SED MSc Dissertation

RETHINKING THE BUILDING ENVELOPE PASSIVE DESIGN STRATEGIES FOR THE VERTICAL LIVING IN SINGAPORE

Xiaxi Qiu Architectural Association School of Architecture Graduate School MSc Sustainable Environmental Design Dissertation Project 2015-16 September 2016

ABSTRACT The Building Envelope dissertation is principally organized into six parts.

Begining with the chapter emphasising on the modern phenomenon of mechanically controlled indoor environment, thus the energy problem used for such purpose is introduced. The following tropical and humid climate chapter depose the functional residing requirements in Singapore. The next chapter is a state-of-the-art literature review focuses on historical and contemporary theories about passive desgin strategies. Sub-headings on adaptive comfort, passive cooling principles, cross ventilation as effective passive cooling, and the debate of high-rise structural construction follow. The literatures are chosen for their role as vehicles of passive design strategies for tropical and humid climate.

The examples of passive desgin strategies are presented in the following vernacular architecture and precedent case study chapter. This chapter discusses vernacular and contemporary precedents in the context of old and new Singapore, with an emphasis on the relationship of the most effective passive cooling strategy, cross ventilation, and the structural construction system. Building envelope construction is chosen as a framework for research due to widely accepted vertical lifestyle in modern Singapore, therefore creating additional passive design opportunities for uprising high-rise living.

Fieldwork is conducted in a typically constructed high-rise apartment in Singapore over the period of a typical week (1-7 May 2016) in the hottest season is presented in the following section. Data loggers, hand-held spot measuring devices, and calibration are preliminarily discussed. In this way, data collected in this chapter shall be used to proceed more rigorous analytic work in the following section.

The analytic work for the Building Envelope dissertation is divided into indoor thermal (OpenStudio) and indoor air flow (Tas Ambiens) simulations. As lessons learn from the previous vernacular architecture and precedent case study, indoor termal simualitons are further divded into sub-headings on air movement; high mass, low mass, low mass and high mass comparison; horizontal shading device, vertical shading device, orientation; and internal condition sensitivity.

The intent behind systematically conducting the analytic work is to develop a knowledge on different structural construction systems' performance in the hottest period in Singapore, which later might be useful for passive design adaptation. The intent behind this analytic research is to define specific design elements which is sensitive to the tropical and humid climate discussed in the previous chapter. Thus to offer passive strategies that serve the lifestyle of the local residents. The conclusion of the Building Envelope dissertation are presented at the end of this chapter. The comparison are made with the changing of each input parameter. The results and recommendations show how high-rise design elements of building envelope might respond to the climatic variations in Singapore.

AUTHORSHIP DECLARATION FORM

AA SED

ACHITECTURAL ASSOCIATION GRADUATE SCHOOL

PORGRAMME:

MSc /MArch Sstainable Evironmental Design 2015 -16

SUBMISSION: Dissertation Project 2015 - 16

TITLE: RETHINKING THE BUILDING ENVELOPE

PASSIVE DESIGN STRATEGIES FOR THE VERTICAL LIVING IN SINGAPORE NUMBER OF WORDS:

15, 230

STUDENT NAME:

Xiaxi Qiu

DECLARATION: “ I certify that the contents of this document is entirely my own work and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledges.”

SIGNATURE:

DATE: 15 September 2016

TABLE OF CONTENTS FIGURE AND TABLES

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ACKNOWLEDGEMENTS

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1.0 HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGPAORE 1.1 THE APPLICABILITY OF VERTICAL LIVING 1.2 LOCAL LIFESTYLE AND VERTICAL LIVING 1.3 THE ENERGY PROBLEM AND RELATED REGULATION 20

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2.0 TROPICAL AND HUMID CLIMATE 28 2.1 TROPICAL MONSOON SEASONS 30 2.2 SOLAR RADIATION 31 2.3 TEMPERATURE AND HUMIDITY 32 2.4 WIND 33 2.5 PRECIPITATION 34 3.0 THE COMFORT THEORY AND PASSIVE COOLING DILEMMA 36 3.1 ADAPTIVE COMFORT 38 3.2 PASSIVE COOLING PRINCIPLES 40 3.3 CROSS VENTILATION AS EFFECTIVE PASSIVE COOLING 42 3.4 THE DEBATE OF HIGH-RISE STRUCTURAL CONSTRUCTION 43 4.0 VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY 44 4.1 VERNACULAR ARCHITECTURE 46 4.2 PRECEDENT CASE STUDY 50 5.0 FIELD WORK 54 5.1 SITE 56 5.2 STRUCTURAL AND BUILDING SYSTEM 57 5.3 DATA LOGGER 58 5.4 CALIBRATION 60 5.5 SPOT MEASUREMENTS 63 5.6 SURFACE TEMPERATURE MEASUREMENTS 66 5.7 OCCUPANT INTERVIEW 69 6.0 ANALYTIC WORK AND CONCLUSION 70 6.1 AIR MOVEMENT 72 6.2 HIGH MASS 74 6.3 LOW MASS 82 6.4 LOW MASS AND HIGH MASS COMPARISON 86 6.5 HORIZONTAL SHADING DEVICE 89 6.6 VERTICAL SHADING DEVICE 90 6.7 ORIENTATION 91 6.8 INTERNAL CONDITION SENSITIVITY 92 6.9 CFD INDOOR AIR FLOW 94 6.10 CONCLUSTION AND DESIGN APPLICATION 98 7.0 REFERENCES

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FIGURE AND TABLES 1.0 HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGPAORE Fig.1.1 Singapore arial view. (Source: http://www.teoalida.com/.)

Fig.1.2 Queensgtown: Tanglin Halt, HDB 1962-1964. (Source: http://www.teoalida.com/.)

Fig.1.3 Queenstown: Princess Margaret, SIT 1952-1958. (Source: http://www.teoalida.com/.)

Fig.1.4 Upper Pickering Street, 1952. (Source: http://www.teoalida.com/.)

Fig.1.5 Yuhua estate Vertical Greenery installed at Yuhua estate Blk 223A. (Source: http://www.hdb.gov.sg/.)

Fig.1.6 Solar Panels for 29 blocks at Blk 233 Jurong East Street 21. (Source: http://www.hdb.gov.sg/.)

Fig.1.7 Coffee shop in Singapore. (Source: http://www.cavinteo.blogspot.com) Fig.1.8 Adaptive actions for local residents to achieve thermal comfort. (Source: Jitkhajornwanich, 2006) Fig.1.9 Elderly using public shared space for social activity in Singapore. (Source: http://www.bloomber.com.)

Fig.1.10 Household energy consumption profile, 2014. (Source: E2 Singapore) Fig.1.11 Public vs private housing average monthly household electricity consumption, 2014. (Source: EMA 2015) Fig.1.12 Public housing average monthly electricity consumption by dwelling type, 2014. (Source: EMA 2015) Fig.1.13 NEA comparison of energy behavirour and user habits. (Source: NEA 2013) Table 1.1 Non-contestable electricity consumption from 2005 to 2014. (Source: EMA 2015) Table 1.2 BCA Green Mark for New Residential Buildings Version RB/4.0, 2013. Point Allocations.

Table 1.3 Prevailing wind direction and sped from NEA. (Source: NEA Singapore, http://www.nea.gov.sg.)

2.0 TROPICAL AND HUMID CLIMATE Fig.2.1 Map showing Singapore in relation to island of Sumatra and Straits of Malacca. (Source: after google map) Fig.2.2 Sun path diagram for Singapore. Top line: summer solstice sun path on 22 Jun; middle line: equinox sunpath on 22 Mar &21 Sep; bottom line: winter solstice sun path on 22 Dec. (Source: Singapore building authority, 2010) Fig.2.3 Singapore solar radiation on 4 orientations. (Source: after Meteonorm) Fig.2.4 Hourly variation of temperature for each month. (Source: http://www.weather.gov.sg/.)

Fig.2.5 Hourly variation of relative humidity for each month. (Source: http://www.weather.gov.sg/.)

Fig.2.6 Average minimum and maximum temperature, AM and PM relative humidity. (Source: http://www.bbc.co.uk/ weather/.)

Fig.2.7 Wind rose in January. (Source: https://www.windfinder.com/.)

Fig.2.8 Wind rose in May. (Source: https://www.windfinder.com/.)

Fig.2.9 Monthly rainfall for Singapore. (Source: http://www.weather.gov.sg/.)

Fig.2.10 Hourly variation of rainfall for each month. (Source: http://www.weather.gov.sg/.)

Table 2.1 Seasonal events and description. (Source: http://www.weather.gov.sg/.)

Table 2.2 Annual average wind and air temperature. (Source: https://www.windfinder.com/.)

3.0 THE COMFORT THEORY AND PASSIVE COOLING DILEMMA Fig.3.1 Adaptive comfort band for warm and humid climate in Singapore. (Source: after Tedkajo, 2012) Fig.3.2 Singapore psychometric chart. (Source: after Szokolay, 2014) Fig.3.3 Singapore psychometric chart showing control potential zone (CPZ) with air movement effect. Solid line is when air movement at 1m/s; dashed line is when air movement is at 2m/s. (Source: after Szokolay, 2014) Fig.3.4 Singapore solar radiation on 4 orientations and diffuse radiation. (Source: after meteonorm) Fig.3.5 Attached vs detached external solar shading strategy. (Source: Holger Koch-Nielson, 2002) Fig.3.6 Natural ventilation in room layout shown in plan. (Source: Wong, 2000) Fig.3.7 Operation of a heavyweight construction with outside insulation. (Source: Szokolay, 2000) Fig.3.8 Airflow turbulence in vertical micro-climate. (Source: T.R. Oke, 1978) Fig.3.9 Re-entrant air space in 5 Parc Emily floor plan, Singapore. (Source: AutoCad) 4.0 VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY Fig.4.1 Site layout of the “kampong” settlement. (Source: Yuan, 1991) Fig.4.2 The indoor space zoning of the “kampong”. (Source: Abidin, 1981) Fig.4.3 Wood carved facade in the “kampong”. (Source: Ismail, 2005) Fig.4.4 Ventilation of the “kampong” in section. (Source: Yuan, 1991)

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FIGURE AND TABLES 4.0 VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY (continued) Fig.4.5 Operable louvered shutters with permanent openings located above windows. (Source: http://smalltalesofsg. wordpress.com) Fig.4.6 Example of mixture of styles of shophouse and terrace house in Singapore. (Source: http://smalltalesofsg. wordpress.com) Fig.4.7 Courtyard and airwell promoting ventilation. (Source: Hashim and Ghafar, 2005) Fig.4.8 Key elements in a typical shophouse. (Source: After Urban Redevelopment Authority) Fig.4.9 Left: north façade with shading devices. Right: south facade with Bay windows, monsoon windows, platers and sunshades. (Source: WOHA architects) Fig.4.10 Transverse section. (Source: after WOHA architects) Fig.4.11 Typical floor plan with 2 apartments. (Source: after WOHA architects) Fig.4.12 Architect’s sketch of monsoon window. (Source: after WOHA architects) Fig.4.13 Variation of window protected from rain. (Source: WOHA architects) Fig. 4.14 Skyville @ Dawson overall plan. (Source: WOHA architects) Fig.4.15 Wind simulation showing air movement speed increase, through enclosed courtyard, in front of the second row of the building. (Source: after The Singapore Engineer, 2010) Fig.4.16 Wind simulation of the building within the context. (Source: The Singapore Engineer, 2010) Fig.4.17 Diagram airflow in between villages. (Source: The Singapore Engineer, 2010) Fig.4.18 Skyville @ Dawson typical floor plan. (Source: The Singapore Engineer, 2010) Fig.4.19 SkyTerrace @ Dawson overall plan. (Source: after SCDA architects) 5.0 FIELD WORK Fig.5.1 5 Parc Emily site map. (Source: Google map) Fig.5.2 Precast flat plate structural system. (Source: A BCA-SIA Publication 2008) Fig.5.3 Internal wall drywall system. (Source: A BCA-SIA Publication 2008) Fig.5.4 Fieldwork apartment block location. (Source: Rhino) Fig.5.5 Location of data logger in the living room.

Fig.5.6 Location of data logger insdie metal fin on the balcony.

Fig.5.7 AC unit in the living room.

Fig.5.8 Fieldwork apartment plan. (Source: AutoCAD) Fig.5.9 Calibration construction details. Section through wall-floor junction and window. (Source: AutoCAD) Fig.5.10 Air temperature and relative humidity data logger results from 4 May 2016. (Source: Testo 174H data loggers and Excel) Fig.5.11 Calibration results, OpenStudio and data logger results from 4 May 2016. (Source: Testo 174H data loggers and Excel) Fig.5.12 Air temperature, relative humidity and air velocity spot measurement results from 03:20 4 May 2016.

(Source: spot measurement) Fig.5.13 Air temperature, relative humidity and air velocity spot measurement results from 10:30 4 May 2016.

(Source: spot measurement) Fig.5.14 Air temperature, relative humidity and air velocity spot measurement results from 13:00 4 May 2016.

(Source: spot measurement) Fig.5.15 Surface temperature measurement results from 03:20 4 May 2016. (Source: spot measurement) Fig.5.16 Surface temperature measurement results from 10:30 4 May 2016. (Source: spot measurement) Fig.5.17 Surface temperature measurement results from 13:00 4 May 2016. (Source: spot measurement) 6.0 ANALYTIC WORK AND CONCLUSION Fig.6.1 Sunpath and shadow diagram aerial view. (Source: Rhino and grasshopper) Fig.6.2 Comparison of the indoor temperature of base case and 24hr ventilation at 5 ach/hr. (Source: Excel and OpenStudio) Fig.6.3 Heavyweight with 50mm construction details. Section through wall-floor juction and window. (Source: AutoCAD) Fig.6.4 Comparison of the indoor temperature with base case heavyweight construction and heavyweight with 50mm outside insulation construction. (Source: Excel and OepnStudio) Fig.6.5 Heavyweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison. (Source: Excel and OpenStudio) Fig.6.6 Comparison of the heavyweight with 50mm outside insulation construction indoor temperature of infiltration at 3ach, 1.5ach and 0.3ach. (Source: Excel and OepnStudio)

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FIGURE AND TABLES 6.0 ANALYTIC WORK AND CONCLUSION (continued) Fig.6.7 Comparison of the indoor temperature with U-value of 4.2W/m2K, 5.8W/m2K, and 1.6W/m2K. (Source: Excel and OepnStudio) Fig.6.8 Lightweight construction details. Section through wall-floor juction and window. (Source: AutoCAD) Fig.6.9 Lightweight insulated construction details. Section through wall-floor juction. (Source: AutoCAD) Fig.6.10 Comparison of the indoor temperature with base case heavyweight construction and heavyweight with 50mm outside insulation construction. (Source: Excel and OepnStudio) Fig.6.11 Comparison of the indoor temperature with lightweight construction and heavyweight with 50mm outside insulation construction. (Source: Excel and OepnStudio) Fig.6.12 Lightweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison. (Source: Excel and OpenStudio) Fig.6.13 Horizontal shading device's location over living room windows. (Source: SketchUp and OpenStudio) Fig.6.14 Vertical shading device's location over living room windows. (Source: SketchUp and OpenStudio) Fig.6.15 Vertical shading device's location over living room windows. (Source: AutoCAD) Fig.6.16 Inlet wind velocity 0.9m/s indoor air velocity. (Source: TAS Ambiens) Fig.6.17 Inlet wind velocity 0.9m/s indoor temperature. (Source: TAS Ambiens) Fig.6.18 Inlet wind velocity 1.7m/s Indoor air velocity. (Source: TAS Ambiens) Fig.6.19 Inlet wind velocity 0.9m/s indoor temperature. (Source: TAS Ambiens) Table 6.1 Heavyweight construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio) Table 6.2 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio) Table 6.3 Lightweight construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio) Table 6.4 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio)

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ACKNOWLEDGMENTS The author of this dissertation wish to thank the excellent teaching staff and supportive colleagues currently enrolled in the Sustainable Environmental Design Programme at the Architectural Association School of Architecture. I would like to acknowledge Dr.Simos Yannas and Dr. Paula Cadima for their leadership, generosity, and encouragment throughout the process of the dissertation research. Herman Calleja, Gustavo Brunelli, Jorge Rodriguez, and Byron Madras were patient and instrumental in helping me understand and implement the analytical tools. This is essential in order to conduct this research. And special appreciation and thanks my tutor Mariam Kapsali for promptly providing feedback and reassurances for the explore of the research, of which result and aims are contained herein .

