contemporary TRANSLUCENT buildings in são paulouniversity by msc.exhibition2019

universit y of westminster. facult y of architecture and environmental design.department of architecture. msc architecture and environmental design 2018/2019.semester 2&3. thesis project module.

contemporary TRANSLUCENT buildings in sĂŁo paulo

j u l i a g a lv e s . s e p t e m b e r 2 0 1 9

ABSTRACT São Paulo, the biggest city in South America, is a showcase of contemporary architecture. The contemporary trend is looking for alternative façade materials and design signed by renowned architects. In this context, new translucent materials started to be explored by São Paulo’s architects as an aesthetic alternative to the often applied colored reflective green glass. However, these new technologies have been specified considering only aesthetics reasons and specific visual effects sensation, setting aside any concern regarding the thermal, daylight and energy performance. The unlikely situation of extreme thermal conditions in São Paulo causes the design professionals to overlook the real problem, which is a high amount of global radiation throughout the whole year. The unawareness of architects about the climate condition, coupled to a strong aesthetics trend informing the design, cause a high probability of overheating, or high cooling demands, in the new constructions in which this translucent materials are applied. Facing this issue, this paper explores the performance of three translucent materials which have been applied in the contemporary architectural context of São Paulo. The research is based in two sections. The first, by an empirical analysis by the fieldwork of two case studies. The second part of the research is based on analytical studies of daylight and thermal simulations of a base case. The research outcome is a guideline of the best environmental performance of translucent material considering the improvement of G-value, addition of external shading, introduction of night ventilation and reduction of window to wall ratio.

TABLE OF CONTENTS 1. Introduction 9 1.1. Overview 11 1.2. Research questions and hypothesis 12 1.3. Methodology 13 1.4. Summary of Results 14 1.5. Structure of the thesis 15 2. Literature Review 17 2.1. Translucent Materials Optical Performance 20 2.2. Translucent Materials Thermal Performance 24 2.3. Human Comfort 28 2.4. Conclusions and Hypothesis 30

5. Analytical Work 75 5.1 Base Case Definition 78 5.2. Daylight Studies 80 5.3. Thermal Studies 95 6. Research Outcomes 6.1. Material Property and Coating 6.2. External Shading and WWR 6.3. Night Ventilation 6.4. Layout Flexibility 6.5. Visual Comfort 6.6 Further Facades Guidelines

119 122 123 126 127 128 129

7. Conclusions 131

3. Context 31 3.1 Location 33 3.2. Climate 34 3.3 SĂŁo Paulo Contemporary Built

8. References 137

Environment 39 3.4. Translucent Materials 41

9.2. Fieldwork 143 9.3. Base Case Definition 149 9.4. Daylight 152 9.5. Thermal 153

4. Fieldwork 47 4.1. Context and Microclimate 50 4.2. EdifĂcio Rio Negro 52 4.3. IMS 62 4.4. Conclusions 74

9. Appendices 141 9.1. Climate 142

AKNOWLEDGMENTS I would like to express my personal gratitude for my tutor. Joana GonĂ§alves, who have been following my academic path ever since my bachelor degree and have encouraged me to pursue a masterâ&#x20AC;&#x2122;s degree. Her lectures have always inspired me to become a better professional and academic, and her guidance in this thesis project supported me to do my most excellent work. I am grateful for Rosa Schiano-Phan for all her support in this master course, by enriching us with knowledge and comforting our minds when needed. I am also thankful for all the AED staff which provided the technical knowledge that allow us to go further. I am also grateful for the architects Marina Acayaba and Marcelo Morettin, who spare their time to grant me an interview about the design of the case studies. It was essential to

understand deeply the sensibility of a design concept and how it was transmitted into materiality. I am thankful for LABAUT staff, especially to Ranieri Higa, who allowed me to use the equipments which were essential for the data collection. I would like to extend my gratitude for Catherine, Daniela and Joana, the case study buildings managers who allowed me to install the continuous monitoring equipments. I am thankful for my USD colleagues, Klaus Bode and Neil Campbell, who willingly gave me inputs to improve my research. Finally, I am extremely grateful for my family, who provided me with all emotional and financial support which allowed me to further my education abroad.

1. INTRODUCTION

SÃ£o Paulo photo by Vanessa Bumbeers

1.1. OVERVIEW According to UNEP (United Nations Environment Program), the global built environment is responsible for 30% of greenhouse gas emissions. Nowadays the biggest emitters in the world are the developed countries, in the long term it is expected that this position will shift to developing countries in which cities are in a rapid urbanization growth, such as São Paulo, in Brazil (Gonçalves, 2016). As the climate of São Paulo is mostly warm, it is evident that the most required demand for indoor comfort is cooling, and as the predominant mentality of the market is air conditioning, this reflects in a higher energy consumption. (Gonçalves; Marcondes; 2015) As an aggravation of this problem, the prevailing brazilian aesthetics mentality is based on the uncritical adoption of the same glazing façade solutions used in Europe and North America standards - which are colder climates countries. Not only, the vast majority of these buildings façades are defined without a specialized environmental consultancy, mainly because stakeholders wrongly considers conditioning spaces essential for indoor thermal comfort

and market valorization. Consequently, São Paulo’s commercial architecture in the last three decades has mainly produced glazed façade buildings - usually darker and reflective types - with fixed windows, basing the user’s comfort exclusively in air conditioning. However, in the last five years, the aesthetics demand have been shifted by real estate agencies (such as Idea Zarvos), which are hiring contemporary architecture offices to design. New façade materials started to be explored in contrast to the dated dark-greenreflective glass. Nonetheless, the application of these new materials seems to be disconnected to a concern of the environmental performance of these technologies and how they affect the cooling loads and occupants comfort. In this context, the research is the study of new translucent materials technologies applied in São Paulo’s contemporary architecture. The aim of the investigation is to understand how these materials can be applied in this climate.

1. INTRODUCTION

1.2. RESEARCH QUESTIONS AND HYPOTHESIS Four research questions were elaborated concerning visual and thermal performance. These questions lead the early study and were responded by the literature review are: How is the visual comfort of a translucent material in comparison with a clear material? How does a full glazed façade perform regarding visual comfort in a sky condition like in the one in São Paulo? How is the thermal performance of transparent materials in a subtropical climate as São Paulo? How would be the thermal performance if external shading devices are added in the façades? From the research questions answers derived from the literature review, the hypothesis that emerge and lead the investigation were: In a subtropical climate like São Paulo, the extensive use of translucent materials cause overheating and glare conditions on the peripheral space near the facade. Diffuse materials seem to have better visual comfort concerning glare probability.

São Paulo photo by Fabio Hanashiro

1.3. METHODOLOGY Finally, the analytical work was done through simulations.The daylight analysis were conducted via Honeybee and Radiance software, that use the Rhinoceros and Grasshopper interface. The daylight simulations were Climate-Based-Daylight-Modelling, which considers the complexity of the skydome and annual results, and data daylight glare probability, useful daylight illuminance and steady state illuminance were collected.

The research was conducted by a combination of methods types: literature review, fieldwork and analytic work. The literature review was based mainly on previous research about the topic by articles and research published by Brazilian investigators. Moreover, information about thermodynamics and visual comfort was The first method applied was the fieldwork. During a week in april, quantitative primary data was collected from two case studies buildings in SĂŁo Paulo, through spot measurements and continuous monitoring of temperature and illuminance. Moreover, qualitative data was also gathered through interviews with architects responsible for the buildingâ&#x20AC;&#x2122;s design, in order to understand the motivation behind the choice of translucent materials. From this information collection, preliminary conclusions were made.

The thermal simulations were held via the software TAS by EDSL, which is a dynamic thermal simulation. From these studies, quantitative data of annual cooling loads and overheating frequency were used to compare each scenario. Moreover, weekly graphs were plotted considering dry bulb temperature, mean radiant temperature and resultant temperature.

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1. INTRODUCTION

1.4. SUMMARY OF RESULTS The daylight studies concluded that translucent materials have a better visual performance than transparent material in a sky like SĂŁo Paulo. It was also proved the benefit of the addition of external shading to avoid glare in the peripheral zone near the facade. The thermal studies findings is that transparent/ translucent facades should have low G-value and also have external shadings to avoid direct radiation gains. The reduction of window to wall ratio proved to beneficial in improving the indoor comfort. Moreover, night time ventilation demonstrated to improve the results in annual cooling loads.

Iguatemi Mall Skylight photo by Vinicius Amano

1.5. STRUCTURE OF THE THESIS The research is structured in five main chapters: Literature Review

Fieldwork

In this chapter, the research questions are investigated and hypotheses are formulated. It is divided into three sections. First, the optical properties of transparent materials, in which the light physics on glass is explored and research about daylight in office in S達o Paulo is reviewed.

The two case studies are presented, first by a macro analysis of location and microclimate, to then approach the investigation further for indoor analysis. Each case study is presented separately, with spot measurements, continuous monitoring and interviews with architects.

The second section is the thermal properties of transparent materials. The thermodynamics physics that affects a transparent material are explained and a research of natural ventilation on offices in S達o Paulo is referred.

Analytical work

Finally, the last section is about human comfort. The thermal dynamics which directly affect the sensation of comfort in a warm climate are presented together with a brief study about visual comfort. Context This chapter aims to introduce the context of S達o Paulo, by presenting the location, climate analysis and conditions of the current built environment trend. Moreover, the translucent materials investigated are introduced.

This chapter is divided into three sections. The first one is the definition of the base case based on a collection of contemporary building production. The second section is the daylight analysis of DGP, UDI and Illuminance. The third section is the thermal dynamic analysis. Research outcomes and design applicability As a conclusion of the research, this chapter presents a guideline summary of ideal strategies to be able to design translucent materials on facades of environmental responsive buildings in S達o Paulo.

2. LITERATURE REVIEW

Fisheye photo of Avenida Paulista by Victor Freitas

OVERVIEW This chapter intends to review published literature related to the application of translucent and glazing materials in façades in a subtropical climate. Glass is one of the main components of architecture. It is the connection between inside and outside, so it can bring the best qualities of the surrounding environment when well applied. It is the main component to bring in the light inside the space, but also one of the trickiest materials when it comes to heat gain and losses. In the book “Architectural material. 3, Glass”, edited by Jinyoun Na, many architects were interviewed and asked a simple question: “What are the strengths and weakness of glass?”. Some architects are aware of thermal and privacy issues regarding translucent materials, as Davide Macullo who affirms a rise in uncomfortable situations due to the extensive use of glass. However, many architects seem to be uninformed of this materiality:

“There are no strengths or weakness but poetics’ potentials only” Donner Sorcinelli Architecture

“Glass doesn’t have any weakness, frames have. A frame always feels like a compromise” SUPA architects “It goes beyond our profession to mention about technical terms of glass materials. However, for the aspect of architectural design, I don’t have much ideas on it” TheeAe architects From these statements, it is evident the existence of a lack of knowledge of material performance by architects, who usually specify glazing based only on its aesthetics and the views provided by it. This poor awareness by design professionals, tied with a disregard of environmental principles and sustainable vision, can cause either thermal and visual discomfort of occupants, moreover generates high cooling and heating demands. The first step in this research was to understand the thermodynamics and optical properties of translucent materials and how its properties can affect the internal comfort of a space.

2. LITERATURE REVIEW

2.1. TRANSLUCENT MATERIALS OPTICAL PERFORMANCE Light is electromagnetic radiation with a wavelength size which is visible for human eyes. The light, once incident on a surface, can be distributed in three different ways: reflected, absorbed and transmitted (SZOKOLAY, 2014). For translucent materials, the sum of these components is 1. On the other hand, there is no light transmitted through opaque materials, therefore the sum of reflected and absorbed components is one. The component provided by suppliers is light transmission (LT). In architecture, the transparency quality of a material refers not only to light permeability but also to the ability to perceive images through

it (WELLER, 2009). This research focuses on the study of diffuse materials, i.e. the light transmitted is scattered and, therefore, the image viewed through it is not clearly perceived. The diagram below shows graphically the difference between the two materials. While in the clear transparent material the light transmission component is only the direct light transmission (LT = LTdir), in the diffuse material, the light transmission is composed by direct light transmission and the diffuse light transmission (LT = LTdir + LTdff).

Considering this difference in optical physics, the first research question is formulated: How is the visual comfort of a translucent material in comparison with a clear material? An initial response to this question can be answered considering visual quality. Luminance is a measure of the brightness from a surface in any direction measured in cd/mÂ˛ (SZOKOLAY, 2014). The difference in brightness is perceived by our eyes and could cause discomfort when the luminance ratio between two or more surfaces is above 1:20, contrast which can cause glare.

The assessment of daylight was commonly evaluated by one point in time simulation, through Daylight Factor. However, dynamic daylight simulations, known as Climate-Based Daylight Modelling (CBDM), started to be applied and standing out as a new alternative method to assess daylight in a more accurate way (MARCONDES et al., 2018). CBDM input in the simulation hourly sun and sky conditions from annual weather data, generating a timeseries of predictions per point evaluated considering extremes daylight condition that happens under real skies (MARDALJEVIC et al., 2012).

