Climate Responsive Façade Design for High Rise Commercial Building in Subtropical Climate

Climate Responsive Faรงade Design for High Rise Commercial Building in Subtropical Climate

Zekun Zhu

September 2019 University of Westminster, College of Design, Creative and Digital Industries School of of Architecture and Cities MSc Architecture and Environmental Design 2018/19 Sem 2&3 Thesis Project Module

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Abstract This research will look at the design of high-rise building façades in subtropical climate zones. The highrise building here will be defined as 20-30 stories, 70-100 meters height, commercial building. This kind of building always uses glass materials to cover most of the building surface for aesthetic reasons. These glass façades will also cause some environmental problems while maintaining the appearance of the building, and this will be the focal point of this study.

The test base case will be the Tokyo area in Japan, which is under a typical subtropical monsoon climate with four distinct seasons and abundant precipitation. As the most developed country in Asia, Japan has built a large number of buildings at the beginning of the 21st century, but few buildings will design façades based on environmental considerations. The current local green building standards, CASBEE and LEED, are only an assessment on the building as a whole part. That means that when the performance of one part is insufficient, it can always be complemented by other parts.

However, this research will target on one point, how the façade of a building affects the overall performance, which is the people’s feeling inside the room. The two most important points will be taken into account, the daylight and energy balance, above which the influence of the external wall on indoor ventilation and the characteristics of some new special materials are also within the scope of the research.

The study will consider both existing bioclimatic and cultural backgrounds to study and evaluate existing building façades, including certified buildings.

After that, the study will propose several different scenarios based on the analysis of local buildings and testing under a specific weather situation, and software analysis will give a consistent result as an improvement. The experimental results can also be used as a general façade solution for green buildings in the future.

Table of Content Abstract Acknowledgement Introduction 5 1.Literature review 9

1.1“Thermal comfort� Theory

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1.2 Climate Responsive Design

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1.3 Environment & Architecture

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2.Context and Precedents 19

2.1Climate analysis

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2.2Building cultural

24

2.3 Filed work & Case study

28

2.4 Research scope & Difficifficulties

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3.Analytic work 33

3.1 Brief

34

3.2 MinatoMirai Center Building:

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3.3 Simplified Base Case:

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3.4 Shading design

44

3.5 Research outcome

50

4. Conclusion

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Table of Figures

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References 59

ACKNOWLEDGEMENT

I would like to express my special thanks of gratitude to Joana Carla Soares Gonรงalves as well as our course leader Dr. Rosa SCHIANO-PHAN, who gave me the golden opportunity to do this wonderful project on the topic of environmental faรงade, and my professor Juan Arevalo, Amedeo Scofone, which also helped me in providing a lot of suggestions and I came to know about so many new things I am really thankful to them.

I would also like to thank Bajcer Ula and her colleague in WSP Global who worked with me to finalize this project within the limited time frame and I appreciate it so much.

The most intuitive feeling for users is the thermal environment. The thermal here refers to the physical environment formed by the four elements of indoor air temperature, air humidity, wind speed, and heat radiation, and sometimes people called indoor microclimate.

Simply put, the so-called thermal comfort refers to people's feelings about the indoor environment.

The environmental factors that generate people's feelings of heat and comfort are more complicated.

These factors include the temperature and humidity of the air, the speed of the airflow, the clothes are worn by people, etc. The combination of these different elements ultimately gives people a feeling of comfortable or not.

Introduction Climate change refers to the impact of natural causes and human activities, it’s a long-term change in large scale including temperature, atmosphere, hydrology, etc. and now referred to as “Global warming”. From the view of data, this change is usually negative and has affected human life. Carbon emissions from human behavior have already caused an increase in the global average temperature, although currently, the rate is very slow, the impact will be severe, with the construction industry accounting for about half of the total energy using.

Therefore, in the construction industry, people are increasingly put more effort into optimization of building performance, which is to ensure indoor thermal comfort with minimum energy consumption. Now in the field of architecture, people have proposed the subject of sustainable building and climate responsive design.

In order to provide a good thermal environment for the office building, the most popular way is to adjust the air conditioning equipment or the mechanical ventilation system to ensure that the temperature in the room is kept within a certain range, which makes people feel comfortable and happy, and significantly improves their work efficiency.

Modern buildings are developing towards green, healthy, environmental-friendly and intelligent, especially in people’s working area, so people put forward higher requirements for the indoor thermal comfort of office buildings.

Theoretical background With the rapid development of social economy, people's requirements for living quality are getting higher and higher, especially for the environmental health of life and work. For most people, most of the time is spent in the office room or home, that means they are always in an indoor environment.

According to data from the US Environmental Protection Agency's (EPA) follow-up survey of nearly 10,000 people in 1993, people spend 87.2% of their time in various indoor environments, which shows that the quality of indoor environment has an important impact in human life [1].

Context With the development of the commercial scale, the number of indoor workers is increasing. If those employees are working in an uncomfortable e nv i ro n m e nt fo r a l o n g t i m e , t h ey ca n n o t concentrate on their work and even affect their physical and mental health. In the view of this situation, the main research object of this paper focuses on commercial building, aiming at the comfortable and healthy indoor thermal environment, taking the glass façade out of the building, that means a glass tower which is common building type in big cities.

As well known, glass materials usually come with a high heat transmittance value only if a special type of double-glazed vacuum glass was applied. If taking a high-rise building in sub-tropical zone, the area which performs the worst user experience.

This research will take the establishment of indoor thermal environment model of indoor space, improving the working environment and provide a good thermal environment for those who sit close to the façade.

In today's society, there are more and more indoor office workers, and the density of indoor office workers is relatively large. Workers need to spend more than 8 hours a day in their offices. If the company can provide a good indoor environment for their employees, they can not only make them physically and mentally healthy, but also It can improve its work efficiency, so it is meaningful to study the indoor environment of office buildings.

Generally, the Indoor Environment refers to the physical environment inside the building, which includes indoor air quality, thermal, lighting, sound, and humidity.

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Research question

The main indicator of the indoor thermal comfort is the indoor air temperature, and the main factors affecting the indoor temperature are the outdoor atmospheric temperature, outdoor solar radiation, and the exothermic heat of indoor heat source such like people and equipment.

Indoor air temperature here referred to DBT (dry bulb temperature), if we want to check the thermal comfort level, we will look on another term called Resultant Temperature (or Operative Temperature), this is the most intuitive feeling of people in the room. So for creating a good indoor thermal environment, we need to focus on the impact of these aspects.

In recent years, high-rise buildings have emerged in an endlessly, and the resulting architectural aesthetics is a symbol of modern architecture. Highrise buildings and iconic buildings, most of which are come with conspicuous large-scale glass façade.

Diverse architectural forms bring new topics in indoor thermal comfort research.

The research point of this paper mainly includes: 1. The current situation of the indoor environment is due to the particularity of the external protective structure of the glass tower office building. The influence of the solar radiant heat from outside is more significant than that of the general building, and the indoor radiance temperature fluctuates greatly.

At the same time, the geographical location, installation method of the façade and the orientation are different, so the factors affecting indoor environment change are more complicated. Therefore, in order to meet the human body thermal comfort requirements and optimize the design of the glass façade structure, it is necessary to understand the current situation of the indoor environment in the office building.

2. Study on the thermal environment influencing factors and heat exchange process in office buildings, through theoretical analysis and modeling test of a simplified office building.

Understanding those influencing factors and their working modes in the office, to analyze the heat exchange process through glass façade in high-rise office buildings, and to clarify the heat transfer mechanism.

3. Optimization of glass façade in high-rise commercial building. Under the climatic conditions of subtropical regions, consider the requirements of indoor thermal comfort, evaluate the glass façade in existing buildings or even certified green buildings, and the optimal curtain wall structure is selected through software simulation.

4. Establish a model of the indoor environment of glass tower office building, and propose a new form of curtain wall structure, including the design of the shading and the selection of glass materials, model an office room in the building with different types of curtain wall structure covered and simulate the indoor thermal comfort with software. The results of the simulation are analyzed to determine a relatively reasonable façade structural form.

As a result, studying the indoor thermal environment of office buildings has the following meanings: 1. Quantitatively describes the effects of outdoor temperature, solar radiation intensity (including direct and diffuse) and enclosure structure on indoor temperature changes.

2. Saving the energy using and precise control of the indoor thermal environment ensure that the indoor operative temperature is kept within the comfortable range of the human body, and energy waste caused by irrational using is avoided.

3. The indoor operative temperature can be kept just within the comfort range because of human adaptability. It is best to keep it in the vicinity of the set value quickly and stably. That means the operative temperature change should not be so significant when there is a large disturbance from outside.

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Methodology

benchmarks and finally, a general glass façade solution was given.

Literature view: Before starting the project, I first learned about theoretical knowledge of building structure and building thermal processes, and looked through local environment regulations, construction materials related to glass façade, energy conservation, and related tests on indoor thermal environment published, including networks, journals, academic conferences, and other relevant materials. By summarizing the advanced research results of the industry, to have a more comprehensive grasp of the current research status in this field, so that I can have certain systematic and innovative research content and ideas.

Report Structure The thesis is composed of the following three parts: Literature review: This part firstly introduces the history of the development of modern architecture. With the changes in the social system, how the architectural patterns have become what it is now, and thus draw forth the research object of this paper is the high-rise commercial building. At the same time, considering the changes in global climate, the environmental regulations promulgated in different countries will also have an impact on local building styles.

Fieldwork: In the early stage of on-site research, I conducted site investigations on some existing office buildings in Kanto area (Japan) and took photographs, and direct communication with users to understand the current status and their experience in local commercial buildings. On this basis, explore the factors affecting the indoor thermal environment, and find a reasonable plan for the glass façade of the office building.

This is followed by a review of the study location, combining Japanese history and local building codes to discuss how existing high-rise buildings achieve energy efficiency or not.

Later, the theory of Thermal comfort and the widely used evaluation criteria for human comfort, including ASHRAE55 and EN-15215, were introduced. Through the discussion of different evaluation methods, we conclude how we define the comfort band in this thesis. Finally, the principle of the glass façade is discussed in detail, including the transmission and reflection of light and heat in different materials, as well as the design of exterior façade and shading structures with different structures.

