periodical for the Building Technologist
PRAKTIJKVERENIGING
BOUT
student association for building technology
57. Energy
www.octatube.nl
Colofon
RUMOER 57 Februari 2014 21th year of publication Praktijkvereniging BouT Room 02.West.090 Faculty of Architecture, TU Delft Julianalaan 134 2628 BL Delft The Netherlands
RUMOER is a periodical from Praktijkvereniging BouT, student and practice association for Building Technology (AE+T), Faculty of Architecture, TU Delft (Delft University of Technology). This magazine is spread among members and relations. Circulation The RUMOER appears 3 times a year, 110 printed copies circulation. Digital versions are available online at: www.PraktijkverenigingBouT.nl
tel: +31 (0)15 278 1292 fax: +31 (0)15 278 4178 www.PraktijkverenigingBouT.nl rumoer@PraktijkverenigingBouT.nl
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Single copies Available at Praktijkvereniging BouT for € 7,50.
ISSN number 1567-7699 Credits Edited by: Text editing: Cover design:
Koen Fischer Reinier Scholten Jelmer Niesten Muhammed Ulusoy Koen Fischer Reinier Scholten Jelmer Niesten Koen Fischer
Sponsors Praktijkvereniging BouT is still looking for (main) sponsors. Sponsors make activities possible such as study trips, symposia, lectures and much more. There is also a possibility of advertising in the RUMOER: € 100,Black & White, full page Black & White, full page, 3x € 250,(once in every edition througout one year) € 200,Full color, full page
Cover image:
Head office WWF (Image courtesy by Kusters fotografie)
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Contents
Editorial
3
From the board
5
Introduction by Andy van den Dobbelsteen
8
Exergy by Sabine Jansen
10
Energy Potential Mapping by Siebe Broersma and Michiel Fremauw Prêt-à-Loger by Osama Naji
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Eart, Wind & Fire by Ben Bronsema
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Smart Energy by Koen Fischer
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Editorial
Although maybe not visible, energy is abundant. Energy is involved in everything we do, see, smell and feel. Although the topic is much more wider, this edition of Rumoer focussus on the reduction and smarter usage of energy in the build enviroment. We found a wide variety of interesting people who where willing to write about their field of expertise. Both the theoretical as practical aspects are discussed both introduces by Andy van den Dobbelsteen. The theoretical part starts with an article by Sabine Jansen who makes us familiar with the terminology of Exergy. The next article, Energy Portential Mapping, written by Michiel Fremouw and Siebe Broersma, describes how energy can play a roll in future spatial planning. On the brink between theory and practice we find the PrĂŞt-Ă -Loger team with their contribution for the Solar Decathlon 2014. Their submission is about transforming existing row houses into zero-energy houses. Ben Bronsema writes in his article Earth, Wind and Fire about the quest to bridge the gap between architecture and technology. Last but not least a article about some architectural applications involving the smart usage of energy by RAU architects. Koen Fischer
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Left to right: Pasquale van Dijk; Koen Fischer; Tyrza Ligthart; Maaike de Haas; Maya de Groot; DaniĂŤl van Staveren
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A New Board Written by: Tyrza, Maya, DaniĂŤl, Pasquale, Maaike & Koen Last year, BouT has had an enormous boost. The former board members Freek, Luuk, Joost and Dwayne have paved the way for a new found well functioning of our student associating. We, the new board members, only can benefit from their commitment and enthusiasm. For the next year(s) to come we will continue this vibe and expand our activities. This year BouT introduces a new board with added positions for sponsorship and education, two new committees to organize a study trip and a symposium. This year the board will hold six positions: Chairman: Tyrza Ligthart Secretary & Media: Maya de Groot Treasurer & Sponsorship: DaniĂŤl van Staveren Education: Pasquale van Dijk Events: Maaike de Haas Rumoer: Koen Fischer The three committees: Study trip: Katja Rossen & Noor Aghina Symposium: Freek van Zeist, Joost van de Ven & Dwayne Halewijn Rumoer: Reinier Scholten & Jelmer Niesten
As in the previous years Bout will organize several events, drinks end barbecues throughout the year. Also we will publish several Rumoers with a wide variety of interesting subjects. More interesting is the new stuff: This year we will expand our activities on the field of education. Besides the educative events we organize, we want to play a role in the improvement of the education taught at our department. As a student, you can expect us to ask you for your opinion concerning the different courses and perhaps changes you would like to see made. As a student association we can communicate and discuss the outcome of this research to the responsible course coordinator. Also new this year is the addition of sponsorship to the position of the treasurer. Until now, nobody was fully responsible for the sponsorships, resulting in a situation where neither the sponsors nor we really benefited from the situation. For the years to come we want to improve, prolong and expand these relationships. If you are reading this and you are interested in sponsoring BouT, the symposium or Rumoer, you are welcome to contact us by mail or phone. Last but not least a new committee will research the possibilities of a (foreign)field trip. We are looking forward to the year to come. We hope you do too. Stay tuned!
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Introduction
Written by: Andy van den Dobbelsteen
The face of the built environment is changing radically: newly built houses have to be energy neutral from 2020 on (In Brussels ‘nearly zero energy’ is a commonly used term, but to acclaim this one has to aim for complete energy neutrality). The existing built environment will follow this aim on a longer term. This major development will have consequences for the building’s appearance. In the least preferable case it implies that we will get an equal building with a thicker facade and solar panels; in a more preferable case it will lead to new forms of architecture, which is a welcome development for the current building practice. It took some time, but by now most architects understand that the energy challenge in the building practice is intertwined with the architectural design itself rather than only the engineering delivered by the building services consultant. The energy performance code has become so strict that engineers conclude adding more technological solutions is not sufficient (and moreover it will not be accepted); The energy challenge is a challenge for integral design. In our department Architectural Engineering + Technology we believe that the changing circumstances demand for new kinds of architects and engineers, who positions him/ 10
herself between the traditional architect and engineer: someone who understands architectural design and has appropriate technical capabilities, for instance, as to creating net zero energy buildings. Within the department we already had the architecture masters of Architectural Engineering, Hyperbody en RMIT, but recently we adapted our master of Building Technology to this new reality. Our future BT graduates will not be listed in the architects’ register, yet they will have an important role in the future of architectural design. Within my own educational chair we see, because of our acquired research funds, this change is not just a fashion hype. We also see that we do not have the solution to an energy-neutral society yet. Thus we perform research on a larger scale, on Energy Potential Mapping: this turned out to be an ideal method to give insight in the demand and supply of energy, but in particular in the sustainable energy potential of an area. Based on the exergy principle urban approaches developed by us, such as REAP (Rotterdam) and the Amsterdam Guide to Energetic Urbanism (Leidraad Energetische Stedenbouw) has led to an important role in European research projects in matters traditional urbanists nor engineers had a solution for.