I would also wish to thank former SED student authors of the past dissertation reports as referance to this dissertation. Their well documneted research method, clear analysis, and detailed source of referance are important to the making of this dissertation.

Addtionally, I would like to thank the numerous visiting lecturers, yet the list is too many too be included here. They were invited to contribute lectures and workshops to the Architectural Association Sustainable Environmental Desgin (SED) Programme. The generous sharing of their incites and expertise are the genuiely inspiration of this dissertation.

Last but not least, I wish to express sincere appreciation and thanks to my supportive colleagues in the AA SED programme. Their consistant caring presence and motivational critics helped me learn in a friendly environment and nurturing atomsphere.

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1.0 HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE APPLICABILITY OF VERTICAL LIVING

“The main rationale for high-rise living is to address housing needs, optimal land use and improve living environment.”

--(Wong, A., & Yeh, S.H.K. (1985). Housing a nation. Singapore: Maruzen Asia.)

Fig.1.1 Singapore arial view.

(Source: http://www.teoalida.com/.)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE APPLICABILITY OF VERTICAL LIVING Urban demographic: the nesseccity of verticality Singapore is a city-state with a limited land area (700 km2) and a growing population, currently 5 million. The resultant population density is more than 6,300 people per km2. The urban built-up density is even higher, over 9,500 persons per km2. Singapore has housed 84% of its resident population in high-rise public housing and improved residents’ living conditions in the process.

Known as on of the least urbanized regions of the world, nowadays Asia’s urbanization is growing at an unprecedented rate through the history. It is expected that, by 2050, 50% of Asians are to live in cities (UN-Habitat, 2008).

Settlements pressure from population and economic growth have expanded with urbanization, especially in case of Singapore where land scarcity is an obvious fact.

Together with the desire for improved housing conditions have led to the skywards celebration of urban verticality. Over a period of 40-50 years, high-rise housing has become the dominant building form and major lifestyle of the population. In Singapore, a greater proportion of its resident has moved to live in high-rise, among the 84% of its resident population in high-rise, 81% is public housing (Yeung and Wong, 2003). the remaining 11% live in Private highrise condominiums. And only 5% live in landed properties such as a detached, semi-detached or terrace house (URA, 2004). “ More homes will be built in the city. There are currently 30,000 housing units in the city. 90,000 more units to be built in the ‘downtown buzz’, where mostly is the New Downtown area at Marina South. The average plot ratio for housing in the New Downtown can be increased to 6.0-7.0. This gives an idea of the predicted density” -- Urban Redevelopment Authority. (2001) Concept plan 2001.

Singapore: Urban Redevelopment Authority.

The height of apartment housing is set to rise. The high-rise living has clearly become a part of the lifestyle. Resident satisfaction surveys have registered continually high satisfaction score, which indicates the likelihood and willingness to live in high-rise housing (Housing and Development board, 2003). The formula against the context of limited land and increasing population seems to have worked (Urban Redevelopment Authority, 2001). The high-rise lifestyle is further elaborated in the following chapter.

There are several attractions offered given the density of high-rise: allowing housing need to be met with minimum land usages, which, in this sense, helps preventing urban sprawl; freeing up space for greenery, which, otherwise would be used for low-density housing development; supporting efficient public transit infrastructure, given the high concentration of residents (Urban Redevelopment Authority, 2001). Planning code and regulation are implemented to ensure a standard service is supplied, which is an important part in acheiving the general framework of modernization. For example, compared with other housing types, high-rise public housing is intentionally planned with convenience access to public daily life facilities, such as open spaces and greenery, parking, schools and markets, which are located within a 5-10min walking radius to the residence. As a result, the non-residential use and service could occupy as much as half of the land in newly planned town. (Wong and Yeh, 1985).

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE APPLICABILITY OF VERTICAL LIVING Urban demographic: the nesseccity of verticality The proposition is that high-rise housing can be an effective sustainable solution that is built with least environmental and ecological impact. The overall global urbanization within the last 2 decades, once again, seems to favor the vertical solution as an inevitable trend for Asia. Particularly, in Singapore, the height of high-rise apartment displayed a trend skyward. Meanwhile, the speed and location the high-rise being built is motivated by new technology: The advent of Otis elevator; steel frame construction; air condition; waste management and service; fire safety with sprinkling system; monitoring and telecommunications are few of the many innovations that have enabled the increasing height of high-rise. Nevertheless, the phenomenon of the increase of tall buildings as living space creates awareness, both for the importance and impact of this built form on urban life. The sustainable advantages and disadvantages in Singapore climate is what inspired and initiated this dissertation.

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE APPLICABILITY OF VERTICAL LIVING History of vertical living in Singapore The Housing & Development Board (HDB) is Singapore’s public housing authority. Established on 1 February 1960 during our nation’s housing crisis, HDB were tasked with providing sanitary living conditions to replace the prevalent unhygienic slums and crowded squatter settlements. In less than 3 years, HDB built 21,000 flats; in 5 years by 1965, 54,000 flats was built. HDB plan and develop Singapore’s housing estates; building homes and renovate towns to create a quality living environment for Singapore people, where various commercial, recreational, and social amenities is included at residents’ convenience.

Today, more than affordable public housing of 1 million flats have been completed in 23 towns and 3 estates across the entire nation for over 50 years.

HDB flats are home to over 80% of Singapore’s resident population, with about 80% of these resident households proudly owning their home. (HDB, 2016) The first Singapore apartment living (1-7 storeys) is lauched in 1953 under the colonial administration of Singapore Improvement Trust (SIT). The first SIT flats are generally smaller public housing with 1 and 2 room flats. Along with the post independence wide scale public housing program, the number, size and quality of the flats increases, as well as the building height: 2 decades later the tallest block was 25 storeys. Taller buildings is added onto the old town through a continuous estate renewal process. During one of the latest strategy, called Selective En-block Redevelopment Scheme (SERS), blocks of older flat are demolished to make way for new 30-50 storeys buildings. (Wong and Yeh, 1985) One of the most well known historical example is Singapore Improvement Trust SIT). SIT was set up in 1927. public housing developments were smallscale, until Tiong Bahru started in 1936 and Queenstown started in 1952 and completed by HDB in 1960s. In 32 years, SIT built only 23,000 flats, housing 8.8% of Singapore population in 1959. The SIT housing was similar with British housing, 2 storeys terraced houses, 3-4 storeys walk-up flats, and since 1950s, 7-9 storeys high-rise flats, plus one 14 storeys block built in Queenstown in 1956 (Fig.1.2 Queensgtown: Tanglin Halt, HDB 1962-1964; and Fig.1.3 Queenstown: Princess Margaret, SIT 1952-1958.). The blocks built at just 10-15 meters apart, which is denser than HDB estates. The problems of these first developed high-rise estates resulted in demolish in the modern times. Another example is the Upper Pickering Street (Fig.1.4 Upper Pickering Street, 1952.) was built by SIT in 1952 and demolished in 2003. Kitchens are noticed to be facing the corridor. It is the first high-rise public housing with lifts.

Fig.1.2 Queensgtown: Tanglin Halt, HDB 1962-1964.

(Source: http://www.teoalida.com/.)

Fig.1.3 Queenstown: Princess Margaret, SIT 1952-1958.

(Source: http://www.teoalida.com/.)

Selective En-block Redevelopment Scheme (SERS) is one of the most recent strategy. SERS was launched in 1995 to demolish old blocks and build new blocks in nearby location to house the affected residents. Between 2008 and 2014, 8 SERS sites were identified, total 6576 flats.

The HDB Greenprint is piloted at Yuhua estate in Jurong, where 38 blocks of flats will be transformed into a ‘Green Neighborhood’. The findings from this pilot project will be used to refine the HDB Greenprint model before it is rolled out to other HDB towns. Residents can look forward to sustainable and green initiatives such as solar panels, sensor-controlled LED lightings, pneumatic waste conveyance system, and enhanced pedestrian networks. (HDB, 2016) Fig.1.4 Upper Pickering Street, 1952.

(Source: http://www.teoalida.com/.)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE APPLICABILITY OF VERTICAL LIVING Future of high-rise living: the ongoing advanture Tall buildings and cities are evidently connectively integrated in the process of urbanization development process. In this inter-relationship, it is perhaps helpful to remember that if tall residential building are not the cause of the problems of contemporary growth, neither are they the solution. They simply presented a form, user and technological challenges, where require specialty in all of these, perhaps entirely new, dimensions. (Appold, 2005)

Fig.1.5 Yuhua estate Vertical Greenery installed at Yuhua estate Blk 223A. (Source: http://www.hdb.gov.sg/.)

These dimensions are out of the expertise of one profession. Inter-disciplinary knowledge transfer and collaboration is called for in developing a holistic urban high-rise design. Much are waiting to be studied and innovated, for example, by architects and structural engineers together to advance in material and technology. (Ali and Armstrong, 1995) The opportunity being explored and content discussed in this dissertation is by no mean exhaustive. For example, vertical greenery in high-rise creates rooftop gardens, which serves both the ecological function by encouraging natural ventilation, evaporative cooling and air purification, and the social function as leisure and public space by promoting interaction in the neighborhood. Place making and re-creating of ground conditions is achieved with the immediate access to nature in the high-rise estate (Sunakorn and Yimprayoon, 2011). Yet such technology, given the increase of humidity level in the microclimate and maintenance, requires careful consideration regarding the applicability and climatic condition (Wong et al., 2009).

At the same time, it is also important that everyone join in to protect the environment. To ensure sustainable living for current and future generations, HDB are bringing sustainable living into existing HDB estates with the HDB Greenprint, which is a framework and guideline for town and residential development.

Such Greenprint neighbourhood project is piloted at Yuhua estate in Jurong.

The project is to demonstrate a eco-liftstyle intergrating effeort in energy efficiency, water convservation and accessible greenary etc (Fig.1.5 Yuhua estate Vertical Greenery installed at Yuhua estate Blk 223A; and Fig.1.6 Solar Panels for 29 blocks at Blk 233 Jurong East Street 21.).

Fig.1.6 Solar Panels for 29 blocks at Blk 233 Jurong East Street 21.

(Source: http://www.hdb.gov.sg/.)

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1.0 HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING

Fig.1.7 Coffee shop in Singapore.

(Source: http://www.cavinteo.blogspot.com.)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING Outdoor lifestyle As the minister for Home Affairs announced, the focus on place identity is accentuated in Singapore’s long term Concept Plan 2001, which aiming at creating a distinctive and alive city identity with rich heritage yet diversity. “The design that not only enhances your living environment, but also endows it with an identity and a community spirit all of its own. A city that we can fondly call home� -- Minister for Home Affairs (Ministers speech at the upgrading and launch ceremony for Indus Precinct, 2000) One of such impressive and essential elements is the outdoor living lifestyle in Singapore. For example, hawker center, also called coffee shop, is an open-air complex, yet the blinds are put down to prevent sunlight or rain (Fig.1.7 Coffee shop in Singapore.). The stalls in the complex sell a variety of inexpensive food. Typical location is in city centres, near public housing estates or transport hubs (such as bus interchange or train stations). Compared to mobile food hawker carts, permanent stalls in open air buildings are provided with hawker licensing. This regulated the street hawkers in the city as well as sanitary of the food. Either common or stall dedicated tables and chairs are provided for customers, with cleaning and collecting service from each stall, as well as waiter serving drinks. Hawker centres is a one stop good variety and high quality food at down to earth prices for the community.

Hawker centres in Singapore sprang up as a result of rapid urbanization in the 1950s and 1960s. The main problem is the unhygienic food preparation by unlicensed street hawkers. Upgrading or reconstruction of hawker centres initiated in the late 1990s. Nowadays, hawker centres are popular civil outdoor space without air conditioning.

Like Hawker center, local residents achieve thermal comfort by taking actions: occupying different places during the times of a day; reducing activities and clothing level; spraying water around; washing skin surface, such as face and body, with cold water; taking cold drinks; creating air movement with hand and mechanicalfan; using trellis and planting trees as shading for sitting areas. Architectural elements are applied in vernacular to provide air movement and shading from solar radiation (Fig.1.8 Adaptive actions for local residents to achieve thermal comfort.). (Jitkhajornwanich, 2006)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING Outdoor lifestyle

Fig.1.8 Adaptive actions for local residents to achieve thermal comfort.

(Source: Jitkhajornwanich, 2006) 15

HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING The high-rise living lifestyle: problem and expectation On the other hand, given the limited land and dense population, high-rise living is also an essential lifestyle especially in the city center. Toward what aspect is high-rise capable of contributing to a good living environment? High-rise as an architectural typology plays an evidential and enduring role in the modern urbanization. High-rise have proliferated and spread globally. It became a milestone of modern civilization, prosperity and growth in different urban settings.

Nevertheless, at certain point during the development, the architecture has become an expression of technology translation, articulated as a dramatic depiction, revealing, or rather concealing, the effects and mechanism of popular technology operations representing the lifestyle of the times. Examples such as Woolworth Building by Cass Gilber, 1913; Seagram building by Mies van der Rohe, 1958; Sear Tower and Hancock Tower by Skidmore Owings and Merrill, 1973 and 1976. As a young nation of 50 years history, Singapore is no exception. (Yuen and Yeh, 2011) Problems are presented in the lifestyle shaped by the western industrialized society. Regardless of its pervasiveness, studies suggest that this is one of the most un-ecological architecture typology. The history of western high-rise development is peppered with cases on how the urban living quickly degenerates into undesirable and problematic in such space. Research indicates that such space in high-rise residential building, without proper openness and daylighting, has a way of magnifying anti-social behavior. Literature is also written that high-rise living is a common anxiety associated with isolation, where lacking of outdoor open space for children to play, opportunities for natural observation and interaction with the community. These serve as an urgent calling to explore the knowledge on how high-rise living is perceived and occupied by its residence. (Lau, 2011) Yeang (Lau, 2011) suggests that high-rise uses much more energy and material resources to build, maintian and, and demolish. However, observed from a urban scale, on the other hand, Lau (Lau, 2011) has suggested that, as a result of urban densification and compactness, building footprint is minimized. The intensification of residence requires concentrated in infrastructure and services, and therefore savings. Nevertheless, the architecture typology, on the contrary, is a heuristic solution for the housing demands for in the city.

More importantly, High-rise creates possibilities to construct sustainably, apply innovative materials, and design passively. Opportunities present in architectural language and design element including the type of facade, spatial configuration and open space that see the sky, balcony, landscape etc. These are imperative opportunities to be explored for building sustainable and resilient high-rise. (Yuen and Yeh, 2011) The advantages of high-rise living and the attraction for potential building residence is, of course, the lifestyle experience related to the environment offered by the interior space. Studies suggests that designer and building professionals are to evaluate the balance of an improved life quality and reduced environmental impact (Lau, 2011). Real or perceived, reducing toxicity in the air, improving ventilation and overall healthier interior space that add value to the wellbeing, and therefore economical investment. One example is the housing units locate in certain level of the high-rise residence are generally expected to have air quality and yield higher value. Chau et al. (2011) in Hongkong have done study using computational fluid dynamics techniques in a three-dimension Reynolds-stress turbulence model to estimate the air quality of each individual housing unit. Afterwards, the results are shown to the potential residence. It is indicated that, when shown the unit specific air quality data, people are more willing to pay for clean air in a high-rise living environment. Residents’ satisfaction in Singapore suggests that other reasons, including better view and less noise, are also aspiration to opt for high-rise living.