Case study: The research area in this paper was selected in the Kanto area in Japan, and a representative commercial building was selected in the local city. Through the modeling analysis of the building, test on indoor thermal condition of the winter and summer in an office, and grasp the characteristics and changing trend of the temperature in different seasons. Combined with the floor plan of the building, the thermal comfort of various parts of the office was determined to lay the foundation for subsequent scenario analysis.

Context & Fieldwork: This section includes a detailed climate analysis in the Kanto region based on Tokyo meteorological data provided by Meteonorm and a detailed discussion of indexes including temperature, rainfall, radiation, illumination, sky component, etc. that affect the comfort of the human body. Since we hope that the subsequent scenario analysis is as simple as possible, we will screen the environmental indicators here and select some parameters that have a great influence on the comfort of the room, and then analyze them later.

Scenario analysis: A simplified office model was created in the context of the local climate, regardless of the occlusion of the surrounding buildings, and the results of the case study were used to divide the indoor area according to the direction. The most important part of this research will focus on was the indoor part close to the facade.

Modeling the exterior wall with different types of glass, calculating energy consumption and combining the design of the shading device to propose new types of façade structures. In the subsequent analysis, the combined structure was further optimized based on local regulation

This part also includes a case study. This article selects the MinatoMirai Center Building in Yokohama City as a bade case, evaluate on the location, materials, and structures of this certified 7

building, and takes a representative floor as the basis for the scenario analysis.

This part, as preparation for analytic work, will state the difficulties that will be encountered later and explain how to deal with them.

Analytic work: Based on the case study, a simplified office room model will be created here under the local climate, after which we will create different scenarios by changing or adding different design elements including curtains, glass façades, and shading devices and using software to analysis on them.

According to research agenda, the analysis will be divided into separate sections such as daylight and thermal. Finally, it’s desirable to find a good combination of shading and daylight access but reduce it as much as possible to minimize the cooling load.

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Literature review

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1. Literature review 1.1 “Thermal comfort” Theory Previous Research:

Background：

At the beginning of the 20th century, the “Thermal comfort” related to how the human body’s feeling gradually became the object of all engineer scholars' research worldwide.

Creating a comfortable and healthy indoor living environment is the life that people always yearning.

From the long-term survey results, it can be seen that in modern living mode, people have spent more and more time under indoor environments. With the advancement of the times, the development of science and technology is changing with each passing day, people's clothing, food, housing, travel, and other aspects have undergone unexpected changes, and they can live and work normally without leaving their house. Therefore, the quality of indoor environment has a significant impact on people's physical and mental health and learning habits and work efficiency [2].

In the late 1960s, the Emergence of the Energy Crisis accelerated the research process of thermal comfort. In 1967, Professor Fanger published an important paper on thermal comfort, which played a powerful role in promoting thermal comfort research. Since then, further research on thermal comfort has started around the world.

In 1919, the American Association of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) did a lot of experiments to formulate the thermal comfort standards that industrial development urgently needed [3].

The indoor environment consists of the physical environment and indoor air quality. The physical environment includes indoor thermal environment, acoustic level, light quality, electromagnetic environment, etc. The indoor thermal environment includes indoor air temperature, humidity, airflow rate, etc. The most important environmental factor for enthusiasm, health, and comfort. Thence, the indoor thermal environment is an important part of the whole indoor environment research, and creating a comfortable indoor thermal environment is also the final goal by our designers.

In the 1960s, many colleges and universities in the United States established laboratories dedicated to the study of human thermal sensation and heat adaptation, to study the effects of environmental factors such as air temperature, relative humidity, and airspeed on human thermal comfort.

Figure 1.1.1 Indoor thermal comfort principle

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International standard: The International Organization for Standardization (ISO) uses the PMV-PPD indicator system proposed

by Professor P.O.Fanger, a well-known scholar at the Technical University of Denmark. In 1962, Macpherson et al. [4] proposed that metabolic rate, and clothing insulation, air temperature, relative humidity, mean radiant temperature, and airflow rate are the main influencing factors of human thermal comfort. On this basis, Prof.

Fanger[5] proposed a famous thermal comfort equation through further analysis and research, and proposed the concept of Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD). The so-called PMV-PPD indicator system is actually based on his research on people’s feeling, an environmental assessment indicator established by statistical test on the thermal sensations of 1396 US and Danish users, due to a large amount of the experimental data it is recognized by the world.

The CBE Thermal Comfort Tool, which published

by UC Berkeley, for ASHRAE 55 allows users to input the six comfort parameters to create an indoor environment and check whether a certain combination complies with ASHRAE 55. The results are always displayed on a psychrometric or a temperature-relative humidity chart. It is worth mentioning that the airflow rate of ASHRAE 55 2013 is 0.2 m/s (0.66 ft/s) higher than the baseline model, so the airflow can directly provide cooling effect on users.

Consequently, using the thermal comfort field survey database, the accuracy of PMV in predicting occupant's thermal sensation was only 34%, that means the prediction is correct in one out of three times. The PPD was overestimating user's thermal unacceptability outside the thermal neutrality ranges (-1≤PMV≤1) and also, The PMV-PPD model's accuracy varies strongly between different ventilation strategies, building types and climates [6].

The United States now generally adopts two systematic standards, one is the ASHRAE 55-2017 standard made based on the PMV-PPD model, which requires at least 80% of users to be satisfied.

There are 7 levels in the ASHRAE standard: -3 (cold), -2 (cool), -1 (slightly cool), 0 (Neutral),1 (slightly warmer), 2 (warm), 3 (hot). PMV reflects satisfaction level of most people in the thermal environment.

The indoor environmental conditions are ideal when the PMV is between -0.5~0.5.

Figure 1.1.2 PMV indicator system

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Some other research:

The other is the Adaptive comfort model, and it can also be implemented in other standards, such as European EN 15251 and ISO 7730 standards.

Although the exact derivation methods and results are slightly different from the ASHRAE 55 adaptive standard, they are basically the same but applicability varies widely. The ASHRAE Adaptive Standard applies only to buildings that do not have mechanical ventilation system installed, while EN15251 can be used in mixed ventilation mode buildings, even if the system is not operational.

In 2012, Paola Ricciardi et al. [7] analyzed the thermal comfort of nine open offices and compared the Predicted Mean Vote values from the questionnaire survey with the operating temperature and found a significant correlation.

A neutral temperature corresponding to thermal comfort is also calculated.

In 2015, M. Indraganti et al. [8] studied the effects of adaptive behavior, gender, and age on thermal comfort. The study found that the comfort temperature of women, young people and lighter weighters was higher than that of men, the elderly and Heavier weights.

In 2006, Xia Bo and Liu Jiaping measured the environmental parameters of a university dormitory in China and asked students to fill out the questionnaire. The results showed that about 80% of the students were dissatisfied with the dormitory environment, but gradually adapted to this. From this research can say that people have certain adaptability to the thermal environment.

In 2011, Mei Lan, Li Baizhan et al. studied the influence of airflow rate on human thermal comfort in summer high-temperature environment and studied human thermal comfort and thermal sensation in the air blowing environment. The result shows that when the summer ambient temperature is high, the physiological parameters and thermal sensation of the human body are significantly reduced under the air blowing environment, and the lower the air temperature, the greater the degree of decline in the case of the same wind speed.

In 2015, Yuan Weiqi et al. proposed the concept of “Clothing coverage� based on the thermal comfort model from Fanger. The model for clothing insulation and skin surface diffusion was appropriately modified. At the same time, taking the badminton activity as an example, the influence of environmental parameters on the thermal comfort of the moving human body was under the study.

Figure 1.1.3 Graphic Comfort Zone Method: Acceptable range of operative temperature and humidity for spaces that meet the criteria specified in Section 5.2.1.1 (1.1 met; 0.5 and 1.0 clo)—(a) I-P and (b) SI.

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Understandingďźš

the clothes. Clothes can be regarded as the heat transfer medium between the human body and the environment.

A comfortable office indoor environment is a basic prerequisite for people to work well. In a comfortable office environment, people's intelligence, reaction and manual operation ability will be in a good state; if they do not under comfort conditions, working efficiency will drop; if the temperature seriously deviates, it will make people feel overheated or too cold, or even make them can't work properly.

The thickness of the clothes directly affects the heat exchange between the human body and the environment, but if we want to discuss all the factors affecting the heat transfer are complex, including the thermal resistance of the material and the internal radiation and convection of the air between the garment layers.

In addition, due to the influence of the humidity of the environment, if the clothes are damp, and the thermal resistance will also be greatly reduced.

The common clothing thermal resistance shows as follows.

The factors that affect the thermal comfort of the indoor human body are mainly environmental factors and personal factors. Environmental factors mainly include: indoor air humidity, temperature, radiant temperature, and airflow speed; Personal factors are mainly the individual's environmental adaptability, activity, and clothing. These factors are mutually influential and interrelated and each of them directly affects people's thermal comfort. The superposition of multiple factors has a great impact on the human body's thermal comfort.

For the human body, the comfort temperature is not a specific value, but a comfort range. The design temperature in summer of the indoor thermal environment in the cold region is usually 26 to 28 °C and in winter is 16 to 18 °C. The air temperature is the most direct and most significant factor in the thermal comfort of the human body. The heat exchange between the temperature and the human body is carried out in a convection and radiation manner. Ventilation will exchange the heat in indoor and outdoor air, adjust the indoor air quality and air temperature and humidity, thus affecting the human body's perspiration efficiency and convective heat transfer. Summer air temperature is always high and indoor airflow will accelerate the evaporation and heat dissipation from human skin surface.

Figure 1.1.4 Thermal resistance of common garment combinations

The radiant temperature is the mean temperature of the total surface radiation from all objects around the environment in which the human body is located. It depends on the distance between body and context and the surface temperature of each object in the room, which will affect the radiation heat transfer of the human body.

The heat of the human body is mainly lost to the surrounding air through the clothes worn, and the heat of the surrounding environment is also absorbed and perceived by the human body through 13

1.2 Climate Responsive Design:

Givoni(1976) developed a bioclimatic design approach based on Olgyay's theory and combined with temperature-humidity diagrams used by air conditioning engineers to form a “Building Bioclimatic Design Chart�.

Although the architecture design has thought of climate considerations from the beginning, and the climate responsive design is an ancient philosophical theory, the systematic theory of the relationship between architecture and climate started from Victor Olgyay.

