ARC 1435 Tropical Design Learning Module PDF
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Far Eastern University
2021
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This is a learning module for ARC 1435, Tropical Design, focusing on understanding climate and its importance to tropical architecture and design considerations. It covers topics such as radiation, wind, precipitation, and major tropical climate zones.
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COURSE LEARNING MODULE ARC1435: TROPICAL DESIGN Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ______________...
COURSE LEARNING MODULE ARC1435: TROPICAL DESIGN Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ TABLE OF CONTENTS INTRODUCTION TO TROPICAL DESIGN............................................................................................................. 5 MODULE 1 UNDERSTANDING CLIMATE........................................................................................................... 7 Climate........................................................................................................................................................................ 7 Radiation.................................................................................................................................................................. 8 Tilt of the Earth’s Axis.............................................................................................................................................. 9 Radiation at the Earth’s Surface............................................................................................................................ 10 The Earth’s Thermal Balance................................................................................................................................. 11 Winds and Annual Wind Shift................................................................................................................................. 12 Influence of Topography........................................................................................................................................ 13 Elements of Climates............................................................................................................................................... 13 Temperature........................................................................................................................................................... 13 Humidity................................................................................................................................................................. 14 Precipitation........................................................................................................................................................... 15 Solar Radiation....................................................................................................................................................... 16 Wind....................................................................................................................................................................... 17 Vegetation.............................................................................................................................................................. 18 Scales of Climate and their importance................................................................................................................. 18 Deviations within the Zone..................................................................................................................................... 19 Factors Affecting Local Climate Variations............................................................................................................ 20 Major Tropical Climatic Zones................................................................................................................................ 23 Climate in the Philippines....................................................................................................................................... 26 Temperature........................................................................................................................................................... 26 Humidity................................................................................................................................................................. 26 Rainfall................................................................................................................................................................... 26 Prevailing Winds in the Philippines........................................................................................................................ 27 The Seasons.......................................................................................................................................................... 27 Typhoons............................................................................................................................................................... 28 Architectural Adaptations to Climate..................................................................................................................... 29 Bahay Kubo............................................................................................................................................................ 30 Bahay na Bato........................................................................................................................................................ 32 Basic design principles for tropical design............................................................................................................. 35 Useful Links............................................................................................................................................................ 36 References............................................................................................................................................................. 36 MODULE 2 DESIGNING WITH NATURE........................................................................................................... 37 Use of Energy in Buildings..................................................................................................................................... 37 Energy Benchmarking............................................................................................................................................ 38 Thermal Comfort...................................................................................................................................................... 40 Thermal Comfort Factors....................................................................................................................................... 40 Body’s Heat Production.......................................................................................................................................... 41 Body’s Heat Loss................................................................................................................................................... 42 Psychrometric Chart............................................................................................................................................... 43 ARC 1435 2 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Energy-efficient Building Systems......................................................................................................................... 44 Active systems....................................................................................................................................................... 46 Passive Systems.................................................................................................................................................... 47 Useful Links............................................................................................................................................................ 49 References............................................................................................................................................................. 49 MODULE 3 GREENING THE CITIES.................................................................................................................. 50 Tropical Design and Sustainable Design............................................................................................................... 50 Urban Heat Island Effect........................................................................................................................................ 50 Factors Contributing to the Heat Island Effect....................................................................................................... 51 Strategies to decrease Urban Heat Island (UHI).................................................................................................... 52 Vegetation.............................................................................................................................................................. 52 Water bodies.......................................................................................................................................................... 54 Topography............................................................................................................................................................ 56 Ground character................................................................................................................................................... 57 Laws Related to the Use of Resources and Sustainable Design........................................................................ 