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING The high-rise living lifestyle: Problem and expectation Interestingly, research has suggested that more women then men are attracted by the view, while more men than woman are attracted to the feeling of height (Haber, 1977). Also, prestige social status related to western lifestyle is often associated with high-rise living (CTBU, 1981). One example is that the prices of penthouse are generally much higher than the other units especially where the view is unobstructed, which enables people to divorce themselves from the normal mundane things that goes along with owning a house (Fincher, 2007).

On the other hand, research on socio-environmental phenomenon in high-rise living raises discussion on the relationship of sustainable design and community development in high-rise living. Compared to vernacular “kampong” house where “Angung” and “Serambi” are both environmentally conducive social spaces for play, dining and entertaining. Besdies protecting indoor spaces from solar radiation, which is to be introduced in the following chapter, the familarity and neighborliness expressed a strong sense of community and ownership, and therefore sense of belonging and security. One example is, comparing to narrow corridors, the residents sharing outdoor space with gardening have a increased exposure to know more neighbours; while gardening create a more desirable environments and social sustainability. And the threshold is also suggested as 2m depth of veranda form 1.4m corridor according to parametric simulation studies (Liang, 2005).

Meanwhile, certain level of privacy is to be traded off to achieve trust and social interaction. However, in 1986 the changing in planning and building regulations discouraged high-rise housing from providing these spaces such as semi-open balconies and forecourt (Bay et al. 2006).

Besides social and environmental benefit, study (Bay et al. 2006) suggest that shared outdoor space with gardening is to achieve thermal comfort. The increase of planting lower the ambient temperature. Bedok Court is a high-rise housing designed without air-conditioning in 1985. According to a resident survey for the warmest month of the year, 80% of the residents felt warm, comfortable, or slightly cool in the afternoon when the indoor temperature is the highest. Compared to indoor thermal comfort, however, the criteria, such as clo level and metabolism rate, for outdoor thermal is different. Given the time and length, unfortunately, this dissertation is on the discussion of the indoor thermal comfort. Yet it is a continuous effort to search for an efficient sustainable technology to opt back to a traditional outdoor lifestyle (Fig.1.9 Elderly using public shared space for social activity in Singapore.).

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE LOCAL LIFESTYLE AND VERTICAL LIVING Livability definition and life quality Livability is an important indicator of quality of life that affect the long-term wellbeing of people and communities, as suggested by multi-disciplines studies. As Lennard et al. (1997) suggested, the character livable environment are likely to be the following: - inviting public space and walk way that is pedestrian friendly; - a less traffic speed and volume; - decent yet affordable housing with desired location; - convenient access to local services such as schools and markets; - a sanitary natural environment with legible and diverse landscape, e.g. parks and open space available within walking distance; - safety yet accepting community for all residence, hence encourage communication and interaction , by emphasizing aspects such as local culture, history and ecology.

Fig.1.9 Elderly using public shared space for social activity in Singapore.

(Source: http://www.bloomberg.com.)

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1.0 HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION The cooling load in high-rise residence High-rise living is a main of lifestyle in Singapore. In a citystate like Singapore, approximately 86% of the population resides in public housing, the majority of which are high-rise buildings. The form of public housing are commonly “slab blocks” of about 12 storeys and “point blocks” of about 30 storeys. Besides that, approximately 7% of the population lives in condominiums, which are mostly apartment blocks.

(Appold and Yuen, 2003). Being said, the researching for high-rise energy saving solution for residential building is of considerable value.

Table 1.1 Non-contestable electricity consumption from 2005 to 2014.

(Source: EMA 2015)

The residential is an accountable part of the total electricity demand in Singapore. Contestable consumers refer to electricity consumers who are allowed to purchase electricity either from third-party retailers or the wholesale market.

According to the Energy Market Authority of Singapore (Table 1.1 Non-contestable electricity consumption from 2005 to 2014), as a major part of the non-contestable electricity consumption sector, total electricity consumed by households in Singapore indicate constant increase from 2005 to 2014. Form 2013 to 2014, in the non-contestable electricity consumption sector, the households electricity consumption raised by 2.5% to 6,936 GWh, among which 59% (4,125 GWh) was by public housing units, while private housing units are accounted for the rest 40% (2,787GWh). (EMA 2015) Using air conditioners as cooling is one of the major electricity consumption. Studies have shown the percentage of households in Singapore who are using air conditioning has increased significantly in the past 20 years from only 7.8% in 1978 to 57.7% in 1998 (Wong, 2009). Air conditioners account for about 36% of the electricity consumption in a household according to a weighted energy consumption profile across all housing type (Fig.1.10 Household energy consumption profile 2014). Nevertheless, private housing household electricity consumption is significant higher than public housing household (Fig.1.11 Public vs private housing average monthly household electricity consumption, 2014). Therefore, the passive cooling design as an alternative cooling solution to reduce cooling load which mainly resulted by the usage of air condition in household, has a significant impact on the energy saving in Singapore.

According to EMA (Fig.1.12 Public housing average monthly house), Data of 2014 indicates that the average monthly consumption of electricity by households is 466 kWh, with monthly consumption by public housing units at 371 kWh and private housing units at 748 kWh. Among the public housing dwelling types, the 4 rooms unit of 383 kWh/yr is used as benchmark: the 1 room/2 rooms unit consumed 162 kWh; 4 rooms unit consumed 383 kWh; 5 room unit consumed 469 kWh. The movement towards air conditioning is particularly prevalent in the case of high-rise buildings where less adaptive opportunity is available, and therefore air conditioning is becoming more and more popular to achieve indoor performance that meets thermal comfort. And studies show that during night-time, when the thermal acceptability higher, however, the usage of air conditioning shows a higher frequency. (Mohanty, Ford and Lau, 2013)

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Fig.1.10 Household energy consumption profile, 2014.

(Source: E2 Singapore)

Fig.1.11 Public vs private housing average monthly household electricity consumption, 2014.

(Source: EMA 2015)

HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION The corresponding policy The total electricity use increased by a tremendous amount in the most recent 20 years (Putra and Han, 2014). For instance, Energy Policy Group was formed in 2006 responding to the increasing energy consumption. The public conservation efforts is geared so as to realize greater saving potential for the future. Studies shows, in light of household’ evolving electricity demand, which is a result of different lifestylses depending on, for example, different income level, is effected by residents’ perception and likelihood to adopt energy conservation policy implemented by the regulator.

Fig.1.12 Public housing average monthly electricity consumption by dwelling type, 2014.

(Source: EMA 2015)

Fig.1.13 NEA comparison of energy behavirour and user habits.

(Source: NEA 2013)

User habits in different lifestyle is noteworthy and it is difficult for households to change, which can limit the effectiveness of information programs and energy saving policy.

For example, according to National Environmental Agency (Fig.1.13 NEA comparison of energy behaviror and user habits.), recommended tips such as ‘set temperatures at 25°C or Higher’ or ‘switch off appliances at the socket’ are practiced more by those who stay in Government-subsidized Housing Development Board (HDB) flats as compared to those who live in private condominiums or landed homes. In addition, one out of eight landed homeowners declared they are not doing anything to save energy. For the public households, more efforts should be made to educate them on the benefits of adopting an efficient appliance, with emphasis not only on future cost savings but also on its value towards thermal comfort and the environment. For the richer families, such as private households, energy conservation should aim towards permanently reducing their consumption with minimal efforts. Technologies such as thermostats that automatically adjust to environmentally-friendly temperature levels, as well as encouraging households to purchase SMART homes and switching electricity suppliers, should be an integrated part of energy conservation policies in the future as income inevitably rises in the future. (Loi and Loo, 2013) Studies suggest that policy and regulation that target electricity savings should be focused on interventions that do not require much effort on the resident, centering on onceoff actions. to supplement main conservation campaigns.

For instance, once-off interventions such as the Resource Efficiency Guide are available from NEA to help new home owners. The guide consists of giving advices on interior designing, providing more informed choices on the electrical appliances and also helps home owners calculate the life cycle cost of the electrical appliance. Rather than being a hassle or disturbance in well-established lifestyles, it is easier to permanently set energy conservation behaviour as part of the households’ default habit, by targeting new homeowners applying design strategy. (Frederiks, Stenner and Hobman, 2015)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION Design code and regulation BCA Green Mark Certification Standard for New Buildings, GM Version 4.1, 2012.

Appendix C Typical insulation in Singapore high-rise residential buildings. As discussed in the previous chapter, the Singapore lifestyle also emphasis on the identity as a whole.

Policy including ministerial Forum on HDB Heartware 2007: Remaking Our Heartlands program where older, middle-aged and new towns will be regenerated into more vibrant homes that offer an appealing lifestyle. This aspect also adds value to the simulation of insulation, which is to be tested in the following chapter.

The BCA Green Mark Scheme was launched by the Building and Construction Authority (BCA) in January 2005 to raise environmental awareness and promote sustainable practice in the construction and real estate. It is a benchmarking scheme which aims to achieve a good environment by incorporating criterias, including environmental elements both in design and construction, and applications of most recent technologies. The BCA Green Mark Scheme aims at the integration of passive designs, co-operation between disciplines and optimizing of energy use in buildings etc. Criteria are divided into 5 categories: - energy efficiency.

- Water efficiency.

- Environmental protection.

- Indoor environmental quality.

- Other green features.

Among the categories in BCA Green Mark for New Residential Buildings Version RB/4.0, energy efficiency has the most point allocation (Table 1.2). And within this category, RB 1-2 Naturally Ventilated Design and Air-conditioning System take up the most points (22 points).

Table 1.2 BCA Green Mark for New Residential Buildings Version RB/4.0, 2013.

Point Allocations.

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION Design Code and regulation BCA Green Mark Certification Standard for New Buildings, GM Version 4.1, 2012.

Appendix C In order to achieve Green Mark Award. All relevant pre-requisite requirements are to be complied with: - building envelope design with Residential Envelope Transmittance Value (RETV).

- Ventilation simulation modeling and analysis to identify the most effective building design and layout. In order to ensure a good natural ventilation, a minimum 80% of the typical dwelling units should have an area-weighted average wind velocity of 0.60 m/s.

- Prescribed system efficiency of air conditioner. Minimum points to be scored under RB 3-1 Sustainable Construction (Table 1.2) According to Appendix C of the Certification Standard, in order to identify the most effective building design and layout, computational fluid dynamics (CFD) should be used to carry out the natural ventilation simulation. The methodology are suggested as following: - all simualtion models shall be carried out under isothermal condition of 33.0°C at steady state condition.

- The computational domain shall include the development of interest, the characteristics of the immediate surroundings and buildings reside within the proximity of minimum 3 times or more the length of the longest distance measure across the boundary of the development.

- In order to resolve the salient flow features, as a guide of the dimension of the grid, the computational element should be set at 0.1-0.2m in the apartment unit; 0.5-1.0m at all buildings and ground level; 10m at the far field boundary with a minimum of 50m away from the ground.

- The meteorological data for the month of December, March, June and September shall be used for CFD simulation using the precise wind direction and velocity of the proposed site location, which is based on local climatic wind data. According to NEA over a period of 18 years, the prevailing wind condition, such as the mean speed and direction for Singapore, is to be taken from Table 1.x below.

- Applying the specified dimension of the grid for computational element stated above, 2 large scale simulation models shall be assessed with the wind flow conditions and air-flow pattern for the development and units. The simulation modeling can be conducted based on the 2 best prevailing wind directions for the building development that is N/NE and S/SE. Table 1.3 Prevailing wind direction and sped from NEA. (Source: NEA Singapore, http://www.nea.gov.sg.)

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION Design ctode and regulation BCA Green Mark Certification Standard for New Buildings, GM Version 4.1, 2012.

Appendix C Stage 1: CFD simulation model for development: - determine up to 5 typical unit design layouts that have the majority number of units overall.

- Taking the context building in to account, conduct a large scale CFD simulation to assess the wind flow conditions around the proposed building. E.g. naturally ventilated corridor linked to the unit should be taken into consideration for the simulation models.

- From the simulation results, determine, first, the wind pressure taken at 0.5m from every assumed opening at mid height level yet capped at 20 storey height; and then, pressure difference of the maximum and minimum wind pressure of the unit. In case of the typical unit layout not designed at mid-height level, the average wind pressure and respective pressure difference should be determined at the level closest to the mid-height level.

- Repeat the previous step and determine the average pressure difference of all units.

- Select the unit with pressure pressure difference that is closest to the average pressure difference for stage 2 simulation. The maximum allowable margin of Âą 10% difference from the average pressure difference is allowable.

STAGE 2: CFD SIMULATION MODEL FOR UNITS - conduct a large scale CFD simulation to assess the air flow conditions of selected unites design layout (up to 5), including all living/functional spaces in the unit expect for enclosed spaces, such as storage. For the simulation model, all windows and doors are assumed to be fully opened except for the main door. Main door is deemed to be closed at all time.

- Determine the area-weighted average wind velocity of selected unit by considering the air flow conditions of the applicable area, for example, living room and open kitchen that is connected to the living room, study rooms and all bedrooms.

The area-weighted average wind velocities of applicable areas are to be computed at horizontal plan 1.2m above the floor level.

The selected unit is acceptable for good natural ventilation if the area-weighted average wind velocity of the unit is not less than 0.6 m/s. The overall percentage of units achieving good natural ventilation is given by the formula below: ∑ (No. of selected units for each layout x Area-weighted average wind velocity) % Total Number of Selected Units x 0.6 m/s

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HIGH-RISE RESIDENTIAL DEVELOPMENT IN SINGAPORE THE ENERGY PROBLEM AND RELATED REGULATION U-value and typical construction in Singapore Meanwhile, as discussed in the previous chapter though not the main focus of this dissertation, the Singapore lifestyle also emphasis on the identity as a whole. Related policy including ministerial Forum on HDB Heartware 2007: Remaking Our Heartlands program where older, middle-aged and new towns will be regenerated into more vibrant homes that offer an appealing lifestyle. This aspect also adds value to the analytical work, again not the directly focused on, in the following chapter.

Buildings in Singapore is intended to be air-conditioned, although with a clear effort has been put to design a euphemism for it. It is becoming more common for residential buildings to be air-conditioned. Therefore, building regulations aim at air-conditioned buildings, and are to achieve the design of adequate envelope insulation (BCA Approved Document: Acceptable Solutions, 2008).

The base case residential unit where the fieldwork is taken is being designed in 2005 and completed in 2008. During this period, since 1979, the OTTV formula was applied for overall thermal transfer value (BCA the development & building control division (P.W.D) Singapore, 1986. https://www.corenet.gov.sg/). The OTTV for the external wall is defined by the formula below. And, as stated in BCA Approved Document: Acceptable Solutions Draft in March 2002, building envelope thermal transfer value is not to exceed 45 W/m2.

(Aw x Uw x TDeq) + (Af x Uf x ∆T) + (Af x SC x SF) OTTVw = A0 WHere Aw : opaque wall area (m2); Uw : thermal transmittance of opaque wall (W/m2K); TDeq : equivalent temperature difference (K); Af : fenestration area (m2); Uf : thermal transmittance of fenestration (W/m2K); ∆T : temperature difference between exterior and interior; SC : shading coefficient of fenestration; SF : solar factor; A0 : gross area of exterior wall (m2) However, a major review of OTTV formula is carried out in the early 2000. According to BCA Code on Envelope Thermal Performance for Buildings 2008. The thermal transfer value (Residential Envelope Transmittance Value/RETV formula) is defined by the formula below. The value is modified to 50 W/m2 in the BCA Approved Document: Acceptable Solutions, issued by Commissioner of Building Control under Regulation 27 of the Building Control Regulations Version 6.0 in February 2008. Yet was set to 25 W/m2 in order to differentiate residential buildings, where the air conditioners are often used during the night-time compared to buildings that operate the air conditioners during the daytime.