In his proposed analysis of building bioclimate design, he demonstrated strategies such as Ventilation, Evaporative cooling, Thermal mass, and Night ventilation to achieve indoor thermal comfort.

It is worth mentioning that Givoni's bioclimate design analysis approach is usually only applicable to residential buildings with a few indoor heat sources.

Olgyay proposed the method of architectural climate responsive design system in 1953. His proposed Bioclimatic Design Method comprehensively considered the impact of all climate factors on architectural design, and the corresponding indoor thermal environment and thermal comfort problem.

Figure 1.2.2 Bioclimatic Chart for pressure of 96.035 kPa (Elev:450m)

Figure 1.2.1 The Bioclimatic Comfort Chart

Victor Olgyay "Design With Climate" 1963

The Bio-climatic Chart, which he proposed in 1963, systematically analyzed the relationship between human comfort zones and climatic environmental factors. Olgyay believes that the lower temperature limit (21 °C) of the comfort zone is determined to under the shadow necessarily. When the outdoor air temperature and relative humidity are below the lower boundary of the comfort zone, it indicates that the outdoor is cold and solar heating from radiance is required for an indoor environment.

Otherwise, certain wind flow is required to get comfort. His method is not suitable for dry and hot areas but is more useful in architectural forms in hot and humid areas.

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From the theory from Olgyay and Givoni, climate responsive design is actually a strategy to control climate factors for the achievement of a targeted thermal comfort environment. In other words, the energy in the building environment is used to neutralize the outdoor environmental climatic conditions to achieve thermal comfort.

In this thesis, "climatic responsive façade design" refers to make a design of façade structure to ensure indoor thermal comfort and reduce energy consumption as much as possible. This simple goal needs to be realized through the combination of various parts of the building, which is very complicated to implement. A systematics passive design needs to be considered in the following aspects.

If ΔQ equals the energy in the building environment need be controlled, then the relationship can be expressed by the following formula. The climatic design strategy is used to achieve the requirement of those energy reductions.

This study will not consider the effects of office internal conditions because this is designed to improve the facade of existing buildings and is limited in high-rise commercial buildings. There may also have different solutions in Japan's climatic conditions and local architectural regulations, which will be discussed later in the context section.

ΔQ = Outdoor weather condition – Indoor thermal comfort condition

Figure 1.2.3 Passive Design strategies

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1.3 Environment & Architecture:

Research status: In the 1970s, after the oil crisis broke out in Europe and the United States, countries began to formulate and implement a series of building energy regulations based on their own energy consumption characteristics.

Background: The development of the city is mainly reflected in the aspects of industry, transportation, and construction, and energy consumption is relatively high. In Europe and the United States, the energy consumption of these three fields has formed a full potential.

The United States promulgated the New Energy Policy Law and formulated economic support measures for those energy efficiency buildings; France promulgated regulations related to energy efficiency in residential buildings; Japan has established the most comprehensive Energy management system, and in order to specifically research on building energy issues, a complete Energy consultancy, and management agencies have been established from the central to local government; in Finland, non-energy- efficient buildings are not allowed to be rated, pre-sale and listed transactions, and existing non-energyefficient buildings need to be retrofitted to meet the requirements before they can be sold.

Building energy consumption is an important part of total energy loads. The definition of “Building energy consumption” is not consistent in the construction field.

Some people think that building energy consumption is mainly energy using during construction, through building materials, and in building ’s internal condition. One argument is that it only includes energy consumption in buildings [9]. The higher international recognition is the energy consumption in the building by equipment and occupancy, that’s the energy consumed by people living and working normally in their environment after the building has been built.

There are many approaches for building energysaving and the simplest one is thermal insulation.

At present, aerated concrete is widely used as a wall energy-saving insulation material in developed countries such as Europe, America, Japan, etc., and is the only single material among all wall materials that can meet the requirements of energy-saving standards [11].

At present, the building generally has problems of high energy consumption, low efficiency, and bad thermal insulation performance of the external enclosure structure. In summer, the air condition system consumes a large amount of electricity, and in the winter, heating energy is also relatively high.

In recent years, the global temperature has risen overall, and the urban area is more obvious. As a major component of building energy consumption, the number of air conditioners is growing at a rate of more than 10 million per year, resulting in continuous growth of cooling load in summer and the proportion of cooling loads in total energy consumption has also risen rapidly. The airconditioning load in large cities accounts for about 40% of the total peak loads in the city [10] when AC system is operated.

Figure 1.3.1 Building's Heat transfer

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In the middle of the last century, the British Pilkington Company developed low-emission coated glass. Later, PPG in US and Saint-Global in France also developed the production process [11].

Then the high-temperature pyrolysis coated float glass was developed, which reduced the cost of glass production and reduced the price to a level acceptable to ordinary buildings. At the end of the 1980s, low-emission (Low-E) glass was widely used indoors and windows over buildings. In the mid-1990s, Germany enacted legislation requiring all buildings to use low-emissivity glass to reduce energy loss due to excessive heat loss from ordinary glass. And the new energy-saving regulations in the European Community came into effect, requiring new and rebuilt buildings to be built thereafter.

The promotion of the use of low-E glass has led to a sharp increase in the demand for low-E glass; Germany, which promotes the popularization of low-E coated, will reach 92% in the future, 90% in Austria and 75% in Poland. A similar policy is now being introduced in many countries, and the use of low-emission coated glass will increase significantly in the future [13].

The thermal insulation performance and airtightness of the building envelope have a considerable impact on building energy performance. In recent years, researchers in the field have done a lot of work in building materials, energy-saving strategies for doors and glass windows, and in product development, design, and production.

At the national level, a series of policies have been introduced to promote new energy-saving and environment-friendly materials.

In buildings, more than 50% of the total energy consumption is lost through the door and glass windows. Choosing the architectural glass which is suitable for the local weather, so that the energy consumption is minimized, and also meets the national green building regulations, is one of the key issues to solve.

The heat loss approach is mainly from conduction, convection and radiation. For buildings, the heat loss through the window is mainly that the glass absorbs the infrared light, releasing the far-infrared rays with longer wavelengths, and the heat loss caused by conduction and convection is relatively Smaller [12].

At present, the insulating glass, vacuum or inert gasfilled glass that we have used in our daily life can effectively prevent the conduction and convection of some heat, and the energy-saving and heat preservation effects are relatively significant

Research on glass material has been ongoing, and efforts are being made to explore the future development of glass faรงade. In recent years, Low-E glass widely used in office buildings can effectively prevent heat loss throughout, and its energysaving efficiency is more than 74%. Moreover, due to the reduced energy consumption of buildings, the equipment investment required for building indoors and office can be reduced, and in particular, the efficiency of building operation costs can be significantly improved.

At present, there are many development projects that use environmentally friendly materials and new energy-saving strategies to achieve energysaving purposes. This will increase the construction cost, but if people understand the value of advance payment in the early stage, there is more values paid back, and for the real estate market is also a big selling point.

In addition, with the increasing awareness of environmental protection, people will be more and more concerned about whether the living space is environmentally friendly or energy efficient.

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Context and Precedents

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Temperature (refers to DBT) A s c a n b e s h o w n f r o m t h e 2 0 1 0 To k y o meteorological data from Meteonorm, the highest peak temperature occurred at 32.3 °C at the end of July and the monthly average temperature was 27.4 °C in August. In July and August, the mean average temperatures were both greater than 26 °C. On the other hand, the minimum winter monthly temperature in the region is 6.34 °C in January and the lowest could drop till 3.24 °C.

2. Context and Precedents 2.1 Climate analysis Sub-tropical climate The Kanto region is an area near the Pacific Ocean in central Honshu Island, Japan. This region includes the Greater Tokyo Area and including seven prefectures. About 45% of the land in this area is the Kanto Plain, and the border is surrounded by the Ibuki Mountains.

Monthly Average Dry Bulb Temperature 35.00 30.00

mean max/min

25.00

mean average

20.00

Adaptive Comfort EN 15251:2007 (Class II)

10.00

Adaptive Comfort EN 15251:2007 (Class III)

oC

15.00

5.00 0.00

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Figure 2.1.3 Monthly Average Dry Bulb Temperature

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That means the Tokyo region has a relatively mild winter under subtropical climates and almost no more than 30 °C in summer. In this thesis, we will define a six-month summer period with the highest temperature, which will be from May to October so the temperature will be 19-27 degrees, and the remaining six months will be the winter period.

Figure 2.1.1 Kanto Region Map

Precipitation The average amount of precipitation in 2010 is 122 mm, the most cumulative rainfall happened in September and October, and the least in January and February. Due to the influence of the monsoon from the Pacific Ocean in summer, there are more than ten days of rain each month throughout the spring and summer season. From the beginning of June, there will usually have a Rainy season lasting for one month. After this month, it will be relatively moderate, and from August to October, there will always meet five or six typhoons landing from the south-east coast, causing damage to the environment and bringing a lot of rainfall.

The geographical features of Japan are mainly divided into six climatic zones, of which the Kanto region is a typical Subtropical Monsoon Climate.

(Köppen climate classification: Cfa). The climate here is temperate, with fairly mild, sunny winters and hot, humid and rainy summers.

Figure 2.1.2 Climate classification map for Japan

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Cumulative Rainfall 250

30

Daylight hours

27

200

24

150

mm

18 15

100

12

days

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Tokyo is at 36° North latitude, compared to 51°N in London, the length of the day will not change too much. In summer, it is about 12 hours daytime in a day, that means half a whole day, and in winter it is reduced by four hours. At noon in the summer, the solar altitude can reach up to 77.7°. Due to the wide range of the solar angle, the south façade will be exposed to direct sunlight throughout the whole year, and in the building with the glass façade, the part close to the façade at noontime, it will receive direct sunlight from almost the top of the head.

Rainfall Days

9 50

6 3

0

Jan

Feb Mar Apr May Jun

Jul

Aug Sep

Oct Nov Dec

0

Figure 2.1.4 Cumulative Rainfall

Humidity The humidity in the monsoon climate varies greatly throughout the year, fluctuating ion the range of 4570%, highest 71.26% in June and lowest 45.37% in January, which needs to be discussed in conjunction with temperature and rainfall.