Head of the Department Architectural Engineering + Technology, Professor of Climate Design & Sustainability and theme leader of ‘Energy in the Built Environment’ for the Delft Energy Initiative
On the smaller scale energy neutrality of a separate building with sufficient roof surface is possible, but if we consider an existing building in a dense urban environment, considerably more severe solutions are needed. These solutions lie in new smart energy systems, such as networks for exchange of heat and cold. Next to that also smart, active facade systems and standardised packages of measures to challenge the large housing renovation problem in the Netherlands, which entails the renovation of obsolete tenement flats, gallery flats, and terraced houses. In the latter category we have a trump card for the Solar Decathlon. This biannual student competition for the design of dwellings solely reliant on solar-energy will take place in Versailles from June 28th to July 14th, next to the gardens of the famous chateau of the sun king. The event will have Olympic proportions, topped off with congress facilities and a village for participants. Amongst the twenty in situ built houses of the competition, we as the TU Delft Prét-a-Loger team are the only one who propose a renovation plan: our plan is to recreate a cross section of a line of terraced houses, to demonstrate how technical design interventions can be make the dwelling energy neutral. Apparently, our ‘NUNA of architecture’ has a potential of winning the competition.
This edition of the RuMoer shows a beautiful palet of the state-of-the-art of energy research and design. I personally hope you as the reader will feel the energy radiating from our research work, just as I feel this when working in our department. The AE+T sections of Climate Design, Architectural Technology, Structures, RMIT, and Computational Performance collaborate incrementally to perform communal energy research and design. If we succeed in resolving the problem of operational energy, embodied energy and circular systems will be the next challenge for the building practice. There will be plenty of work for us in the coming 30 years, and thus also for RuMoer…
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Exergy
A better way of looking at energy systems
Written by: Sabine Jansen
The law of conservation of energy, stating that energy cannot be created nor destroyed, is inadequate to measure the performance of energy systems in the built environment: Even though energy figures suggest differently, these systems generally present a very poor performance, as they achieve only a fraction what is theoretically possible. By looking at exergy a much more meaningful insight into the performance of energy systems is obtained, which can greatly support the development of energy systems with a reduced need for high quality energy.
water to heat up cold water in a bathtub, but the reverse process is not possible. In these two processes the energy may not be lost, but something must be lost since we cannot re-obtain the original situation without adding new energy. What is lost in this process is the ‘exergy’ of the energy, which is often referred to as the ‘quality’ of energy. Figure 1 shows a sketch of this process, which in fact is very similar to the traditional way of heating our homes by using a condensing boiler. The energy efficiency of this process is 100%, but the exergy efficiency certainly is not.
What is exergy ? Most people, including engineers, look at energy systems through ‘first law’ spectacles: the amount of energy going into a system is equal to the amount going out. The fact that the energy has changed from one form to another (for example from chemical energy contained by gas into thermal energy contained by hot water) is obviously important, since it is the objective of the process in the first place, but no further analysis of this change is considered. However, we know from experience that processes always take place in a certain direction: it is possible to heat up water in a pan by using butane gas and to use the pan of hot 12
Figure 1. Energy and exergy values of three different forms of energy
Sabine Jansen studied at the Faculty of Architecture of Delft University of Technology and received her master’s degree within the Building Technology master programme in 2002. After her studies she moved to Barcelona, Spain, where she worked at Aiguasol Enginyeria as a consultant on building physics and energy use in buildings. In 2004 she returned to the Netherlands where she worked for Deerns Consulting Engineers and Cauberg-Huygen Consulting Engineers. In December 2006 she started her PhD research on the application of exergy in the built environment, supervised by Professor Peter Luscuere and Professor Andy van den Dobbelsteen. She successfully defended her thesis entitled “Exergy in the built environment: The added value of exergy in the assessment and development of energy systems for the built environment” on November 5th 2013.
Figure 2. Which device will be more efficient for heating a room: an electrical heater or a refrigerator?
Now let’s have a look at another example: Suppose we can choose between an electrical heater and a refrigerator for heating a room. Which device will be the best option for heating the room? Both devices use electricity as input and both devices have to obey the law of energy conservation. The electrical heater converts all electricity into heat, which means the energy efficiency is 100%. The refrigerator on the other hand ‘produces’ cold: It extracts heat from the inside of the fridge and emits heat at the back of the fridge. In fact, it transfers heat from the colder to the warmer side by using electricity. In order to obey the energy conservation law the amount of heat emitted at the back must equal the
amount of electricity plus the amount of heat extracted from the inside of the fridge. As a net heat ‘producer’ the fridge therefore also has an energy efficiency of 100%. This fact will not be new to people familiar with heat pump systems, as will be the fact that you can choose to put only one side of the fridge to the room and the other to the outside. This way the resulting heating (or cooling) can exceed the required electricity input. The efficiency of heat pumps or refrigerators can thus exceed 100% and is therefore usually referred to as the ‘coefficient of performance’ or COP. Naturally, the process still obeys the first law, due to the intake of ‘free’ heat at the cold side of the device. The fact that heat pumps perform better than electrical heaters is also not new, but the shortcomings of the energy approach become very clear when evaluating these devices: If the energy efficiency of an electrical (resistance) heater is 100%, while we know we can use the same electricity plus an additional input of ‘free’ energy with no value to produce more heat, what is the significance of this 100% energy efficiency? It does not mean the process cannot be better. We know it can be better. Common heat pumps have COP’s around 4, meaning 4 times as much heat can be produced with the same amount of electricity. 13
That’s much better, but still these values are no indication of how much heat (or cold) could ideally be obtained with the same electricity. This is why exergy has such a great added value in addition to energy: While an energy efficiency of 100% does not necessarily mean the process cannot be improved, the ideal and therefore maximum exergy efficiency is always 100%, since in thermodynamic ideal processes no exergy is lost. All real exergy efficiencies are below this value and
the distance from 100% quantifies the exergy losses and thereby the ideal improvement potential. Exergy therefore does not only indicate where but also quantifies how much an energy conversion could be improved. This information cannot be obtained with an energy analysis.
Thermodynamic definition of exergy and the exergy factor
In thermodynamics, exergy is defined as ‘the maximum amount of work obtainable from a system as it comes to equilibrium with the environment’. The reference environment is the surrounding environment that is unlimitedly available and unaltered as a result of a process; the environment can thus be used as an unlimited energy source (as is the case with the heat pump example) or sink of a process. The exergy factor fex is defined as the amount of exergy per unit energy. Energy with a high exergy factor can be called ‘high-exergy’ or ‘high-quality’ energy; energy with a low exergy factor can be called ‘low-quality’ or ‘low-ex’
Figure 3. Exergy factors of various forms of energy and fuels
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Figure 4. Exergy factor of heat according to equation fex=exergy/energy=(1T0/T) (in Kelvin)
energy. In figure 3 the exergy factors of various forms of energy are listed. The exergy factor of heat depends on the temperature according to the formula (1-T0/T), where T0 is the temperature of the environment (T in Kelvin). In figure 4 a graph of the exergy factor of heat is shown.
The exergy performance of current energy systems Now let us have a look at the performance of current energy systems for the built environment. The doctoral study by the author (Jansen, 2013) presents a detailed study of the exergy performance of several current energy systems for a Dutch single family dwelling. In this article the results of the following three cases are briefly described: Case 1) using a radiator and a condensing boiler. Case 2) using a radiator and a small-scale unit for combined heat and power production (micro CHP) Case 3) using a heat recovery unit, floor heating and a heat pump.
is much smaller than the energy demand. The energy efficiency of the system (defined as the energy demand divided by the energy input) seems quite good – especially of case 3 where the ‘free’ outdoor air is not included in the input – but the exergy efficiency (exergy demand divided by exergy input) is relatively low. This means that in theory there is a large room for improvement, which cannot be concluded from the energy figures. In figure 6 the energy and exergy losses occurring at each system component of the cases studied are shown. This chart shows two bars for each case study: one bar for the energy values and another for the exergy values. The first item on each bar represents a copy of the energy or exergy demand; the subsequent stacked items represent the energy or exergy losses occurring in each system component. The demand and losses together equal the total input as shown in figure 5.