From the graph, we can assume that the light transmitted by the diffuse material could spread more evenly through space, which reduces the chances of glare. Therefore, from this first theoretical analysis, the diffuse material seems to have a better visual performance regarding the visual quality of the light. Further analytical investigations are conducted in chapter 5. Another measurement to assess visual comfort is illuminance, which is the quantity of light incident on a surface and it is measured in lux. This measure refers to the functional performance of light, i.e. if there is enough light for the occupant to perform a specific task, and it is required by code and regulations. 21

2. LITERATURE REVIEW

The Useful Daylight Illuminance (UDI), proposed by Nabil and Mardaljevic, is a CBDM parameter which measures the annual frequency of illuminances on a plane under a threshold considered useful to do an office work task, which initially is 100 lux to 2000 lux . The Daylight Availability is a parameter which also measures the annual frequency of illuminance, but only defines a minimum threshold (MARCONDES et al., 2018). From this perspective, a second research question is elaborated: How does a full glazed façade perform regarding visual comfort in a sky condition like in the one in São Paulo?

is more appropriate in assessing this office typology in this skydome condition. The weather file of São Paulo used in the simulations has its source from Energy Plus and was based on the representative year of 1992. From this, Marcondes analyses the sky condition of the city and concludes that is partially or totally clouded 60% of the year. The typical day on summer is mostly cloudy, with both high diffuse and direct radiation, while in winter most of the day the sky is totally clear, with direct radiation high above 600 W/m². typical summer day

Marcondes, Cunha and Gonçalves, in the paper Daylight performance of office buildings: a dynamic evaluation for the case of São Paulo (2018), investigates the performance of a typical deep-plan office building built between 2005 - 2015. The research base case studied has a low ceiling to floor heigh of 2.75m and window to wall ratio of 70%. Moreover, the addition of external shading is investigated. Furthermore, CBDM parameters of Daylight Availability (DA) and Useful Daylight Illuminance (UDI) are compared to determine which one

typical winter day

typical sky conditions in São Paulo (MARCONDES, 2018)

The analytical work conducted by the research shows that the addition of external shading on this typology of deep plan building with high window to wall ratio is beneficial to avoid extremes levels of illuminance near the façades, avoiding visual discomfort. Therefore, it is an architectural strategy that proves to be positive on this peripheral zone of the plan, however, it reduces the illuminance availability on the deeper distances, which should need complementary artificial lighting. The first outcome of the research is that the UDI parameter is more appropriate than the DA because it defines a maximum level of illuminance on the assessment. Therefore, this metric is able to avoid and evaluate the visual discomfort by glare (MARCONDES et al., 2018). The research concludes that due to the high daylight availability of São Paulo’s skydome, the potential of working on architecture components of external shading to provide solar control, the flexibility and adaptability of users inside the office plan, the UDI threshold of 1003000 lux is applicable. Moreover, the research also introduces the concept of a passive zone for daylight on office plans, considering a minimum frequency of 75% of UDI. This zone would be the offset area near the façade in which most of the time the lighting could be

natural, therefore named “passive zone”. At the same time that the passive zone provides an area in which daylight is appropriate, it is also the area more exposed to the solar heating gains through radiation by the windows. For this reason, some studies support that the maximum UDI threshold to avoid glare but also balance thermal and luminous performance would be 1000 lux maximum (SHEN; TZEMPELIKOS, 2012). On chapter 5 of this research, in order to balance the findings from Marcondes (who considered applicable for São Paulo skydome the high bound of 3000 lux) and the possibility of overheating, the maximum threshold considered was 2000 lux.

UDI simulation without (left) and with (right) external shading (MARCONDES, 2018)

2. LITERATURE REVIEW

2.2. TRANSLUCENT MATERIALS THERMAL PERFORMANCE While the previous subsection described the luminous performance of translucent materials based on visible wavelength radiation, this section focus on the thermal aspect. The thermodynamics in which any material is exposed must be explained to further the analysis of how translucent bodies perform. The basic concepts of thermal physics are explained by Szokolay, in his book “Introduction to architectural science the basis of sustainable design”:

Conduction is a heat flow that occurs when materials are in contact with one another and depends on the conductivity characteristics of them. The materials once joined form a construction and its conduction property is known as u-value, which is the heat flow density with 1K temperature difference between the air outside and inside in contact with the construction area, and the units are W/m²K (SZOKOLAY, 2014). Therefore, the heat loss or gains are calculated by Q = A x U x ΔT.

“Heat is a form of energy, contained in substances as molecular motion or appearing as electromagnetic radiation in space. [...] Temperature (T) is the symptom of the presence of heat in a substance” (SZOKOLAY, 2014)

CONDUCTION

U value

This energy flows from a higher temperature body to a lower one and can occur in three different dynamics: conduction, convection and radiation.

Finally, radiation is when a body with a higher surface temperature emit heat to a lower temperature one. The heat flow through radiation depends on the temperature of the receiving and emitter surfaces and their qualities of reflectance (ρ: how much of the incident radiation is reflected), absorptance (α: how much is absorbed by the material) and emittance (ε: how much of the absorbed radiation is emitted to the interior) (SZOKOLAY, 2014). All of these properties are decimal fractions.

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Convection is when a fluid such as air exchange heat with a solid body. The convection coefficient (Hc) depends on the surface position, the fluid velocity and the direction of the heat flow (SZOKOLAY, 2014). The heat gain/loss is calculated by Q = A x Hc x ΔT

Conduction and convection heat flow work equally for opaque and translucent materials. However, regarding radiation, the difference between them relies on a fourth property inexistent on opaque materials: transmissivity (τ) - the ability of a material to transmit direct radiation.

gain, by absorbing the heat and not emitting it inside. However, the surface temperature gets warm so it can dissipate heat thought convection (SZOKOLAY, 2014). Therefore, the application of curtain walls in a climate with these characteristics should always be done with absolute carefulness.

Therefore, the radiation that falls on a opaque material can be deconstructed in α+ρ=1, meaning that the total radiation is either absorbed or reflected, to then eventually be re-emitted inside through second radiation (emissivity). On the other hand, regarding transparent materials, the incident radiation can be deconstructed in α+ρ+τ=1, which implies that some of the radiation is directly transmistted inside the space through the body, besides the second emission caused by

According to these issues, the research questions were elaborated:

the absorbed bit. This property is related to the solar gain factor (θ or sgf), also known as G value (SZOKOLAY, 2014). So, while opaque materials solar gains are defined by Gs = A x G x α, transparent materials gain is Qs = A x G x θ. Consequently, when considering climates with high radiation, either direct or diffuse as the climate of São Paulo, a lower G value is a property of which should be highly considered to avoid unnecessary solar gains. Special glasses such as tinted ones can reduce the solar 26

How is the thermal performance of transparent materials in a subtropical climate as São Paulo? How would be the thermal performance if external shading devices are added in the façades?

Jo達o Cotta, in his research Natural ventilation and window design for office space in S達o Paulo investigates the comfort achievement for occupants of work areas. In his study, he balances inputs such as window to wall ratio, external shading and airflow during occupied and unoccupied hours (night ventilation).

is not justified as the comfort can be easily achieved by other adaptability opportunities such as table fans and clothing. Moreover, the simulations were done using single glazing, proving that double-glazing is not necessary at any moment of the year to achieve thermal comfort.

Regarding window to wall ratio, his first analysis concludes that, due to S達o Paulo climate where the direct and diffuse solar radiation is very high, the most efficient strategy to avoid solar heat gain is to reduce the glazing area. Moreover, it is also important to do external shading as it avoids direct radiation rather than internal blinds. From the graphs below, it is possible to see how effective is the addition of external shading to avoid solar heat gains in summer months. On winter, the reduction of WWR and the external shading blocking direct radiation does not affect the interior comfort, as the internal gains are sufficient to maintain comfort. The studies made by Cotta concludes that office buildings in S達o Paulo can be natural ventilated if there is an effective shading of direct radiation combined with air movement and adaptability of users to open the windows. On the most extreme hot conditions of the year where overheating occurs the air conditioning

Graphs by Cotta (2018), WWR and shading influence in solar heat gain

2. LITERATURE REVIEW

2.3. HUMAN COMFORT People spend most of their lives in indoor spaces. It is the architect’s responsibility to design a space in which the occupants feel comfortable. Comfort has been defined as ‘that condition of mind that expresses satisfaction with the environment’ (ASHRAE, 2010 cited by CIBSE, 2015). There are many factors that affect human comfort, be it visual, thermal and acoustic. The environmental factors that impact on thermal comfort are: air temperature, air movement, humidity and radiation. Moreover, personal factors also affects the sensation of comfort, as an activity that the occupant is doing (metabolic rate), the clothing, the state of health and acclimatization, which is related to a cultural perception of weather (SZOKOLAY, 2014). As the focus of this study is the impact of translucent facades on the human comfort, the radiation is a factor which must be highlighted. When solar radiation falls on a window the transmitted short wave radiation is almost all absorbed by the internal surfaces. This raises the temperature of these surfaces which, as well as contributing to the convective gain, augments the mean radiant temperature. In comfort terms, the most significant component is the direct radiation falling on occupants near the window (CIBSE, 2015)

As explained previously, the heat exchange through radiation depends on the difference of temperature of the surrounding surfaces measured by mean radiant temperature (MRT). In warmer climates, due to lower clothing level, the MRT has the same impact level as DBT(SZOKOLAY, 2014). Moreover, to avoid local discomfort, it must be avoided asymmetric thermal radiation, which is the phenomenon where there is MRT difference between the plane radiant temperatures on opposite sides of the human body (CIBSE, 2015).

In the case of a warm climate like SĂŁo Paulo, this can happen by solar radiation through glazing. According to CIBSE, the radiant temperature asymmetry should not contribute for more than 5% of dissatisfied, which for a warm wall is 23K (CIBSE, 2015). However, Szokolay arguments that at or near comfort levels the difference between DBT and MRT should not be greater than 3K. Furthermore, the concern about extensive use of translucent materials on facade is not

only about thermal comfort, but visual as well. People exposed to direct solar gain may also experience discomfort due to glare and veiling reflections (CIBSE, 2015). Moreover, the translucent materials can affect the visual comfort regarding views out. This is important for the occupants to refocus their eyes and break the monotony of the indoor environment. According to BREEAM, the window to wall ratio must be greater than or equal to 20%.

graph from CIBSE (2015 - figure 1.11) Percentage dissatisfied due to asymmetric radiation only (Fanger et. al, 1980, 1985); data from climate chamber experiments, air temperature adjusted to compensate for cool or warm wall or ceiling.

impact of views out Rio Negro Building

2. LITERATURE REVIEW

2.4. CONCLUSIONS AND HYPOTHESIS The literature review highlights the concern of the high radiation and daylight availability of the climate in SĂŁo Paulo and how it has an impact on thermal and visual comfort, specially involving fully glazed facades. In terms of daylight, it was concluded the benefit of assessing by UDI, and the advantage of external shading as a way to avoid glare on the peripheral zone near the facade. In regard to thermal, the same strategy proved to be beneficial to reduce the solar radiation gains. Moreover, the reduction of window to wall ratio should be considered. From this, the hypothesis formulated and that are further investigated are: In a subtropical climate like SĂŁo Paulo, the extensive use of translucent materials cause overheating and glare conditions on the peripheral space near the facade. Diffuse materials seem to have better visual comfort concerning glare probability.

3. CONTEXT

OVERVIEW This chapter aims to contextualize the issue by introducing the location and climate analysis. Further, the circumstances regarding the built environment in São Paulo is presented to then further information about the materials studied.

3.1 LOCATION São Paulo, the largest city in the Americas, is located in the southeast of Brazil at latitude 23.5º S and longitude 46.6°W. The city’s altitude is 760m above sea level.

46.6°W

23.5°S

3. CONTEXT

3.2. CLIMATE In this subsection, the climate of São Paulo is first examined considering the Koppen-Geiger classification, followed by a deeper analysis of each climate component: temperature, humidity, wind, precipitation, sun path and radiation. Finally, conclusions and basic environmental guidelines for this climate are presented. The weather file used for the climate analysis and for the simulations was sourced from the weather database software, Meteonorm v.7.2. Specifically, the weather file used was SaoPaulo_2005-hour.epw, which is a representative of the typical weather in São Paulo. The weather data was post-processed using the climate analysis excel table from Dr. Juan Vallejo and ladybug software for Rhino.

3.2.1. CLASSIFICATION According to Koppen-Geiger climate classification, São Paulo is considered to be a Cfa zone: warm temperature fully humid hot summer. This first description suggests a high probability of overheating in the summer months.

3.2.2. TEMPERATURE The mean average throughout the year is between 18°C in winter (July) to 24°C in summer (February), with the mean maximum temperature reaching 26°C and mean minimum 13°C. The highest peak temperature is 32°C and occurs in January and February at 4 pm, while the lowest peak is 7.6°C in July at 7 am.

3.2.3. HUMIDITY The mean average throughout the year is high, between 70% - 80%. The mean maximum humidity is 95% occurs in April and the mean minimum is 48% in August. The highest peak relative humidity is 100 % and happens in February at 6 am, while the lowest peak is 31% in August at 3 pm.

3.2.4. WIND During summer, the main wind direction is from southeast and east, with a maximum speed of 7m/s. In winter, the direction is mainly from east-southeast.

summer

winter

3. CONTEXT

3.2.5. PRECIPITATION The summer months are the ones with higher cumulative rainfall, particularly in January when it almost reaches 200mm, with fewer days of occurrence which results in pouring rains. March is the month with the most frequency of rain, but with a cumulative rainfall of 100m. The dry season is on winter, where the cumulative precipitation is as low as 25mm in June. 3.2.6. SUN PATH In summer months, the sun path is high with the azimuth of 90° at noon, time in which the dry bulb temperature is also higher. The daytime lasts from 5:30 am to 6:30 pm. In midseason, the daytime is from 6 am to 6 pm, and the highest DBT occurs at the end of the day, when the sun azimuth is lower than 30°. In winter, the highest azimuth is 43° at noon. The highest temperature befalls in the afternoon when the sun is between 30° to 20°.

summer (21.12)

midseason (21.03)

winter (21.06)

3.2.7. RADIATION The daily average horizontal radiation is high most of the year, mainly above 3kW/m². The highest average occurs in February and November, reaching 5 kW/m². Regarding vertical radiation, the facades which most need attention are east and west on summer months, period in which it can reach 3 kWh/m².

3.2.8. SKY COVER The sky cover is partially or totally unobstructed in 63% of daytime hours of the year. This happens mainly in winter months, while in summer months we can see a higher occurrence of obstructed sky, which results in diffuse radiation.