Figure 2.1.7 Daylight situation Figure 2.1.5 Precipitation & Humidity & Temperature

During the summer, due to the relatively high temperature and long-term heavy rainfall in June and September, even July, which is a gentle month, maintains a high humidity level. The relative humidity in winter is kept at around 50%, keeping the weather dry and dry with almost no snow.

Figure 2.1.8 Frequency of Sky types (8-18)

Monthly Average Relative and Absolute Humidity 100.00 90.00 80.00

%

70.00 60.00

RH mean max/min (%)

50.00

AH mean max/min (g/kg)

40.00

RH mean average (%)

30.00

AH mean average (g/kg)

20.00 10.00 0.00

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Figure 2.1.6 Monthly Average Relative and Absolute Humidity

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Radiation & Illuminance

Wind

Daily average global radiation is higher than 2 Kw/ m2 in Horizontal surface throughout the year and is around 4 Kw/m2 or more in the summer season, reaching a peak of nearly 4500 w/m2 in May. In June, the amount of radiation decreased slightly due to the Rainy weather. About 65%-75% of the summer daylight radiation comes from diffuse. From the vertical radiation data, we can also know that the radiation acceptance difference from faรงade in the north and south in the summer is not very big.

The amount of radiation also affects the global illumination. From the results of Meteonorm weather data, the Design sky illuminance is 13451 lux. If we need the indoor illuminance in the range of 300-2500 lux which is normal office benchmark, we can calculate that the 2.2% DF value is required.

The annual average wind speed in the Tokyo area is 3m/s and comes from Northwest. The summer wind is weak and mainly comes from the northeast and southwest direction. In contrast, the winter wind is dominantly from the northwest direction and is relatively strong. This part might have a great impact on the prevailing wind direction throughout the year.

This means that if the wind-driven natural ventilation in summer needs to be taken into account during the design of the building to reduce the heat, the window opening in the southsouthwest direction may be beneficial.

Monthly Average Global Vertical Radiation 3.50 3.00

kWh/m 2

2.50 North

2.00

East

1.50

South

1.00

West

0.50 0.00

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Figure 2.1.11 Monthly Average Global Vertical Radiation

Figure 2.1.9 Daily Average Global Horizontal Radiation

Daily Average Horizontal Radiation 5.00 4.50 4.00

kW/m2

3.50 3.00 2.50

Global

2.00

Diffuse

1.50 1.00 0.50 0.00

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Figure 2.1.10 Daily Average Horizontal Radiation

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Nov

Dec

Thermal comfort-PMV Local climatic conditions are the main influencing factor in building's indoor thermal comfort and play an important role in determining the types of passive strategies that can be incorporated into sustainable building design.

The climatic analysis above shows that in the Kanto region, represented by Tokyo city, due to the high solar angle and the summer temperature of around 26 degrees, if a glass commercial tower in an urban area is considered, a large scale of transparent façade will bring a large amount of heat gain from solar to indoor, means that there is usually under a very high radiant temperature during the daytime.

In order to reduce this part of the heat, a massive and high-power mechanical AC system will be put into use. We call this part of the energy consumption “Cooling loads”.

If the window on the façade are openable, the airflow caused by the temperature difference would promote heat exchange. The practicality of this part will be proved in the following analytic work.

The temperate climate with almost no below 0 degrees in winter, combined with the energy gained from the solar radiation, should maintain a relatively mild environment in the room.

Figure 2.1.12 Tokyo PMV Chart in 2010 by GH.

23

Building culture in Japan

2.2 Building cultural

The architecture of Tokyo is widely influenced by its history. In modern history, the metropolis was left behind twice: first is the Great Kanto Earthquake in 1923, and later is a large-scale bombing after the Second World War. Due to this factor, most of Tokyo's current urban landscapes are made of modern buildings, with few old constructions. Tokyo used to be a city with a low-rise building and a large number of single-family houses.

Climate change: Tokyo is a typical example of “Urban heat island” and is particularly acute in some area, so it becomes a convincing case of a typical relationship between “urban growth” and “climate change”. According to the Tokyo Government, the average annual temperature has risen by about 3 °C over the past 100 years.

Now the city is more concerned about highrise buildings and urbanization. However, with the development of building culture, the risk of natural disasters is also increasing, and this building structure has to undergo tremendous changes.

Since the 1990s, sea level rise has become huge risks near the Tokyo Bay, along with volcanoes and major earthquakes. Therefore, new emphasis is placed on Marine disasters such as sea-level rise and earthquakes. Today, Tokyo has grown to more than 500,000 inhabitants, and the city center has moved to the southeastern part. As population growth speeds up, the city has to develop vertically to take advantage of their using land.

The IPCC proposes two scenarios for the future.

One is the scenario “A1B”, assuming that the future world will have more global economic growth without considering environmental protection. The other is the scenario “B1”, assuming that the future world will have a global green economy.

The scenario shows the daily increase in mean temperature in Japan during the period of 2071 to 2100. The temperature will be increased by 3.0 °C in Scenario B1 and 4.2 °C in A1B compared to that in 1971 to 2000, and the daily maximum temperature in Japan will increase by 3.1 °C in B1 and 4.4 °C in A1B. The precipitation in summer in Japan will increase steadily due to global warming also.

At the same time, Tokyo has taken some measures to reduce greenhouse gas emissions：

Japan's initial urban planning was based on a Western model, similar to the United States, where cities were divided into various types of commercial, residential, and industrial areas.

Governor Shintaro Ishihara created Japan's first Emission Cap System, which aims to reduce greenhouse gas emissions by 25% from 2000 levels by 2020. (En.wikipedia.org, 2019)

In 2006, Tokyo released a new development plan and a series of policies and goals: Establish seismic standards for urban buildings in order to strengthen the disaster prevention capabilities of the lands in Tokyo. The seismic standards of residential facilities in Tokyo are all required to reduce the degree of damage to more than 95%, and the requirement for public buildings and facilities, which under a high frequency of using, is 100%.

In 2006, the “Green Tokyo 10-years Project” was established. It’s aimed to increase the number of roadside trees in Tokyo to 1 million (from 480k) and add 1,000 hectares of green space within ten years.

Cool Earth 50 (also known as Cool Earth) is a plan developed by Japan to reduce global CO2 emissions 50% by 2050.

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Figure 2.2.1 Traditional Japanese Residential in Nora

Figure 2.2.2 Modern Commercial building in Tokyo

25

Building culture in Subtropical Climate

The New Energy Policy, which aims to balance the environment-friendly and achieving economic growth, sets a safe energy supply system with a self-supporting and decentralized energy source.

Provide urban energy development strategies with efficient energy using as the basic starting point and vigorously promote new energy policies.

The main characteristics of urban in Sub-tropical climate: 1) Relatively weak solar radiation: Due to the development of the city, the atmosphere is polluted, so the transparency of the air is poor.

Compared with the suburbs, solar radiation inside the city is reduced by 10%-15%.

Make Tokyo the world's smallest and most advanced low carbon city, actively promote international cooperation. Set green evaluation b e n c h m a r ks fo r b u i l d i n g s , p ro m o te a n d popularize low-carbon buildings.

2) High temperature in urban areas: As known as heat island effect. The temperature inside the city is usually higher.

3) Low air humidity: Because of the large number of artificial surface materials used, precipitation is mainly lost through the drainage system. The dry surface adds on the high temperature, the annual average relative humidity is lower.

Form a natural and abundant three-dimensional green network. Increase the greening spaces such as roofs and walls of all public buildings in Tokyo.

4) Wind speed is low, and direction is unstable: due to the staggering of streets and the difference in height of buildings, the wind is easily blocked by tall buildings and changes direction while moving.

As a result, in the design of urban buildings in subtropical areas, some measures are usually taken to insulate and cool down: Vegetation roof, by planting plants on the roof to block the side effects of solar radiation on the roof and using the transpiration of plant foliage to absorb solar radiation to achieve the purpose of heat insulation and cooling.

Window shading, which can block a large amount of solar radiation entering the room and reduce indoor air temperature sufficiently.

Sub-floor on the top, or Roof Terminals. Because the heat will naturally rise up, usually the top floor of the building is erected to isolate the accumulated heat, but usually only used in residential buildings.

Light-colored faรงade: The light color always reflects more daylight and absorb less, the color of the building's exterior walls is usually in light colors, but if it is a glass tower, this will be considered.

26

Façade design principles

3) VT: Visible light transmittance The visible light transmission is the amount of light in the visible portion of the spectrum pass through the glass material. A higher VT means more daylight in the space, and if properly designed, it can offset the artificial lighting and its associated cooling loads.

Visible light transmission is affected by the type of glass, the layers of panels and any glass coating. The VT of the glass ranges from more than 90% of the uncoated clear glass to less than 10% of the Highly reflective coating on the colored glass.

Glass façade as transparent enclosing structure, some important parameters related to energysaving design are listed below 1)

K Value: Thermal conductivity

The K value is the amount of heat transferred through the 1m2 area in 1 second when the temperature difference between the two sides of the structure is 1 degree under the condition of stable heat transfer situation.

It’s referred to as U-Value (Thermal conductivity) in some countries. When talking about glass materials in the industry, people customarily using U-Value to express its energy-saving effect. The larger the U value, the stronger the heat transfer coefficient, and the more heat is lost through the structure, which is less conducive in terms of energy saving.[14]

And from the definition we can easily know:

2)

Sc: Shading coefficient

SC is the ability of glass materials to withstand sunlight and is used to measure the sunlight energy transmittance of the glass. It is defined as the ratio of solar energy passing through the glass to total solar energy passing through 3mm Clear Float Glass under the same conditions.

After 1990s window design evaluation criteria have moved from Shading Coefficient to Solar Heat Gain Coefficient (SHGC), which is defined as the fraction of incident solar radiation which actually enters a building as heat gain through the entire window structure (not just the glass portion).

A conversion from SC to SHGC is not necessarily straightforward but for an approximate conversion from SC to SHGC, multiply the SC value by 0.87.

Figure 2.2.3 Commercial building in Shibuya Region (by Fieldwork)

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2.3 Filed work & Case study Fieldwork:

MinatoMirai Center Building:

In early June 2019, I conducted a one-week field trip to Tokyo and the surrounding areas. I visited some local buildings to understand their operating situation. Unfortunately, due to the extreme personal privacy of the Japanese, most buildings are not allowed to enter or even take pictures. The good thing is that I did talking some friends who lived in Japan and learned about the experience and feedback of local occupants in the office building from their mouths, and these contents would be referred in the Analytic Work section to evaluate the indoor environment.