RETV = 3.4(1-WWR)Uw + 1.3(WWR)Uf + 58.6(WWR)(CF)(SC) Where RETV WWR Uw Uf CF SC

: residential envelope transmittance value (W/m2); : window-to-wall ratio (fenestration area/gross area of exterior wall); : thermal transmittance of opaque wall (W/m2K); : thermal transmittance of fenestration (W/ m2K); : correction factor for solar heat gain through fenestration; : shading coefficients of fenestration;

However, alternative Deem-to-satisfy Criteria for RETV are given with by Window to Wall Ratio (WWR) and Shading Coefficient of fenestration (SC): WWRBldg < 0.3 and SCfacade < 0.7; or WWRBldg < 0.4 and SCfacade < 0.5; or WWRBldg < 0.5 and SCfacade < 0.43.

Where SC (Shading Coefficient of fenestration) = SCGlass x SCshading device. And each SC of the facade must not exceed the prescribed value.

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103° 49’ E

2.0 TROPICAL AND HUMID CLIMATE

1° 21’ N

Fig.2.1 Map showing Singapore in relation to island of Sumatra and Straits of Malacca.

(Source: after google map)

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TROPICAL AND HUMID CLIMATE TROPICAL MONSOON SEASON Singapore locates at latitude 1°22’ N, Longitude 103°58’E, belongs to tropical and humid climate, with abundant precipitation, and high temperature and humidity level that do not vary much from month to month. On the other hand, due to daily variations from hour to hour is more prominent with strong influence by solar conditions.

The climate is separated by 2 monsoon seasons with inter-monsoonal periods in between (Table 2.1 Seasonal events and description.). The Northeast Monsoon occurs from December to early March, and the Southwest Monsoon from June to September. The major weather systems affecting Singapore that can lead to heavy rainfall are: - monsoon surges, or strong wind episodes in the Northeast Monsoon flow bringing about major rainfall events.

- Sumatra Squalls Lines (SSL) developed over the island of Sumatra or Straits of Malacca west of Singapore an organized line of thunderstorms travelling eastward across Singapore.

(Fig.2.1 Map showing Singapore in relation to island of Sumatra and Straits of Malacca.)

- Afternoon and evening thunderstorms caused by strong surface heating and by the sea breeze circulation that develops in the afternoon.

The occurrence of these seasonal events and gusty present dilemma yet opportunities to design for natural ventilation. During the rain, windows are usually shut to protect the rain water from coming indoor. Monsoon window introduced in case studies in the following case studies, for example, is one of the design innovations tackling such issue. At the same time, such climate offers sufficient opportunity for local vegetation. This dissertation by no means pretend to be the final solution, nevertheless, a researching effort towards it.

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Table 2.1 Seasonal events and description.

(Source: http://www.weather.gov.sg/.)

Period Prevailling wind Northeast mon- North to Notheast soon season (Dec - early Mar)

Weather features Early Northeast monsoon (wet phase): Monsoon Surges cause widespread continuous moderate to heavy rain. At times with 7.0 - 9.7m/s wind in the first half of the season from Dec to early Jan. Rapid development of afternoon and early evening showers.

Late Northeast monsoon (dry phase): windy and relatively dry in the later part of the season from Jan to early Mar. Inter - monsoon Light and vari- Thunderstorms, at times severe, occur period able, interacting in the afternoon and early evening. Hot (late Mar - May) with land and sea afternoon with maximum temperature breeze above 32°C. Southwest mon- Southeast to South Occasional Sumatra Squalls with wind soon season gusts of 11 - 22 m/s occur between (Jun - Sep) midday and predawn. Short duration showers or thunderstorms in the afternoon.

Intermonsoon Light and vari- Thunderstoms, at times severe, occur period able, interacting in the afternoon and early evening.

(Oct - Nov) with land and sea Generally wetter than the inter - monbreeze soon season period earlier in the year.

TROPICAL AND HUMID CLIMATE SOLAR RADIATION In high-rise residential building, the solar gain almost all come from facade, while the roof effects the upper apartments. Given the latitude at 1°22â&#x20AC;&#x2122; N of the equator, the position of the sun is almost directly overhead throughout the year (Fig.2.2 Sun path diagram for Singapore.)

Solar radiation reaches 0.837kWh/ m2 on 21 December and reaches minimum 0.737kWh/m2 on 21 September. East and West orientations receive the low-angle sun and most solar exposure, and therefore consider minimizing the amount and size of opening; North and South are better orientation. However, given the cloud cover in warm and humid climate, the amount of diffuse solar radiation is also notable (Fig. 2.3 Singapore solar radiation on 4 orientations).

Fig.2.2 Sun path diagram for Singapore. Top line: summer solstice sun path on 22 Jun; middle line: equinox sunpath on 22 Mar &21 Sep; bottom line: winter solstice sun path on 22 Dec. (Source: Singapore building authority, 2010)

Fig.2.3 Singapore solar radiation on 4 orientations.

(Source: after Meteonorm)

Sunshine duration refers to the cumulative time during which an area receives direct irradiance from the sun of at least 0.120 kW/m2. The length of its day is relatively constant throughout the year and so is the amount of sunshine it receives. Daily sunshine hours are mainly influenced by the cloud coverage level. They average from 4-5 hours during the wettest months to 8-9 hours during the drier periods. February and March have the largest number of sunshine hours, while November and December have the lowest. Nonetheless, the amount of diffuse solar radiation is to be considered all year.

It is the first step to consider reducing solar gain. MRT response to radiant besides air temperature. In climate with light clothing, mean radiant temperature is about twice as significant as dry bulb temperature. For example, effective shading protects the facade from solar gain; while the high thermal performance of the envelope protects the indoor from solar heat gain. MRT formula is to be discussed in the following theory chapter.

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TROPICAL AND HUMID CLIMATE TEMPERATURE AND HUMIDITY The temperature and humidity varies little through out the year yet maintains high temperature and humidity levels.

Annual mean temperature 27.5°C. During the hotter months of April, May and June, the mean daytime temperature is 28.3°C and relative humidity is 82%; during the colder months of November, December and January, the mean daytime temperature is 26.6°C and relative humidity is 86%.

Temperature variation is relatively small from month to month. Meanwhile, the diurnal temperature different is no more than 10ºC. The daily temperature range has a minimum of 23-25ºC during the night, and maximum of 31-33ºC during the day. May and June have the highest average monthly temperature of 27.7ºC and 27.8ºC; December and January are the coolest monthly temperature of 26.0ºC (Fig.2.4 Hourly variation of temperature for each month).

Notice coastal climate also exist in an island as Singapore.

Studies show water has a larger heat capacity than the land surface, which means a greater amount of heat is required to increase the water temperatures. For example, during afternoons, conditions often relieved by sea breezes. The diurnal temperature variation is further discussed regarding its effect on the passive cooling strategies in the following theory chapter.

Humidity, on the other hand, has more remarkable diurnal variation more than 90% in the morning just before sunrise, and falling to around 60% in the mid-afternoon on days when there is no rain. The mean annual relative humidity is 84.0%. Relative humidity frequently reaches 100% during prolonged periods of rain (Fig.2.5 Hourly variation of relative humidity for each month.

A combined chart comparing monthly average minimum temperature, average maximum teperature, relative humidity during the am hours and relative humidity pm hours is shown as in Fig.2.x (Fig.2.6 Average minimum and maximum temperature, AM and PM relative humidity. )

Fig.2.4 Hourly variation of temperature for each month.

(Source: http://www.weather.gov.sg/.)

Fig.2.5 Hourly variation of relative humidity for each month.

(Source: http://www.weather.gov.sg/.)

The relationship of sensible air temperature of the environment, decided by Mean Radiant Temperature (MRT) and Dry Bulb Temperature(DBT), and humidity further effect the temperature sensed by human body. This thermal comfort is discussed in the following theory chapter.

Fig.2.6 Average minimum and maximum temperature, AM and PM relative humidity.

(Source: http://www.bbc.co.uk/weather/.)

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TROPICAL AND HUMID CLIMATE WIND Reflecting the dominance of the monsoon seasons in Singapore, the most prominent winds in Singapore are from the northeast and the south. Winds generally follow the prevailing monsoon flow, except for being modified by terrain or weather systems such as showers, thunderstorms, land or sea breezes.

During the Northeast Monsoon from December to March, wind directions are mainly from North to Northeast, among which January has higher wind velocity. At the same time, December and January have the highest average monthly temperature.

Fig.2.7 Wind rose in January.

(Source: https://www.windfinder.com/.)

During the Southwest Monsoon from June to September And from South to Southeast. Notice that the wind strength is greater during the Northeast Monsoon compared to Southwest Monsoon, as well as the inter-monsoon seasons.

The strongest winds occur during the Northeast Monsoon in January and February. However, the average wind speed difference is not as significant. The inter-monsoon seasons (April, May, October and November) are transition periods between the monsoons and show lighter and more variable winds (Table 2.2 Annual average wind and air Temperature.). And June is selected as one of the hottest months for the analytical work in the following chapter.

Diurnal variation is shown through out the year with lighter night-time winds and stronger daytime winds. Wind speed normally is less than 2.5 m/s except when during the Northeast Monsoon surge, where mean wind speed of 10m/s or more is observed. Strong wind also occurs in thunderstorms.

Surface wind gusts are produced from thunderstorm downdrafts and from the passage of Sumatra Squall Lines (SSL) resulting in gusty rain. SSL develop over night at Sumatra, usually between April and November, and then steered towards the west coast of Singapore by southwesterly winds, and arrives during the pre-dawn or early morning. The Monsoon window, discussed in the following theory chapter, is an endeavor responding to such gusty rain phenomenon.

Fig.2.8 Wind rose in May. (Source: https://www.windfinder.com/.)

As in Szokolaysâ&#x20AC;&#x2122;s Psychometric chart, the thermal comfort zone is to be extended with air movement effect Control potential zone (CPZ). Szokolayâ&#x20AC;&#x2122;s Psychometric chart and CPZ, thermal comfort zone extension, at different air velocity is to be further discussed in the following theory chapter.

Table 2.2 Annual average wind and air temperature. (Source: https://www.windfinder.com/.)

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TROPICAL AND HUMID CLIMATE PRECIPITATION There is no distinct wet or dry season in Singapore, monthly variations in rainfall do exists. Higher rainfall occurs from November to January during the wet phase of Northeast Monsoon season (Fig.2.9 Monthly rainfall for Singapore).

The driest month is February which is during the dry phase of the Northeast Monsoon.

Rainfall in Singapore shows a remarkable diurnal variation.

Daytime rain occur more often, particularly in the afternoons when solar heating is strongest (Fig.2.10 Hourly variation of rainfall for each month.).

As mentioned above, thunderstorms is often accompanied by wind, usually between April and November from the passage of Sumatra Squall Lines (SSL). And the daytime rainfall together with higher wind speed result, as mentioned above, results in gusty rain. During such gusty wind, windows are usually shut to protect the rain from coming indoor. This presents a design challenge for natural ventilation to intake cooler outdoor air. The Monsoon window, ditscussed in the following theory chapter, is one of the design innovations where design decision is made based on climatic conditions and the adaptive thermal comfort of the local residents.

Fig.2.9 Monthly rainfall for Singapore.

(Source: http://www.weather.gov.sg/.)

CLOUD COVER Cumulus, stratocumulus and cumulonimbus clouds are the most common low cloud types in Singapore. On an average day, cumulus clouds start to develop in the mid-morning, increasing to about 3-4 oktas (one okta is one eighth of the sky) by midday with bases of around 0.6 km and tops from 2.5 to 3.5 km. During the afternoon and early evening, these cumulus clouds may develop into cumulonimbus clouds with tops reaching between 9 to 12 km. The clouds diminish and begin to flatten into stratiform layers by dusk and slowly disperse during the night. Nevertheless, weather systems act to intensify or reduce this diurnal cycle of cloud development.

34

Fig.2.10 Hourly variation of rainfall for each month.

(Source: http://www.weather.gov.sg/.)

35

3.0 THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA

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THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA ADAPTIVE COMFORT Studies suggest (Givoni 1994), especially in developing countries, people have the adapt ability and would accept higher sensational expectation for temperature and humidity. Research has acclimatize neutral temperature for residential building in developing countries (Humphreys, 1975). Adjusted model from the original Humphrey’s equation can be used to used to establish the neutrality temperatures. The range of monthly adaptive comfort band is applied as following formula (Szokolay, 2014): Tn =17.8 + 0.31To.av ; Where Tn is the neutrality temperature standing for the median of many people’s vote; To.av is the mean monthly temperature. Comfort band for 90% acceptability of people can be taken with from (Tn- 2.5)°C to (Tn +2.5)°C. (Szokolay, 2014) Notice, as well as mentioned by the formula above, comfort range of people is acclimatized in Singapore (Givoni, 1994).

According to Jitkhajornwanich (2006), in the contexts of contemporary architecture and vernacular environments, comfort band for warm and humid climate is shifted up from Humphreys comfort band by 2.55 degrees according to a fieldwork in occupants in residential building (Fig.3.1 Adaptive comfort band for warm and humid climate). The new proposal comfort zone is: the range of air temperatures were 25.6-31.5 °C and of relative humidity were 62.290.0%. This study shows that people with light clothes (0.1 - 0.5 Clo. value) response to hot and humid condition, and have adapt themselves by doing sedentary works, staying under shade and creating airflow at body level. And the neutral temperature sensations with comfort range for warm and humid climate indicates that a major part of the outdoor temperature is within comfort band (Tedkajo, 2012). Thus, during this part of the day, outdoor air as intake for natural ventilation is possible and desirable.

PSYCHOMETRIC CHART FOR SINGAPORE The model in the Psychrometric chart is the first step to study the climate context and climatic problems. With moisture content within 4 - 12 per g moisture to per kg dry air as recommended by Szokolay (2014) (Fig.3.2 Singapore psychometric chart.).

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Adaptive Comfort Band 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

300

250

200

150

100

50 2.6

2.8

2.1

1.5

1.6

1

2

3

4

5

2

2.3

2.4

7

8

2

1.5

1.4

2 0

6

9 °C)

°C)

°

10

11

12

°C)

°

Fig.3.1 Adaptive comfort band for warm and humid climate in Singapore.

(Source: after Tedkajo, 2012)

THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA ADAPTIVE COMFORT In order to apply psychometric chart for Singapore climate, the range of monthly adaptive comfort band is applied as following formula (Szokolay, 2014): Tn =17.8 + 0.31To.av ; Where Tn is the neutrality temperature standing for the median of many people’s vote; To.av is the mean monthly temperature. Comfort band for 90% acceptability of people can be taken with from (Tn- 2.5)°C to (Tn +2.5)°C. (Szokolay, 2014) Notice, as well as mentioned by the formular above, comfort range of people is acclimatized in Singapore (Givoni, 1994). Comfort zone is plotted on psychometric chart for Singapore climate (Fig. 3.2 Singapore psychometric chart).

Fig.3.2 Singapore psychometric chart.

(Source: after Szokolay, 2014)

In Singapore, comfort zone does not vary much in colder and warmer period. The dry bulb temperature and relative humidity of 12 months is marked for the climate. The distribution distance indicating the small diurnal variations less than 10°C; the lines above 12 g/kg indicating the humidity problem; and the lines to the right of the comfort zone indicating overheating. (Szokolay, 2014) Studies show that ventilation is applicable to regions and seasons when outdoor maximum air temperature does not exceed 28-32°C with diurnal temperature range less than 10°C. A physiological cooling effect can be achieved even when the humidity level and indoor air temperatures are high (Givoni, 1998). Natural ventilation is considered to reduce temperature perception according to the formula as following: dT = 6Ve – 1.6Ve 2

Fig.3.3 Singapore psychometric chart showing control potential zone (CPZ) with air movement effect. Solid line is when air movement at 1m/s; dashed line is when air movement is at 2m/s.