All cases are based on the same type of single family terraced dwelling (‘Senternovem referentie tussen woning’ in Dutch) with an equal demand for space heating. The energy and exergy demand of this dwelling are displayed in figure 5, together with the energy and exergy input of these three cases. For all cases the electricity is assumed to be supplied by a best practice gas power plant, which means the input of all cases consists of natural gas only. By assuming an exergy factor of 1 for gas, the exergy value of the input equals the energy value of the input. As can be seen the exergy values of the electricity demand are equal to the energy values, but the exergy demand for heating (both space heating and domestic hot water)
Figure 5. Energy and exergy demand of cases 1, 2 and 3.
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Figure 6. Energy and exergy losses of cases 1, 2 and 3.
The exergy losses (referring to both losses and destruction) offer a totally different insight than the energy losses: The first losses are introduced in the ‘room air’ component, presenting the losses between the demand (at indoor temperature) and the emission system. These losses are nonexistent in the energy approach. Furthermore major exergy destruction takes place in the boiler, as is almost commonly known. Also significant exergy destruction takes place at the Micro CHP, while the energy efficiency is 100% (80% heat and 20% electricity). Moreover, the heat pump and the heat recovery system present exergy losses, even though the energy losses are considered negative as a result of disregarding the input of free environmental or waste heat. It can also be concluded that the main losses take place in the components used for space heating and domestic hot water; the exergy efficiencies for providing heating are therefore particularly poor. 16
These results show that exergy analysis points in a totally different direction for improving these systems than energy analysis. While the energy figures suggest that the only way to reduce the required high-quality energy input is to (further) reduce the demand, the exergy figures show that the heating demand is actually low-ex energy and that avoiding exergy destruction can also reduce the input significantly. An energy approach leads to concepts such as the passive house concept (i.e. a drastic reduction of the demand), while an exergy approach shows it can be equally beneficial to develop a smarter and exergetically more efficient system.
Closure: What to expect from the exergy approach? From the introduction to exergy and the case studies presented in this article it can be concluded that: • Exergy offers a different and more meaningful insight into the performance and improvement potential of energy systems than energy. • Our current energy systems have a very poor performance when compared to the ideal, which means theoretically there is much room for improvement In Jansen (2013) several guidelines are given to use the exergy concept for developing systems with minimized exergy losses and thus reduced input of high-quality energy, including the use of exergy principles and the use of quantitative analysis of exergy losses. Further research is required to investigate the maximum efficiency obtainable in practice. As explained in this article exergy is a better tool for this investigation than energy. The more you know about exergy, the stranger it seems not to use it.
The application of the exergy concept to energy systems in the built environment is relatively new but it received growing interest in the last two decades. Much literature can be found on the topic and two related international research projects have taken place: IEA ECBCS Annex 37 (www.lowex.net) and IEA ECBCS Annex 49 (www.annex49.com). This article is partly based on the authors’ doctoral study, which is mentioned in the biography.
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Energy Potential Mapping and urban energy approaches
Written by: Siebe Broersma and Michiel Fremouw
The Energy Potential Mapping (EPM) method has evolved over the years and was initially developed to visualize local (renewable) energy potentials and demand of energy, in order to support spatial planning towards more energy-efficient urban or rural environments [1,2,3]. EPM has led to a process whereby energy becomes an extra parameter of spatial planning during the design of sustainable built environments. Until now, fossil fuels (with a high energy density, being extracted from the underground, easy to transport and converted into for example electricity at central locations) have been sufficiently available, so historically the distribution of energy has hardly interfered with spatial planning. In a future energy system, however, renewable sources will mostly need to be accessed at or near the Earth’s surface, have a low energy density, are spread out over larger areas and some forms tend to be less easy to transport. This means that in a sustainable world based on renewables, energy = space, and sources and sinks must be spatially connected in smart ways. The EPM method is a means to map and quantify renewable energy potentials (e.g. solar, wind, geothermal, and biomass) and demand in an easily comprehensible way. [4] 18
EPM methodology The figure below (Figure 1) illustrates the methodology of EPM, starting on the left with redefining the current primary energy use in an area (for example a region, city or neighbourhood) into the actual energy demand of heat, cold, electricity and fuel. Simultaneously on the right, the theoretic potentials are defined out of the basic input for each source and into the available heat, cold, electricity and fuel after regarding the limitations. Sources and sinks meet in the middle, where they can be smartly connected in energy based plans. After defining the desired output, available literature and (monitored) data sources need to be studied to obtain the optimal available input on the quantities, qualities, and geographic and temporal dispersion of all defined sources and sinks. Data obtained at the smaller scale e.g. available residual heat of small industries and the biomass of individual farms, is often unavailable. In the absence of such primary data, alternative methods need to be applied to calculate or estimate these, or alternatively the scale at which to express the output must be enlarged.
Siebe Broersma (1980) and Michiel Fremouw (1979) both studied at this faculty and graduated within the section of AE+T (Building Technology), sustainability being an integral part of their theses: Siebe graduated on an outer sunshade system with integrated solar cells, Michiel on GIS-based renewable energy potentials. Together they work as researchers within the Green Building Innovation research programme at prof. Andy van den Dobbelsteen’s chair of Climate Design and Sustainability, being involved in urban and regional renewable energy studies. These studies focus on Energy Potential Mapping and urban energy approaches. In essence, the goal is to define and quantify sustainable interventions for the built environment that contribute to the transition towards sustainability, energy neutrality, -autonomy and carbon reduction. Next to their research commitments, Siebe and Michiel are involved in education as well: they teach in those parts of the curriculum where sustainability and climatic design are substantially integrated into the assignments, from BK2ON2 to mentoring graduation projects. SINKS
SOURCES
ELECTRICITY
FUEL
ENERGY BASED PLANS
E F
C E F
C
UNDERGROUND
NATURE & ARGRICULTURE
BUILT ENVIRONMENT & INDUSTRY
F
INFRASTRUCTURE
SINKS
ENERGY SYSTEM
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LAND USE
TRANSPORT
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WATER
UNDERGOUND
NON-RESIDENTIAL
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WIND
CLIMATE
RESIDENTIAL
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TOPOGRAPHY
SUN
H
BASIC INFO
COLD
THEORETIC POTENTIAL
HEAT
LIMITATIONS
DEMAND
CONVERSION LOSSES
CURRENT USE
PRIMARY USE
DEFINED POTENTIALS
SOURCES
Figure 1. EPM scheme DEMAND
DEFINED POTENTIALS COLD
ELECTRICITY
FUEL
BASIC IN
HEAT
PL
CONVER
CURR
PRIM
H
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energy usage patterns
urban energy system energy saving in the city
generation elsewhere
regional generation
generation in the city
reuse exchange cascade store
discharge elsewhere
regional exchange
generation elsewhere
city region
discharge elsewhere
Figure 2. Urban and regional energy flows
As the availability of data may change over time, an EPM study gives an overview of the best available data at that moment. If at a later date more accurate data or real-time measurements become available, the catalogue of energy potentials can be updated. [4]
Urban energy approaches At the basis of our urban energy approaches is the New Stepped Strategy, summarized as reduce, reuse and generate sustainably, and displayed as a series of spatial flows 20
in Figure 2. Most present day energy systems (represented here by the grey arrows) generate exactly the required amount of energy elsewhere (still primarily using fossil fuels) and discharge waste outside the region (for example as CO2 into the global atmosphere). Not only does this involve a finite energy source frequently imported from abroad, the lengthy transport and distribution system introduces additional vulnerabilities, both technical and geopolitical. Familiar examples include an army helicopter severing high voltage cables in the Dutch Bommelerwaard in 2007, affecting over 100.000 people, and several natural
gas disputes between Russia and Ukraine in the 2000s, affecting European gas deliveries in winter. Energy systems therefore benefit from mostly using local and regional sources, which are frequently of a renewable nature, and only importing any demand still remaining (or exporting the surplus). As renewable sources tend to have a fluctuating output, a fully renewable system for a specified area will most likely both include a mix of sources as well as a means of energy storage (for example biomass), and reduce peak demand by shifting loads (for example running washing machines on sunny or windy hours).