Background & Internal conditions: This building is located in an ecologically-friendly Business Center in the eastern part of Yokohama City and has very convenient transportation 30 minutes away from Narita Airport. Due to its proximity to Tokyo Bay, this business center is also surrounded by six public parks. I chose this building as representative because it not only meets our research building requirements, a glass façade tower but also is a CASBEE-certified S-Rank green building.

At the same time, it also has the characteristics of a normal urban building, tall (98.2 m) and surrounded by other buildings which may have a greater impact on indoor lighting.

Although Japan has a complete regulation of Green Building Assessment System (CASBEE), we still believe that the actual user experience is the design concept instead of a general benchmark.

MinatoMirai Center Building, as a city landmark, use blue and white exterior appearance to form an impression of MinatoMirai District in Yokohama.

Exterior design based on vertical lines to keep a sense of unity with the buildings constructed ahead of this building in the same block. The

Figure 2.3.1 Location of MinatoMirai Center Building

( みなとみらいセンタービル )

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layout of building and planning for open spaces in consideration of the prevailing wind direction in summer to ensure natural airflow. And on the third floor, there is sharing space, by surrounding users of the space with wooden louvers and eye-catching vegetation, the building engenders a sense of comfort and ease.

Office area in the building is from the 4th floor to the 21st floor. This block has almost the same floor plan on each floor. The interior of each floor is about 80 meters long and 46 meters width. The middle part along the northeast-southwest direction is the corridor and public space. The main body of the office area in each floor can be roughly divided into eight blocks of similar size, and independent offices and functional areas are designed based on these blocks.

Figure 2.3.3 MinatoMirai Building Office Floor plan

Inside of building has large open space such as a courtyard at the center of the block in coordination with adjacent buildings, and a variety of open spaces, including recreation spaces such as flower garden, open lawn space, and bustling open spaces such as a pergola. In general, shaded area accounting for 21.26% of the lot area, a ratio of green coverage of 13.47%, and a ratio of green coverage on the roof of 21.47%.

Thermal mass: The whole building adopts Low-E glass with an opening ratio of less than 50% and low reflectivity to against Light Pollution and structural frames are prestressed concrete with paint. The building inside widely use recycled materials for free access floor and interlocking concrete block pavement for exteriors.

Overall heat transmission (U-Value) of exterior walls and windows is 0.88 W/m2K and 5.17 W/m2K, respectively, and the shading coefficient (SC) of windows of 0.38 are ensured by the unitary thermal insulated facade.

Lighting system: The building applies a special daylighting system called T-Soleil, that moves in response to the outside environment to let natural light in corridors.

For daylight control inside of the facade using vertical louvers and horizontal blinds. Widely using

Figure 2.3.2 MinatoMirai Building masterplan

29

2.4 Research scope & Difficulties

motion sensor control to achieve an illuminance level of 750 lux or more (779 lux) in the office

As the title of this paper said, the scope of this research is limited to façade solutions for high-rise commercial buildings in urban areas in a subtropical monsoon climate.

HVAC system: In order to achieve unified control of the entire floor, engineer developed a district heating and cooling system. Using air handling units (AHUs) are laid out separately and decentrally (8 sets per standard floor) with respect to each orientation and minimum compartment. Cooling/heating operation is selectable and controllable for each minimum compartment.

The building's façade system includes glass façade, shading sy stem, interior windows and all the parts that are associated with the façade structure. Since the building façade directly affects the indoor thermal comfort, the performance of the façade system will be also expressed by analyzing the indoor daylight, energy balance, and ventilation. So, the model analyzed will include the façade system and the indoor space connected to it.

The use of the atrium in the common area of the office for the pathway of exhaust air to shorten the length of the pathway, and reduce the power required to discharge the exhaust air, at the same time, outside air is taken into the building from top of the building through the void.

The study is to research on the exterior wall design of the Tokyo area and give suggestions for optimizing, and finally to give an external wall solution that can be applied under similar climatic conditions.

In the current society, more and more research shows that open working space can greatly enhance the user's satisfaction. At the same time, from an environmental point of view, the open workspace has no wall blocking inside, in terms of ventilation and lighting and could help extend the well-lit zone as much as possible. The following Analytic Work will be based on this principle, considering the test area as an open space for the analysis.

Figure 2.3.4 MinatoMirai Building Overview

In the process of the project research, due to technical limitations, I cannot professionally test the performance of the glass used in Japanese local building. Therefore, the simulation will use the data in the Global Glass Handbook by Pilkington which are materials commonly used in the global market today. It is not excluded that some buildings might use some special glass which is very expensive in order to achieve a higher energy performance, but we believe that using low cost materials to achieve the best performance is the significance of architectural research.

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Figure 2.3.5 MinatoMirai Building Photo

31

32

Analytic work

33

3. Analytic work

objectively assess the performance of a building, from several aspects of how the building affects the external environment, whether it saves operating costs, and if the user feels comfortable to evaluate the building.

3.1 Brief: This chapter, following the introduction about the external environment around the building and combines the external weather with the indoor conditions to determine the theoretical thermal comfort of the indoor users through the analysis of the internal office space and the building façade.

However, due to the particularity of a single building, the performance of the building does not fully represent the other local buildings. Therefore, the research point of this paper may be slightly different. The scenario part analyzes and improves several factors that are important to the user by simplifying the case as much as possible.

The standard proposes a concept of Building Environmental Efficiency (BEE). The lower the environmental load, the better the building performance and quality, and the higher score would achieve during the comprehensive evaluation.

Because it may be partially different from the current using assessment CIBSE Guide and LEED in the UK, some of the benchmarks related to the indoor environment in CASBEE evaluation criteria are briefly listed below as a reference, and subsequent optimization will be implemented based on this standard.

As a result, the scenario aims to evaluate the indoor conditions referring to daylight and thermal comfort in the office of the new design.

In the place of using the task and ambient lighting method according to this: • The Task lighting is in between 500lux to 1000lux, • And the Ambient lighting is 1/3 to 2/3 of the Task lighting, • And the vertical illuminance of the wall is over 100lux and the reflectance is over 30% • Or the horizontal illuminance of the ceiling is over 100lux and the reflectance is over 50% • Requires a ventilation standard of 35m3/h/ person in the area equipped with central air conditioning and ventilation system • Set of separately air condition zones (under 40m2) based on different orientation and position • Building materials properties: • Windows: shading coefficient: 0.2 and U-Values= 3W/m2K • Exterior wall: 1 W/m2K

Since this paper is a collaborative project with WSP Global, in the process of data analysis, I also consulted WSP's professional team in the design of building façade to ensure that the direction and method of research are correct.

To support the research process mainly two software was used. One is Grasshopper in Rhino, Honeybee and Ladybug Plugin by calling Daisy and Radiance's material database make an efficient and accurate contribution on daylight and thermal analysis. The other one called TAS developed by EDSL was used to simulate dynamic thermal condition on a detailed architectural model.

3.2 MinatoMirai Center Building: Comprehensive Assessment System for Built Environment Efficiency (CASBEE) is a sustainable building assessment standard designated by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) in Japan in 2001. It is used to

The MinatoMirai Center Building got the highest S Rank (2007) in the CASBEE assessment, so this chapter uses the construction material properties used in the CASBEE assessment report for the analysis.

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Façade solar radiation

We run summer and annual façade solar radiation analysis. It is obvious from the results that if we use 60Wh/m2 as a bond, we can see that the daylight radiation amount on southeastern façade varies greatly with height, and it’s affected by higher buildings in the southeast. In summer, because of the higher solar angle, the surrounding environment cannot block this part of sunlight, it has a relatively identical value on each level.

The first step is to check the outer façade of the building. Since it was found in the site visit process as a commercial center, although it is close to the park and Tokyo Bay, the building is also under the shadow of other buildings so the morning sunlight will be blocked by the surroundings. In the model, a context is set there based on the actual situation around the building to prove the result.

At the same time, referring to the global vertical radiation results in Context chapter, the radiation intensity of the near-vertical sunlight on the vertical plane is not very large compared to the direct sunlight from the low angle, which explains why the amount of summer radiation in the southwestern facade is less than the annual result.

Figure 3.2.2 Annual facade solar radiation (North-West)

Figure 3.2.1 Annual facade solar radiation (North-West)

Figure 3.2.3 Summer facade solar radiation (North-West)

Figure 3.2.4 Summer facade solar radiation (South-East)

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Sky View factor:

From this analysis, it can be seen that the two main factors affecting the external faรงade of the building to receive solar radiation are: the surrounding context and the solar angle. The purpose of this paper is to provide a common solution for the commercial building so all the contexts have been removed from the subsequent scenario analysis.

We believe that it is meaningless to use the specific context of the Yokohama area to conduct all the analysis. Each building is in its own environment and of course, they will have different surroundings.

According to the results of faรงade radiation, it will not be affected by surroundings only if on the higher floors so in this part, in order to understand the internal office, it will be based on the 16th floor of the building (60 meters high), and set up test points within 2 meters away from inner faรงade.

Respectively, compared to the total height of the building is 98 meters, the position is in the upper part, at the same time, from the research scope of high-rise buildings, then this height is easily reached and representative in most of the commercial buildings.

If our solution could be taken under the most extreme situation without context then in the actual implementation, the developer only needs to make some adjustments according to their site and it is easy to achieve the goal.

The SVF is defined as the ratio between the visible sky and a hemisphere centered to cover the analyzed location at a point in space (Oke. 1981).

The analysis of Shading mask can be considered as if a person sitting in a place two meters away from the faรงade and looking out of the building, the percentage of the sky he can see in his total field of view and the part behind is removed.

Even the setting point is on 60 meters height, a large part of the sky in front of the person is still blocked by the surrounding context. The SVF value of the northwest side is 24.14% and the southeast side is 10.86%. This result shows that in urban areas, it is always difficult for people sitting indoors to grab an open vision field. This is an actual issue in the field of urban planning and this article will not talk on this point too much.