(Source: after Szokolay, 2014)

where dT is the temperature sensed by human body drop due to cooling effect of air movement, and Ve is effective air velocity at body surface (Ve=V-0.2, V (m/s) is air velocity). The expression is valid up to 2 m/s air velocity, of which dT is up to 5.6°C. (Szokolay, 2014) Thermal discomfort results from the combination of heat sensation and sensible perspiration hence the higher indoor air velocity would be an effective solution (Mohanty, Ford and Lau, 2013). Comfort zone can be extended by natural ventilation (Fig. 1.4 Singapore psychometric chart showing control potential zone (CPZ) with air movement effect), which is shown as the control potential zone (CPZ).

The solid line is when air movement at 1m/s; dashed line is when air movement at 2m/s.

For developing countries that considers the acclimatization resulting from living in naturally ventilated buildings, most of the warm and humid climate falls inside the control potential zone with air movement effect (Fig.3.3 Singapore psychometric chart showing control potential zone (CPZ) with air movement effect.). There are some proportion of rainy periods which fall outside comfort band because of humidity level. And overheating during the hottest hours of the day in outdoor environments is a challenging problem.

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THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA PASSIVE COOLING PRINCIPLES Solar orientation and shading In Singapore, the first step is to consider solar orientation as one of the most essential parameter. For example, creating desirable orientation and site planning so that the temperature in the microclimate and outdoor air is precooled as air intake into indoor environment. Nevertheless, optimized solar massing orientation and layout is to be considered both for indoor and outdoor environment (Case studies building planning massing Singapore Building Authority, 2010). East and West orientations, compared to North and South, receive the low-angle sun and most solar exposure (Fig.3.4 Singapore solar radiation on 4 orientations and diffuse radiation) and, therefore, consider minimizing the amount and size of opening. North and South are better orientation. Nevertheless, given the cloud cover in warm and humid climate, the amount of diffuse solar radiation is also notable.

Singapore Month Helios 450 400 350 300 250 200 150 100 50 0

Jan

Feb

Mar

G_Gh

Apr

G_GvE

May

Jun

G_GvS

Jul

G_GvW

Aug

G_GvN

Sep

Oct

Nov

Fig.3.4 Singapore solar radiation on 4 orientations and diffuse radiation.

(Source: after meteonorm)

In climate with light clothing, according to the formula below, mean radiant temperature is about twice as significant as dry bulb temperature.

EnvT= 2/3MRT + 1/3DBT Where EnvT is the environmental temperature; MRT is mean radiant temperature, which is the temperature of the surrounding surface elements; DBT is dry bulb temperature. However, the difference between MRT and DBT is not to be greater than around 3K (Szokolay, 2014) MRT response to radiant besides air temperature. Radiant input should be reduced, for example, by efficient shading device without impeding air movement. At the same time, in high-rise residential building, the solar gain almost all come from facade, while the roof effects the upper apartments. Singapore is located only 1°22â&#x20AC;&#x2122; N of the equator, the position of the sun is almost directly overhead throughout the year (Fig.2.x Sun path diagram for Singapore.).

Also, details are suggested by studies (Holger Koch-Nielsen, 2002) that external solar control system is to be detached from the building structure, including assemblies such as louvers, in order to dissipate the hot air caught by the shading device (Fig.3.5 Attached vs detached external solar shading strategy)

40

Dec

G_Lin

Fig.3.5 Attached vs detached external solar shading strategy.

(Source: Holger Koch-Nielson, 2002)

THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA PASSIVE COOLING PRINCIPLES 5 principles of passive cooling Only after optimize solar orientation, then passive cooling is to be considered to remove heat. In principle, there are 5 types of passive cooling including stack ventilation, evaporative cooling, radiative cooling, night flushing, and air movement (Givoni,1994). Meanwhile, new technology such as phase-change material (PCM) and earth cooling system is also being explored. For example, earth cooling system, using the moderate and consistent temperature of the soil to act as a heat sink and provide cooler air, is being more and more widely used in warm climates. The humidity from intake air should be removed so as to avoid condensation in the pipes.

Stack effect is not reliable in warm and humid climate. In order for warm air to rise and stack effect to work, indoor temperature need to be higher than outdoor temperature, which would be too high; downdraft is formed when the indoor temperature is lower than outdoor temperature.

However, there is the possibilily to apply solar chimney.

Controllable air inlet should be designed so as to eliminate undesirable hot air from indoor environment.

High humidity in Singapore climate suggests that evaporative cooling is neither effective nor comfortable. However, only by increasing considerably amount of air movement, evaporative cooling could be an applicable strategy in warm and humid climate. Nevertheless, indirect evaporative may achieve certain sensible cooling without adding humidity to the supply air.

Radiant cooling, for example, can be applied to roof with thermal mass. However, given the small diurnal temperature difference and high cloud cover level in Singapore, such practice it is not favored to dissipate heat through radiant cooling at night. Another example is to run cold water pipe through surfaces such as ceiling, wall and floor, yet the surface temperature should be carefully controlled against condensation. (Koch-Nielsen, 2007) Night flushing with massing can not be relied on given the comparatively small duirnal temperature difference. However, a hybrid design of massing and lightweight construction may provide heat sink and ensure indoor temperature close to the dayâ&#x20AC;&#x2122;s minimum for daytime rooms such as kitchen. Yet sufficient ventilation should be provided to dissipate the heat stored from massing at night time. While cool bedroom is desired at night time where lightweight construction and cross ventilation is applied to achieve a quick response.

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THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA CROSS VENTILATION AS EFFECTIVE PASSIVE COOLING Ventilation is used for 3 different processes with different purposes: to supply of fresh air; to remove internal heat when To < Ti; to promote heat dissipation from the sky, such as physiological cooling. Among the above, air velocity is the mostly critically required at body surface in order to achieve the last one.

The best way to remove internal heat, as indicated by Singapore psychometric chart (Fig.3.6 Singapore psychometric chart showing control potential zone (CPZ) with air movement effect.), is to ensure adequate air movement with natural ventilation, where the air velocity is measured at the body surface and the cooling effect is valid up to the air velocity of 2m/s with cross ventilation. In a typical residential space the floor to ceiling height is 3m, and thus the depth of space is strongly recommended to be designed within 15m. Note, as for daylighting, which is a primary concern rather for office buildings, the deeper the floor plate, the harder it is to bring natural daylight into spaces therefore increasing the dependence on artificial lighting. Floor plates in excess of 27.5 m will have difficulty achieving effective daylighting to spaces (Case studies building planning massing Singapore Building Authority, 2010). This does not interfere with the ventilation requirement.

The effectiveness of cross ventilation depends on several factors. First, it depends the flow of air between the two sides of building envelope. Shape and geometry of the building and room should encourage wind to pass through.

Compactness should be avoided. The pressure differences drive air into the buildingâ&#x20AC;&#x2122;s envelope on the windward side where is the positive pressure zone, and out of the building through the openings on the leeward side where is the negative pressure zone (Fig.3.x Pressure distribution). Meanwhile the wind-induced airflow rate indoor is proportional depends on the outdoor wind speed in front of the inlet window, as well as effective opening area and interior permeability as shown by wind-induced airflow rate formula below. Orienting the building to prevailing wind direction up to about 60 degrees from the perpendicular to make the pressure possible and use windows as inlet on the facade.

Q = K * Aeff * V Where Q is the wind-induced flow rate; K is the permeability factor, which is about 0.7 for a space with direct cross-ventilation without internal obstructions; Aeff is the value of the effective area, where smaller value is taken into account when inlets and outlets are not of the area; V is the perpendicular wind.

Second, room layout and internal partitions should not be designed to impede air movement (Fig. 3.x Natural ventilation in room layout shown in plan).

Openings should be large and well distributed through out the room layout. For example, rooms arranged in a row allowing big inlet and outlet openings for cross-ventilation.

Roof should also be ventilated where itâ&#x20AC;&#x2122;s applicable. The solar radiation received by roof could increase MRT, especially in the top apartments. As discussed, since MRT has twice the effect of DBT, air movement through roof removes solar heat gain from the outer layer of the roof and help to provide indoor comfort for top apartments. (Szokolay, 2014) The case studies in the following chapter focus on the principles applied in practice. Examples including high-rise residential buildings, as well as vernacular architecture.

42

Fig.3.6 Natural ventilation in room layout shown in plan.

(Source: Wong, 2000)

THERMAL COMFORT THEORY AND PASSIVE COOLING DILEMMA THE DEBATE OF HIGH-RISE STRUCTURAL CONSTRUCTION Research and debates have been currently going on about the heavy weight construction which found itself contradictory of lightweight construction system found in traditional vernacular architecture. The lightweight construction, however, prerequisite both adequate shading and porous facade allowing maximum airflow. This presents a challenge against the structural intuition of contemporary high-rise construction, one example is the fast speed precast reinforce concrete construction. Meanwhile, the noise level and air pollution, especially at lower level in high-rise residential, made airflow a challenging topic to address. (McKee, 2015)

Fig.3.7 Operation of a heavyweight construction with outside insulation.

(Source: Szokolay, 2000)

Fig.3.8 Airflow turbulence in vertical micro-climate.

(Source: T.R. Oke, 1978)

Re-entrant air space

Fig.3.9 Re-entrant air space in 5 Parc Emily floor plan, Singapore.

(Source: AutoCad)

Studies done by Szokolay suggest that heavyweight construction system is arguably applicable. For example, as mentioned in the hybrid design above, only when adequate shading and massing is insulated outside from solar gain can such construction system be appropriate. The outside insulation protect the massing from solar gain. Together with sufficient shading, the massing remains relatively cooler during the day compared to the rest of the structure. Nevertheless, massing is to be considered with room zoning depending on the time schedule and internal gain (Fig 3.7 Operation of a heavyweight construction with outside insulation). Thus the massing act as heat sink during the daytime; at night-time, sufficient ventilation is to penetrate so as to remove stored heat. Together with sufficient shading, 50mm of resistive insulation on the outside of heavyweight concrete construction, which is the thermal mass, achieves slightly lower the indoor temperature than lightweight construction, which is an option taken after the vernacular architecture. Second, this strategy requires the decoupling of the interior during the hottest time of the day, which, fortunately, is when the most pollution and noise is at the highest (Mckee, 2015). The shaded and relatively cooler thermal mass, which is the result from the night before and early morning, functions as thermal modifier and store internal heat gain during this time when interior is sealed. Finally, in the night-time, when outdoor pollution and noise level is decreased (Mckee, 2015), controlled night flushing should be directed in order to dissipate the heat stored during the daytime.

(Szokolay, 2000) Besides, research suggests that it is possible, if appropriately applied, that the hybrid design in heavyweight construction is more efficient for mixedmode design where mechanical conditioning is required during certain periods of the day or season.

However, the reality presents the dilemma as always. For example, in a dense urban context, the vertical micro-climates might not always be reliable for natural ventilation because of airflow turbulence (Fig.3.8 Airflow turbulence in vertical micro-climate). And variations need to be adjusted dynamically according to the difference in vertical micro-climate (McKee, 2015). Another example is the rooms closer to the core suffer from poor ventilation and daylight and the re-entrant air shafts (Fig. 3.9 Re-entrant air space in 5 Parc Emily floor plan, Singapore.) are introduced. Unfortunately, these area are also mounted with air-conditioning condenser units, and therefore flooded with heated exhausts which eliminate the likelihood for window opening. Data (Bruelisauser et al., 2014) indicates that the temperatures in side these space can climb by over 20°C when the air conditioning is on. And the exhaust air rises up to the upper floors. Therefore, the mixed-mode systems is to be adopted where condenser units should be placed where adequate exhaust diffusion is allowed without compromising the air quality at upper levels.

Last yet not least, in order for the design to work according to occupancy pattern. The devices designed for opening should be easy to use and controllable for the users. Also consider that the opening only benefits indoor air movement if it protects privacy, as well as from rain and burglary. The analytical work in the following chapter tests the theoretical possibility of the mysterious climate.

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4.0 VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY

44

45

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY VERNACULAR ARCHITECTURE Maylay “kampong” house, Malaysia 100 years ago, all the buildings were naturally ventilated.

Tradition and culture gives us disciplines about the relationship of building performance and climatic conditions. The site is well vegetated and therefore shaded. The shape of roof shades the indoor space from solar radiation. Building form accelerates air into the building interior space which are open for proper ventilation. The full length full operable window opennings are strategically positioned at body level to promote air movement in order to remove heat from body through perspiration. The earth is used as heat sink, with floor elevated to catch higher wind velocity below it. The whole house is lightweight construction raised on stilts, with natural resourced material such as timber and bamboo used and, therefore, low thermal mass.

Malaysia is located in the Southeast of Asian with hot and humid climate. The temperature is between 21 - 33°C throughout the year. Average rainfall is between 250 to 300cm. (Yuan, 2001) The “kampong”, one example of the different types of Malay houses, refers to Malay vernacualr houses that locates in all the rural villages. The second meaning of “kampong” indicates the connection between the local residents and their mosque in the Islamic culture. The particular type of Malay house have different roof shapes, yet are similar in essence of social value and design.

Site of the “kampong” settlement is arranged with careful planting. The kampong houses are laid out to ensure that wind is not blocked for the indoor space, as well as for the houses in the latter path of the wind. Traditionally, many Malay houses are oriented to face Mecca for religious purpose. This West-East orientation protect the house from the exposure to direct solar radiation and the housing complex is also well shaded with vegetation (Fig.4.1 Site layout of the “kampong” settlement.). (Ahmad, et al., 2007) The zoning of the spaced are distinguished by the level of privacy required. As the Malay house is built on stilts, the main entrance of the house is reachable through stairs leading to “anjung”, which is an open space where unfamiliar guests are entertained. The first functional space of the house entering from the porch is “serambi gantung”, which is an extended linear space cross ventilated with low window openings, where the guests are to be entertained. The “serambi samanaik” and “serambi gantung” are circulation spaces leading to “selang”, meanwhile enhanceing the cross ventilation. “Selang” is a walkway connected to the back of the house which is the kitchen area. Females use this space to socialize and entertain with other females. moreover, the passageway highly influence the thermal comfort, while reinforcing the daylighting. “Rumah Dapur” is the kitchen area. The females are much more confined in the back of the house preparing food and washing. This is on the lowest floor level. Some of the modern kitchens in new Malay houses are dropped to the ground level and the floor is cemented (Fig.4.2 The indoor space zoning of the “kampong”.). (Abidin, 1981) 46

Fig.4.1 Site layout of the “kampong” settlement.

(Source: Yuan, 1991)

Fig.4.2 The indoor space zoning of the “kampong”.

(Source: Abidin, 1981)

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY VERNACULAR ARCHITECTURE Maylay “kampong” house, Malaysia Facade is embellished with geometrical Islamic carving patterns. And air vents are openings at the top of the walls.

Meanwhile the facade reduces the glare. The open sky and bright areas is excluded from the visual field. Windows are kept low and shaded by large roof overhangs. Meanwhile, large area of glare is broken up into tiny ones by the embellishment, yet allow the indoor space to be well lighted (Fig.4.3 Wood carved facade in the “kampong”.).

(Ismail, 2005) Roof is simply funnel shaped. Besides providing shading for indoor spaces, the roof ventilation is achieved by using ventilation grilles at the gable ends (“tebar layar”) and ventilation joints (“patah”). The sail-like gable end of the roof is used to trap and direct air to ventilate the roof space.

