differently the three tenets evaluated. In the scenarios with exchange of flows between functions, there are more possibilities for re‐using and recycling. In the search for a building design which at the same time mimics a circular metabolism, uses renewable resources and brings up biodiversity for its region, the ‘Hybrid Scenario’ took shape. Its design intends to mix the main features of the previous scenarios, achieving the center of their balance. It produces great amount of renewable energy and water, at the same time that it brings biodiversity to the Biotope and the Sunrise Campus. Even though it is not entirely self‐sufficient yet, it can become autarkic by implementing other technologies that are out of the selection of technologies of this thesis, or by importing organic waste. Concluding, by understanding the local resources and their flows, many technologies can be assembled in multiple ways with the objective of managing their connections. The design appears as the medium through which these technologies, human activities and ecosystems interact. By creating a balance between flows and functions, it is possible to generate a diverse, clean and healthy environment.
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REFERENCES
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ANNEX 1 – TECHNOLOGY INDEX Annex 1 – Technology index ENERGY TECHNOLOGIES
page
anaerobic digestion solid waste anaerobic digestion wastewater ATES ATES FiWiHEx CPU management green roofs greenhouse village insulation materials passive lighting and diming control PV cells PV windows solar tubes use of LED lamps wind turbines
62 78 46 74 43 57 80 45 42 48 48 42 43 81
WATER TECHNOLOGIES
page
anaerobic digestion wastewater constructed wetlands efficient faucets greenhouse village
78 66 50 80
Living Machine
66
low flush toilets vacuum toilets
50 79
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ANNEX 2 – POTENTIAL WATER APPLICATIONS (ASANO, 2006) Annex 2 – Potential Water Applications (Asano, 2006) GENERAL CATEGORY
POTENTIAL APPLICATION
Agricultural irrigation
Crop irrigation Commercial nurseries Public parks and school yards Roadway medians and roadside plantings Residential lawns Golf courses Cemeteries Greenbelts Industrial parks
Landscape irrigation
Industrial
Groundwater recharge
Recreation/environmental
Non‐potable urban uses
Indirect potable use
Cooling water Boiler feed water Process water Heavy construction (dust control, concrete curing, fill compaction, and cleanup) Groundwater replenishment Barrier against brackish or seawater intrusion Ground subsidence control Surface water augmentation Wetlands enhancement Fisheries Artificial lakes and ponds Snowmaking Toilet flushing Fire protection Air conditioning Sewer flushing Commercial car wash Driveway and tennis court wash down Blending with public water supplies (surface water or groundwater)
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ANNEX 3 – WATER APPLICATION QUALITIES AND VOLUMES IN SUNRISE CAMPUS BUILDINGS Annex 3 – Water application qualities and volumes in Sunrise Campus Buildings DEMAND TYPE QUALITY QUANTITY (m³/year) l/day WORKERS PRODUCTION industrial production drinking water, coffee and tea wash basin toilet flush dishwasher total human use OFFICES drinking water, coffee and tea wash basin toilet flush dishwasher total human use R&D industrial production drinking water, coffee and tea wash basin toilet flush dishwasher total human use BIOTOPE drinking water, coffee and tea wash basin toilet flush dishwasher food processing total human use OTHER USES car wash irrigation total human use Q1 total human use Q2 total human use Q3 total human use total industrial production
Q2 Q1 Q1 Q3 Q2 Q1 Q1 Q3 Q2 Q2 Q1 Q1 Q3 Q2 Q1 Q1 Q3 Q2 Q1 Q3 Q2 Q1 Q2 Q3 Q1+Q2+Q3 Q2
54.146 52.640 57 220 169 650 1.183 4.552 95 368 1.505 459 1.766 1.352 5.202 9.468 36.417 765 2.944 12.046 30.276 22.245 306 1.177 901 3.468 6.312 24.278 510 1.963 8.030 183 706 541 2.080 3.787 14.566 306 1.177 173 667 4.992 4.144 1.678 20.751 26.574 74.885
300
2400
1600
960
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ANNEX 4 – WATER CONSUMPTION IN WORKING ENVIRONMENTS IN THE NETHERLANDS. Annex 4 – Water Consumption in Working Environments in the Netherlands. Domestic water consumption 2007 in the Netherlands (Geudens, 2007)
l/ person.day
bath washbasin toilet flush washing, by hand washing, by machine washing up, by hand washing up, by machine
2,5 5,3 37,1 1,7 15,5 3,8 3
food preparation drinking coffee, tea and water
1,7 1,8
other total
5,3 127,5
office/ human use in production halls water consumption 2007 bath washbasin toilet flush washing, by hand washing, by machine washing up, by hand washing up, by machine food preparation drinking coffee, tea and water other total3
Human water consumption in working environments (l/ person.shift) 2,17 15,17 0 0 0 1,23 0,70 0,74 20
3
According to Cijfers en tabellen 2007, the average consumption of water in offices is 20l/day (SenterNovem, 2007)
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Acknowledgment First of all, I would like to thank my supervisor, Ingo Leusbrock, for all the time he spent with me. I would also like to thank my teachers, Claudia Agudelo‐Vera for her extensive support and her always helpful remarks and suggestions, and Ljiljana Rodic‐Wiersma, for broadening my vision and enriching the discussion of the thesis. Appreciation also goes to Bas van de Westerlo, for the inspiring discussions we had. I could not forget to thank my good friends for the cultural and knowledge exchange during this period. They were always by my side for whatever I needed, and I know they will be there for a long time. Thank you Jack, Yasmina, Sampurna, Maria and Taicia. Furthermore, I would like to thank my parents, Debora and Jakub, and my brothers, Daniel and Marcelo, who always made me feel that they were nearby, even though there is an ocean between us. Finally, I would like to thank my partner and friend, for bringing me to this country where I could learn so many good and new things. Ivan, thank you for everything!
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