Oostland study To illustrate these methodologies, we’ll look at a recent energy study[5,6] examining the Oostland region (east of Delft). This area consists of the Pijnacker-Nootdorp and Lansingerland municipalities and is dominated by greenhouses between the towns of Bleiswijk, Bergschenhoek and Pijnacker. Conventional greenhouses tend to be significant energy users, but have great potential not just in simply reducing their demand but also in downright generation, as well as cascading and exchanging with surrounding areas. In order to provide well founded and quantified spatial interventions during the second part of the study, a thorough regional energy analysis has been carried out. This resulted in a series of energy potential maps, some of which are shown in Figure 3. Topics include electricity and heat demand of dwellings, greenhouses and other non-residential functions; electricity and heat generation potential from secondary surfaces (mainly south facing roofs, primary surfaces are excluded as that would interfere with other functions); ground source heat pump (GSHP) potential; intermediate and deep geothermal potential for suitable aquifers, and finally potentials for
Figure 3. Energy potential maps Oostland; demand and supply
biomass and wind. Being in the vicinity of an airfield (vliegveld Zestienhoven a.k.a. Rotterdam Airport) meant that for the latter potential, turbine height restrictions had to be taken into account, requiring wind turbine planning to be focusing on the northern half of the region. For biomass, waste flows were investigated. As with electricity and heat generation, primary surfaces were not considered. First generation biomass sources (i.e. energy crops) would use land suitable for food production, thus, even though renewable in the biological sense, shouldn’t be considered long term sustainable.
Interventions When combined, the results provided an energy catalogue for the region, which was used as a basis for defining local short term interventions; first as generic concepts suitable to the now known Oostland energy mix, and subsequently as specific proposals connecting and quantifying the best fitting local sources and sinks. 21
Biogasproductie + WKK groeninzameling
Legenda
Dijkshoorn Bleiswijk
Biomassa
Geothermiecascade
Legenda
Pijnacker - Oostland
Geothermiebron
WKK
Vernieuwde glastuinbouw
Biovergister
Oude woonwijk
Warmtevraag
Nieuwe woonwijk
Elektriciteit
Warmtenet
25o
70o
Biomassa stroom Restwarmte stroom Biogas Biovergister/WKK locatie
35o 50o
100m
100m
Legenda
Biogasproductie groeinzameling + groen-gas-tankstation
Biomassa
Delta Milieu Bergschenhoek
Biovergister Mest G
Biogastankstation
G
Legenda
Gerenoveerde wijk met zonnecollectoren en diepe warmteopslag/geothermie
Bergschenhoek
Geothermiebron Gerenoveerde wijk met zonnecollectoren Warmtenet potentiele warmtevraag
Wegtransport
70o
Biogasstroom Biomassastroom Biovergister locatie
100m
100m
Figure 4. Schematic examples of local sustainable interventions projected on the map
Figure 4 shows a few examples of these proposals, projecting concepts on specific map locations. In the town of Bleiswijk (top left), a biogas production plant and combined heat and power station (CHP) were proposed at a biodegradable waste collection point located in a greenhouse area. This would allow the closing of several cycles, as the biodegradable waste from the greenhouses is fed into an anaerobic digester, producing biogas for the CHP plant, 22
and thus heat, electricity and CO2 for the greenhouses. Finally, the residual digestate from the biogas phase can be returned to the greenhouses as a soil conditioner. The geothermal cascade proposal (top right) is based on
the idea of extracting the most possible energy out of a single well, by reducing water temperature as much as possible before reinsertion in consecutive usage steps, a concept known as cascading. This requires the vicinity of sinks with a comparable energy demand but at different temperature ranges. The ground below the town of Pijnacker is quite suitable for geothermal heat extraction. Furthermore, part of the town centre requires a heating inlet temperature of 70°C and has an outlet temperature of 50°C, which means this can subsequently be fed into a more recently built, better insulated neighbourhood and finally used in a newly planned adjacent greenhouse area. This would result in a final outlet temperature for the cascade of about 25°C, thus making much better exergetic use of the same amount of heat.
Outlook Although studies like these often start out with straightforward questions from concerned parties about how to accelerate their transition to a renewable energy system, they provide both valuable base data and a viable area for case studies. As a result, both the EPM method and our approaches towards local sustainable interventions evolve and improve continuously; the current focus for the first is exploring GIS-based maps and methods, and that of the second is developing a generic applied structural approach.
Refences 1. van den Dobbelsteen, A.; Jansen, S; van Timmeren, A.; Roggema, R. Energy Potential Mapping –A systematic approach to sustainable regional planning based on climate change, local potentials and exergy. In Proceedings of the CIB. World Building Congress 2007, CIB/CSIR, Cape Town, South Africa, 2007. 2. Dobbelsteen, A. van den; Broersma, S.; Stremke, S.; Energy Potential Mapping for Energy-Producing Neighbourhoods. Int.J.Sustain.Build.Technol.Urban.Dev. 2011, 014, 170-176. 3. Broersma, S.; Fremouw, M.; van den Dobbelsteen, A ‘Heat Mapping the Netherlands - Laying the foundations for energybased planning’. In Proceedings SB11 Helsinki World Sustainable Building Conference (CD-Rom); Helsinki, Finland, 18-21 October 2011. 4. Broersma, S.; Fremouw, M.; van den Dobbelsteen, A Energy Potential Mapping: Visualising Energy Characteristics for the Exergetic Optimisation of the Built Environment. J Entropy. 2013, 15, 490-506. 5. Broersma, S.; Fremouw, M.; van den Dobbelsteen, Energiepotentiestudie Oostland. J TVVL Magazine. 2013, 06, 10-12. 6. Broersma, S.; Fremouw, M.; van den Dobbelsteen, Energiepotentiestudie Oostland – Met regionale een energy-analyse naar lokale duurzame ingrepen. Report 2013, June.