This cools the house effectively (Fig. 4.4 Ventilation of the “kampong” in section) . (Yuan, 1991) The “kampong” is a timber house is constructed on stilts.

It is a post and lintel construction with wooden or bamboo walls and a attap thatched roof. All materials are low thermal mass.

Fig.4.3 Wood carved facade in the “kampong”.

(Source: Ismail, 2005)

Fig.4.4 Ventilation of the “kampong” in section.

(Source: Yuan, 1991) 47

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY VERNACULAR ARCHITECTURE Shophouse and terrace house The shophouse is a building in which commercial activities take place on the ground floor and private accommodations are located on the upper floor. This building typology was brought by migrant Chinese workers from southern provinces of China to Malaysia in the 1800’s. And changes were made to the original building typoloty in order to provide thermal comfort for the local hot and humid climate (Fig.4.6 Example of mixture of styles of shophouse and terrace house in Singapore.) (Hashim and Ghafar, 2005) A typical traditional terrace house has 1 storey with a street level porch in the front. As in Malay “kampong” house, natural ventilation and shading is also emphasized in shophouse and terrace house.

Facade fenestrations are operable, for example, to allow airflow while blocking solar radiation. And permanent openings located above windows at higher level to allow air flow at all times (Fig.4.5 Operable louvered shutters with permanent openings located above windows.).

Fig.4.5 Operable louvered shutters with permanent openings located above windows.

(Source: http://smalltalesofsg.wordpress.com)

The pitched roof has pitched roofs with deep overhangs to provide shade to the indoor space. The courtyard and airwell breaks up the deep and narrow space by promoting ventilation, as well as daylight. (Fig.4.7 Courtyard and airwell promoting ventilation.). “Five footway”, which is a continuous covered pedestrian walkway” linking the front of the shophouses, is required by the colonial British rulers in the late 1800s. The depth of this covered walkway is usually 1.5 - 3.0m deep. Similar to “anjung” in “kampong” house, the overhang leading to the entrance provide space for socializing (Fig.4.8 Key elements in a typical shophouse.).

Fig.4.6 Example of mixture of styles of shophouse and terrace house in Singapore.

(Source: http://smalltalesofsg.wordpress.com) 48

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY VERNACULAR ARCHITECTURE Shophouse and terrace house VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY

The major construction materials for the shophouse and terrace house are brick, plaster, concrete and timber. This is different compared to “kampong” house. These are local material with easy availability. Brick are used as load bearing walls, the thickness and the nature of the material of which provides thermal mass delaying radiant heat transfer into the indoor space. Clay tiles is used on roof for its poor heat conductivity. On the other hand, timber boards is used for floor with gaps in between enabling the air flow.

These shophouse and traditional terrace house are built in continuous repetitive units forming a block with long narrow lots. The sizes of the lots are from 6.6m and 7.2m in width, and 21m and 30m in length.

The shop house and traditional vernacular terrace house are designed more than 100 years ago, creating thermal comfort for its occupants without mechanical assistant.

Many are still being used in their original state, where no mechanical means were added expect for a ceiling fan.

Fig.4.7 Courtyard and airwell promoting ventilation.

(Source: Hashim and Ghafar, 2005)

Pitched rood with clay tiles Main building

Fire wall/

Rear court Rear boundary wall Airwell Timber floor board Timber staircase “Five footway”

Fig.4.8 Key elements in a typical shophouse.

(Source: After Urban Redevelopment Authority) 49

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY PRECEDENT CASE STUDY Moulmein rise, 2003, Singapore, Architect: WOHA 1 Moulmein rise is a 28 story residential tower, including 50 units with 48 apartments and 2 penthouses, in a neighborhood 10 minutes walk from the CBD of Singapore. The form is a slander rectangle with north-south orientation (Fig.4.9 Typical floor plan with 2 apartments.). It has a footprint of 230m2, and height of 102m.

Ground floor is elevated to allow the continuity of air flow. On the ground floor level swimming pool over three tiers and other water features are designed to promote evaporative cooling. Vegetation are also designed to provide outdoor comfort.

And all of its facades are designed to allow air to penetrate and cross ventilation for the units, while the south specifically open up to the desirable view. The façade elements of the tower being the perforated curtain wall with diverse detail such as planters, bay and casement windows, screens and sliding doors (Fig.4.13 Variation of window protected from rain.), allowing indoor airflow for 24 hours natural ventilation, especially during the rainy days when the outdoor air intake is of much lower temperature. (Mohanty, et al., 2013).

Fig.4.9 Left: north façade with shading devices.

Right: south facade with Bay windows, monsoon windows, platers and sunshades. (Source: WOHA architects)

The main feature to acheive 24 hours natural ventilation is the monsoon window. When it rains in Singapore, the temperature drops to 24 - 27°C. However, rain is often accompanied by gusty winds. The monsoon window attached to the bay window is a traditional feature of Malay, Vietnamese and Indonesian vernacular architecture. The contemporary version allows cool air intake and air flow, as well as adding about 10 percent to the size of the apartment (Fig.4.12 Architect’s sketch of monsoon window.).

At the same time, variable openings in the façade help the occupants to control their indoor environment as for their comfort requirement.

Metal Roof is separated from the residential units while the top penthouses are double height, therefore, eliminating radiant heat gain from the top of the building.

50

Fig.4.10 Transverse section.

(Source: after WOHA architects)

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY PRECEDENT CASE STUDY Moulmein rise, 2003, Singapore, Architect: WOHA The choice of construction is lightweight construction determined by issues of economy, durability and availability, while avoiding storage of heat by the structure. Aluminum and wood, are used for windows. However, given the nature of high-rise construction, massing is used for the core structure, where daytime rooms such as kitchen are arranged together with circulation. While lightweight construction for rooms like bedroom where quick cooling response is desired at night time (Fig.4.11 Typical floor plan with 2 apartments.).

N

Fig.4.11 Typical floor plan with 2 apartments.

(Source: after WOHA architects)

Steel mullion Fixed tempered Perforated aluminium fixed to hinged frame with insect screen Slidable MDF Board Handle winder Fixed tempered glass Parquetry flooring with marine ply underlay Outside

Post occupancy survey were taken among the apartment owners who are urban professionals. The result of satisfaction level in living room showed that 80% of the of the the occupants are comfortable (Mohanty, et al., 2013). Free-running is achieved in a 3 occupant apartment 19th floor by keeping the monsoon windows “always open”. Energy saving is witnessed by a 1 occupant apartment on 24th floor who kept the monsoon windows “open all the time”. However, the occupant did find the manual operable mechanism of the monsoon window “could have been more efficient”. (Ali, 2007).

Inside

Fig.4.12 Architect’s sketch of monsoon window.

(Source: after WOHA architects)

Fig.4.13 Variation of window protected from rain.

(Source: WOHA architects) 51

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY PRECEDENT CASE STUDY Skyville @ Dawson, 2015, Singapore Architect: WOHA As the winner for Green Mark for Buildings Awards and Platinum category at Building Construction Authority awards 2010, Skyville @ Dawson saves 322,552 kWh/yr. The building is located within landscaped master plan to fulfil the vision of housing in a park, providing 960 residential units.

The slander blocks of the building are oriented towards the prevailing wind and are free of obstruction from the context (Fig.4.16 Wind simulation of the building within the context). The building is vertically divided every 9 floors into villages. Suction effect creates negative pressure zone behind and on the top the village (Fig. 4.17 Diagram of airflow in between villages). Meanwhile, shape of overall plan (Fig.4.14 Skyville @ Dawson overall plan) encourages airflow to speed up to 2.5m/s in front of the the second row of the building. (Fig.4.15 Wind simulation showing air movement speed increase, through enclosed courtyard, in front of the second row of the building).

The structure allows bean-free ceiling with the core located in the middle of every unit (Fig.4.18 Skyville @ Dawson typical floor plan). The open plan allows flexible interior openings and therefore air movement accrodss the unit. While the projection, where service yard is located next to kitchen and bathroom, assist airflow into these space for ventilation.

N

Fig. 4.14 Skyville @ Dawson overall plan.

(Source: WOHA architects)

m/s 2.7 2.5 2.1 1.7 1.3 0.9 0.5 0

Fig.4.15 Wind simulation showing air movement speed increase, through enclosed courtyard, in front of the second row of the building.

(Source: after The Singapore Engineer, 2010)

Fig.4.16 Wind simulation of the building within the context.

(Source: The Singapore Engineer, 2010) 52

VERNACULAR ARCHITECTURE AND PRECEDENT CASE STUDY PRECEDENT CASE STUDY Skyville @ Dawson, 2015, Singapore Architect: WOHA Similar construction approach is used to avoid massing in apartment units in SkyTerrace @ Dawson in Singapore, where form is taken of open plan arranged around the core structure, maximizing cross ventilation in apartment units by prevailing wind (Fig.4.19 SkyTerrace @ Dawson overall plan.).

Fig.4.17 Diagram airflow in between villages.

(Source: The Singapore Engineer, 2010)

N

Fig.4.18 Skyville @ Dawson typical floor plan.

(Source: The Singapore Engineer, 2010)

Fig.4.19 SkyTerrace @ Dawson overall plan.

(Source: after SCDA architects) 53

5.0 FIELD WORK

54

55

FIELD WORK SITE 5 Parc Emily is a private condominium located on the gentle slop of a hill on Mount Emily Road near MacKenzie Road and Selegie Road. Towards the west of the development is Mount Emily Park. While located nearby the historical zone of Bugis, the condominum is surrounded by low-rise shop houses and sets back from the street towards the east (Fig.5.1 5 Parc Emily site map.). The site is less dense with fewer high-rise compared to city center.

The whole development is 11,977 m 2, consisting of 5 blocks of 8 story apartment block, providing 295 housing units in total. The top floor are 2 story pent house. The units types including studio, 2 bedroom, 3 bedroom, 4 bedroom and duplex units.

Fig.5.1 5 Parc Emily site map.

(Source: Google map)

56

FIELD WORK STRUCTURAL AND BUILDING SYSTEM As commonly used for residential towers for buildable and fast construction in, 5 Parc Emily, built in the year of 2005, adopted the precast flat plate structural heavyweight system. Shear wall, for example, are all precasted to ensure the speed of the construction. Internal wall partitions is made of lightweight drywall system so as to eliminate wet work on site. Other feature including the PBU (prefabricated bathroom units) are done off-site to insure the quality. (Sustainable architecture, A BCA-SIA Publication 2008, Issue No.1)

Fig.5.2 Precast flat plate structural system.

(Source: A BCA-SIA Publication 2008)

Fig.5.3 Internal wall drywall system.

(Source: A BCA-SIA Publication 2008)

57

FIELD WORK DATA LOGGER t

Fig.5.4 Fieldwork apartment block location.

(Source: Rhino)

58

FIELD WORK DATA LOGGER 2 data loggers are used to record a typical summer week 2-6 May 2016. 1 data logger is put inside the living room sits behind the sofa to record indoor air temperature and relative humidity (Fig.5.5 Location of data logger in the living room.). 1 data logger is put outside on the balcony sitting in the shadow of one the metal fins on the West wall (Fig.5.6 Location of data logger inside metal fin on the balcony.). Air conditioner was set on cooling mode at 23oC (Fig.5.7 AC unit in the living room.). The occupants switch on the air conditioner when they are in the space without adjusting the temperature setting on the remote.

Results from data logger are shown in the following figures. 4 May 2016 Wednesday is selected for calibration as a typical summer day. The windows are shut with internal blinds up all the day. Occupant scheduel is as a typical work day.

Datalogger results: - external temperature and relative humidity.

- Internal temperature and relative humidity.

Fig.5.5 Location of data logger in the living room.

Fig.5.7 AC unit in the living room.

Fig.5.6 Location of data logger insdie metal fin on the balcony.

59

FIELD WORK CALIBRATION - Floor area 57 m2.

- Total volume 170 m3.

- Occupancy 2pp.

Construction u-value: - Wall 4.1 W/m2K - Floor/Ceiling 2.6 W/m2K - Window 4.2 W/m2K Internal conditions: - Infiltration

3.0 ach.

- Ventilation

0.1 ach.

- Lighting gain 0.79 W/m2.

- Occ. sensible gain 2.82 W/m2.

- Occ latent gain 0.71 W/m2.

- Eqmt. sensible gain 5.80 W/m2.

Fig.5.8 Fieldwork apartment plan.

(Source: AutoCAD)

60

FIELD WORK CALIBRATION The data logger results are decoupled from out door temperature indicating massing in the construction. For indoor temperature, the data logger is placed underneath the sofa. For outdoor temperature, the data logger is placed outside on the balcony in the shadow of one of the metal fins, which was likely hit by the morning sun and temperature raised earlier and higher compared to weather station data. The weather station data for outdoor temperature for 4 May 2016, which is a typical summer day, is 26-32oC. A computer model was constructed in OpenStudio software to corroborate the results from datalogger. Occupancy schedule is applied as a work day. AC is turned off in the model.

Paint 10mm

Hollow concrete block 300mm partially granited Single glazing 5mm Marble flooring 20mm

Fair-face concrete 250mm Paint 10mm

Fig.5.9 Calibration construction details.

Section through wall-floor junction and window.

(Source: AutoCAD)

61

FIELD WORK CALIBRATION

May 4 Calibration 80.00

35.00 34.00 33.00

70.00

32.00 31.00

60.00

30.00 29.00 28.00

50.00

27.00 26.00

40.00

25.00 24.00

30.00

23.00 22.00 21.00

20.00

20.00 19.00

10.00

18.00 17.00 16.00

1:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

10:00

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15:00

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17:00

18:00

19:00

20:00

21:00

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23:00

0:00

0.00

5/4/2016 Data Logger Outdoor Temp (°C)

Data Logger Indoor Temp (°C)

Data Logger Outdoor Humidity (%)

Data Logger Indoor Humidity (hr)

Fig.5.10 Air temperature and relative humidity data logger results from 4 May 2016.

(Source: Testo 174H data loggers and Excel)

May 4 Calibration 35.00

80.00

34.00 33.00

70.00

32.00 31.00

60.00

30.00 29.00 28.00

50.00

27.00 26.00

40.00

25.00 24.00

30.00

23.00 22.00 21.00

20.00

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1:00

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16:00

17:00

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5/4/2016 Data Logger Outdoor Temp (°C)

Data Logger Indoor Temp (°C)

Infil3.0_300mmConcreteTemp (°C)

Data Logger Outdoor Humidity (%)

Data Logger Indoor Humidity (hr)

Infil3.0_300mmConcrete Humidity (%)

Fig.5.11 Calibration results, OpenStudio and data logger results from 4 May 2016.

(Source: Testo 174H data loggers and Excel)

62

21:00

22:00

23:00

0:00

0.00

FIELD WORK SPOT MEASUREMENTS Spot measurements are taken at 03:20, 10:30 and 13:00 using 1m grid.

4 May 2016 (clear sky - partially couldy) Time: 3:20.

Air temperature: 30oC. Relative humidity: 76%.

Wind Speed: 0.6m/s.

73.1% 0.6m/s 30.7oC

73.3% 0.1m/s 31.0oC

72.5% 0.1m/s 31.1oC

79.8% 0.6m/s 29.1 oC

72.9% 0.1 m/s 30.7 oC

74.6% 0.4m/s 30.6oC

80.4% 0.6m/s 29.0oC

73.2% 0.4m/s 30.7oC

73.6% 0.9m/s 30.5oC

79.6% 0.6m/s 29.4oC

75.0% 0.2m/s 30.8 oC

74.0% 1.1m/s 30.4oC

77.2% 0.5m/s 29.8oC

73.3% 0.4m/s 30.9oC

74.0% 1.0m/s 30.5oC

76.6% 0.4m/s 30.0oC

73.9% 0.1m/s 33.3 oC

73.1% 0.1m/s 30.9oC

73.7% 0.8m/s 30.6oC

76.0% 0.4m/s 30.2oC

73.5% 0.4m/s 31.0 oC

72.6% 0.1m/s 31.2oC

74.0% 0.7m/s 30.7oC

76.5% 0.1m/s 30.3oC

72.7% 0.1m/s 31.1oC

71.5% 0.1m/s 31.1oC

73.9% 0.4m/s 30.6 oC

74.3% 0.1m/s 30.4oC

72.2% 0.7m/s 31.1oC

74.2% 0.4m/s 30.6oC

76.3% 0.4m/s 30.5oC

N

Fig.5.12 Air temperature, relative humidity and air velocity spot measurement results from 03:20 4 May 2016.