Figure 3.2.5 West facade shading mask

Figure 3.2.6 East facade shading mask

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Daylight – visual comfort: In terms of “Indoor environment”, this paper could think that the most important is visual and thermal comfort, so we performed an indoor daylight analysis on the same 60-meter-height floor.

This part evaluates on the natural visual comfort in the room from three aspects. In order to reduce the energy consumption caused by artificial lighting to achieve “Passive” as much as possible, the optimal situation is to make the area of which UDI value is above 80% as much as possible. Following scenarios would contribute this by changing the glass material and adding an external shading device.

Since it’s a passive design project, the artificial lighting will not be considered in the test. According to the relevant research, the UDI analysis in this paper adopts the benchmark of 300-2500 lux, that means we called that the illumination of more than 2500 lux at the desk level is glare, and if it is less than 300 lux we think it’s hard to work without artificial lighting. Under this standard, we will have a result greater than 80% which is part of called "daylight passive zone". From Climate analysis we know the Design sky illuminance in this area is 13451 lux, so we need a 2.2% Daylight factor value to ensure a minimum of 300 lux.

The UDI result in the figure below shows that within the 80*46 floor plan, only the area around 2-4 meters near the façade meets this benchmark, the northwest is a bit more and the southeast is less.

Daylight Autonomy and Daylight Factor results could also be checked as a reference.

Figure 3.2.7 MinatoMirai Building indoor UDI (300-2500lux)

Figure 3.2.8 MinatoMirai Building indoor Daylight Factor

Figure 3.2.9 MinatoMirai Building indoor Daylight Autonomy

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Energy consumption:

Combined with previous external climate analysis, July and August are the hottest seasons, so the energy consumption for these two months is the highest throughout the year and is mainly generated

by AC. The annual energy consumption is assumed by mechanical ventilation, lighting, and equipment as three major components. A large amount of mechanical ventilation is because no natural ventilation is applied in this condition, so in order to maintain the ventilation demand of 3680m2 area, this result is acceptable. In the last part, we know that natural daylight in 80% of the space is insufficient, the relevant requirements of the artificial task light are also mentioned in the CASBEE standard. This part is also reliable in combination with the actual situation.

In this part of the analysis, we make assumptions about how people using the office and simulate the normal situation through a series of settings.

In construction material, the U-Value of the external wall was setting to 0.883W/m2K and glass façade solar transmittance is 0.33 and light transmittance is 0.361 with U-Value of 5.17. In this case we consider it as a normal single-glazed laminated clear glass which is reasonable under subtropical climate. For internal conditions, the office was operated from 8 to 18, ten hours a day, and set occupancy density as 10m2 per person. Air conditioning system is used throughout the environment to keep the temperature in summer and setting point is 24°C and heating setting point is 22°C in winter.

So, through this typical internal condition, we can see the operative temperature in office hour during the whole year could generally be kept in adaptive comfort range, that’s why this building could be certified as a high-performance structure.

Figure 3.2.10 Indoor Total Monthly Energy Consumption (kWh/m2)

Figure 3.2.11 Daily Temperature & Comfort band by each Month

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3.3 Simplified Base Case: Brief: At this stage, we will make basic model simplified based on last chapter analysis. As mentioned above, this model must be representative of commercial buildings in the general subtropical region, while there are no other context barriers around. We will consider the same 60m high landscape indoor office room with fully glazed faรงade on all four walls. In this climatic, we will use single glazed laminated glass, which is widely used by most local buildings.

The model will be set as a 30 by 30 meters room with 3 meters floor to ceiling height. This site is easy to divide by 9 areas to analysis different situation on each faรงade. Following simulation will be taken on Daylight and Thermal analysis.

Figure 3.3.1 Floor Section

Figure 3.3.2 Simplified Base Case Model

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Daylight: In this test, we set the glass light transmittance to 0.437 which is 2*6mm laminated green glass and the UDI test also uses the 300-2500 lux benchmark.

From the annual UDI result, because of no context, there is a significant glare zone close to the façade shown as blue color in UDI test and in center part there is an insufficient lighting area around 10810 meters. This result could directly approve our Base case principle which means no matter how big the room is, it is almost impossible to achieve full-year passive lighting in this weather condition, 10 meters away from the inner façade. This situation may vary slightly from season to season.

Figure 3.3.3 Annual UDI Value (300-2500 lux)

In summer, we would have an area 5-7 meters away from façade which has a perfect (>90%) natural daylight condition on each façade, and in winter, due to the low solar angle, more sunlight could go directly into the space, we can see at east and south façade we have a serious issue with glare – almost 10 meters depth. In mid-season, we take fall as instance, this is the worst season due to the sunlight condition, not only with a large insufficient area in the center but also have a wide range of glare zone.

Figure 3.3.4 Annual Daylight Autonomy

Figure 3.3.5 Seasonal UDI Value (300-2500 lux)

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As we said, one of the reasons why we make it 30*30 is that we want to divide the room by orientation, from the support of the daylight analysis, we know that we are not going to talk about center part which is insufficient anyway, so we generate four thermal zones for the following simulation, each zone is a 10*30 meters rectangle.

Once we have some coincident part but it’s not a mistake, this room is just an approach, we don’t design for an exact 30*30 meters room, our research pointed on “The area close to each façade”

West Zone

East Zone

North Zone

South Zone

Figure 3.3.6 Thermal Zones

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Thermal:

Inside of the building was considered as a typical landscape office, several air walls were assigned in the program to divide our thermal zone, those “walls” will not affect anything just for grouping the data by orientations.

As we know, in a subtropical climate, winter season doesn’t have extreme cold and in office building, internal gain is much higher because of equipment and ventilation system. In contrast, summer season has a big issue in thermal comfort.

In the figure below listed the temperature changes of the southern thermal zone in the continues week from July 22 to July 29. In the TAS program, the value of Resultant Temperature (To) is the average of Radiant Temperature (Tr) and Dry Bulb Temperature (DBT).

In this part, we use EDSL TAS to make a thermal model, some important construction material properties were listed below, those values are taken from CASBEE Assessment.

As can be seen from the figure, due to the use of the mechanical AC, during the work time, the DBT is controlled at 2°C, the same as setting point, during which the cooling loads are generated. In the daytime, as the sunshine hours increases, the indoor To. also Gradually increasing, because the test area is close to the glass façade, the specific heat capacity of the glass is much smaller relative to the opaque wall, so the temperature rises extremely fast and reaches a maximum value at noontime.

As a result, we assume AC setting point ±2°C as the comfort zone according to the comfort adaptability of the human body, that’s 22-26°C, and simulate the To. of the four thermal zones.

Figure 3.3.7 Internal Conditions and Construction Materials

Radiant Temperature Resultant Temperature

Comfort Zone: 24±2 ℃

Dry bulb Temperature

Figure 3.3.8 Temperature Change in a Summer week

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Figure 3.3.9 Indoor Resultant Temperature in Summer without Shading

Hours above 26℃ North: 41.98% South: 45.00% West: 44.77% East: 44.07%

Cooling Loads(kW/m²) 25 20 15 10 5 0

MAY

JUNE

JULY

AUGUST

SEPTEMBER

OCTOBER

The results are shown in the following chart. JulySeptember is the hottest season of the year, and the temperature in the room easily exceeds 26°C even with applying of the cooling system. Through the data analysis of excel, we can get the percentage of overheating hours in four thermal zones. It can be seen that without shading panel, the worst case is the south zone and over 40% of the time in the summer half-year is overheated in the whole room.

Cooling loads(kW/m²) 25 20 15 10 5 0

JULY

AUGUST north

south

West

SEPTEMBER East

Figure 3.3.10 Summer Cooling loads (by each orientation)

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3.4 Shading design

Then some shading component should be generated on that.

Scenario making

Solar angle was observed as 33.3° at the time of 8 AM 12th July on South façade, so a certain gap between horizontal shading panels is set to block all the direct sunlight higher than this angle. In reality that means after 8 AM, which is office hour started time, as the sun goes higher, it will not get into the indoor space directly, and heat gain through solar radiation will not be too high through this method. The shading component is not touched with façade body, and the material of fins would be a 9% transmittance panel. As a user, people do not want to stay in a room surrounded with some dense opaque materials and those low transparency fins would make people feel more comfort in mind and easily blend into one with the transparency glass façade.

From the simulation on the base case, we could find that if we want a high performance – good daylight and thermal condition, and high efficiency – low energy consumption. We need to solve the problem of glare, in summer season, close to the façade especially south, and try to reduce summer cooling loads.

Typically, most of the buildings use Vertical and Horizontal shading on different orientation to achieve different solar angle changing. Horizontal always applied on south façade to block the light along the altitude change in a day, it affects the depth of inlet daylight through obstructing specific high angle. Vertical shading was used to block the light along azimuth on West or East façade. In this project, the issue is to prevent the glare close to façade but keep the sunlight depth (visual comfort zone) as much as possible so some particular combination would be tested on this principle.

O n c e t h e s o u t h fa ça d e wa s s e t , t h e s a m e approaches were applied to all orientations based on different solar angle, this scenario is a basic design and would support how the horizontal shading system perform in this situation. Daylight and thermal analysis would be tested on this.

The first step is to check the Daily Average Global Illuminance in climate profile to define which time period is the worst situation we need to solve. We take the day with highest illuminance and find that in 12th of July it has a high temperature and high radiation level, so we consider this day as a “Hottest day” in a year. Although we thinking about that each year has its own profile and things may change all the time, but this step is just to check how is the sun position in the hot day but not the particularity of that day.

Figure 3.4.1 Typical Shading Methods

Horizontal shading: • Block the light along Altitude • Affect the depth of sunlight • Usually applied on South Façade

Vertical shading • Block the light along Azimuth • Might block the view • Usually applied on West/East Façade

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Figure 3.4.2 Daily Average Global Illuminance (lux)

July Global Illuminance (lux) 120000

12th

100000 80000 60000 40000 20000 0

Figure 3.4.3 July Daily Global Illuminance (lux)

Summer

June July Aug

Figure 3.4.4 12th July Sun path Diagram

8:00 – 18:00

Horizontal shading: with setting angle: N: 40° S: 33. 3° E: 33.3° W: 54.6°

The day with highest illuminance

Higher monthly average temperature With high radiation also Less Rain fall Good sky condition

Shading with Tr.9% Transparent Material

Figure 3.4.5 Design Process

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Daylight: From the daylight analysis, due to the shading was designed for the summer day, UDI results in summer is shown as good – north/south orientation would have 7 meters width visual comfort zone and in east/west façade would have 8 meters width.