3. CONTEXT

3.2.9. CONCLUSIONS AND STRATEGIES The main issues of the climate analysis are summarized in the graph below, which relates dry bulb temperature, average horizontal radiation and sky cover. Therefore, the mainly mild temperatures in SĂŁo Paulo indicates the possibility of natural ventilation in order to achieve comfort in most hours of the year. However, this strategy must be coupled up with other passive approaches, such as high thermal mass exposed materials and external shading devices. The last one is justified by the high direct radiation most of the year from all the directions and also to considerable diffuse radiation subsequent of the often overcast sky in summer (GONĂ&#x2021;ALVES; MARCONDES; 2015).

3.3 SÃO PAULO CONTEMPORARY BUILT ENVIRONMENT São Paulo, the biggest city in South America, has always been a showcase for architecture. The city had even its own segment inside Brazilian modernist architecture, known as Escola Paulista or Brutalism, which included

According to Fernando Serapião, an architecture critic, around the ’70s the building design withdraw the use of external shading and start applying colored glass as an indiscriminate replication of North American building design

the extensive use of exposed concrete. This modernism from the ’50s had environmental strategies such as cross ventilation and brisesolei to avoid solar heat gains.

of curtain walls. This resulted in insolation issues and extensive use of air conditioning (Serapião cited by Teixeira and Correa, 2013).

Banco Sudamericano do Brasil building by Rino Levi

São Luiz Gonzaga building retrofited by Edison Musa Arquitetos

(1963)

Associados (1997)

3. CONTEXT

This trend persisted until the 2010s, populating commercial neighbourhoods of the city such as Avenida Berrini, Avenida Faria Lima and Avenida Paulista. Roberto Aflalo, director architect from Aflalo & Gasperini, a practice based in São Paulo and defensor of this type of architecture, declares that new glazing technologies allow light - but no heat - to be transmitted through. Moreover, he states that energy efficiency simulations that there is an insignificant difference in the energy performance of a tall and deep plan office building when external shading is applied (Aflalo cited by Teixeira and Correa, 2013). It is necessary to highlight here that not only sources of these studies were presented, but also the interest is only related to the energy consumption and not to human comfort. On the other hand, after 2010, a new contemporary architecture trend started looking for contemporary solutions in the saturated city of São Paulo. IdeaZarvos, a recent construction developer company, saw the opportunity of investing in a different part of the city, at the bohemian neighbourhood of Vila Madalena. The sites in this area are smaller, which results in buildings of smaller scale and that can be more personalized. In such circumstances, renowned architects are hired by these companies to design unique 40

buildings with higher market value. In this context, new translucent materials started to be explored by São Paulo’s architects as an aesthetic alternative to the often applied coloured reflective green glass. However, these new technologies have been specified considering only aesthetics reasons and specific visual effects caused by the experience sensation of light, setting aside any concern regarding the thermal, daylight and energy performance.

W305 building by Isay Weinfeld (2011)

3.4. TRANSLUCENT MATERIALS This research focuses on the study of three different translucent materials that have been applied in recent constructions in Sรฃo Paulo. These materials are opposed to the coloured transparent glass with a good thermal performance, which is the previous alternative in faรงade. This subsection presents the properties of the materials studied. 3.4.1. MATERIALS PROPERTIES Coloured Transparent Glass Coloured (or body-tinted) glass is made by the addition of metal oxides.This material absorbs shortwave radiation and then re-emits it as longwave; therefore the direct transmitted radiation is reduced. However, a large part of the solar radiation is absorbed by the glass and, therefore, it can be remitted inside the room through secondary radiation (CIBSE,2015).

Bonarka 4 Business buildings by Biuro architektoniczne Krakรณw

3. CONTEXT

Textured Glass The textured glass is a simple glass with the addition of a decorative pattern obtained by rolling the cast glass between two engraved cylinders. (information from Saint Gobain website)

Nihonbashi Yayoi Building by A. Kuryu Architect & Assoc. Tokyo

Profiled Glass Profiled glass is a U-shaped casted material which, due to its shape, has the advantage of being self-structured. It is annealed glass, fitted with longitudinal wire reinforcement make sit a highly durable product.

The Nelson-Atkins Museum by Steven Holl Kansas

3. CONTEXT

Polycarbonate Polycarbonate (PC) is a crystal clear, high impact thermoplastic (information from Rodeca brochure).The energy used to extrude one sheet is generally a fraction of that to manufacture glass. Polycarbonate sheets are also durableâ&#x20AC;&#x201D;250 times more impact-resistant than glass and virtually unbreakable (Sims, 2018). The polycarbonate panel property depends on the number of layered sheets inside the material. On this study, it was considered one with only four sheets

National Centre for Synchrotron Science (NCSS) Melbourne

Summary The following table presents the summary and properties of the studied materials. icon

description

name

supplier

coloured transparent glass

parsol green

saint gobain

73%

5.7 W/m²K

55%

86%

5.7 W/m²K

79%

70%

1.8 W/m²K

63%

profiled glass - one layer profilit

pilkington

profiled glass - two layers

textured glass - two layers

master-carre

saint gobain

70%

2.6 W/m²K

63%

polycarbonate

PC 2540-4 MC

rodeca

60%

1.2 W/m²K

58%

3. CONTEXT

3.4.2. MATERIALS PRECEDENTS A brief research of precedents was made to understand where are the common location in which these materials are applied. The data was collected from the suppliers website. Mainly, these materials are applied in temperate climates like in the USA and Europe. Moreover, the polycarbonate is also applied in tropical climates. The texture glass Master-Carre, as explained previously, is a decorative glass, and the records show that it has only been applied in facades in a building in Tokyo and in SĂŁo Paulo.

polycarbonate profiled U glass textured (master carrĂŠ)

4. FIELDWORK

Avenida Paulista photo by Sergio Souza

INTRODUCTION From April 16th to April 23rd, fieldwork studies were conducted in Sรฃo Paulo. Two translucent faรงades buildings located in the same avenue were analysed through spot measurements and thermal continuous monitoring. The first case study, an office building named Rio Negro, had its faรงade was retrofitted in 2019, changing the regular single glass to a doublelayered U glass. The second case study is a multicultural building named IMS, and it is a new construction which has a double-layered glass faรงade, with the exterior layer in textured glass Master Carre. The aim of these studies was to understand the real performance of these materials applied in the built environment. Moreover, the architects responsible for the design of each building were interviewed about the project development and the choice of materials. The devices used on this fieldwork were: a lux meter, to measure illuminance levels, a Thermo hygrometer, which measures temperature and humidity, and three sets of data loggers which measured temperature and mean radiant temperature. Note 1: The measurement equipment used on this fieldwork were kindly borrowed from FAU USP. Note 2: The third data logger had a malfunction so data was only collected from two spots

4. FIELDWORK

4.1. CONTEXT AND MICROCLIMATE Avenida Paulista, the most famous avenue in São Paulo, is located at the top of a hill and its axis direction is northwest to southeast. It is one of the busiest avenues in the city, with a high amount of vehicles transit which results in noise and bad air quality, as pointed out by IPT data from 2016 (Instituto de Pesquisas Tecnológicas). The two case studies are located a few meters apart from one another. Rio Negro is located in a corner with no surroundings, having a more exposed condition than IMS, which is situated in an urban canyon situation between two high rise buildings. The spot measurements were collected at 11 am on April 23rd, a Tuesday, and the route consisted of walking from one building to another on the sidewalk. The data informs that the condition of exposure of Rio Negro surroundings caused it to have a 1.5°C higher temperature than the IMS context. The area with higher sun exposition, in the crossing with Rua da Consolação, registered the highest temperature of 30.7°C. The relative humidity follows the trends of inverse relation with temperature - the higher the temperature, the lower is the RH, and it is in the acceptable range between 40-70% (Nevins cited by CIBSE, 2015).

Legend CO concentration (ppm) 0-9 good 9-11 average 11-13

slightly bad

13-15 bad >15

extremely bad

Avenida Paulista pollution levels source: IPT

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4.2. EDIFÍCIO RIO NEGRO 4.2.1. OVERVIEW Edifício Rio Negro is an office building of 12 storeys built in the late ’60s. Located on the street corner of Avenida Paulista and Avenida Angelica, it has a rectangular plan of 15.05m x 27.30m and its axis is directed to northeastsouthwest. The floor to ceiling height is 3.15m. The façade facing southeast, overlooking at Angelica avenue, has a window to wall ratio (WWR) of 75%, while the southwest is 40%. In 2018, the building façade was retrofitted by AR Arquitetos, who replaced the dark reflective single glazing for a double layer U-glass alternated with a single clear glass window. Moreover, glazing area, which used to be openable, was reduced for. The spot measurements and continuous monitoring were taken on the same floor (3rd) in an open plan unoccupied office. Regarding the materiality, it had exposed concrete ceiling and columns painted in white and wood flooring. The windows were all closed.

data logger location 0

4. FIELDWORK

4.2.2. INTERVIEW WITH THE ARCHITECT On April 11th, the architect Marina Acayaba, a founding partner from AR Arquitetos, gave an interview to explain the retrofit design process of Rio Negro building. Here, only the bits related to the design process and environmental performance of the material are presented. For the full interview, please refer to the appendices.

JG: As you know, I am researching about contemporary glass facades to understand new solutions that are aesthetically more pleasant and which performs better environmentally. And I believe the U glass seems like a very nice option and that is why I decided to study it. So, I wanted to understand a little about the project, how you decided on the material and how was the whole architectural concept of the retrofit. MA: It didn’t actually have a previous façade project. We bought the material, it was an aesthetic decision. As it is double-layer glass, it has thermal inertia so it has more heat protection. When we bought it, the owner of the company made several tests of how it would work, how it would improve. Comparing to the façade previous glass, it improved the acoustics amazingly from the outside noise, because of this double layer. Also, 54

the luminosity improved a lot, because before, as it was all glazing, there was always direct sun coming in. To install the façade, we had to do all the burst tests, wind pressure. U-glass has a problem: it is simple glass, not tempered glass. So it is not suitable for a full glazed facade like this. The company sold us the wrong glass. [...] In addition, we have installed the Eastman film, which prevents the glass from breaking and shattering - [...] so this film allows the glass to get stuck in it, and also improves the whole issue of solar incidence. [...] We made this project with variable windows, we reduced the amount of window for ventilation because we realized that the occupants never open all windows. By having one window on one each side it would be enough to create cross ventilation. As this avenue is very noisy, the occupants rarely want to open all the windows. JG: What about the people in the occupied offices, are they enjoying it? MA: There are people who like, I think this issue of thermal and noise has improved a lot. Now there are people who complain because they do not have the view anymore. We also exchanged all air conditioning for VRF

which is much more economical. We changed the system, because before it was that window air conditioner. And it saves 30% on electricity. Unintentionally, the project became sustainable. We are having a lot of demand for rentals. JG: Would you work with the material again?

The facade engineer had never worked with anything other than usual reflective coloured glass. There are no technicians with know-how here [in Brazil]. Here, it is only used the default design, which is the reflective coloured glass facade, which they know how to solve, which everyone does. And that often does not open the window.

MA:It was a nice system. But I donâ&#x20AC;&#x2122;t know if I would do it again. Only on a smaller scale.

Marina Acayaba and Juan Pablo Rosenberg, founders of AR arquitetos

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4.2.3. SPOT MEASUREMENTS On April 15th at 3 pm, spot measurements of temperature and illuminance were taken on the 3rd floor. Regarding thermal, the average indoor temperature is 25.3°C, which is 1.7°C lower than the outside of 27°C. The highest temperatures are near the façades, with a peak of 25.6°C on southwest façade.

Regarding daylight, the highest illuminance levels are near the windows, with a peak of 6600 lux on southwest faรงade, which is the faรงade with higher SVF. On the deeper side of the plan, the illuminance level drops up to 410 lux, reducing in less than 10% the amount of illuminance near the windows. Still, the quantity is sufficient for office space, inside the threshold of 300-500lux defined by CIBSE.

4. FIELDWORK

Further daylight studies were made through HDR photo to analyse the quality of light by false color mapping which evaluates luminance. Luminance is a measure of brightness of a surface that reaches the human eye and its units is cd/mÂ˛ (SZOKOLAY, 2014). It relates to the quality of light, and the assessment of glare as it allows to quantify the luminance ratio difference.

The photos were taken using the HDR photo and further post processed in the software hdrscope. The luminance mapping from the Rio Negro shows the different performance of a translucent material and a clear glass. It is possible to verify that the luminance that falls on the floor through the U-glass (translucent) is much more homogenous than the one from the clear glass, which presents different levels of luminance and contrast.

cd/m² 180 150 120 90 60 30 0

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4.2.4. CONTINUOUS MONITORING A data logger was placed on the southwest façade and it monitored the radiant and dry bulb temperature during the week of April 16th to 23rd. As explained in the overview section, the floor was unoccupied, windows were closed and there was exposed concrete on the ceiling. From the graph analysis, it is possible to see a thermal inertia happening inside the building,

Note: comfort band threshold based on ASHRAE 55

as the air temperature drops slowly during nighttime, period in which outside temperature goes as low as 14.2°C. This relates to the heavyweight material on the ceiling and the low U-value of the façade material, which makes it harder the heat losses through conduction. As expected, the radiant temperature is higher when the sun is incident, as it is visible on the sun path.

Even though the temperature is all within the comfort band, it must be noted that the floor had no internal condition gains, which would increase the temperature considerably. Moreover, the ceiling is expected to be covered in gypsum board, which would increase the risk of overheating.