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Prêt-à-Loger
Written by: Osama Naji, Director of Communications Prêt-à-Loger
House with a Skin
WHO WE ARE:
Prêt-à-Loger
Evolve not change, improve WHAT WE BELIEVE: not replace WHAT WE DO:
House with a Skin
Solar Decathlon The Solar Decathlon began as an initiative from the U.S. Department of Energy in 2002 to demonstrate the applicability, feasibility and quality of solar technology for the housing industry by designing and building a zeroenergy house. It is a competition between universities from around the world which can be described as a combination between a building fair and the Olympics! The competition proved so successful that, over the past decade, it has expanded to Europe and Asia where the state-of-the-art is continuously being redefined. With over 300,000 visitors, this is an incredible opportunity for companies, students and universities to showcase their know-how and products on the world stage. 24
The Prêt-à-Loger team consists of Students from TU Delft who are looking to renew the world. Our project ‘House with a Skin’ will compete in the Solar Decathlon Europe 2014 competition in Versailles and aims to solve the problems relating to the current building stock by laying a new skin over existing houses. In this way, the homes of the inhabitants can be preserved while new spaces are created to the front and rear of the house. The insulated skin will provide a climatic buffer zone to the outside, generate its own power and reclaim the somewhat lost relationship to the public street thus tackling issues regarding ecological and in particular social sustainability.
Vision Prêt-à-Loger aims to transform existing houses and neighbourhoods into sustainable homes and communities. Our motto “Evolve not change, Improve not replace” stems directly from the belief that there is a priceless character and quality to existing buildings that cannot simply be replaced. A visionary statement by Team Captain David Jacome underlines this idea: “We are not designing a house in the future, we are designing so that our homes will make it there”.
Osama Mohammad S. Naji was born in Jeddah, Saudi-Arabia in 1986 to a Saudi-Arabian father and German mother. In 1995, his family moved to Dubai, UAE, where he went to an international school and gradueated with an International Baccaulaureate in 2004. After studying 2 semester of Graphic Design in Berlin, he pursued a more technical career in architecture and moved to the UK. From 2006 to 2010, he completed two bachelor degrees; one in Architecture and the other in Architectural technology. From then on he spend two years in Germany completing the mandatory Zivildienst (national service) before undertaking an internship in Cologne at Getermann + Schossig Architekten in 2012. Osama moved to Delft in September 2013 to study Architectural Engineering at the TU Delft. During the Bucky Lab courses he quickly found an interest in the Solar Decathlon which were introduced to him by his fellow students. Osama is now Director of Communications for Pret a-Loger.
experience and enjoy. The house will be represented as if it were a slice that is taken directly from the existing neighbourhood. The goal is that the house with a skin will stand out not only as a slice of Holland, but will be perceived as a genuine slice of home.
Sponsors Background The neighbourhood in question lies in the town of Honselersdijk. It lies in close proximity to Delft and is famous for its acres of greenhouses and horticultural industry. With the focus on the row-house, Pret-a-Loger takes on a typical Dutch issue. 6 out of 10 Dutch live in their so-called ‘Doorzonwoning’ – more than any other European country. This typology also makes up 42% of the current building stock and represents a mass market for the application of the Skin.
We are pleased to announce that steady progress is being made with getting partners on board! Over the past few weeks we have welcomed Van Dorp installaties, Deerns, Ministerie van Binnenlandse Zaken en Koninkrijksrelaties (Ministry of Interiors and Kingdom relations) as well as sto isoned to our existing team that already includes Ecobouw, Komplot, PrinterPro, Solarevent, the green village and TU Delft. We hope to expand our network of partners over the coming weeks to get our project to Paris successfully.
Versailles 2014 In the summer of 2014, Prêt-à-Loger will represent one of these existing houses with our designed intervention for all visitors of the Solar Decathlon Europe to 25
so that they continue to stress how much our concept is needed in the competition. 2.
2nd Workshop in Versailles The second workshop (6-9 November 2013) in Versailles made clear to us that we are the only team that will represent an existing house in the competition. Where nearly all other concepts focus on the stylish additions to the existing building stock – their designs all neglect the existing buildings which they seek to improve. Our message, all the way from who we are, down to what we do, addresses the way that real people live in real homes and neighbourhoods. French Housing Minister – Cecile Duflot showed her enthusiasm for our project by acknowledging the unique way that we address the existing housing situation – our concept is the most direct and relevant approach.
Four reasons to support us: 1.
IN IT TO WIN IT
Our optimism was confirmed by the feedback from the SD organizers who are impressed with the unique way in which we tackle the issue of existing housing and the way we represent our vision in the competition. So much 26
REPRESENTING THE NETHERLANDS
This will be the first time that the Netherlands will compete in this truly international competition. But it may be the last, as the previous 2012 entry from the TU Delft, the Re-volt house was forced to withdraw their entry shortly before the competition. We are a small country, but our impact on the world has traditionally been immense. By taking a piece of the Netherlands to Versailles we intend to build upon this tradition and leave a lasting impression as the eyes of the world are watching. 3.
BE THE FIRST
When the French team ‘Canopea’ won the Solar Decathlon in 2012 with their concept of building upon existing rooftops, they simultaneously set the trend for the following competition. We are in the unique position to do the same with the way we directly deal with real life issues and by actually representing an existing house in Versailles! 4.
REAL PROJECT
This project has a realistic perspective well beyond the competition in 2014. With the right support, we can make a difference by tackling a real Dutch problem – retrofitting the existing building stock, together! There is never a guarantee for victory, but we can promise this: NOBODY will work harder than us to represent the Netherlands proudly and with dignity next summer in Versailles. We are thankful for your support and continue to count on it.