In winter and mid-season, the area which closes to façade shows better results but more inside part has a serious problem of not well-lit issue. In this case, if we go back to the principles, we want to solve the problem of glare and it succeeds. In an office room, comparing artificial lighting system and mechanical AC system, we would say the lighting is more adaptive and low cost, exactly we didn’t reduce the daylight so much in four thermal zones and from the case of MinatoMirai Building we could see center part was always designed as some transition space and functional areas, as a result we want the “Area close to façade” become the most often use and most comfort space.

Figure 3.4.6 Annual UDI Value (300-2500 lux)

Glare

Glare

Figure 3.4.7 Seasonal UDI Value (300-2500 lux)

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Thermal: As what we did in the base case, the same summer week was taken to show the To as a comparison, from the figure shows the To decrease a lot to around 26°C which is in our comfort band. July to September still there is some time under high temperature in special period of time.

Through this scenario, we got the fact of how the temperature change: F ro m l a t e J u l y t o A u g u s t , a s t h e ex t e r n a l temperature reaches over 30°C and the strong sunlight, indoor Radiant temperature must be 0extremely high. In this square room, without natural ventilation, with the equation of To. = average (Ta.+Tr.) only if Tr lower than 28°C, To. will be no exceed 26°C in the program. In reality, users’ thermal comfort affected by lots of factors and people could adjust themselves to fit the environment. This project is trying to make passive situation as pleasant as possible.

Figure 3.4.8 Temperature Change in a Summer week

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In comparison, we can see: Overheating hours in summer were decreased around 40% through this horizontal shading, equals to cooling loads, the energy consumption of cooling system in summer, it decreases 9-13% because of the low solar heat gain. This is the approach to show how the design shading system would help to improve internal thermal comfort.

The shading device does not solve the thermal problem perfectly. The specific energy use and thermal improvement also need the assistance of other systems but because the research object of this thesis is only for façade and shading, other systems will not be considered.

With the implementation of the designed horizontal shading system, the following figure shows the relationship between UDI Value and the distance to façade. The result improves so much, and even the area close to the façade which is under glare before now is over 70% UDI. Now the visual comfort comes to a good stage.

Hours above 26℃ North: 26.56% South: 24.86% West: 23.52% East: 20.74%

Figure 3.4.9 Indoor Resultant Temperature in Summer with Shaing

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Cooling Loads(kW/m²)

Hours over 26℃ in Summer 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0%

25 Decrease 36.7%

Decrease 44.7%

Decrease 47.4%

Decrease 52.9%

20 15

Decrease 18.4%

Decrease 13.1%

Decrease 10.1%

Decrease 9.2%

Decrease 7.1% Decrease 17.3%

10 5 North

South No Shading

West

0

East

MAY

JUNE

JULY NoShading

With Shading

Figure 3.4.10 Overheating Hours Comparison

AUGUST

SEPTEMBER

OCTOBER

WithShading

Figure 3.4.10 Cooling Loads Comparison

Figure 3.4.11 Indoor UDI Value variation

100 90 80 70 60 50 40 30 20 10 0

0.3 0.9 1.5 2.1 2.7 3.3 3.9 4.5 5.1 5.7 6.3 6.9 7.5 8.1 8.7 9.3 9.9 10.5 11.1 11.7 12.3 12.9 13.5 14.1 14.7 15.3 15.9 16.5 17.1 17.7 18.3 18.9 19.5 20.1 20.7 21.3 21.9 22.5 23.1 23.7 24.3 24.9 25.5 26.1 26.7 27.3 27.9 28.5 29.1 29.7

UDI Value-No Shading

W to E

S to N

100 90 80 70 60 50 40 30 20 10 0

0.3 0.9 1.5 2.1 2.7 3.3 3.9 4.5 5.1 5.7 6.3 6.9 7.5 8.1 8.7 9.3 9.9 10.5 11.1 11.7 12.3 12.9 13.5 14.1 14.7 15.3 15.9 16.5 17.1 17.7 18.3 18.9 19.5 20.1 20.7 21.3 21.9 22.5 23.1 23.7 24.3 24.9 25.5 26.1 26.7 27.3 27.9 28.5 29.1 29.7

UDI Value-Horizontal Shading

W to E

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S to N

Distance to the Facade

3.5 Research outcome

After testing on designed horizontal shading, we are looking more on daylight analysis and trying to improve the center part if possible. We looking on the south part as the object because it’s the place where could get direct sunlight in the hottest noon time and it should be taken care carefully. Different approaches were taken under simulation step by step.

South Facade UDI Test

1.5m height panel - opaque with 0.6 reflectence Horizontal shading - 9% Tr. Glass

1.5m height panel -9% Tr. glass Horizontal shading - 9% glass

2m height panel -9% Tr. glass Horizontal shading - 9% glass

2m height panel -opaque

Figure 3.5.1 Facade design proposals

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As we have seen from analysis, both of the façade glass materials and shading design will affect indoor visual comfort. After thinking of those approaches, we find the final outcome as suggestion.:

For south façade, an extra unique shading will be added on. This system was made of a 2 meters height movable vertical shading and on top of that is a 90% transparent panel to fit the total 3 meters floor height. The movable vertical shading panels were set as rotated throughout the day automatically when the solar is so strong, it will be rotated facing the sun to block the light, and in cloudy day it will be rotated following the sun, in this condition they will not affect daylight. The transparent panel on top is to keep, slightly weakened, the sunlight a little far away from the façade, at the same time, occupants indoor can see the scenery through this part outside then they look up.

Firstly, the glass façade material would be changed to 60% transmittance Low-E clear glass, still laminated. All of four orientations would be applied with horizontal shadings with a specific distance between fans. Compared with the first scenario, we make the southern shading fins denser due to the severe direct sunlight, and western shading was denser also to reduce the glare. Northern fins were more disperse, as instead, staggered panel shading was applied on. On north orientation, there is almost no direct sunlight throughout the whole year, as a result, keep the sunlight off evenly is more helpful to prevent glare, and also, fixed vertical staggered structure also looked more common in exterior wall.

Horizontal shading: with setting angle: N: 60.44° S: 33.73° E: 33.8° W: 29°

North façade: staggered panel shading South façade: Movable Vertical Shading (2m height) Transparent panel (2-3m height)

Figure 3.5.2 Final Solution Brief

Figure 3.5.3 Rotatable fins

Tr. : 60% Low-E Clear Glass Façade

Tr.: 90% Transparent

Tr.: 60% Opaque

Tr.: 9% Transparent 51

Simulation on the final solution is shown below, annual UDI generally improved in the whole space above 60% and almost 8-10 meters far away from façade becomes passive daylight comfort area.

Looking on each season, only in mid-season days have some dark zone 6 meters away from façade.

The line chart shows, the test room, means 15 meters away from façade in each orientation, could keep annual UDI over 60% and half of those is above 80%. Areas which UDI is between 60% to 80% could be used as transitional space and other public facilities.

This approach is to make people close to façade have a good working environment, especially in the aspect of daylight. In this case – the normal office building with glass façade but no surrounding context – we consider this design as a final strategy as a suggestion Figure 3.5.4 Annual UDI Value (300-2500 lux)

Figure 3.5.5 Seasonal UDI Value (300-2500 lux)

Figure 3.5.6 Indoor UDI Value variation

100 90 80 70 60 50 40 30 20 10 0

0.3 0.9 1.5 2.1 2.7 3.3 3.9 4.5 5.1 5.7 6.3 6.9 7.5 8.1 8.7 9.3 9.9 10.5 11.1 11.7 12.3 12.9 13.5 14.1 14.7 15.3 15.9 16.5 17.1 17.7 18.3 18.9 19.5 20.1 20.7 21.3 21.9 22.5 23.1 23.7 24.3 24.9 25.5 26.1 26.7 27.3 27.9 28.5 29.1 29.7

UDI Value-Designed Shading

W to E

52

S to N

Conclusion

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4. Conclusion:

The reason why this case chose the Kanto region of Japan is that the Tokyo metropolitan area is Japan's economic center and one of the largest cities in Asia - it is now a well-developed city. The larger the economy of a metropolis, the more energy and pollution it will come with. Japan doesn’t have a lot of resources in its own country so it pays great attention to research in the field of environmental protection while developing the economy. The concept of green building was put on the agenda as early as the last century. Nowadays, a relatively complete set of green building evaluation system called CASBEE has been formed. In this context, many high-performance and sustainable buildings have been born. With the development of globalization, more and more developing countries have begun to attach importance to this issue, but most countries do not have corresponding local regulations, so this paper explains how to improve indoor occupants feeling while keeping the external glass façade through analysis of a certain case.

In the process of urban development, with the increase of population density, the building is also getting higher and higher. Some shortcomings such as structural load-bearing and high cost of glass material are gradually solved in the progress of science and technology, so more and more buildings are trying to start using the glass-made façade because it is aesthetically pleasing and can be creatively changed with the designer's mind.

However, due to the physical characteristics of glass materials - usually high transparency and low U-Value - the effects on indoor and outdoor environments when used as building facades are often not considered by designers. As we have seen, some reflective glass façades bring serious light pollution to the surrounding environment while being aesthetically pleasing.

In the interior of glass towers, due to the high efficiency of heat transfer, the temperature rises and falls faster, and often requires a large amount of energy from air conditioning systems to maintain a comfortable temperature. This is why in the design of a conventional green sustainable building, some thick materials are often used as walls for construction. Of course, the situation will change with the location of the case. Therefore, this paper attempts to determine the performance of the use of glass façades in high-rise commercial buildings under urban environments in subtropical regions through an analysis of a case building in the Kanto region of Japan.

The base case-MinatoMirai Center Building is located in the coastal area of Yokohama and it is surrounded by several parks. The building is about 94 meters high and got the highest rank in sustainable commercial building assessment by CASBEE. The analysis was modeled by extracting the upper floor of the building and performing thermal and light tests in the Grasshopper to learn how could a certified building perform well.