4. FIELDWORK

4.3. IMS 4.3.1. OVERVIEW IMS, short for Instituto Moreira Salles, is a museum and multi-cultural building designed by Andrade Morettin Architects. Built in 2017, the building was a product from an architectural contest. One of the challenges of the architects was the site per se: a narrow area, located between tall buildings and few connections to the outside. The solution is a glazed envelope which embraces the 9 storeys building with a â&#x20AC;&#x153;ground lifted floorâ&#x20AC;?: to avoid the sensation of claustrophobia, the architects created an open podium level on the fifth floor, connected to the streets via mechanical escalators. The plan is a rectangle of 13.9m x 42.2m. The floors have a high ceiling of at least 5m, with some double heigh ceiling of 6m. The envelope is composed of two laminated glass, with the outside layer as the Master-Carre texture glass by Saint Gobain. All the envelope is fixed, except for the lifted ground floor. The three higher levels of the building are occupied by the museum, while the lower levels are located the library, classrooms, offices and theatre.

ution

â&#x20AC;&#x201D; FaĂ§ade

_insulated glass 6mm | serigraphy + 1.52 PVB + 6mm 12mm insulation 6mm + 1.52 PVB + 4mm

_main metallic structure _vertical laminated-glass piece

_metallic extender _horizontal metallic piece

70 x 70 x 1.8â&#x20AC;?

_main metallic rod _metallic rod

_main metallic structure

Program Distribution

_ exhibition spaces _ mediatheque _ administration _ restaurant _ technical facilities _ parking _ art storage room

4. FIELDWORK

1 biblioteca _ library 2 bibliotecário _ librarian 3 sanitários _ bathrooms 4 administração _ management 5 área de espera _ waiting room 6 sala de aula _ classroom 7 foyer _ foyer 8 bar _ bar 9 área técnica _ technical area 10 auditório _ auditorium 11 palco _ stage 12 vestiário _ dressing room 13 apoio ao palco _ support area 14 sala de projeção _ projection room 15 sala de tradução _ translation room 16 rádio _ radio 17 camarim _ dressing room a escadas rolantes _ public escalators b escada de visitantes _ visitors stairs c elevador de visitantes _ visitors lift d elevador de funcionários _ staff lift e elevador de carga _ cargo lift

data logger location 0 2

+4.20 midiateca _ mediatheque

5 6

+7.35 midiateca _ mediatheque

+10.50 midiateca _ mediatheque

c c

15 14

3 2

+13.65 midiateca _ mediatheque

+4.20 midiateca

_ mediatheque

_Bioclimatic strategies

_light control _natural ventilation _mechanical ventilation

4. FIELDWORK

4.3.2. INTERVIEW WITH THE ARCHITECT On April 12th, the architect Marcelo Morettin, a founding partner from Andrade Morettin Arquitetos, gave an interview to explain the design process of IMS building. Here, only the bits related to the design process and environmental performance of the material are presented. For the full interview, please refer to the appendices.

JG: How was your process of choosing the facade? MM:[...] The image we would like the building to have, not simply in the aesthetic sense, but the quality of the building has a lot to do with the quality of the light, not just for those inside the building, but also how it responds to who is passing on the Paulista Avenue. This [the intention of the light] we knew from the beginning. [..]So we used this image from the inside out, because it synthesized what we wanted for the building, as a presence, meaning that it could be seen and at the same time not fully revealed. It would not have this quality of total transparency, which is very modern, [...] But at the same time, making a closed museum was not an option because it loses its relationship with the street. So the question was: how to bring the energy of the street, the vibration that Paulista Avenue has inside the museum and, at the same time, preserve a certain necessary introspection for the museum.

Maison de Verre by Pierre Chareau the house facade inspired Andrade & Morettin

This was answered both by the strategic point of view, by the construction of the spaces, which is basically the creation of the elevated square, which guarantees the free route and

from there you see the city, you are already in that atmosphere created by the glass. And also by creating the skin, which shelters all the programme, the museum above and the library below, and gives you the chance to see the city without revealing it completely. [...] The IMS gave excellent working conditions. All the professionals were contracted, involved, the process was well done. We made a request that the facade consultant be really very good. Front inc, an American office that has worked with OMA, with Chipperfield, in short, they really are very good and with a lot of knowledge. They

opened possibilities for us. Together, we built this facade idea. Shortening the story a bit, we created a constructive and material solution.[...] In the end, we built this spirit of translucency and at the same time met all the needs we wanted, the details, the lightness. It was an amazing experience. We were able to detail a component that was vital to the project.

Vinicius Andrade and Marcelo Morettin, founders of Andrade Morettin

4. FIELDWORK

[...]It is exactly what we wanted today: depending on the light it changes, depending on the time of day, the position of the observer, sometimes you see the red box inside, sometimes you don’t see it, sometimes it reflects the light, sometimes it absorbs, he’s kind of a mutant, like it’s got a temper, sometimes it’s in a bad mood, it’s kind of grey, sometimes it’s bright.

of the skyline. And we went to find a glass in which he [did not] had this condition, so even if you see in the pictures that were taken from inside you can see the other side of the Paulista, there the ghostly shadows of the buildings, and we wanted that the glass transfigured reality but you felt in the middle of nowhere, as if you were in a fog.

And for those inside, that was a pretty big research, because the translucent glass sometimes, a meter, or even less, after the glass the view is completely blurred, and you lose some sense of what is happening outside. You have a very beautiful light but you lose reference

[...] A special chapter of research and performance has to do with the choice of glass because we wanted this envelope to also serve as a thermo-acoustic filter [...] How to do this? And we didn’t want to give up the translucency. It’s very complicated to do that,

IMS photo by Pedro Vannucchi

especially in subtropical climates, as you said because there are very hot times of the year. And there, that main face is a southwest, so it receives in summer a low angle sun facing the front. [...] The glass is a double laminate. Two glasses, air layer, two glasses. The exterior is a textured glass - that creates the condition of translucency. The interior glass is also a low-e. And then we have the air layer. This guarantees very good thermal performance. And coupled with this condition, we have underfloor heating when needed, mechanical ventilation, natural movement of the air reinforced with extractors, this whole set makes the elevated square work as a transition between external and internal temperature. JG: And has that glass ever been used somewhere else? Or was it the first time? MM: It’s interesting because the elements of the glass construction are there in the market. Including the textured. And that was a long research too. It’s all documented.

better the performance, the worse the effect as it gets darker, it starts to create annoying reflection effects. So it was a tug of war between the performance and the effect we wanted. It was really interesting that even. They even found a newer technology glass of similar performance but less dark. So yeah, the glasses are on the market. Having this consultancy, supported by IMS, we were able to use the latest technology in the market. But the way it was built, this glass sandwich, this composition is unique. There is no other construction. It is a unique thing.[...] This is the story. This is a very cool case from the point of view of the process. It’s interesting to tell how the process worked, which starts with an intention and then how to construct it. Sometimes it happens that the process gets corrupted when the intention is not viable.

We ordered 8 big size samples, of 1.6 x 2.5m, each one of them varying a component, like the PVB, the composition of these glasses, varying the thermal performance factor that met the consultancy’s requirement... for example, choosing this low-e was a war. Because the 69

4. FIELDWORK

4.3.3. SPOT MEASUREMENTS On April 16th at 11:30 am, spot measurements of temperature and illuminance were taken on many floors of the building. As it was occupied, most areas had artificial lighting and mechanical ventilation. The spot measurement started at the outside of the building, at the sidewalk, where there is the highest temperature or 26.5°C. This relates to the microclimate condition and high flow of

people and vehicles. The fieldwork route was to climb the mechanical stairs in direction of the lifted groundfloor. That area, which is 17m above the ground floor, had a temperature of 25.6°C, almost 1°C lower than the street level. The conditioned areas of the museum had a temperature between 25°C to 24°C. The library, where the ceiling is lower, the temperature was 23°C.

Regarding daylight, the highest illuminance level was at the northeast faรงade at the lifted ground floor, with 6500 lux. In the middle of this same floor, there is the lowest illuminance of 190lux.

4. FIELDWORK

4.3.4. CONTINUOUS MONITORING A data logger was placed on the northeast façade and it monitored the radiant and dry bulb temperature during the week of April 16th to 23rd. It was placed in a meeting room of dimensions 5m x 5.5m and high ceiling of 6m. The room floor and ceiling have wood boards and mechanical ventilation extractors. The room as eventually occupied as shown in the graph and the occupants avoided using air conditioning during that week.

Note: comfort band threshold based on ASHRAE 55

Similarly, as it happens in the previous case study, it is possible to see thermal inertia happening as the air temperature drops slowly during nighttime, period in which outside temperature goes as low as 14.2°C. This relates to the low U-value of the façade material, which makes it harder the heat losses through conduction.

As expected, the radiant temperature is higher when the sun is incident, as it is visible on the sun path. The dry bulb temperature is all within the comfort band of natural ventilated building by ASHRAE. However, if considered a more restricted threshold of 24Â°C +- 2Â°C, as this is a mechanical ventilated building, we can see that are few moments when the temperature reaches higher than 26Â°C, related to higher radiant temperature.

4. FIELDWORK

4.4. CONCLUSIONS The fieldwork analysis was conducted in two translucent materials faĂ§ade buildings in the city of SĂŁo Paulo. Even though the buildings have different typologies, the focus here is to understand the performance of the material in a similar microclimate condition. The first conclusion, regarding the design process, shows the importance of material knowledge by the professionals. The first case study, Rio Negro, had a very difficult process originated from a choice of material despite its properties. On the other hand, the IMS process was supported by faĂ§ade professionals and environmental consultancy which helped the architects in doing an informed decision. However, the design process originated from a very clear design intention - which seemed to care more about aesthetics and visual sensations than an environmental performance per se. Moreover, the fieldwork analysis allowed to verify the visual and thermal performance of these materials. In respect of the visual, the luminance mapping was an important tool to evaluate the difference between clear and translucent glass performance, proving that the latter has a more homogeneous performance which could lower the glare probability.

The continuous monitoring of thermal performance of both buildings allow to observe the thermal inertia of the materials - due to the low U-value, the heat is trapped inside the building even during night time, when we have lower temperatures. Therefore, this characteristic of the material is inconvenient in summer months as it can cause overheating by keeping the internal and solar gains inside the building.

5. ANALYTICAL WORK

SÃ£o Paulo photo by Davidson Luna

OVERVIEW This section of the research is based on analytical studies of the material performances. The investigation started with daylight analysis from which the peripheral vulnerable zone is defined, as a complementary aspect to the passive zone (MARCONDES,2018). This vulnerable zone is further investigated in thermal studies. All the simulations considered the same geometry and the same weather file from SĂŁo Paulo 2015 provided by the software Meteonorm 7.1. .

5. ANALYTICAL WORK

5.1 BASE CASE DEFINITION The first step was to define a base case building for analytical studies. A research was done by collecting drawings and data of ten recent constructed buildings in São Paulo. As explained in section 3.3 (São Paulo Built Environment), these buildings are located in narrow sites so the plan is not so deep and, usually, they have a high floor to ceiling height, which allows the lessee to eventually add a mezzanine and, therefore, have more area. The full database collected and study dimensions can be referred at the appendix. From this database, the base case plan was developed by the average dimensions of this data: a 20m for 30m deep plan, with a 5m height ceiling. As the plan is not so wide, the core is located on one of the façades. These buildings are usually not so high, with an average of 15 floors. In all the studies it was considered a middle level (7th floor).

The window to wall ratio is 88%, with all facades as the coloured transparent glass, which is the commonly used material in São Paulo. Moreover, regarding thermal studies, the windows are always closed and the air conditioner is on during occupied hours, as this is the common practice for this typology. The interior design of these new buildings follow an industrial aesthetics trend, so there is exposed concrete ceiling, wooden flooring and open plan office, to allow more flexibility for the occupants. More details about the materiality and its properties is explained in section 5.3.1.

5. ANALYTICAL WORK

5.2. DAYLIGHT STUDIES 5.2.1.METHODOLOGY The daylight studies were performed using the plugin Honeybee and Radiance for grasshopper. It must be noted that the ideal approach for translucent materials would be to simulate through BSDF (bidirectional scattering distribution function) component of the plugin Honeybee plus. This component uses a .xml (eXtensible Markup Languagefile) which is a file provided by the material supplier that contains the information of how the light is scattered spatially.

for the development of the analytical studies, it was impracticable to follow the research via Honeybee plus.

However, during this research, this essential information was not presented by the suppliers. The .xml file could be generated by a third software named Window, by Berkeley Lab. But also, it would require lab experiments with specific equipment to quantify how the light is spread through the materials, to then write the .xml script via Window software. Due to the absence of this equipment on the University of Westminster Fablab, and the restricted time

Once more, the information concerning these details was not provided by the suppliers. The only property which was given was the Light Transmission (LT) component. For a translucent material, the total LT is the sum of diffuse and specular transmission, while a clear transparent material has all of its light transmission transmitted specular.

For the reasons listed above, this analytical study was done via Honeybee with the component trans material. The component requires that the information regarding reflectance and transmission, both diffuse and specular conditions, is inputted by the user :

As the information regarding the ratio between specular and diffuse transmission was not provided, for this research it was considered the most extreme case of translucent material with 90% LT component diffuse. The daylight performance was made comparing only two materials: the base case, as transparent coloured glass, which has a light transmission of 0.73, and the translucent material as the U-glass, with a total light transmission of 0.7 decomposed in 0.6 diffuse and 0.1 specular transmissions. BSDF suface rendering by bsdf2rad (MCNEIL, 2015)

screenshot of BSDFviewer (MCNEIL, 2015)

5. ANALYTICAL WORK

5.2.2.DAYLIGHT GLARE PROBABILITY The first set of studies had the purpose of understanding the quality of light produced by the materials. The interview with the architects in chapter 4 shows the importance of this element for the architectural quality of the space. Moreover, the luminance data gathered in the fieldwork and the Rio Negro’s architect statement regarding the occupants positive view about daylight suggested that the translucent material does have a better performance in comparison to the clear glass at it avoids contrast luminances, and therefore, glare.

angle of view

The Daylight Glare Probability (DGP) is an annual dynamic simulation run via Honeybee and Daysim that results in an annual graph with the percentage of people in discomfort for a specific point of view. The limits are imperceptible (≤0.35), perceptible (≤0.40), disturbing (≤0.45) and intolerable glare (>0.45) (WIENOLD, 2014).