(Source: spot measurement)

63

FIELD WORK SPOT MEASUREMENTS 4 May 2016 (clear sky - partially couldy) Time: 10:30.

Air temperature: 32 oC. Relative humidity: 60%.

Wind Speed (m/s): 0.9m/s.

58.5% 0.9m/s 32.9oC

58.8% 0.1m/s 33.0oC

59.1% 0.6m/s 33.0oC

58.9% 0.8m/s 32.2 oC

60.4% 0.7m/s 32.2oC

60.6% 1.2m/s 32.4oC

59.3% 0.4m/s 32.6oC

61.5% 0.6m/s 32.8oC

58.1% 0.4m/s 32.7oC

61.0% 1.1m/s 32.6oC

57.5% 0.7m/s 32.8oC

59.0% 0.5m/s 32.8oC

58.1% 0.5m/s 32.9oC

57.5% 0.6m/s 32.9oC

63.0% 0.7m/s 32.9oC

64.6% 0.8m/s 32.9oC

60.5% 0.5m/s 33.0oC

63.0% 1.3m/s 32.9oC

58.3% 1.0m/s 33.0oC

58.5% 1.1m/s 33.0oC

61.5% 0.6m/s 32.9oC

56.9% 0.4m/s 32.9oC

58.7% 0.5m/s 32.9oC

62.5% 0.9m/s 32.9oC

59.6% 0.9m/s 33.0oC

57.8% 0.5m/s 33.0oC

61.7% 0.7m/s 33.0oC

60.5% 0.6m/s 33.0oC

58.0% 1.2m/s 33.0oC

59.5% 0.5m/s 33.0oC

58.5% 0.7m/s 33.0oC

N

Fig.5.13 Air temperature, relative humidity and air velocity spot measurement results from 10:30 4 May 2016.

(Source: spot measurement)

64

FIELD WORK SPOT MEASUREMENTS 4 May 2016 (clear sky - partially couldy) Time: 13:00 Air temperature: 33 oC Relative humidity: 59% Wind Speed (m/s): 1.2m/s

51.0% 1.0m/s 33.8oC

52.5% 0.5m/s 33.2oC

52.5% 0.5m/s 33.3oC

65.3% 1.2m/s 29.5oC

53.8% 0.8m/s 33.4 oC

50.3% 0.4m/s 33.9oC

62.9% 1.0m/s 30.3oC

54.5% 0.5m/s 33.4oC

53.0% 0.7m/s 33.8oC

60.1% 0.8m/s 30.9oC

55.3% 0.5m/s 33.2oC

49.9% 0.6m/s 33.8oC

57.6% 1.1m/s 31.4oC

55.2% 0.7m/s 33.1oC

50.0% 0.4m/s 33.7oC

56.9% 0.7m/s 31.6oC

51.9% 0.7m/s 33.3oC

53.0% 1.0m/s 32.9oC

50.2% 0.6m/s 33.7oC

53.2% 0.7m/s 32.0oC

51.5% 1.7m/s 33.3oC

52.8% 1.0m/s 32.8oC

52.1% 0.6 m/s 33.6oC

53.7% 0.9m/s 32.2oC

51.3% 0.9m/s 33.5oC

52.6% 0.5m/s 32.7oC

53.1% 0.6m/s 32.6oC

52.1% 0.5m/s 32.4oC

55.7% 0.4 m/s 32.0 oC

57.9% 0.4 m/s 31.7 oC

58.3% 0.5 m/s 31.0 oC

N

Fig.5.14 Air temperature, relative humidity and air velocity spot measurement results from 13:00 4 May 2016.

(Source: spot measurement)

65

FIELD WORK SURFACE TEMPERATURE MEASUREMENTS Surface temperature measurements are taken at 03:20, 10:30 and 13:00 using 1m grid.

4 May 2016 (clear sky - partially couldy) Time: 03:20.

Air temperature: 30oC. Relative humidity: 76%.

Wind Speed: 0.6m/s.

Wind Speed (m/s)

29.8oC 29.5oC 29.7oC

30.3oC 30.7oC 30.5oC

29.1oC 29.0oC 29.4oC

31.5oC 31.1oC 32.0oC

30.1oC 29.3oC 29.6oC

30.3oC 30.2oC 29.9oC

30.0oC 29.7oC 29.3oC

30.1oC 29.7oC 29.6oC

30.4oC -30.3oC

29.5oC 29.2oC 29.4oC

Fig.5.15 Surface temperature measurement results from 03:20 4 May 2016.

(Source: spot measurement)

66

N

FIELD WORK SURFACE TEMPERATURE MEASUREMENTS 4 May 2016 (clear sky - partially couldy) Time: 10:30.

Air temperature: 32 oC. Relative humidity: 60%.

Wind Speed (m/s): 0.9m/s.

31.3oC 31.0oC 30.8oC

34.7oC 38.9oC 52.8oC

30.0oC 32.7oC 35.1oC

33.5 oC 34.3 oC 36.0 oC

32.5oC 33.1oC 32.2oC

32.0oC 31.9oC 31.8oC

32.0oC 32.7oC 31.6oC

31.6oC 31.6oC 31.2oC

32.2oC -31.6oC

31.6oC 30.7oC 32.1oC

N

Fig.5.16 Surface temperature measurement results from 10:30 4 May 2016.

(Source: spot measurement)

67

FIELD WORK SURFACE TEMPERATURE MEASUREMENTS 4 May 2016 (clear sky - partially couldy) Time: 13:00 Air temperature: 33 oC Relative humidity: 59% Wind Speed (m/s): 1.2m/s

30.9oC 30.3oC 30.2oC

36.3oC 38.2oC 50.5oC

34.2oC 34.1oC 40.7oC

33.1oC 33.2oC 35.1oC

32.3oC 32.8oC 32.2oC

33.3oC 33.2oC 33.0oC

33.6oC 33.8oC 32.6oC

30.4oC 29.9oC 30.0oC

33.2oC -32.6oC

30.6oC 30.2oC 29.6oC

Fig.5.17 Surface temperature measurement results from 13:00 4 May 2016.

(Source: spot measurement)

68

N

FIELD WORK OCCUPANT INTERVIEW The occupant get interviewed is the male host of the apartment, who is around 35 years old american.

Q: How long have you been living in the current apartment?

A: 1 year.

Q: Do you find it comfortable?

A: From time to time, but not (uncomfortable) with the heat.

Q: You mind elaborating the uncomfortable part?

A: Well I don't like the humidity. Need to turn in (on) AC or open windows.

Q: When do you usually choose to open the windows instead of turning on AC? A: Open windows at night, or minimal clothing.

Q: Do you use (mechanical) fan in the apartment?

A: No, (we) don't have one.

69

6.0 ANALYTICAL WORK AND CONCLUSION

21 Dec 9:00

21 Dec 12:00

21 Dec 15:00

21 Mar 9:00

21 Mar 12:00

21 Mar 15:00

21 Jun 9:00

21 Jun 12:00

21 Jun 15:00

Fig.6.1 Sunpath and shadow diagram aerial view.

(Source: Rhino and grasshopper) 70

71

ANALYTICAL WORK AND CONCLUSION AIR MOVEMENT The base case is as introduced in the previous chapter with window shut all the time. Then 5ach/hr, which is an achievable indoor air speed, and 10ac/hr is applied for 24hr ventilation. May is selected as one of the hottest months in the year, and from 19 to 26 May is selected as a typical week.

Air Movement Base Case_5ach Comparison 36

250

35

240 230

34

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33

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190 180

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10 0 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

16

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Outdoor Temperature (째C)

Base Case No Vent Temp (째C)

5ach/hr 24hr Vent Temp (째C)

10ach/hr 24hr Vent Temp (째C)

*Global Horizontal Radiation [Wh/m2]

10ach/hr 24hr Vent Humidity (%)

5ach/hr 24hr Vent Humidity (%)

Base Case No Vent Humidity (%)

Fig.6.2 Comparison of the indoor temperature of base case and 24hr ventilation at 5 ach/hr.

(Source: Excel and OpenStudio)

72

26/5/16

ANALYTICAL WORK AND CONCLUSION AIR MOVEMENT Conclusion During daytime, the indoor temperature during the hottest time of the day, which is in the later afternoon, is lowered by around 1oC depending on the solar radiation and outdoor temperature: when the solar radiation is stronger and outdoor temperature is higher, the indoor temperature reduction is less significant; when the solar radiation is less stronger and outdoor temperature is lower, the indoor temperature reduction is more significant.

Duing night-time, the indoor temperature duing night-time is lowered by around 1oC with 5ach/hr and 2oC with 10ach/hr depending on the difference between daytime and night-time outdoor temperature: when the difference between daytime and night-time outdoor temperature is bigger, the indoor temperature reduction is more significant; when the difference between daytime and night-time outdoor temperature is smaller, the indoor temperature reduction is less significant.

73

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight and heavyweight with 50mm outside insulation comparison According to Szokolay's theory disscussed in the previous theory chapter, first, heavyweight construction with 50mm insulation on the outside of the wall is tested. Construction details of wall, floor, ceiling and window are shown as the drawing below (Fig.6.3 Heavyweight with 50mm construction details.). U-value of wall 0.7W/m2K. As suggested by the previous air movement experiement, use the model with 24 hour ventilation with total airmovement at 5 ach/hr.

Paint 10mm

Hoow concrete block 300mm partially granited

Marble flooring 20mm

Fair-face concrete 250mm Thermal insulation 50mm

Paint 10mm

Fig.6.3 Heavyweight with 50mm construction details.

Section through wall-floor juction and window.

(Source: AutoCAD) 74

Single glazing 5mm

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight and heavyweight with 50mm outside insulation comparison Heavyweight construction is compared with heavyweight with 50mm outside insulation construction (Fig.6.4 Comparison of the indoor temperature with base case heavyweight construction and heavyweight with 50mm outside insulation construction.).

During the daytime, the indoor temperature of heavyweight construction is around 1oC higher than heavyweight with 50mm outside insulation construction, depending on the amount of solar radiation and outdoor temperature.

During the night-time, the indoor temperature of heavyweight construction is around 1oC higher than heavyweight with 50mm outside insulation construction.

Heavyweight_Heavyweight 50mm Outside Insulation Comparison 36

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10 0 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

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Outdoor Temperature (°C)

Heavyweight 50mmInsul_24hr Vent Temp (°C)

Heavyweight_24hr Vent Temp (°C)

Heavyweight 50mmInsul_24hr Vent Humidity (%)

*Global Horizontal Radiation [Wh/m2]

Heavyweight_24hr Vent Humidity

26/5/16

Fig.6.4 Comparison of the indoor temperature with base case heavyweight construction and heavyweight with 50mm outside insulation construction.

(Source: Excel and OepnStudio) 75

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight and heavyweight with 50mm outside insulation comparison For the month of May, hourly temperature for heavyweight construction and heavyweight with 50mm outside insulation construction is shown in Table 6.1 (Table 6.1 Heavyweight construction with 24hr ventilation hourly indoor temperature in May.) and Table 6.2 (Table 6.2 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May.). And comparison is made in the chart (Fig.6.5 Heavyweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison.)

Table 6.1 Heavyweight construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio)

Heavyweight 24hr Ventilation 26-28 28-30 30-32 32-34 34-36 Total

Count of hourly Temperature 43 205 318 148 30 744

Table 6.2 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio)

Heavyweight with 50mm Outside Insulation 24hr Ventilation 26-28 28-30 30-32 32-34 34-36 Total

76

Count of hourly Temperature 108 314 242 80 0 744

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight and heavyweight with 50mm outside insulation comparison Conclusion Compared to heavyweight with 50mm outside insulation construction, heavyweight construction has 98 hours more fall in to the range above 32oC, which is the overheating temperature defined by upper comfort band for the month of May in Singapore. For the hourly temperature below 32oC, 78 more hours fall into the range of 30-32oC; 109 less hours fall into the range of 28-30oC; 65 less hours fall into the range of 26-28oC. Compared to heavyweight with 50mm outside insulation construction, heavyweight construction overall temperature is higher, and the overheating hour is 98 hours more.

Heavyweight_Heavyweight 50mm Outside Insulation Comparison

314

318

242

205

148

108 80

43 30 0

0

0 24-26

26-28

28-30 Heavyweight 24hr Vent

30-32

32-34

34-36

Heavyweight 50mm Outside Insulation 24hr Vent

Fig.6.5 Heavyweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison.

(Source: Excel and OpenStudio)

77

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight with 50mm outside insulation closing the window and Infiltration comparison Second, for heavyweight with 50mm outside insulation construction, test ventilation schedule with windows closed during the day from 10:00 to 20:30. Change infiltration from 3ach to 1.5ach and 0.3ach in heavyweight with 50mm outside insulation construction.

Heavyweight 50mm Insulation_Infiltration Comparison 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

16

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Outdoor Temperature (°C)

INFIL0.3_HeavyWeight50mm_Window Shut (°C)

INFIL1.5_HeavyWeight50mm_Window Shut (°C)

INFIL3 HW50mm_Window Shut (°C)

INFIL1.5_Heavyweight50mm_24hrVent (°C)

*Global Horizontal Radiation [Wh/m2]

INFIL1.5_HeavyWeight50mm_Window Shut Humidity (%)

INFIL1.5_HeavyWeight50mm_24hr Vent Humidity (%)

26/5/16

Fig.6.6 Comparison of the heavyweight with 50mm outside insulation construction indoor temperature of infiltration at 3ach, 1.5ach and 0.3ach.

(Source: Excel and OepnStudio)

78

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight with 50mm outside insulation closing the window and Infiltration comparison Conclusion For heavyweight with 50mm outside insulation construction, compare infiltration at 3ach, 1.5ach and 0.3ach (Fig.6.4 Comparison of the heavyweight with 50mm outside insulation indoor temperature of infiltration at 3ach, 1.5ach and 0.3ach.).

Closing the windows does not have an effective impact when the infiltration is at 3ach; the indoor temperature is similar to 24hr ventilation. Closing the windows lower the highest indoor temperature during the day have similar effect when infiltration is at 1.5ach and 0.3ach.

During the daytime when the outdoor is the hottest during the day, during the days when the outdoor temperature and solar radiation is extremely high, closing the window lower the indoor temperature by 1oC. And the highest indoor temperature is 2oC lower then the highest outdoor temperature during the day. An example of such extreme day is 20 May. However, on the other hand, when the outdoor temperature and solar radiation is not extremely high, the highest indoor temperature of 24hr ventilated is lower than closing the windows. An example is 24 May. During the night-time, the lowest indoor temperature at 1.5ach and 0.3ach infiltration is lower than the lowest indoor temperature at 3ach infiltration by less than 1oC, depending on the outdoor temperature.

79

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight with 50mm outside insulation glazing u-value comparison As suggested by the previous construction type experiement result, use the model with 50mm outside insulation construction with infiltration at 1.5ach. Meanwhile ventilation at 5 ach/hr with windows shut from 10:00 - 20:30, change the U-value of the glass. Glazing with U-value of 5.8W/m2K single glazing and triple glazing 1.6 W/m2K is applied to windows.