CORE TEAM MEMBERS
The Team: ADVISORY COMMITTEE Drs. M.J.M. (Maxime) Verhagen, president Bouwend Nederland Ir. M.A.E. (Marc) Calon, president Aedes (Association for housing associations) Dr.ir. P. (Peter) Fraanje, director Dutch Association of Suppliers for Building A. (Annemarie) Jorritsma-Lebbink, chairman Association of Dutch Municipalities Prof.ir. K. (Karin) Laglas, Dean Faculty of Architecture, TU Delft Prof.ir. K.C.A.M. (Karel) Luyben, Rector Magnificus TU Delft Drs. E.H.T.M. (Ed) Nijpels, president NL Ingenieurs Ir. W.H. (Willem Hein) Schenk, president BNA, Union of Dutch Architects Ir. S. (Stefan) van Uffelen, manager Dutch Green Building Council Mr.drs. M. (Marjan) Minnesma MBA, director of the Urgenda foundation T. (Titia) Siertsema MBA, Chair of UNETO-VNI (branch society of building services companies)
Contest Captain/Student team leader: David Jacome Polit (c.d.jacomepolit@student.tudelft.nl) Project Manager: Matthaios Zarmpis (info@pretaloger.nl) Project Architects: Dennis IJsselstijn (d.ijsselstijn@student.tudelft.nl), Josien Kruizinga (j.kruizinga@student.tudelft.nl) Urbanism: Daniel Radai (D.P.Radai-1@student.tudelft.nl) Site Operations Coordinator: Petar Zhivkov (P.R.Zhivkov@student.tudelft.nl) Electrical Engineer: Stelios Stavroulakis (s.stavroulakis@student.tudelft.nl) Instrumentation Contact: Hardik Joshi (h.joshi@student.tudelft.nl) Events Management: Nick Kerckhaert (events@pretaloger. nl) Communications Coordinator: Osama Naji (marketing@pretaloger.nl) Sponsorship Manager: Tim Jonathan (partners@pretaloger.nl) Structural/Project Engineer: George Xexakis (G.Xexakis@student.tudelft.nl) Sustainability: Carolin Bellstedt (C.H.Bellstedt@student.tudelft.nl) Health and Safety Team Coordinator: Gini Arimbi (GiniArimbi@student.tudelft.nl)
PRIMARY FACULTY ADVISOR Prof. Andy van den Dobbelsteen PhD MSc, Faculty of Architecture, Climate Design and Sustainability (A.A.J.F.vandenDobbelsteen@tudelft.nl)
DAILY FACULTY ADVISOR Dr. Craig Lee Martin, MA, Faculty of Architecture, Climate Design and Sustainability (C.L.Martin@tudelft.nl) 27
TEAM MEMBERS
OTHER FACULTY ADVISORS
Architecture: Minyoung Kwon, Stefan Hoekstra, Bernardo
Prof. Thijs Asselbergs, MSc, Faculty of Architecture, Architectural Engineering Prof. Ulrich Knaak, PhD MSc, Faculty of Architecture, Design of Constructions Prof. Rob Nijsse, MSc, Faculty of Architecture / Civil Engineering and Geosciences, Structural Engineering Prof. Miro Zeman, PhD MSc, Faculty of Electrotechnical Engineering, Photovoltaic Materials and Devices Prof. Hans Wamelink, MSc, Faculty of Architecture, Design and Construction Management Prof. Anke van Hal, PhD MSc, Faculty of Architecture, Sustainable Housing Transformation Dr. Arno Smets, MSc, Faculty of Electrotechnical Engineering, Photovoltaic Materials and Devices Dr. Hielkje Zijlstra, MSc, Faculty of Architecture, Research and Education of Modification, Intervention and Transformation Dr. Marcel Bilow, MSc, Faculty of Architecture, Product Development Dr. Olindo Isabella MSc, Faculty of Electrotechnical Engineering, Photovoltaic Materials and Devices
Rossi, Luca De Stefano, Futura Falco, Oana Anghelache, Vincent Marchetto, Timo Knibbe, Gabriele De Leo, Jan Portheine, Kim Warmerdam Urbanism: Todor Kesarovski, Eelco Herfst Construction Management: Gini Arimbi, Niels Hoogeveen Electrical Engineering: Vasilis Tzimitras, Dimitra Tasoula, Shree Harsha, Maria Anastassaki Energy Efficiency: Paul van Kan Marketing: Leo Zhang, Esti Tichelaar, Rianne den Ouden, Shumeng Chang, Kuan- Ling Tseng, Laurence Gibbons Partners’ Liaison: Tim Ras, Jasper Overduin, Sevan Markerink Structural Engineering: Angela Greco, Davide Zanon, Sergiu Troian Sustainability: Carolin Bellstedt
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Earth, Wind & Fire Natural Air Conditioning
Written by: B. Bronsema, PhD, BEng
“Architecture will, therefore, become more informed by the wind, by the sun, by the earth, by the water and so on. This does not mean that we will not use technology. On the contrary, we will use technology even more because technology is the way to optimize and minimize the use of natural resources”(Richard Rogers). Who says Richard Rogers (figure 1) thinks of the Centre Georges Pompidou that he and Renzo Piano designed in 1977. An impressive architectural and technological tour de force, including its air-conditioning system. His statement above, many years later, is indicative of the direction in which architecture is moving; a direction in which technology is used to support architecture.
earth mass, wind and sun, metaphorically referred to as Earth, Wind & Fire. This strategy gives the architect a major role in designing the indoor environment and the energy efficiency of buildings as an integral part of architecture. Climate facilities are elements of the architectural expression. Climate technology is no longer subordinate to architecture but part of architecture itself. The design of a building as a climate machine has become the task of the architect who is, therefore, also partly responsible for the indoor climate and energy management.
However, there is a gap between technology and architecture and my research, “Earth, Wind & Fire Natural Air Conditioning”, was a quest for the necessary knowledge and science to bridge this gap. The strategic set-up of the research was focused on the development of Climate Responsive Architecture in which climate design, building physics, and HVAC [heating, ventilation, and air conditioning] systems are connected to an architectural assignment. A building is in this way designed as a “climate machine”, a machine which is activated by gravity and the ambient energy of 30
Richard. Rogers, Designer of: Centre Pompidou with R. Piano (1977)
Ben Bronsema was born in 1935 and studied mechanical engineering at Groningen Academy Minerva, completing his studies in 1955. His military obligations fulfilled he worked from 1958 till 1971 at a big mechanical HVAC contractor, ending as managing director at a branch office. He continued his career as consulting engineer and partner at a Delft based company, where he was responsible for the climate design in numerous buildings. He retired in 1998, continuing as freelancer and arbitrator in several institutes. 1993 he was appointed as guest lecturer at Delft University of Technology, Faculty of Architecture, where he coached an supervised master students on indoor environmental issues and building services in their final architectural projects.2007 he started as principal investigator the research project Earth, Wind & Fire, funded by Agency NL, which was rounded off by taking his PhD in 2013. During his career he played a role in the international building services community. He is REHVA honorary fellow and member of TVVL and ASHRAE.
Why natural air conditioning?
Challenges for architect and climate engineer
Mechanical air-conditioning systems in buildings deliver room temperatures within the comfort zones during every season, but are nevertheless only moderately appreciated. Many people dislike the low frequency noise of the fans and the quality of the indoor air, which is deteriorated by passing through contaminated air filters and ducts. They complain about draught and dry air. The infamous Sick Building Syndrome is more common in air conditioned buildings than in buildings with natural ventilation.Furthermore mechanical air-conditioning is a complex technique. The often complicated control systems require significant maintenance and are in many cases not understood by its users, causing troubles with the operation. The investment and maintenance costs are high, and the mechanical air transport through the air handling unit and duct systems uses a lot of energy. This is in contradiction with national and EU objectives, which require zero-energy buildings in the near future.
Energy conservation in the building environment has primarily been the domain of building physics and HVAC technologists. Both have, in recent decades, contributed an excellent performance, but a declining value in these sectors may be observed.
For the architect, the integration of the HVAC system in the building design is often a cumbersome task. The space requirements for the air handling plants are substantial and air ducts usually require an increased floor height.
Architecture however, the discipline that has the greatest impact on the built environment, has remained largely aloof. By directly involving the architect with his significant creativity and influence on the building process in the issues of energy and the indoor environment, new possibilities are, in principle, opened up on the basis of a truly integrated design. Giving architecture and architectural elements a place within the overall package of HVAC services in a building also complies with the primary objective of the study: reducing the gap between architecture and HVAC engineering. The direct deployment of natural elements for regulating the indoor climate takes the architect back to his basic profession of integrated designer, a role that he has
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always played in the past. He can practice his profession at a higher level by being the designer of the building as well as playing an important role as technical and artistic co-designer of the climate systems. “Back to the Future”. For the HVAC engineer it is a challenge to operate at a higher level of profession while significantly integrating with architecture. The research for Earth, Wind & Fire was a quest for the necessary paradigm change in the building industry. “Architecture and Climate technology working together symbiotically”.