For this simulation, it was considered the northeast view with the building axis of northsouth. The results show that overall performance of both material regarding glare probability is similar. The frequency of visual discomfort during daylight hours is 10% for transparent glass against 13% of the translucent material. Daylight Glare Probability (%) - Hourly

Transparent Coloured Glass

Diffuse Glass â&#x2030;Ľ0.45

intolerable

0.40

percetible

â&#x2030;¤0.35

imperceptible

5. ANALYTICAL WORK

5.2.3. USEFUL DAYLIGHT ILLUMINANCE

5.2.3.1.SCENARIO 01: BASE CASE

The Useful Daylight Illuminance (UDI), as explained in details in chapter 2.1, is a CBDM parameter which evaluates the frequency of minimum and a maximum threshold of illuminance throughout the year. In the set of simulations of this research, the bounds considered were 100 to 2000 lux, with the intention of limiting the possibility of overheating in the passive zone defined by the UDI. For these studies, the passive zone, a concept defined in chapter 2.1, considers the same limit defined by Marcondes (2018) of the minimum frequency of 75%. The simulations were done for the building considering all axis orientation, as the façade which contains the core of the building has a reduced area of glazing and this interferes with the daylight distribution. In this section, only the west-east axis with core placed on north façade is presented, as the overall results are similar. For further studies of orientations, please refer to the appendix.

The first simulation considered the building as it is, with both high floor to ceiling height and window to wall ratio. The comparison between the transparent and translucent glass demonstrates a considerable difference in daylight performance. The plan with transparent glazing has 19% of the area inside the acceptable threshold (above 75%), while the translucent’s area is 39%.

Transparent Coloured Glass

(%) 100 90 80 70 60 50 40 30 <20

Diffuse Glass

During the occupied hours, the areas adjacent to the facades are always above 2000 lux, which indicates the risk of glare and, moreover, overheating. Differently from Marcondesâ&#x20AC;&#x2122;s research, which a deep plan office was studied and defined the â&#x20AC;&#x153;passive zoneâ&#x20AC;? from the offset of the facade, the smaller plan glazed building results in a passive zone concentrated in the centre of the plan. In this research, the interest is the combined impact of both visual comfort and overheating caused by translucent facades. Therefore, the study object is no longer the passive zone, but the peripheral vulnerable zone, which is the area adjacent to the facade and more likely to suffer from visual discomfort (glare) and overheating. The thermal aspects of this zone are further investigated in subchapter 5.3. The image on this page shows the peripheral vulnerable zone, and the offset distance from the facade regarding each orientation.

8 5

Transparent Coloured Glass 5

5 5

3 Diffuse Glass

5. ANALYTICAL WORK

5.2.3.2 SCENARIO 2: MEZZANINE ADDITION The second studied scenario was the addition of a mezzanine. As explained in subchapter 3.3, the current built environment trend in SĂŁo Paulo consists in buildings with high floor to ceiling height, which allows the tenant to eventually add a mezzanine to increase the total area. For this scenario, it was added a mezzanine of 5m deep, offsetted from the facade (middle of the plan has double height ceiling).

The addition of this intermediate floor results in a similar UDI performance of both materials, with transparent glazing has 68% of the area inside the acceptable threshold and translucent area is 78%. The peripheral vulnerable zone reduces in both cases.

Transparent Coloured Glass

(%) 100 90 80 70 60 50 40 30 <20

Diffuse Glass

5.2.3.3 SCENARIO 3: EXTERNAL SHADING ADDITION The final tested scenario was the addition of horizontal brise-solei on all facades. It was considered a shading of 50cm deep with azimuth of 40Â°, which is the angle to protect from the summer sun in north facade, and helps to reduce the sun incidence on midday hours for west and east.

The addition of this external shading was most effective to achieve a high frequency of UDI in both cases, with transparent glazing has 100% of the area inside the acceptable threshold and translucentâ&#x20AC;&#x2122;s area is 99%.

Transparent Coloured Glass

(%) 100 90 80 70 60 50 40 30 <20

Diffuse Glass

5. ANALYTICAL WORK

5.2.4. ILLUMINANCE The illuminance analysis is a steady state simulation, so it considers the illuminance level on a surface in a specific moment in time. For this set of simulations, it was considered a representative date in summer, with high radiation and temperature (February 22nd) and in winter with low temperature (July 16th). The hours tested were 10am, 1pm and 4pm as indicative hours in which the office occupants are working. Finally, it was considered a sunny sky with no sun, as the main condition of the sky in sĂŁo paulo is partially covered.

5.2.4.1 SCENARIO 1: BASE CASE In all tested hours, the illuminance curve is very sloped towards the sun direction (east on morning, north on midday and west on afternoon). Even though on the first meter near the facade the illuminance level are higher on the translucent glass, it quickly drops and maintains a average of 400 lux lower than the transparent glass, which is always 1000lux even in the middle of the plan. Regarding the comparison of performance within seasons, winter has at least 200lower lux level than in summer. Also, it is notable how the peripheral vulnerable zone changes up to 5 meters (transparent glass 1pm).

transparent glass summer winter

diffuse glass summer winter

lux

16.02 10:00

lux

16.02 13:00

lux

16.02 16:00

5. ANALYTICAL WORK

5.2.4.2 SCENARIO 2: MEZZANINE ADDITION The same mezzanine simulated on UDI was added in the illuminance simulation. In this case. This addition proved to be beneficial for the area on the middle of plan, as the curves are much more horizontal, that indicates a more homogenous light, and within the range of 300 to 800 lux. However, the first two meters near the facades have high illuminance levels; this difference in illuminance ratio can cause visual discomfort by contrast.

transparent glass summer winter

diffuse glass summer winter

lux

16.02 10:00

lux

16.02 13:00

lux

16.02 16:00

5. ANALYTICAL WORK

5.2.4.3. SCENARIO 3: EXTERNAL SHADING ADDITION Finally, the last tested scenario - the addition of external shading - proved to be the most efficient strategy to achieve visual comfort. The illuminance curves are much more uniform, specially when applied in the transparent glass, even though the illuminance level is high, with an average of 1000lux in all section. The translucent glass curve still presents a sloped variation of luminance near the facades, but all within the threshold of 2000lux, due to its property to scatter the light. The difference between season performance is much more reduced, up to 100 lux.

transparent glass summer winter

diffuse glass summer winter

lux

16.02 10:00

lux

16.02 13:00

lux

16.02 16:00

5. ANALYTICAL WORK

5.2.5. DAYLIGHT CONCLUSIONS The daylight analysis focused to assess the visual performance regarding quality (DGP) and quantity (UDI and Illuminance curves). The comparison between the materials shows that, overall, the translucent glass has a better visual performance if no passive strategies are applied. The addition of a mezzanine demonstrated to be helpful for both materials visual performance on the centre of the plan, as the peripheral zone can still suffer from high illuminance levels. Finally, the addition of external shading proved to be the most beneficial in providing a most homogenous daylight and enough illuminance level during occupied hours throughout the year. The daylight analysis evidentiated the carefulness necessary to design a building with high ceiling and window wall ratio in a sky such as in SĂŁo Paulo. The high amount of daylight can cause discomfort near the facades and, therefore, strategies must be considered when designing a full curtain wall. The best recommendation is to apply external shading, as proved by analytical studies. Regarding the performance within seasons, winter has at least 200 lower lux level than in summer. Also, it is notable how the peripheral vulnerable zone changes up to 5 meters. 94

5.3. THERMAL STUDIES The previous daylight studies introduced the concept of a peripheral vulnerable zone near the facades which suffer from excessive illuminance. Moreover, this zone is also more susceptible to overheating due to its proximity to the transparent surface which, as explained in the literature review, will absorb and reemit the radiation, alongside with the direct radiation transmitted. This section of the analytical studies will focus on the thermal performance of the building impacted by the transparent material. 5.3.1. METHODOLOGY Thermal studies were conducted using the software TAS by EDSL, which is a dynamic thermal modelling simulation tool. The base case building was modelled considering the

transparent glass

orientation east-west axis and the larger glazed facade facing south, as this was the orientation which resulted the best daylight results. The peripheral vulnerable zone was defined for each facade orientation by adding a null wall. This zone is different for the transparent and translucent material, as evidenced in section 5.2.3.2. Therefore, in all simulations there are six zones: east, south, west, northeast, northwest and work zone. Apart from the window pane, all the building constructions and internal conditions are the same. The U-value, the schematic drawing of the constructions and the internal conditions are as its shown on the next page.

diffuse glass

5. ANALYTICAL WORK

TAS zoning - transparent coloured glazing

TAS 3d model

TAS zoning - diffuse glazing

solar irradiation on facades during summer simulation by ladybug - west facade more exposed

internal conditions

constructions

5. ANALYTICAL WORK

Taking into account all these inputs, seven different scenarios were tested: 1. Comparison between all four materials 2. Comparison between transparent coloured glass and single layer u-glass 3. Comparison between transparent coloured glass and single layer u-glass with the addition of external shading 4. Comparison between transparent coloured glass and single layer u-glass with the addition of external shading with night time ventilation 5. a. Comparison between transparent coloured glass and single layer u-glass with the addition of external shading with night time and natural ventilation (free running ) b. Comparison between transparent coloured glass and single layer u-glass with the addition of external shading with night time and natural ventilation (mixed-mode ) 6. coloured glass and single layer u-glass with the addition of external shading night time and natural ventilation (mixed-mode) and addition of a mezzanine 7. Comparison between transparent coloured glass and single layer u-glass with the addition of external shading with night time and natural ventilation (mixed-mode) and reduction of window to wall ratio.

The results for each scenario are presented in frequency of overheating, annual cooling loads, and the curve profile of west facade on typical week in summer. The chosen facade to represent the case was the west as this is the most exposed to radiation during summer months - as shown in the simulation on the previous page. For other facades, please refer to the appendices. As it is a mechanically conditioned building, the threshold for comfort considered 24Â°C +- 2Â°C. The frequency of overheating is a percentage of the hours when the room resultant temperature is above 26Â°C, during occupied hours (monday to friday from 9am to 6pm). For discriminated frequency per zones, please refer to the appendix. The week profile comparison between materials presents two graphs per facade. The first one shows DBT and resultant temperature, which visually enables to assess comfort. The second one displays the facade internal surface temperature and the mean radiant temperature.

NATURAL VENTILATION

CASE

2 3 4 5A 5B 6 7

MATERIAL

Uvalue

Gvalue

WWR

AC SET POINT

EXTERNAL SHADE

COLOURED GLASS

5,7

0,55

88%

24 °C

NIGHT TIME VENT -

UGLASS

1,8

0,63

88%

24 °C

WINDOWS OPENING

SETPOINT

MEZANINE

MASTER CARRE

2,6

0,63

88%

24 °C

POLYCARBONATE

1,2

0,58

88%

24 °C

COLOURED GLASS

5,7

0,55

88%

24 °C

SINGLE UGLASS

5,7

0,79

88%

24 °C

COLOURED GLASS

5,7

0,55

88%

24 °C

horizontal

SINGLE UGLASS

5,7

0,79

88%

24 °C

horizontal

COLOURED GLASS

5,7

0,55

88%

24 °C

horizontal

25%

24 °C

SINGLE UGLASS

5,7

0,79

88%

COLOURED GLASS

5,7

0,55

88%

SINGLE UGLASS

5,7

0,79

88%

COLOURED GLASS

5,7

0,55

88%

24 °C

horizontal

25%

horizontal

25%

50%

20 °C

horizontal

25%

50%

20 °C

horizontal

25%

50%

20 °C

SINGLE UGLASS

5,7

0,79

88%

24 °C

horizontal

25%

50%

20 °C

COLOURED GLASS

5,7

0,55

88%

24 °C

horizontal

25%

50%

20 °C

COLOURED GLASS

5,7

0,55

58%

24 °C

horizontal

25%

50%

20 °C

SINGLE UGLASS

5,7

0,79

58%

24 °C

horizontal

25%

50%

20 °C

5. ANALYTICAL WORK

5.3.2. RESULTS 5.3.2.1. SCENARIO 1 The first scenario consisted in the comparison of the three translucent materials with the transparent coloured glass. The annual cooling loads and the frequency out of overheating are all very high, and there is an inverse relation with the U-value: the higher the U-value, the lower is the annual cooling load. Despite the orientation, the graphs of DBT and RT shows that the material with lower U-value has the worst thermal performance, resulting in higher RT. When the air conditioning is on, the transparent coloured glass RT is 5°C higher than the DBT, while the translucent materials difference reaches 7°C.

OVERHEATING FREQUENCY 93%

96%

ANNUAL COOLING LOADS 98%

186 kWh/m² 166 kWh/m²

72%

100

128 kWh/m²

194 kWh/m²

outside air temperature comfort band transparent glass

U glass (profiled glass)

Resultant DBT

master carre (textured glass) Resultant DBT

Resultant DBT

polycarbonate Resultant DBT

101

5. ANALYTICAL WORK

5.3.2.2. SCENARIO 2 As the previous scenarios demonstrated that high U-value is not beneficial in a climate like São Paulo, the second scenario is the comparison between the base case (transparent coloured glass) and the single layer U-glass. The withdrawn of one layer of the U-glass makes its u-value the same as the coloured glass. Now, the difference between the materials lie on the G-value, which is lower for the coloured glass. Nonetheless, the cooling loads and frequency of overheating maintain high. In this case, even though the U-value of the materials are the same, the resultant temperature of the U-glass is up to 4°C higher than the coloured glass. However, the surface temperature of the coloured glass reaches temperatures much higher than the U-glass due to its lower G-value. The material absorbs the radiation and slowly reemits it back into the room, as show the mean radiant OVERHEATING FREQUENCY

temperature. The U-glass, on the other hand, has a high G-value which translates in a lower surface temperature and a high mean radiant temperature, since most of the radiation is directly transmitted inside the room. Even though the solar gains are similar between materials, it is possible to assume a correlation between sky cover and G-value. When the sky cover is high (cloudy) the material with higher G-value have bigger solar gain, while when the sky is clear, the material with lower g-value has a slightly bigger solar gain.