Glazing U-value Comparison 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

5/19

5/20

5/21

5/22

5/23

5/24

5/25

Outdoor Temperature (째C)

U-value 4.2 Temp (째C)U-value 4.2 Humidity (%)

Trp Clr 3mm-13mm Arg U-value 1.6 Temp (째C)

U-value 5.8 Temp (째C)

*Global Horizontal Radiation [Wh/m2]

U-value 4.2 Humidity (%)

Trp Clr 3mm-13mm Arg U-value 1.6 Humidity (%)

Fig.6.7 Comparison of the indoor temperature with U-value of 4.2W/m2K, 5.8W/m2K, and 1.6W/m2K. (Source: Excel and OepnStudio)

80

5/26

ANALYTICAL WORK AND CONCLUSION HIGH MASS Heavyweight with 50mm outside insulation glazing u-value comparison Conclusion During the daytime, compared to base case glazing U-value of 4.2W/m2K, U-value of 1.6W/m2K increase the indoor temperature during the middle of the day. However, changing the glazing U-value to 5.8W/m2K doesn't have an impact on the indoor temperature. Therefore, The U-value of glazing in Singapore is not to be high; while cheaper glazing is recommended to save the construction cost without effecting the indoor temperature.

81

ANALYTICAL WORK AND CONCLUSION LOW MASS Lightweight and lightweight insulated construction comparison Lightweight construction with low mass is tested as disscussed in the previous chapter on theory and venacular architecture. Ventilation is at 5 ach/hr applied for 24hr.

Construction details of wall, floor, ceiling and window are shown as the drawing below (Fig.6.6 Lightweight construction details of wall, floor, ceiling and window.). U-value of wall 0.40W/m2K; floor 0.50 W/m2K.

Internal lining 12mm Services cavity 50mm Wood panel 12mm Wood frame 60x250mm

LIGNATUR box element Wood panel 12mm

Paint 10mm

Fig.6.8 Lightweight construction details.

Section through wall-floor juction and window.

(Source: AutoCAD) 82

Single glazing 5mm

ANALYTICAL WORK AND CONCLUSION LOW MASS Lightweight and lightweight insulated construction comparison Lightweight insulated construction with low mass is tested for comparison. Ventilation is at 5 ach/hr applied for 24hr.

Construction details of wall, floor, ceiling and window are shown as the drawing below (Fig.6.7 Lightweight insulated construction details of wall, floor, ceiling and window.). U-value of wall 0.45W/m2K; floor 0.50W/m2K.

Internal lining 12mm Services cavity 50mm Wood panel 12mm Wood frame 60x250mm

LIGNATUR box element Insulation 250mm, e.g. cellulose wool 12mm

Wood panel 12mm

Paint 10mm

Fig.6.9 Lightweight insulated construction details.

Section through wall-floor juction.

(Source: AutoCAD) 83

ANALYTICAL WORK AND CONCLUSION LOW MASS Lightweight and lightweight insulated construction comparison Conclusion Lightweight construction is compared with lightweight insulated construction (Fig.6.8 Comparison of the indoor temperature with lightweight construction and lightweight insulated construction.). Lightweight construction overall temperature is lower than lightweight insulated construction.

During the daytime, the indoor temperature of lightweight construction is around 1oC lower than lightweight insulated construction.

During the night-time, the indoor temperature of lightweight construction is around 1oC lower than lightweight insulated construction.

Lightweight Insulated Comparison 37

250

36

240 230

35

220

34

210

33

200

32

190

31

180 170

30

160

29

150

28

140

27

130

26

120

25

110 100

24

90

23

80

22

70

21

60

20

50 40

19

30

18

20

17

10

16 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

0

19/5/16

20/5/16

21/5/16

22/5/16

23/5/16

24/5/16

25/5/16

Outdoor Temperature (°C)

LightWeight_NOSchedule Temp (°C)

LightWeight_250mmInsul Temp (°C)

*Global Horizontal Radiation [Wh/m2]

LIghtWeight_NOSchedule Humidity (%)

LIghtWeight_250mmInsul Humidity (%)

26/5/16

Fig.6.10 Comparison of the indoor temperature with base case heavyweight construction and heavyweight with 50mm outside insulation construction.

(Source: Excel and OepnStudio) 84

85

ANALYTICAL WORK AND CONCLUSION LOW MASS AND HIGH MASS COMPARISON The better result from low mass and high mass is compared (Fig.6.9 lightweight construction and heavyweight with 50mm outside insulation construction.). During the daytime when the outdoor is the hottest during the day, first, with 24hr ventilation at 5 ach/hr, the highest indoor temperature of lightweight construction is higher than the highest indoor temperature of heavyweight with 50mm outside insulation construction by less than 1oC, depending on the solar radiation and outdoor temperature. During the day with extreme solar radiation and outdoor temperature, such as 20 May, the highest indoor temperature of lightweight construction is higher than the highest indoor temperature of heavyweight with 50mm outside insulation construction by 0.5oC. And the highest indoor temperature of heavyweight with 50mm outside insulation construction is lower than the outdoor temperature by 1oC. Second, applying the ventilation schedule with window closed from 10:00 to 20:30 to heavyweight with 50mm outside insulation construction, however, does not have an effective impact on the indoor temperature when infiltration is at 3ach.

During the night-time, the lowest indoor temperature of lightweight construction is lower than the lowest indoor temperature of heavyweight with 50mm outside insulation construction by less than 1oC, depending on the outdoor temperature. At the same time, the indoor temperature of lightweight construction decrease faster than the indoor temperature of heavyweight with 50mm outside insulation construction when the outdoor temperature start to decrease.

Lightweight_Heavyweight 50mmInsul Comparison 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0

36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00 1:00 4:00 7:00 10:00 13:00 16:00 19:00 22:00

16

19/5/16

20/5/16

21/5/16

22/5/16

23/5/16

24/5/16

25/5/16

Outdoor Temperature (째C)

Heavyweight 50mmInsul_Close Window Temp (째C)

Heavyweight 50mmInsul_24hr Vent Temp (째C)

Lightweight_24hr Vent Temp (째C)

*Global Horizontal Radiation [Wh/m2]

50mmInsul_24hr Vent Humidity (%)

26/5/16

LIghtWeight_24hr Vent Humidity (%)

Fig.6.11 Comparison of the indoor temperature with lightweight construction and heavyweight with 50mm outside insulation construction.

(Source: Excel and OepnStudio) 86

ANALYTICAL WORK AND CONCLUSION LOW MASS AND HIGH MASS COMPARISON For the month of May, hourly temperature for lightweight construction and heavyweight with 50mm outside insulation construction is shown in Table 6.3 (Table 6.3 Lightweight construction with 24hr ventilation hourly indoor temperature in May.) and Table 6.4 (Table 6.4 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May.). And comparison is made in the chart (Fig.6.10 Lightweight and heavyweight hourly indoor temperature comparison.)

Table 6.3 Lightweight construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio) Lightweight 24hr Ventilation 24-26 26-28 28-30 30-32 32-34 34-36 Total

Count of hourly Temperature 11 140 281 217 87 8 744

Table 6.4 Heavyweight with 50mm outside insulation construction with 24hr ventilation hourly indoor temperature in May. (Source: Excel and OpenStudio)

Heavyweight with 50mm Outside Insulation 24hr Ventilation 24-26 26-28 28-30 30-32 32-34 34-36 Total

Count of hourly Temperature 0 108 314 242 80 0 744

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ANALYTICAL WORK AND CONCLUSION LOW MASS AND HIGH MASS COMPARISON Conclusion Compared to heavyweight 50mm outside insulation construction with 24hr ventilation, lightweight construction with 24hr ventilation has more overheating hourly temperature above 32oC which is the upper comfort band for the month of May in Singapore. For the hourly temperature above 32oC, 7 hours more fall in the range of 32-34oC and 8 hours more is above 34oC. For the hourly temperature below 32oC, lightweight construction with 24hr ventilation has 32 hours more fall in the range of 26-28 oC; 58 hours less fall in the range of 28-32oC. Compare to heavyweight 50mm outside insulation construction with 24hr ventilation, lightweight construction with 24hr ventilation overall indoor temperature is lower, however, the overheating hour is 15 hours more. (Fig.6.10 Lightweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison.).

Additionally, close windows 10:00 to 20:30 in heavyweight with 50mm outside insulation construction lower the peak temperature during the days when the outdoor temperature and solar radiation is extremely high.

Lightweight_Heavyweight 50mm Outside Insulation Comparison

314

281

242 217

140

108 87

80

11

8

0 24-26

26-28

28-30 Lightweight 24hr Vent

30-32

32-34

0 34-36

Heavyweight 24hr Vent

Fig.6.12 Lightweight construction and heavyweight with 50mm outside insulation construction hourly indoor temperature comparison.

(Source: Excel and OpenStudio) 88

ANALYTICAL WORK AND CONCLUSION HORIZONTAL SHADING DEVICE As suggested by the previous air movement experiement result, use the model applied 24hr ventilation at 5 ach/hr, horizontal shading of 0.5m, 1m and 2m is added to the windows for living room (Fig.6.11 Horizontal shading device's location over living room windows.)

Conclusion The horizontal shading device does not have an effective impact on indoor temperature. When applied with horizontal shading device of 0.5m, 1m and 2m, the indoor temperature was lowered by less then 1oC.

0.5m 1m 2m

0.5m 1m 2m

Fig.6.13 Horizontal shading device's location over living room windows.

(Source: SketchUp and OpenStudio) 89

ANALYTICAL WORK AND CONCLUSION VERTICAL SHADING DEVICE As suggested by the previous air movement experiement result, use the model applied 24hr ventilation at 5 ach/hr, vertical shading of 0.5m, 1m, 2m is added to the windows for living room (Fig.6.12 Vertical hading device's location over living room windows.)

Conclusion With the increase of the length of the horizontal shading device from 0.5m, to 1m and 2m, the impact on the indoor temperature makes a difference for less than Âą1 oC. Vertical shading device don't have much effect on indoor temperature.

At the same time, note that vertical shading device shading device has more obstruction on indoor cross ventilation as disscussed in previous theory chapter.

0.5m 1m 2m

0.5m 1m 0.5m 1m 2m

Fig.6.14 Vertical shading device's location over living room windows.

(Source: SketchUp and OpenStudio) 90

2m

ANALYTICAL WORK AND CONCLUSION ORIENTATION As suggested by the previous air movement experiement result, use the model applied 24hr ventilation at 5 ach/hr , the model is rotated every 45o.

Conclusion

N

The rotations make a difference for less than Âą1 oC, and don't have much effect on indoor temperature. Therefore, orientation is to be considered regarding prevailling in order to achieve maximum indoor air movement.

Fig.6.15 Vertical shading device's location over living room windows.

(Source: AutoCAD) 91

ANALYTICAL WORK AND CONCLUSION INTERNAL CONDITION SENSITIVITY As suggested by the previous air movement experiement result, use the model applied 24hr ventilation at 5 ach/hr , change internal gain by applying schedule of, first, home office and second double the occupant number. Home office has 1 person work from home with 1 laptop from 9:00-17:00.

Conclusion The changing of occupancy and equipment schedule make a difference for less than Âą1oC, and don't have much effect on indoor temperature. The high mass construction, both the heavyweight and the heavyweight with 50mm outside insulation construction are not sensible to internal condition applied.

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93

ANALYTICAL WORK AND CONCLUSION CFD INDOOR AIR FLOW t

94

ANALYTICAL WORK AND CONCLUSION CFD INDOOR AIR FLOW

ft/s

m/s

IW V

6.20 1.9

1.7 5.31 1.5

4.43

1.3

3.54 1.1 0.9 2.66 0.7

1.77

0.5 0.89

0.3

0.1 0.00

Fig.6.16 Inlet wind velocity 0.9m/s indoor air velocity.

(Source: TAS Ambiens)

°F

oC

102.2 38.0

96.5 Â&#x192;) 35.0 32.0 90.9 29.0

85.2

26.0

79.6

23.0

73.9

20.0 68.3

17.0 62.6

14.0

Fig.6.17 Inlet wind velocity 0.9m/s indoor temperature.

(Source: TAS Ambiens)

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ANALYTICAL WORK AND CONCLUSION CFD INDOOR AIR FLOW As suggested by precedent case study Skyville @Dawson by WOHA in the previous chapter , test when the inlet wind velocity is at 33oC. Inlet: - Air temperature 33oC. - Wind velocity 1.7m/s.

- Relative humidity 60%.

Surface temperature: - Wall 32oC. - Floor

31oC. - Ceiling 32oC. Gain: - Occupancy 2pp.

- Sensible Gains 160W. - Latent gains 40W. Outlet: - Wind velocity

96

1.4m/s.

ANALYTICAL WORK AND CONCLUSION CFD INDOOR AIR FLOW

ft/s

m/s

IW V

6.20 1.9

1.7 5.31 1.5

4.43

1.3

3.54 1.1 0.9 2.66 0.7

1.77

0.5 0.89

0.3

0.1 0.00

Fig.6.18 Inlet wind velocity 1.7m/s Indoor air velocity.

(Source: TAS Ambiens)

°F

oC

102.2 38.0

96.5 Â&#x192;) 35.0 32.0 90.9 29.0

85.2

26.0

79.6

23.0

73.9

20.0 68.3

17.0 62.6

14.0

Fig.6.19 Inlet wind velocity 0.9m/s indoor temperature.

(Source: TAS Ambiens)

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ANALYTICAL WORK AND CONCLUSION CONCLUSION AND DESIGN APPLICATION The intention behind the research in this dissertation was to investigate the relevant environmental parameters influencing the high-rise residential buildings in tropical humide climate, and offer design modifications to the most common construction type for high-rise residential building in Singapore.

Different construction applications of the building envelope is tested in order to reduce the dependency on air conditioner by minimizing overheating hour.

The research was subsequently organized by testing the theory in literature review. Base case is based on field work apartment and the living room of which is being studied.

Singapore climate is tropical and humid. The greatest challenge is the overheating during the hottest season towards achieving adaptive thermal comfort. The key findings of this dissertation focus on improving building envelope through the construction of heavyweight concrete, airtighness and window glazing U-value. At the same time, this dissertation explores the curiocity towards vernacular architecture, local standard recommendations (BCA Greenmark), as well as the local culture through observation such as closing the window during the hottest days.

Each design modification option is evaluated using dynamic thermal simulations (OpenStudio), and wind velocity is evaluated using CFD (TAS Ambiens). Studies suggest the depth of the plan is not to exceed 5 times the height (in this dissertation, as well as the most common in Singapore residence, the floor to ceiling height is 3m, and therefore the depth is not to exceed 15m) to achieve cross ventilation. The results suggest that significant indoor temperature reduction in heavyweight concrete construction is to be achieve with 50mm outside insulation at air change rate of 5ach. Closing the window during the extreme day reduce the overheat hour, and hence peak cooling load. In this way, with the hope that generalizable knowledge could be obtained, this report is to assist design decisions, at the same time, offer an energy saving guide for high-rise residents, especially those who are not familiar with the local climate.

However, how to achieve indoor air flow remains the biggest challenge. In the simulations, for example the input indoor air speed is at 5ach/hr for 24 hour ventilation. This assumption is achievable, for example, by opening the windows and using mechanical fan. Yet the most suitable time to open the windows and use outdoor air for ventilation is not neccessariliy the most desirable time. During the daytime, the outdoor air temperature is lower when it rains, yet, at the same time, likely to be windy as well. In the case of gusty rain the windows are shut, although exception is to be made using the monsoon window disscussed in the case study chapter. During the night-time, related safety and private issues etc., again, prevent windows from opening for ventilation. On the other hand, as in the interview with the occupant, given the fact that the household doesn't have a mechanical fan, its effectiveness in achieving indoor thermal comfort is not realized. And this remains the research effort the aurthor of this dissertation.

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REFERENCES Internet Sources BBC Weather http://www.bbc.co.uk/weather/.

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