The Earth, Wind & Fire concept Initially, various analytical and intuitive ideas were mathematically developed and a selection was subsequently made from the most promising concepts. These included three responsive architectural elements including the Ventec Roof, the Climate Cascade, and the Solar Chimney or Solar Façade. These elements were initially developed separately, optimized, and evaluated but, ultimately, they constitute a complete concept of air-conditioning as a symbiosis with the architecture of a building – see the figure below.
Climate Responsive Architecture Bioclimatic architecture focuses primarily on the architectural integration of systems for daylight, passive heating, natural ventilation, and cooling. The well-known bioclimatic architect, Ken Yeang, mentions ecological, social and cultural motivations for this. Ecological because of the reduction of energy consumption and increase in the sustainability of buildings. Social because of improving human welfare, especially in highrise buildings. Cultural because of the continuous human learning process in adapting buildings to the local climate. Climate Responsive Architecture as discussed below in the Earth, Wind & Fire concept broadens the concept of bioclimatic architecture by actively overmaking use of the natural environmental energy in the outside environment and the earth mass. According to this concept, a building is designed as a “Climate Machine activated by the combined forces of the sun, wind, and gravity. By engaging the architect in indoor climate and energy matters a great intellectual and artistic potential is opened up for an intrinsically integrated design. This strategy also promises a potential improvement of the building quality and a reduction in failure costs. 32
Principle Earth, Wind & Fire (cross section), by B. Bronsema
Exploded view Ventecdak, by B. Bronsema
Ventec Roof
(Principles Earth, Wind & Fire concept)
The Ventec Roof exploits positive wind pressures for supplying ventilation air through the over pressure room (1) and the Climate Cascade to the building. Negative wind pressures are utilized to extract air from the building via the Solar Chimney and the Venturi ejector (6). This concept utilizes the relatively good air quality at higher altitudes. Furthermore, due to the horizontal separation between supply air and exhaust air, short-circuiting between the two air flows is avoided.
In the over pressure room, wind turbines are provided (not illustrated in the drawing) by which, in principle, a substantial power production can be realized. Potential noise problems are easily resolved by the indoor positioning, and maintenance can be performed from the inside of the building. As these wind turbines are part of the technical building services, no environmental permit is required.
The Ventec Roof, in principle, can also be employed for the generation of wind and solar energy.
The upper roof is provided with a thin film PV roofing foil that, despite a lower efficiency, has a better costeffectiveness than solar panels. 33
hydraulic pressure and the downward thermal draft, pressure is built up at the foot of the cascade, making fans superfluous. The required cold is extracted from the soil, and heat is directly or indirectly supplied by the solar chimney.
Solar Chimney and Solar Faรงade Ventilation air is extracted through the Solar Chimney or Solar Faรงade in which solar energy is harvested to be exploited for heating the building during the heating season. With the assistance of a heat exchanger at the top of the solar chimney, the solar heat is transferred to circulating water and fed to the heat and cold storage in the soil under the building. This technology is applied in horticulture for cooling and heating greenhouses. The Venturi ejector in the Ventec Roof serves partly to compensate for the pressure loss of the heat exchanger. For the morphology of a solar chimney, numerous variants are conceivable in which the gable covering the Solar Faรงade yields the highest energy performance.
The Research Mock-up Climate Cascade, by B. Bronsema
Climate Cascade The core of the climate system is the Climate Cascade, which is designed as an architectural shaft and performs as a gravity-activated heat exchanger for airconditioning. Within the Climate Cascade, ventilation air is being cooled or heated, dried or humidified as needed. At the top, in summer and winter, water of approximately 130C is fed through nozzles and, by momentum transfer from droplets to air, the downward air movement from the over pressure room is enhanced. Together with the 34
A research team Earth, Wind & Fire was formed as a joint project between the TU Delft, TU Eindhoven, and VVKH Architects. Principal investigator of the project was Ben Bronsema, BEng, REHVA Fellow, assisted by academic staff of the Faculties of Architecture of Delft and Eindhoven Universities of Technology. The research was guided by an advisory board composed of prominent representatives of Dutch architecture (BNA), the building industry (SBR), and the installation sector (TVVL/VNI). The research was conducted with funding from the Ministry of Economic Affairs, Agriculture, and Innovation, Energy Research Subsidy scheme: long term (Article 18b).
(III) Earth, Wind & Fire - Research Climate Cascade and Climate Geo-Concept. (IV) Earth, Wind & Fire - Indoor environment: Symbiosis of Architecture and Climate Technology
The partial reports (I) through (III) provide a detailed report of the three studies and guidelines for the design of the responsive components including (I) Solar Chimney or Solar Faรงade, (II) the Ventec Roof and (III) the Climate Cascade. Part (IV) discusses the necessary interaction between architecture and climate technology and presents the main points of sections (I) through (III). In this section, a case study is also presented. The four sections are independent units and individual reading.
Mock-up Solar Chimney, by B. Bronsema
The results of the research are reported in compact form in the present thesis. A detailed reporting is made in the following final reports dated March 2012 (in Dutch - available online): (I) Earth, Wind & Fire - Research Solar Chimney and Solar Faรงade. (II) Earth, Wind & Fire - Research Natural Ventilation, Wind and the Ventec Roof.
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Modeling and simulation by B. Bronsema
Modeling, Simulation and Validation
Numerical flow modeling with CFD [2]
The research and development of the Ventec Roof, the Climate Cascade, and the Solar Chimney are developed according to the method of modelling, simulation, and validation as illustrated in the figure below. (Modelling and Simulating)
The basic analysed concepts have been developed into virtual prototypes utilizing CFD numerical flow models which provided insight into the heat transfer and flow patterns at micro level. This allowed the physical effects to be further analysed and, using simulation techniques, determine whether and to what extent models could be scaled up to full size components.
Basic modeling [1]
Dynamic simulation with ESP-r [3]
In the development of the various concepts, simple calculation models were being formed which provided a first impression of the feasibility and potential of the corresponding draft. Such models are close to the engineering practice and enable a swift evaluation of alternatives that is partly based on experience and intuition.
The Excel calculation model and the CFD simulation model are employed as tools for the calculation and design of the Climate Cascade and the Solar Chimney under stationary conditions. For the study of the dynamic behaviour and estimates of the annual energy performance of these responsive elements, the dynamic simulation model ESP-r is employed.
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Validation by measurements in a physical model [4] Based on the basic modelling in Excel and the examination, verification, and detailing using CFD simulations,​​ physical models are constructed of the Solar Chimney, the Climate Cascade, and the Ventec Roof. Using these under various conditions and in real time, the actually occurring phenomena of heat transfer and flows are measured. On the basis of the measurement data from the physical models, the Excel calculation model and the CFD and ESP-r simulation models have been calibrated and validated in a feedback loop. Computational model for practice [5] For the Solar Chimney, a dominant architectural building element, a user-friendly calculation model has been developed. In the conceptual phase of the building design, the architect can use this model to vary the dimensions of a Solar Chimney and directly read the associated performance. For the conceptual design of a Ventec Roof and a Climate Cascade, overall design data is recorded.