ANNUAL COOLING LOADS

-8%

-44 kWh/m²

88% 72% 128 kWh/m²

102

142 kWh/m²

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

103

5. ANALYTICAL WORK

5.3.2.3. SCENARIO 3 As the previous scenario resultant temperature were high due to solar gains, the next step was the addition of external horizontal shading. This strategy is the same used in section 5.2.3.4 of daylight, which protects from the summer sun in north facade, and helps to reduce the sun incidence on midday hours for west and east. The external shading proved to be extremely beneficial for the building performance as it reduced significantly the overheating frequency and cooling loads in both materials. The overheating frequency for the U-glass is higher, 25% of the occupied hours, but only 7% of hours it is above 27°C. The surface temperature of the U-glass is very similar to the outside temperature, while the coloured glass has some peaks above 30°C. Similarly, the mean radiant temperature of the U-glass reaches some temperature above 30°C. OVERHEATING FREQUENCY

ANNUAL COOLING LOADS

-63% -63% -56 kWh/m²

72 kWh/m² 25% 9%

104

-65 kWh/m²

77 kWh/m²

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

105

5. ANALYTICAL WORK

5.3.2.4. SCENARIO 4 The fourth scenario tested the strategy of night ventilation in addition to the external shading. As explained in the climate analysis, during night time there are some temperature drops of up to 15°C throughout the year. . This strategy reduced 12% the cooling loads in both materials. The overheating frequency for the clear glass is still above the acceptable of 3% (EN15251).

OVERHEATING FREQUENCY

ANNUAL COOLING LOADS

-8 kWh/m² -7% -3% 6%

106

18%

64 kWh/m²

-10 kWh/m² 67 kWh/m²

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

107

5. ANALYTICAL WORK

5.3.2.5. SCENARIO 5 The fifth scenario consisted of the addition of two strategies: first, it was tested free running with windows opening 50%. The second strategy tested was a mixed mode operation, in which windows would be open when the inside temperature is up to 24Â°C, whereas would close above this temperature and introduce air conditioning.

5A. FREE RUNNING

The elevated window to wall ratio makes the free running inapplicable as the overheating happens in a third of the occupied hours. The graphs demonstrated that the free-running building air temperature are closely correlated to the outside.

OVERHEATING FREQUENCY

30%

108

36%

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

109

5B. MIXED MODE The mixed mode operation had a small increase in the overheating frequency when compared to the fourth scenario. However, the cooling loads had a 45% reduction from the previous case.

OVERHEATING FREQUENCY

+4% +2% 8%

110

22%

ANNUAL COOLING LOADS

-20 kWh/m² -20 kWh/m² 44 kWh/m²

47 kWh/m²

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

111

5. ANALYTICAL WORK

5.3.2.6. SCENARIO 6 The sixth scenario consisted in the addition of a mezzanine, besides the previous applied strategies of external shading, night ventilation and mixed mode. It was only tested on the coloured glass as it performed better. Regarding overheating frequency, it maintained the same as the previous case. However, there was a small reduction in the cooling loads.

OVERHEATING FREQUENCY

+4% +2%

112

22%

ANNUAL COOLING LOADS

-20 kWh/m² -20 kWh/m² 44 kWh/m²

47 kWh/m²

outside air temperature comfort band transparent glass Resultant DBT Mean Radiant Surface

113

5. ANALYTICAL WORK

5.3.2.7. SCENARIO 7 The final scenario tested was the reduction of window to wall ratio to 58%, in addition to the strategies of external shading, night ventilation and mixed mode operation. In this case, the coloured glass reached the EN15251 criteria of overheating up to 3%. The cooling load are similar to the scenario 5. This relates to the reduction in the mean radiant temperature, that reduced the resultant temperature.

OVERHEATING FREQUENCY

-12% -5% 3%

114

10%

ANNUAL COOLING LOADS

-2 kWh/m²

42 kWh/m²

45 kWh/m²

outside air temperature comfort band transparent glass

single U glass (profiled glass)

Resultant DBT Mean Radiant

Surface

115

5. ANALYTICAL WORK

5.3.3. SUMMARY OF RESULTS AND CONCLUSIONS The thermal simulations enable to draw some conclusions in concern to the thermal performance of transparent materials in the subtropical climate of São Paulo. The first finding is the requirement of external shading for facades with large area of glazing. This interferes directly not only in the cooling loads, but especially in the indoor thermal comfort. The solar radiation that falls on the transparent surface impacts in a raise of the mean radiant temperature, which results in a high resultant temperature. This strategy showed a reduction of 50% on the annual cooling loads and 87% reduction on overheating frequency from the scenario 01. Furthermore, the climate of São Paulo fluctuates up to 15°C from day to night time. This indicates the possibility of night ventilation which was proved by analytical studies to be beneficial to reduce the resultant temperature as it removes the heat gains inside the room. Finally, mixed mode operation, by combining natural ventilation and air conditioning when necessary helps reduce the annual cooling load. Moreover, another strategy to mitigate this issue is the reduction of the glazing ratio.This strategy showed a reduction of 35% reduction on overheating frequency from the scenario 5b. 116

transparent glass

single U glass (profiled glass)

kWh/mÂ²

ANNUAL COOLING LOADS

scenarios

OVERHEATING FREQUENCY

scenarios

117

118

6. RESEARCH OUTCOMES

119

6. RESEARCH OUTCOMES

Parc Relais del a Soie by Clément Vergély architectes

120

OVERVIEW The research, both empirical analytical, demonstrated that transparent and translucent facades are vulnerable to thermal and visual discomfort due to skydome conditions of SĂŁo Paulo. Therefore, architects must be aware of this weakness when designing fully glazed buildings in this city. This section of the research aims to assist these professionals by providing measures and guidelines which they can refer to. From the studies, a series of conclusions were made. Below, there is an overview list of these conclusions and the architectural answer to each one of them:

The advantage of low G-value: material property and coatings

2. The reduction of direct radiation: external shading and window to wall ratio 3.

The role of in reducing heat gains night time ventilation

4. The vulnerability of the zone near the facade: layout flexibility 5.

The visual comfort views out

121

6. RESEARCH OUTCOMES

6.1. MATERIAL PROPERTY AND COATING When specifying a transparent of translucent material in a warm climate with high amount of global radiation, the architect must be aware of the G-value of the material rather than its U-value. As demonstrated in the literature review and the thermal studies, this has a direct impact on the amount of direct radiation transmitted inside the room. Alternatively, when the architect has no other option but to use a material with a high G-value, a solar control coating can be applied on the material. The architect must have in mind that a low G-value material is not enough to prevent discomfort. The material will absorb the solar heat gain and eventually re-emit back inside the room, causing a rise in the MRT.

facade by Pierre Hebbelinck

122

6.2. EXTERNAL SHADING AND WWR As explained previously, the transparent material must also be protected by direct solar radiation, and the key strategies are external shading and the reduction of window to wall ratio. Environmental responsive buildings have different solutions for each facade given that the sun path and incident radiation varies for each orientation. The reduction in window to wall ratio can be coupled with the translucent material in the interest of maintaining a uniform external view of the facade.

opaque or diffuse glass

transparent glass

123

6. RESEARCH OUTCOMES

6.2.1. South and North: Horizontal Shading The south facade has incidence of sun on the summer months, from late October until the beginning of February. The north facade, on the other hand, has an incidence of sun on most of the year, from March until Late September. As the sun has high angles, it is most effective to use horizontal shading.According to Cotta, it is beneficial to reduce the window to wall ratio up to 50% with the additional of external shading (COTTA, 2015). Moreover, the shading can be achieved by transitional spaces of extended slabs or balconies.

terraces by Herzog & De Meuron

124

horizontal shading by LCR Architectes

6.2.1. East and West: Vertical Shading The east facade has incidence of morning sun while west receives afternoon sun. The sun angles are low as 35Â°, and it can be even more prejudicial on the west facade, where the angle is low as 10Â° at 6pm on the summer solstice. Therefore, the most effective shading is vertical. According to Cotta, it is beneficial to reduce the window to wall ratio up to 75% with the additional of external shading (COTTA, 2015).

vertical shading made in diffuse glazing by Project Meganom

125

6. RESEARCH OUTCOMES

6.3. NIGHT VENTILATION By virtue of SĂŁo Paulo climate, where the night temperatures are low up to 15Â°C compared to daytime, night ventilation is a good strategy as a way to release the heat gained throughout the day. As security is a sensitive issue, this system can be independent from the regular windows, by applying automated opaque louvers or windows with small openings.

louvres windows by Bower Architects

126

6.4. LAYOUT FLEXIBILITY A current trend in office is the flexibility on layout. A survey made by Memoori, an organisation that research smart buildings, recognized that through layout flexibility it is possible to offer each employee what they need to be productive at any given time: “From this concept, the multi-space office layout was born. While on the surface the open office layout still dominates, those collaborative workplaces are now incorporating more and more areas for isolated, focused work time, as well as areas for relaxation or reflection, and others that inspire creative thinking,” explains the layout section of our comprehensive report.” (MEMOORI, 2017) The vulnerability of the peripheral area near the facade, exposed to radiant temperature and excessive glare, makes this zone unsuitable for a work activity which requires many hours in the same position. However, other activities, such as transitional and leisure spaces, are adequate for this area. The flexibility on the layout allow the occupants to engage with the office areas in order to achieve their best personal comfort.

127

6. RESEARCH OUTCOMES

6.5. VISUAL COMFORT The daylight studies demonstrated that, without any external shading, the translucent material has a daylight performance superior than the transparent glass. However, when designing a facade with a translucent material, it is important to consider 20% of facade area as transparent glass to allow occupants views out.

128

6.6 FURTHER FACADES GUIDELINES The facade of the building acts like its skin. It is the filter between outside and inside environment. To design environmental responsive buildings, architects must be aware of the climate and microclimate in which the building is inserted. The guidelines in this section are general ideas which can auxiliate architects to design better transparent buildings in SĂŁo Paulo. However, as this is a broad guidance, it is important that the architects also evaluate the context of application. This means that sometimes the external shading might not be necessary if the surroundings are creating enough shade.

129

130

7. CONCLUSIONS

131

7. CONCLUSIONS

10 brock street by Wilkinson Eyre Architects

132

CONCLUSIONS The climate of São Paulo is subtropical with mild temperatures in summer and winter, where annual mean temperatures are between 16°C to 24°C. The improbable situation of extreme temperature condition makes the architects to São Paulo’s climate issue which is high global radiation throughout the year. The average annual cumulative radiation is 743 kWh/m² on north facade and 677 kWh/m² on the west facade. Despite this condition, it is common to see in São Paulo office buildings with full glazed facades based on an inadequate replication of north america’s reflective glass towers. On the other hand, the contemporary architectural production started to explore alternative façade materials based on translucent materials, such as profiled glass and polycarbonate. However, architects commonly specify these materials considering only the aesthetical visual aspect, ignoring thermal conditions and daylight performance that this exposed facade can create in the indoor environment. Due to this sky condition of São Paulo, literature review show the benefits of external shading to avoid glare on the peripheral zone near the facades, as this strategy extinguishes areas with UDI above 3000 lux. Moreover, previous research shows that the same strategy

coupled with the reduction of window to wall ratio proved to be beneficial for the reduction of solar radiation gains up to 75%. Additionally, the thermodynamics physics that the transparent material are exposed highlights that, in warm climates, the solar radiation gains are the most critical, resulting in direct and secondary heat gains. This has a direct impact on human comfort as it affects the MRT especially on the zones near the facades. The literature review allowed to respond some research questions and to formulate the two hypotheses about the thermal and visual performance of translucent materials in São Paulo, which were: In a subtropical climate like São Paulo, the extensive use of translucent materials cause overheating and glare conditions on the peripheral space near the facade. Diffuse materials seem to have better visual comfort concerning glare probability. The hypothesis was first supported by the study of two buildings with translucent facades in São Paulo. The luminance mapping indicated that the translucent glass resulted in a more homogenous light than the transparent glass, endorsing the hypothesis of better visual performance of diffuse material. Moreover, the continuous monitoring of the two case studies 133

7. CONCLUSIONS

demonstrated facades of thermal inertia due to low U-value, resulting that the heat gained throughout the day kept trapped inside the building. This indicates a high probability of overheating during summer months, when the temperatures and radiation are even higher than the conditions in which the fieldwork was conducted during april. Furthermore, the interview with the architects indicated an unfamiliarity of materials properties by this professionals. Not only, as the design process in Brazil is usually held without an environmental consultancy support, this could increase the probability of overheating and discomfort. The analytical work was based in thermal and daylight dynamic simulations. The first set of simulation assed visual comfort comparing an extreme diffuse material with a transparent one. When no strategies are applied, it was concluded that the diffuse material has a better visual performance, with UDI within the threshold area 48% bigger. However, when external shading is applied, the area in compliance is similar. The daylight analysis introduced the concept of a vulnerable peripheral zone near the facade, that is exposed to glare discomfort. This same area was evaluated in the second set of simulations that assessed the thermal 134

performance. Seven different scenarios were tested and compared between the overheating frequency and annual cooling loads. Regarding transparent/translucent facades, the first finding is the requisite of external shading in order to achieve adequate performance. This strategy reduced the overheating frequency in 87,5% and the annual cooling loads in 56 kWh/m² compared with the base case of transparent glazing. The second strategy applied of night time ventilation resulted in a reduction of overheating frequency of 33% and annual cooling loads of 8 kWh/m² from the previous case. The introduction of mixed mode ventilation (natural ventilation when the temperature is up to 24°C and air conditioning when the temperature is above) proved to be beneficial in reducing the annual cooling loads in 20kWh/m², resulting in an annual total of 44kWh/m². Finally, the last strategy was the reduction of window to wall ratio, that proved to be helpful in reducing the mean radiant temperature and had a direct impact in the overheating frequency. For the transparent coloured glass, the overheating frequency achieved 3%, in compliance with EN 15251. All the findings from the fieldwork and analytical work were translated into the guidelines to auxiliate architects in designing

translucent facades buildings in SĂŁo Paulo in an environmental responsive approach. The first recommendation is the awareness of the G-value of the material to be applied on the facade. This property has an effect on the amount of direct radiation that is transmitted into the room and, therefore, affects the resultant temperature and comfort sensation. But, as the radiation is absorbed and eventually emitted back inside the room, the second recommendation is the addition of external shading, measure that avoids radiation to fall upon the facades. Moreover, the reduction of window to wall ratio is also beneficial to reduce the solar gains. The next recommendation is the implementation of night ventilation, as the climate of SĂŁo Paulo is favourable for such strategy. This research makes way for further investigations daylight performance of diffuse materials. As explained in section 5.2., the proper methodology for simulation can be improved if further information of the materials is provided by the suppliers or by lab tests.