The result is similar to the expectation, and the temperature inside the building is always in a good comfort zone throughout the year under the implementation of the air conditioning system.

In terms of lighting, due to the influence of surrounding high-rise buildings in the east, there are few glare problems even in the parts close to the fully glazed façade. However, because of the large floor plan of the building, it is inevitable that the central part must rely on artificial lighting to maintain the working environment.

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Based on this case study, a simplified model was created: a 30*30*3 meters square room with the same climatic background of the case above as the scenario. The reason for this size is that from the result of case study, it is difficult to ensure that there are good passive lighting conditions inside the room that is ten meters away from the facade.

Therefore, this simulation is only to maximize the temperate illumination without any glare problems.

Better indoor natural lighting means less artificial lighting energy use, and the use of appropriate sunshade devices to block unwanted direct sunlight can also reduce summer indoor heat gain and significantly reduce cooling loads, which means energy consumption. This has great significance in terms of energy-saving and human comfort. But this simulation does not consider the surrounding context which blocking the sunlight, which means that compared to the actual building environment, this simulation is based on more demanding conditions, if it can find a relatively complete solution in this environment, then it must apply to most common situations.

Following thermal analysis also showed that even with the cooling system set to 24°C, the actual To. is still about 40% of time higher than 26°Cover the summer (6 months) due to the higher radiant temperature. So based on this result, a shading system will be designed to help improve glare and overheating issue.

Later, some different shading combinations were tested. The horizontal and vertical shadings were placed in different directions depending on the way they were used. At the same time, the use of transparent materials was also considered, so that when the sunshade system was installed in a large area, it was guaranteed the user does not completely obscured from the inside.

In the details of the shading fins, the sun angle of several special time periods in summer (July) is used to cover the strongest sunlight during the noontime. After some attempts, a suggested solution was given. In the test model - a 30*30*3 meters landscape office – through the application of this designed shading system, it is possible to successfully reduce the cooling loads inside the room by 9-17% and keep the space of 6-7 meters away from the façade to achieve the office comfort standard without artificial lighting.

The daylight analysis of this model shows that glare becomes a very serious problem without surrounding context and shading, and the area of 3-4 meters near the four-sided façade is bad performed due to excessive light, especially in the eastern and southern façade, and as the seasons change, the difference in solar altitude angle will also have different effects on indoor lighting conditions. If the issue of glare happens in the office, people usually use indoor curtains or blinds to block from the inside when they feel strong light.

As discussed in the Literature review section, “Comfort ” has different meanings for each individual. Although some international human comfort standards such as ASHRAE are widely using today, we still have to check the local climate environment and the surrounding context, human adaptation, and even cultural background for specific case. Just as this project was to study the design of glass facades and shading systems throughout the subtropical region, the analysis only used the special climate background of the Kanto area and a simple house model. We just hope that through the design of this case, if a proper shading system is used in the building, it can effectively help improve the indoor daylight and thermal environment to meet the standards of sustainable buildings.

However, in doing so, while improving the condition near the façade, about 90% (depending on the material) of the natural sunlight loss will cause the internal illuminance level in the whole orientation to be greatly reduced, and at the same time, the heat from the sunlight will not be blocked the radiation will still transfer through the excellent conductivity of the fabric and raise the indoor temperature.

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Table of Figures Figure 1.1.1 Indoor thermal comfort principle

10

Figure 1.1.2 PMV indicator system

11

Figure 1.1.3 Graphic Comfort Zone Method: Acceptable range of operative temperature

and humidity for spaces that meet the criteria specified

in Section 5.2.1.1 (1.1 met; 0.5 and 1.0 clo)—(a) I-P and (b) SI.

Figure 1.1.4 Thermal resistance of common garment combinations

12 13

Figure 1.2.1 The Bioclimatic Comfort Chart

Victor Olgyay "Design With Climate" 1963

14

Figure 1.2.2 Bioclimatic Chart for pressure of 96.035 kPa (Elev:450m)

14

Figure 1.2.3 Passive Design strategies

15

Figure 1.3.1 Building's Heat transfer

16

Figure 2.1.1 Kanto Region Map

20

Figure 2.1.2 Climate classification map for Japan

20

Figure 2.1.3 Monthly Average Dry Bulb Temperature

20

Figure 2.1.4 Cumulative Rainfall

21

Figure 2.1.5 Precipitation & Humidity & Temperature

21

Figure 2.1.6 Monthly Average Relative and Absolute Humidity

21

Figure 2.1.7 Daylight situation

21

Figure 2.1.8 Frequency of Sky types (8-18)

21

Figure 2.1.9 Daily Average Global Horizontal Radiation

22

Figure 2.1.10 Daily Average Horizontal Radiation

22

Figure 2.1.11 Monthly Average Global Vertical Radiation

22

Figure 2.1.12 Tokyo PMV Chart in 2010 by GH.

23

Figure 2.2.1 Traditional Japanese Residential in Nora

25

Figure 2.2.2 Modern Commercial building in Tokyo

25

Figure 2.2.3 Commercial building in Shibuya Region (by Fieldwork)

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Figure 2.3.1 Location of MinatoMirai Center Building

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Figure 2.3.2 MinatoMirai Building masterplan

29

Figure 2.3.3 MinatoMirai Building Office Floor plan

29

Figure 2.3.4 MinatoMirai Building Overview

30

Figure 2.3.5 MinatoMirai Building Photo

31

Figure 3.2.1 Annual facade solar radiation (North-West)

35

Figure 3.2.2 Annual facade solar radiation (North-West)

35

Figure 3.2.3 Summer facade solar radiation (North-West)

35

Figure 3.2.4 Summer facade solar radiation (South-East)

35

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Figure 3.2.5 West facade shading mask

36

Figure 3.2.6 East facade shading mask

36

Figure 3.2.7 MinatoMirai Building indoor UDI (300-2500lux)

37

Figure 3.2.8 MinatoMirai Building indoor Daylight Factor

37

Figure 3.2.9 MinatoMirai Building indoor Daylight Autonomy

37

Figure 3.2.10 Indoor Total Monthly Energy Consumption (kWh/m2)

38

Figure 3.2.11 Daily Temperature & Comfort band by each Month

38

Figure 3.3.1 Floor Section

39

Figure 3.3.2 Simplified Base Case Model

39

Figure 3.3.3 Annual UDI Value (300-2500 lux)

40

Figure 3.3.4 Annual Daylight Autonomy

40

Figure 3.3.5 Seasonal UDI Value (300-2500 lux)

40

Figure 3.3.6 Thermal Zones

41

Figure 3.3.7 Internal Conditions and Construction Materials

42

Figure 3.3.8 Temperature Change in a Summer week

42

Figure 3.3.9 Indoor Resultant Temperature in Summer without Shading

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Figure 3.3.10 Summer Cooling loads (by each orientation)

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Figure 3.4.1 Typical Shading Methods

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Figure 3.4.2 Daily Average Global Illuminance (lux)

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Figure 3.4.3 July Daily Global Illuminance (lux)

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Figure 3.4.4 12th July Sun path Diagram 8:00 – 18:00

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Figure 3.4.5 Design Process

45

Figure 3.4.6 Annual UDI Value (300-2500 lux)

46

Figure 3.4.7 Seasonal UDI Value (300-2500 lux)

46

Figure 3.4.8 Temperature Change in a Summer week

47

Figure 3.4.9 Indoor Resultant Temperature in Summer with Shading

48

Figure 3.4.10 Overheating Hours Comparison

49

Figure 3.4.10 Cooling Loads Comparison

49

Figure 3.4.11 Indoor UDI Value variation

49

Figure 3.5.1 Facade design proposals

50

Figure 3.5.2 Final Solution Brief

51

Figure 3.5.3 Rotatable fins

51

Figure 3.5.4 Annual UDI Value (300-2500 lux)

52

Figure 3.5.5 Seasonal UDI Value (300-2500 lux)

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Figure 3.5.6 Indoor UDI Value variation

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REFERENCES [1]: Bluyssen P M, Cox C. Indoor environment quality and upgrading of European office buildings [J]. Energy & Buildings, 2002, 34(2): 155-162 [2]: Wyon D P. The effects of indoor air quality on performance and productivity [J]. Indoor Air, 2010, 14(s7):92-101 [3]: ASHRAE. ASHRAE Hand book, Fundamentals (51). American Society of Heating, Refrigerating and Air Engineers, 2001 [4]: Lin Z, Deng S. A study on the thermal comfort in sleeping environments in the subtropics-Developing a thermal comfort model for sleeping environments[J]. Building & Environment, 2008, 43(1):70-81 [5]: Fanger P O. Calculation of thermal Comfort, Introduction of a Basic Comfort Equation[J]. ASHRAE TRANS, 1967,73(2): 5-8 [6]: Cheung, Toby; Schiavon, Stefano; Parkinson, Thomas; Li, Peixian; Brager, Gail (2019-04-15). "Analysis of the accuracy on PMV – PPD model using the ASHRAE Global Thermal Comfort Database II". Building and Environment. 153: 205–217.

[7]: Ricciardi P, Buratti C. Thermal comfort in open plan offices in northern Italy: An adaptive approach[J].

Building & Environment, 2012, 56(3):314-320 [8]: Indraganti M, Ooka R, Rijal HB. Thermal comfort in offices in India: Behavioral adaptation and the effect of age and gender[J]. Energy & Buildings, 2015, 103:284-295 [9]: Hu Fangfang. Comparison of Green (Sustainable) Building Evaluation Standards between China, Britain and the United States [D]. Beijing: Beijing Jiaotong University, 2010 [10]: Aimin Wei, Yang Song. The Current Situation and Analysis of Building Energy Efficiency [J]. Doors and Windows,2008,02 [11]: Li Fangxian;Chen Youzhi;Chen Jie;Kong Xiangxiang. Development Status and Prospect of Self-energysaving Wall Insulation System[J]. Wuhan: Bricks & Tiles.2008 [12]: Zhang Bo, Zhang Jianxin, Cai Wei. Research progress of low-radiation building energy-saving glass [J].

Glass and enamel 2008.12.36 [13]: Shangguan Anxing. Research and application of glass energy-saving technology in architectural design [D]. Tianjin University. 2009.05 [14]:ICC (2009). 2009 International Energy Conservation Code.

[15]: https://www.commercialwindows.org/vt.php

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