Summary Building blocks of the concept are fundamental physics, technological expertise, design creativity, and an understanding of practical applicability. The Earth, Wind & Fire concept is construed as scientifically relevant by the methods of modelling, simulation, and validation. The Earth, Wind & Fire concept is also socially relevant as the validated models and formulas are available for practical application and thus can contribute to the goals of zero energy buildings and independence from fossil energy sources. 37
Smart Energy
High tech results with low-tech solutions
Written by: Koen Fischer
For RAU architects energy is an important aspect in there design process. The office of Thomas Rau has been designing buildings which are energy and CO2 neutral for years. Nowadays there appear more and more energyproducing buildings in their portfolio. These building are designed to reduce the use of energy as much as possible but also have the ability to produce enough energy to provide for both themselves and other buildings. While designing, RAU architects will not initially consider high tech solutions. They rather pursue high tech results with low-tech solutions. Using the site-specific conditions for heating, cooling, illumination and ventilation characterizes the office. A healthy environment and the well being of the users will always be top priority.
Notice the SUN Each design by RAU architects is designed on the basis of site-specific conditions. One of the best examples of this principle is the design for the new headquarters of housing association “De Woonplaats” in the town of Enschede. Although the building has mostly transparent facades its sun shading is one of the most thought through aspects of the building. Following the path of the sun, the twisting movement creates the building’s own wedge-shaped access area, over which the floors 38
Headquarters of housing association “De Woonplaats”, Enschede. (Image courtesy by Christian Richters)
Thomas Rau studied fine arts and dance at the Alanus University of Arts in Bonn and architecture at RWTH Aachen University. He has been working as an architect in Amsterdam since 1990 where he established RAU in 1992. Thomas Rau is ranked nr. 4 among the Top 100 Dutch key players in sustainability, a list published annually by the established Dutch national newspaper Trouw. He is Dutch Architect of the Year 2013 and received the 2013 Arc Oeuvre Award for his pioneering work of 21 years. Town Hall Brummen, the first building designed as a raw materials depot, was selected as Dutch sustainable building of the year 2013.
Photo by Hans Lebbe
increasingly arch as they move higher. This way every floor is shaded by the floor above. To reduce the discomforts of direct sunlight even further, aluminum fins are placed in such a way they only allow indirect sunlight to pass into the building. The angle of the fins is precisely calculated to find the right ratio between visibility and sun blocking. The fins are only applied were needed, thereby the north facade and the staircases are not covered.
Breathing facades The contradiction between the need for large solar collecting transparent facades in the winter and the need for small, just for enough daylight windows in the summer is one of the most difficult design questions. For passive heating one must harvest as much sunlight as possible in winter, to keep a building cool one must block as much sunlight as possible in the summer. To solve this problem RAU introduced a breathing facade for the Woopa office building in Lyon. It combines large transparent surfaces and the ability to get rid of excess heat. Triple glazing is installed all around the building. In order to provide optimum protection against the higher heat load on the eastern, southern and western facades, the elements on these sides of the building have a more advanced construction than the ones on the northern
Breathing facade principle. (Image courtesy by RAU)
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side. A sandwich construction, consisting of a doubleglazed unit with sun louvres and a layer of single glass, will not only provide excellent insulation against the cold but also additional sun and heat protection, which users will even be able to control themselves. Small openings above and below the window will enable the air to circulate between the panes. In the summer in particular, this will ensure that warm air does not remain trapped between the glass panes but instead is able to circulate. The façade will breathe, so to speak, and cool the building as a result.
Energy neutral When the Dutch department of the World Wide Fund for Nature (WWF) outgrew their old office and had to look for a new building they found an old agricultural laboratory in the town of Zeist. Built in 1950’s, the building did not meet the contemporary requirements and did not suit the look and appearance of the WWF. Out of nine architects RAU was commissioned to (re)design the existing building. RAU has taken this seriously and presented the first CO2-neutral and self-sufficient office building in
Old agricultural laboratory, Zeist. (Image courtesy by RAU)
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the Netherlands. The energy performance of the building is very good; the building is CO2-neutral, it is (almost entirely) self-sufficient and achieves an A++ rating at the EPBD energy label by the European Union. Triple glazing and wooden lamellas in front of the large windows ensure efficient isolation and heat resistance. Solar cells on the roof generate electrical energy and solar thermal collectors are used for heating up water. Even the body heat of the building’s users is captured and re-used. Cool ground water is used for cooling the building before flushing toilets. Summer’s surplus warmth is stored in a water reservoir in the ground, and used for heating the building during winter. Likewise, cooling energy is stored underground during winter months and is used for cooling in summer. Large parts of the façade are made of glass. This open design lets daylight penetrate deep into the building and offers unhindered views of the surrounding nature. Wooden lamellas placed all around the façade protect the building from overheating. High-energy summer sunlight can enter the building only indirectly, whereas low-energy winter sunlight can pass through the lamellas unhindered.
Head quarters of WFF Netherlands, Zeist. (Image courtesy by Kusters fotografie)
All walls and ceilings in the building are plastered with mud. Mud can absorb moisture very efficiently and is a good thermal buffer. Embedded in the mud just below the surface is a mesh of fine capillary tubes covering large areas of the ceiling. The building is heated and cooled by pumping warm or cold water through the tubes. Because the system works with very large surfaces for thermal exchange, the distribution of cool or warm air is very homogeneous and subtle and corresponds to the natural temperature regulation in the human body. The temperature remains balanced throughout the year.
Radiators and air-conditioning are unnecessary. No airconditioning units and radiators also mean higher ceilings and a maximized use of the floor plan.
Energy Producing The more recent buildings designed by RAU architects are taken a step further. Besides using a lot of smart solutions for reduction of energy consumption, these buildings have a surplus of energy. One of the most prominent buildings with this ability is the “Christiaan Huygens College� in the city of Eindhoven. For the third branch of the school,
Climate and energy diagram of WWF head quarters, Zeist. (Image courtesy by RAU)
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the director asked for a ‘More striking and more famous’ building than the nearby futuristic congress building. The school building is the first CO2-neutral, energy-plus school in the Netherlands. Mainly due to the Energy Roof used in its construction, the school building designed by RAU generates more energy than the school needs for its own use. This surplus energy will be used in the adjoining sport hall and nearby apartments by Trudo housing corporation. The energy costs saved by all three buildings together amounts to 130,000 euros a year. The new building uses a compact construction in order to limit the surface area of the façade, thus reducing excess heat in summer and heat loss in winter. At the same time, well-insulated windows allow natural daylight to flood the building without causing overheating. SolarTech International developed the Energy Roof in cooperation with Volantis and TU/e. It is a thermal system based on solar power, which uses an evacuated tube collector with a heat exchanger, which is invisibly incorporated into the insulating layer of the roof construction. The tube collector is covered in synthetic roofing material with an integrated layer of photovoltaic cells that generate
Christiaan Huygens College, Eindhoven. (Image courtesy by Norbert van Onna)
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electricity. During peak hours, the system produces more energy than the school, the sport hall and the adjoining homes need. That surplus is stored in an underground water bell storage system. In the winter, this energy can be brought back up to heat the buildings. SenterNovem calculates a 98.5% CO2 reduction from the Energy Roof and the photovoltaic foil covering the roof, making the building almost completely CO2 neutral.
Weekend energy diagram of Christiaan Huygens College, Eindhoven. (Image courtesy by RAU)
Tipical school day energy diagram of Christiaan Huygens College, Eindhoven. (Image courtesy by RAU)
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