IMS paulista photo by Nelson Kon

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8. REFERENCES

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8. REFERENCES

BREEAM Visual Comfort Views out. (2019). Available from: https://www.designingbuildings. co.uk/wiki/BREEAM_Visual_comfort_View_out [accessed Aug 22 2019]. CIBSE (2015) . Environmental design : CIBSE guide A , 8. London: CIBSE. Code for lighting (2002). Oxford: Butterworth-Heinemann. Cotta, J. (2015). A ventilação natural e o projeto de janelas para ambientes de trabalho em São Paulo, in Edifício Ambiental. São Paulo, Brazil: Editora Oficina de Textos. Gonçalves, J (2016). The value of environmental design in the context of the green economy. Cities, buildings, people: towards regenerative environments. PLEA, Los Angeles Instituto de Pesquisa Tecnológicas (2017). IPT mapeia qualidade do ar na Avenida Paulista por meio de redes de sensores móveis embarcados em veículos. Available from: http://www.ipt.br/noticias_interna.php?id_noticia=1287 [accessed Aug 10 2019]. Marcondes, M. P. C.; Cunha, G.R.M.; Gonçalves J.C.S. (2018). Iluminação Natural em Edifícios de Escritórios: avaliação dinâmica de desempenho para São Paulo. Campinas, Brazil: PARC Pesquisa em Arquitetura e Construção Mardaljevic, J.; Andersen, M.; Roy, N., Christoffersen, J. (2012). Daylighting metrics: is there a relation between useful daylight illuminance and daylight glare probability?. Available from: https://www.researchgate.net/publication/267556994_Daylighting_metrics_is_there_a_relation_ between_useful_daylight_illuminance_and_daylight_glare_probability [accessed Aug 03 2019]. McNeil, A. (2015). genBSDF Tutorial. Available from: https://www.radiance-online.org/learning/ tutorials/Tutorial-genBSDF_v1.0.1.pdf [accessed Aug 22 2019]. Memoori (2017). New Survey Explores Productive Style Office Layout. Available from: https://memoori.com/new-survey-explores-productive-style-office-layout/ [accessed Aug 22 2019]. 138

Na, J. (2018). Architectural material. 3, Glass. Seoul: Damdi Publishing House. Nicol, F. (2019). TM52 The limits of thermal comfort: avoiding overheating in European buildings. Available from: https://www.cibse.org/getattachment/Networks/Regions/South-Wales/SouthWales-Past-Presentations/TM52-The-limits-of-thermal-comfort-Cardiff.pdf.aspx [accessed Aug 15 2019]. Serapião, F. (2009). Mudança de Ares: edifícios prometem mudar positivamente paisagem urbana da zona oeste de São Paulo. São Paulo, Brazil: Arcoweb. Available from: https://www. arcoweb.com.br/projetodesign/artigos/edificios-residenciais-inovacao-ou-modismo-edificiosprometem-18-08-2009 [accessed Aug 08 2019]. Sims, T. (2018). 8 (New) Energy Efficient Materials Architects Should Know. Available from: https:// www.archdaily.com/886414/8-new-energy-efficient-materials-architects-should-know [accessed Aug 22 2019]. Shen, H., Tzempelikos, A. (2012) Daylighting and energy analysis of private offices with automated interior roller shades. Indiana: Solar Energy. Available from: https://doi.org/10.1016/j. solener.2011.11.016 [accessed Aug 04 2019]. Szokolay, S.V. (2014). Introduction to architectural science the basis of sustainable design / London: Routledge. Teixeira, R. Correa,V. (2013) “Pele de vidro” se torna padrão para edifícios corporativos em SP. São Paulo, Brazil: Folha de São Paulo. Available from: https://www1.folha.uol.com.br/ saopaulo/2013/05/1276495-pele-de-vidro-se-torna-padrao-para-edificios-corporativos-em-sp. shtml [accessed Aug 08 2019]. Weller, B. (2009). Glass in building: principles, applications, examples, 1. Basel, Switzerland: Birkhäuser.

139

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Wienold, J. (2014). Daylight Glare analysis and metrics. Lausanne, Switzerland: EPFL. Available from: https://www.radiance-online.org//community/workshops/2014-london/presentations/ day1/Wienold_glare_rad.pdf [accessed Aug 11 2019]. MATERIALS INFORMATION Pilkington Profilit Brochure. Available from: https://www.pilkington.com/en-gb/uk/products/ product-categories/glass-systems/pilkington-profilit#brochures [accessed Aug 22 2019]. Danpalon vs Traditional Glazing. Available polycarbonate-panels/ [accessed Aug 22 2019].

from:

https://www.danpal.com/category/

Rodeca, Translucent Buildings Elements 40mm. Available from: https://www.rodeca.de/en/ downloads.html [accessed Aug 22 2019]. Saint Gobain, Decorative Patterned Glass. Available from: https://uk.saint-gobain-building-glass.com/en-gb/decorative-patterned-glass [accessed Aug 22 2019]. Pilkington Profilit. Available from: https://www.pilkington.com/en-gb/uk/products/productcategories/glass-systems/pilkington-profilit [accessed Aug 22 2019].

140

9. APPENDICES

141

9.1 CLIMATE

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

mean max o C 26,10 26,94 26,56 24,97 22,39 22,06 21,42 23,17 22,78 24,98 24,37 25,59

Ta RH AH mean average mean min mean max mean averagemean min mean max mean averagemean min mean max m o o o % % % g/kg g/kg g/kg C C C 22,55 18,98 93,97 78,30 61,71 16,53 14,62 12,82 21,38 22,95 18,98 94,89 77,62 59,79 16,91 14,78 13,21 21,85 22,72 19,22 94,00 76,90 57,97 16,50 14,55 12,90 21,52 21,00 17,27 95,73 78,30 59,47 15,25 13,26 11,80 20,08 18,24 14,50 94,26 75,78 55,71 12,34 10,77 9,43 16,90 17,48 13,51 93,37 75,51 56,10 11,55 10,17 9,04 16,53 16,65 12,35 93,42 73,15 52,45 10,79 9,35 8,16 15,45 18,09 13,40 91,16 69,77 47,87 11,38 9,79 8,63 16,42 18,25 13,97 94,07 74,98 54,50 12,16 10,69 9,38 17,13 20,38 16,07 94,61 76,22 57,35 13,88 12,49 11,07 19,20 20,60 16,75 96,13 78,76 60,10 14,61 13,07 11,73 19,54 21,85 18,02 94,87 78,24 60,48 15,96 14,04 12,50 20,77 240,74 20,06

Ta RH AH mean max mean mean max mean averagemean min mean m AH Tp average mean min RRaveragemean min mean max G_Gh G_Dh FF mean max o o o % % % Cmean min odaily C average C ean averagemean min mean C max mean average daily average average g/kg cumulativeg/kg cumulativeg/kg o o Jan 26,10 18,98kW/m 293,97 78,302 61,71 16,53 21,38 g/kg g/kg m/s mm 14,62 days 12,82 C C 22,55 o C kW/m Feb 26,94 22,95 18,98 94,89 77,62 59,79 16,91 14,78 13,21 21,85 14,62 12,82 21,38 19,58 17,38 4,51 2,53 2,79 195 16 Mar 26,56 76,90 57,97 21,52 14,78 13,21 21,85 19,8222,72 17,77 19,22 4,99 94,00 2,60 2,90 16,50 136 14,5516 12,90 Apr 24,97 21,00 17,27 95,73 78,30 59,47 15,25 13,26 11,80 20,08 14,55 12,90 21,52 19,57 17,70 4,05 2,45 2,80 101 25 May 22,39 18,24 14,50 94,26 75,78 55,71 12,34 10,77 9,43 16,90 13,26 11,80 20,08 18,12 16,07 3,60 1,87 2,70 35 21 Jun 22,06 75,51 56,10 10,1719 9,04 16,53 10,77 9,43 16,90 15,2217,48 13,09 13,51 3,19 93,37 1,53 2,60 11,5530 Jul 21,42 16,65 12,35 93,42 73,15 52,45 10,79 9,35 8,16 15,45 10,17 9,04 16,53 14,47 12,33 2,95 1,38 2,40 21 20 Aug 23,17 18,09 13,40 91,16 69,77 47,87 11,38 9,79 8,63 16,42 9,35 8,16 15,45 13,40 11,03 3,21 1,52 2,41 51 13 Sep 22,78 18,25 13,97 94,07 74,98 54,50 12,16 10,69 9,38 17,13 9,79 8,63 16,42 14,30 11,92 3,72 2,10 2,60 42 14 Oct 24,98 76,22 57,35 12,4912 11,07 19,20 10,69 9,38 17,13 15,1120,38 12,72 16,07 3,74 94,61 2,36 3,10 13,8860 Nov 24,37 20,60 16,75 96,13 78,76 60,10 14,61 13,07 11,73 19,54 12,49 11,07 19,20 17,25 14,87 4,03 2,52 3,10 93 12 Dec 25,59 78,24 60,48 20,77 13,07 11,73 19,54 17,8121,85 15,84 18,02 4,99 94,87 2,89 3,40 15,96 106 14,0414 12,50 14,04 12,50 20,77 18,92 16,90 4,53 3,08 3,20 144 14 240,74 20,06 1013 196

MONTH

142

9.2. FIELDWORK 9.2.1. RIO NEGRO COMPLETE INTERVIEW JG: As you know, I am researching about contemporary glass facades to understand new solutions that are aesthetically more pleasant and which performs better environmentally. And I believe the U glass seems like a very nice option and that is why I decided to study it. So, I wanted to understand a little about the project, how you decided on the material and how was the whole architectural concept of the retrofit. MA: It didn’t actually have a previous façade

simple glass, it breaks into pieces, so this film allows the glass to get stuck in it, and also improves the whole issue of solar incidence. So we had to install this film on all the glasses. This film has been applied to both layers for safety, for those who are outside and inside. Speaking about the strengths of the material, the installation is very fast. They install one floor a week or so, that’s the productivity. And if one of the U-glass breaks, you can easily change it individually, it has a simple maintenance. We made this project with variable windows, we

project. We bought the material, it was an aesthetic decision. As it is double-layer glass, it has thermal inertia so it has more heat protection. When we bought it, the owner of the company made several tests of how it would work, how it would improve.

reduced the amount of window for ventilation because we realized that the occupants never open all windows. By having one window on one each side it would be enough to create cross ventilation. As this avenue is very noisy, the occupants rarely want to open all the windows.

Comparing to the façade previous glass, it improved the acoustics amazingly from the outside noise, because of this double layer. Also, the luminosity improved a lot, because before, as it was all glazing, there was always direct sun coming in.

JG: And regarding the material research, did you find it by precedents?

To install the façade, we had to do all the

MA: In fact, the building had a project that would be done by a company called KIR, which is a company that does facade retrofit in São Paulo. They take this aluminium sheet and envelope the building and change the glass. At the time,

rupture tests and wind pressure. U-glass has a problem: it is simple glass, not tempered glass. So it is not suitable for a full glazed facade like this. The company sold us the wrong glass. Then what we had to do, because it would be a curtain wall, with only a few thin structural profiles outside. We had to reduce the size of the glass in order to withstand the wind pressure here, which is very high. In addition, we have installed the Eastman film, which prevents the glass from breaking and shattering - as it is a

we thought about hiring a facade engineer, and really needed it, but only realized it later. So this is actually a project that we can see a lot of mistakes. We didn’t hire a facade engineer, which might not be the best material to make. Because, for example, IMS, I talked to the IMS engineer, it was all designed to be U-glass. Who made the project was Galtier. They produced this other glass to replace U-glass, because the glazed facade is enormous. The original design was supposed to be U glass and then changed 143

to this other glass. In our case, it was all a posteriori, because we bought the material and then fixed the errors. So it was changing the size, buying the film, hiring the facade engineer… actually, the company that sold the material was going to do the whole project, but he was a bad professional and miscalculated everything. He did a rupture test in which the material broke and he didn’t tell us, he faked the test. It was a life-threatening issue. It was a backwards process. We decided that we wanted to do with the material. We did that law school contest with this material and at that time we got in touch with the T2G company, and they said they could make it happen, etc. But in the end, it was not a very good company. In the ned, we hired Pedro, the facade engineer. I even contacted Galtier but it was very expensive. That was the process. JG: What about the people in the occupied offices, are they enjoying it? MA: There are people who like, I think this issue of thermal and noise has improved a lot. Now there are people who complain because they don’t have the view anymore. We also exchanged all air conditioning for VRF which is much more economical. We changed the system, because before it was that window air conditioner. And it saves 30% on electricity. Unintentionally, the project was becoming sustainable. We are having a lot of demand for rentals.

JG: Would you work with the material again?

144

MA: It was a nice system. But I don’t know if I would do it again. Only on a smaller scale. The facade engineer had never worked with anything other than usual reflective coloured glass. There are no technicians with know-how here [in Brazil]. Here, it is only used the default design, which is the reflective coloured glass facade, which they know how to solve, which everyone does. And that often does not open the window. The facade engineering brought no environmental input.

9.2.2. IMS COMPLETE INTERVIEW JG: How was your process of choosing the facade, why? How they got to that glass. Starting from the contest, IMS was the result of a contest, a closed contest, very interesting, very well organized. The image we would like the building to have, not simply in the aesthetic sense, but the quality of the building has a lot to do with the quality of the light, not just for those inside the building, but also how it responds to who is passing on the Paulista Avenue. This [the intention of the light] we knew from the beginning. So much that in the jury, the presentation opened with a picture of Pierre Chareau Maison de Verre. It’s a project in France, from the 30’s if I’m not mistaken, it’s a simple building, a house; it is actually a small building, an apartment for one person, in which the building envelope is a kind of glass brick. This, at that time, was very impactful, because it ends up working as a skin and not using the material in a conventional way. The effect on those inside is striking, it’s like an aura, a bubble of light. And at the same time, it created some privacy for those inside. Because glass brick has a certain mass, it has no transparency but a certain translucency. So we used this image from the inside out, because it synthesized what we wanted for the building, as a presence, meaning that it could be seen and at the same time not fully revealed. It would not have this quality of total transparency, which is very modern, the modern has it even by the spirit, “let see”, a kind of truth. But we didn’t want it to be so for the sake of

the route, the certain mood we wanted people to have when they entered the museum, that of having more introspective attention. But at the same time, making a closed museum was not an option because it loses its relationship with the street. So the question was: how to bring the energy of the street, the vibration that Paulista Avenue has inside the museum and, at the same time, preserve a certain necessary introspection for the museum. This was answered both by the strategic point of view, by the construction of the spaces, which is basically the creation of the elevated square, which guarantees the free route and from there you see the city, you are already in that atmosphere created by glass. And also by creating the skin, which shelters all the programme, the museum above and the library below, and gives you the chance to see the city without revealing it completely. So it was curious, because the presentation started with this slide, we talked about all this, the project was already built with some changes, and the glass appeared as intention, but we did not know at the time how it would be built. So we talked about uncertainty, it was not an insecurity. But they realized that we had such a clear intention that we could achieve it. The first images of the contest are different, because the construction of the facade changed a lot, because we didn’t know how to do that. So much so that the first representation resembled a U-glass. Because it has this translucent condition, it is self-supporting, reminiscent of the qualities of polycarbonate, which is a material that we like a lot but that in 145

that scale had no place. So it was all born of this very clear party intention and an uncertainty of how to build.

senseof what is happening outside. You have a very beautiful light but you lose reference of the skyline.

The IMS gave excellent working conditions. All the professionals, all, were called, involved, the process was well done. We made a request that the facade consultant be really very good. Front inc, an American office that has worked with OMA, with Chipperfield, in short they really are very good and with a lot of knowledge. They opened possibilities for us. Together, we built this facade idea. Shortening the story a bit, we created the constructive and material solution. The facade is structured in itself, has the heritage of U glass with glass risers. It’s like a profiled glass. While horizontally we have aluminum profile every two floors that structures the panel. The vertical load is attached to stainless steel cables that are fixed above the main façade which creates the atrium. On the sides, the mullion is attached directly to the core or metal frame.

And we went to find a glass in which he had this condition, so even if you see in the picture that were taken from inside you can see the other side of the paulista, there the ghostly shadows of the buildings, and we wanted that the glass transfigured reality but you did not feel in the middle of nowhere, as if you were in a fog.

In the end, we built this spirit of translucency and at the same time met all the needs we wanted, the details, the lightness. It was an amazing experience. We were able to detail a component that was vital to the project. It is exactly what we wanted today: depending on the light it changes, depending on the time of day, the position of the observer, sometimes you see the red box inside, sometimes you don’t see it, sometimes it reflects the light, sometimes it absorbs, he’s kind of a mutant, like it’s got a temper, sometimes it’s in a bad mood, it’s kind of gray, sometimes it’s bright. And for those inside, that was a pretty big research, because the translucent glass sometimes, and the glass brick case, a meter, or even less, after the glass the view is completely blurred, and loses some 146

And then there is this creation you about you leave the paulista climbs the escalator back to the square you see the paulista from above. It’s nice that the noise starts to get more attenuated too because the perforated wooden box works as an attenuator. You notice the vibration but it is already more controlled. And then when you go up the stairs and into the puff room you are already inside and your attention is all inside the room. A special chapter of research and performance has to do with the choice of glass because we wanted this envelope to also serve as a thermoacoustic filter because of the noise, just below the square you have the library overlooking the avenue. It is thermal because, finally, that square is the atrium, and all public roads do not work with traditional air conditioning but with a heat attenuation system that [is underfloor heating, ventilation and air extraction at the top of the atrium. How to do this? And we didn’t want to give up the translucency. It’s very complicated to do that, especially in subtropical climates, as you said, because there are very hot times of the year. And there, that main face, is a southwest, so it receives in summer a low angle sun facing the front. And we said no, we will solve this with

the resources we have, with the advice of the front and greenwatt. What was the concept: create in most of the building, but it varies. If The glass is a double laminate. Two glasses, air layer, two glasses. The exterior is a textured glass - that creates the condition of translucency. The interior glass is also a low-e. And then we have the air layer. This guarantees a very good thermal performance. And coupled with this condition, we have underfloor heating when needed, mechanical ventilation, natural movement of the air reinforced with extractors, this whole set makes the elevated square work as a transition between external and internal temperature. Because here it may be 21 ° C depending on the healer. And out here may be 24 ° C. So we didn’t want the square to be at 21 ° C. In greenwatt simulations, you can see, the temperature of the square is a transition. Depending on the conditions, this value passes between 23-27 ° C. But this is given by all this set, the design of the glass and the ventilation conditions of the square. All in all, it’s a very balanced solution, we got everything we wanted. 95% of the time the doors are open. So the wind doesn’t bother, the rain doesn’t bother. This cross ventilation is essential for the system to function and is one of the coolest parts of the building, the elevated square. From time to time it has been very insistent to the people to regulate this element that the stairs on the 8th floor get hotter than I would like. The square is always regulated, but from now on, I think maybe because of a fan working, its speed, I don’t know, maybe on a very hot day, that the wind is not contributing and worse

time, 5 pm, I think I would like to improve this issue. Every summer I go there to dig and repair. If I go there in the morning, it’s one thing. If I go there at the end of the day, which has been warming all day… It’s fine as a transitional place. Greenwatt engineer Luís helped regulate after the summer of 2017 to get the best out of the system itself. It was this self-criticism. To always be aware of the critical points. This is where we will eventually create discomfort, a problem. JG: And has that glass ever been used somewhere else? Or was it the first time? It’s interesting because the elements that make up the glass are there in the market. Including the textured. And it was a long research, that too. It’s all documented. We ordering the samples. Then in the shed they put 8 samples of real size, 60 x 2.5m, and we took 8 of these varying the pVB, the composition of these glasses varying the screen. performance factor that met greenwatt. For example, choosing this low-e was a war. Because the better the performance, the worse the effect as it gets darker, it starts to create annoying reflection effects. So it was a tug of war between the performance and the effect we wanted. It was really cool that even They even found a newer technology glass of similar performance but less dark. So yeah, the glasses are on the market. Having this consultancy, supported by IMS, we were able to use the latest technology in the market. But the way it was built, this glass sandwich, this composition is unique. There is no other construction. It is a unique thing. The glasses, when they pass in front of the red box and the core, they are not double. They are just laminated as there was no need. But the translucency effect is guaranteed by the first 147

set. The second layer of glass has a thermal function.

This is the story. This is a very cool case from the point of view of the process. It’s cool to tell how the process worked, which starts with an intention and then you have to build to get what you would like. Sometimes it happens that the process gets corrupted when the intention is not viable. JG: And the sample for what was built, was exactly the same? It looked exactly the same. Of course, yes, that certain of good anguish. Because when you have a small sample you never have the same condition as the end. In renders you can see this evolution of the envelope. The image of the building, due to the construction, is changing. The final image, which was used as a reference, was very similar to the actual construction. Nothing replaces the experience. When you go there, and see these changes [of light], when you go through… it’s always different from the picture. It is always richer. The other day I went there, early in the morning. And this time of year the sun is beating low over the south façade. And two hours later it is no longer: the building changes. It’s impressive. Because the shallow light is as if the facade had its own light. Then the sun goes north and the south facade goes dark and changes.

148

9.3.BASE CASE DATA COLLECTION 9.3.1. POP+, ANDRADE MORETTIN (2013)

9.3.2. BOX 298, ANDRADE MORETTIN (2014)

9.3.3. W305, ISAY WEINFELD(2012)

149

9.3.4. LORENA OFFICES, AFLALO GASPERINI (2017)

9.3.5. AUGUSTA SANTOS, ISAY WEINFELD (2017)

9.3.6. JOÃ&#x192;O MOURA, NIETSCHE ARQUITETOS (2008)

150

9.3.7. 555, ISAY WEINFELD

151

9.3. DAYLIGHT UDI results for the same plan oriented axis south-north

Transparent Coloured Glass

Diffuse Glass

BASE CASE

MEZZANINE ADDITION

(%) 100

EXTERNAL SHADING

ADDITION

80 60 50 40 30 <20

152

1 0,63 0,58

1,8

2,6

UGLASS

MASTER CARRE

5,7

COLOURED GLASS

SINGLE UGLASS

5,7

SINGLE UGLASS

5,7

COLOURED GLASS

5,7

SINGLE UGLASS

0,79

5,7

COLOURED GLASS

5,7

SINGLE UGLASS

5,7

COLOURED GLASS

0,55

5,7

SINGLE UGLASS

0,79

0,55

0,79

0,55

0,79

0,55

0,79

0,55

0,79

0,55

1,2

5,7

POLYCARBONATE

COLOURED GLASS

0,63

0,55

5,7

COLOURED GLASS

Gvalue

Uvalue

MATERIAL

58%

88%

WWR

24 °C

AC SET POINT

horizontal

EXTERNAL SHADE

25%

NIGHT TIME VENT -

50%

WINDOWS OPENING

MEZANINE

10%

22%

36%

30%

18%

25%

88%

72%

98%

93%

96%

72%

>26

17%

13%

62%

32%

78%

64%

72%

32%

>28

OVERHEATING FREQUENCY

142

128

194

166

186

128

cooling loads

summary of results

CASE

NATURAL VENTILATIO N

9.4. THERMAL

153

summary of results per facade

CASE

154

MATERIAL

OVERHEATING FREQUENCY ABOVE 26°C PER FACADE

NORTH

SOUTH

WEST

EAST

NORTH

SOUTH

WEST

EAST

COLOURED GLASS

77%

65%

71%

74%

42%

26%

31%

34%

MASTER CARRE

93%

90%

92%

93%

68%

58%

64%

67%

U GLASS

96%

95%

96%

75%

69%

73%

75%

POLYCARBONATE

98%

97%

98%

79%

75%

78%

80%

COLOURED GLASS

77%

65%

71%

74%

42%

26%

31%

34%

SINGLE UGLASS

88%

84%

87%

66%

56%

61%

63%

COLOURED GLASS

11%

10%

SINGLE UGLASS

26%

24%

26%

27%

COLOURED GLASS

SINGLE UGLASS

19%

20%

COLOURED GLASS

30%

29%

30%

31%

13%

12%

13%

SINGLE UGLASS

36%

35%

36%

17%

COLOURED GLASS

SINGLE UGLASS

23%

22%

23%

24%

COLOURED GLASS

SINGLE UGLASS

10%

11%

9.5.1. CASE 1, SUMMER outside air temperature

coloured glass

master carre

comfort band

u glass

polycarbonate

155

9.5.2. CASE 2, SUMMER DBT AND RESULTANT

156

outside air temperature

coloured glass

comfort band

u glass

9.5.2. CASE 2, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

157

9.5.3. CASE 3, SUMMER DBT AND RESULTANT

158

outside air temperature

coloured glass

comfort band

u glass

9.5.3. CASE 3, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

159

9.5.4. CASE 4, SUMMER DBT AND RESULTANT

160

outside air temperature

coloured glass

comfort band

u glass

9.5.4. CASE 4, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

161

9.5.5. CASE 5A, SUMMER DBT AND RESULTANT

162

outside air temperature

coloured glass

comfort band

u glass

9.5.5. CASE 5A, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

163

9.5.5. CASE 5B, SUMMER DBT AND RESULTANT

164

outside air temperature

coloured glass

comfort band

u glass

9.5.5. CASE 5B, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

165

9.5.6. CASE 6, SUMMER DBT AND RESULTANT outside air temperature comfort band

166

coloured glass

9.5.6. CASE 6, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

167

9.5.7. CASE 7, SUMMER DBT AND RESULTANT

168

outside air temperature

coloured glass

comfort band

u glass

9.5.7. CASE 7, SUMMER MEAN RADIANT AND SURFACE TEMPERATURE outside air temperature

coloured glass

comfort band

u glass

169

COURSEWORK COVERSHEET FORM CA1

UNIVERSITY OF WESTMINSTER MARYLEBONE CAMPUS

I confirm that I understand what plagiarism is and have read and understood the section on Assessment Offences in the Essential Information for Students. The work that I have submitted is entirely my own (unless authorised group work). Any work from other authors is duly referenced and acknowledged. STUDENTS MUST COMPLETE THIS SECTION ONLY IN FULL AND IN CAPITALS Surname Forename BENITEZ GALVES JULIA Registration No:

Module Title

Thesis Project

Module Code

ARCHITECTURE AND ENVIRONMENTAL DESIGN 7AEVD005W.2

Assignment No:

1/1

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Course

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14,351

Joint Submission

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170

2019