57 PD 1152: Philippine Environment Code................................................................................................................. 58 PD 1067: Water Code of the Philippines................................................................................................................ 58 RA 6969: Toxic Substances, Hazardous and Nuclear Waste Control Act of 1990................................................ 58 RA 8749: Philippine Clean Air Act of 1999............................................................................................................. 58 RA 9003: Ecological Solid Waste Management Act of 2000................................................................................. 58 RA 9275: Philippine Clean Water Act of 2004....................................................................................................... 59 PD 1096 Referral Code: Philippines Green Building Code of 2015....................................................................... 59 PD 1586: Establishing an Environmental Impact Statement system, including other environmental management related measures and for other purposes.............................................................................................................. 59 Sustainable Tropical Building Design Principles................................................................................................. 59 Energy and emissions............................................................................................................................................ 59 Water and waste water.......................................................................................................................................... 61 Indoor environment quality..................................................................................................................................... 64 Waste and construction materials.......................................................................................................................... 64 Local environment.................................................................................................................................................. 66 Sustainability Benchmarks..................................................................................................................................... 67 Stakeholders using sustainability benchmarks:..................................................................................................... 67 Green building case studies................................................................................................................................... 68 Zuellig Building....................................................................................................................................................... 68 Sun Life Centre...................................................................................................................................................... 70 Readings in Sustainable Tropical Architecture.................................................................................................... 70 01 Green Design in the Hot Humid Tropical Zone by Ken Yeang.......................................................................... 71 02 Socio-environmental dimensions in Tropical semi-open spaces of high-rise housing in Singapore................. 71 03 Policy and evaluation system for green building in subtropical Taiwan............................................................ 71 04 In search of a habitable urban space-built ratio: A case study of building and planning regulation in Dhaka City............................................................................................................................................................................... 71 05 Designing high density cities - parametric studies of urban morphologies and their implied environmental performance........................................................................................................................................................... 72 06 Urban Heat Island Effect in Singapore.............................................................................................................. 72 07 Tropical Urban Street Canyons......................................................................................................................... 73 08 Tropical and traditional: Inventing a new housing model for the old 36 Streets Quarter in Hanoi, Vietnam..... 73 09 ECOPET 21: An innovative sustainable building system for ecological communities in tropical regions......... 74 Useful Links............................................................................................................................................................ 75 References............................................................................................................................................................. 75 MODULE 4 BUILDING STRUCTURES IN A HOT HUMID CLIMATE................................................................... 76 ARC 1435 3 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Bioclimatic Design................................................................................................................................................... 76 Climatic Issues in a Tropical Climate..................................................................................................................... 77 Tropical Design Strategies...................................................................................................................................... 78 Passive cooling through orientation....................................................................................................................... 78 Passive cooling through site layout........................................................................................................................ 79 Passive cooling through façade design.................................................................................................................. 80 Passive cooling through solar control devices....................................................................................................... 83 Sun-shading devices.............................................................................................................................................. 86 Sun-path diagram................................................................................................................................................... 87 Passive daylight concepts...................................................................................................................................... 91 Passive cooling by vertical landscaping................................................................................................................. 95 Landscaping for cooling buildings.......................................................................................................................... 96 Passive cooling by wind and natural ventilation..................................................................................................... 97 Basic ventilation concepts...................................................................................................................................... 99 Wind concepts...................................................................................................................................................... 102 Useful links........................................................................................................................................................... 106 References........................................................................................................................................................... 106 ARC 1435 4 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ MODULE 3 GREENING THE CITIES Compiled and edited by Mar Lorence G. Ticao In this module, we will get a broader perspective on the impacts of development in an urban context – how a building uses up energy and how it affects the surrounding areas. At the same time, we will highlight the significance of climate responsive structures as an efficient and sustainable response to the impacts of development. By the end of the module, you will learn more about energy use and how this in turn results to more climate issues. You will get more awareness of existing environmental laws in our country that help protect our welfare and the environment. And finally, you will get a deeper understanding of how our individual design decisions can cause a ripple effect to a whole city, urban region, and even globally. Tropical Design and Sustainable Design How we design and build structures can directly or indirectly affect the environment. Directly, when we build in previously undeveloped sites. Indirectly, through extracting resources to create building materials; emitting greenhouse gases in the manufacturing and transportation of materials to the site; and through using energy sources such as electricity once the building is operating. Tropical architecture is designing and building thermally comfortable structures that respond to the tropical climate conditions through passive design systems. Sustainable design seeks to reduce negative impacts on the environment, and the health and comfort of building occupants, thereby improving building performance. They are not the same. But tropical design is embodied in sustainable building design. We can build houses that are tropically designed but without the intention for sustainability. A client might want a totally passive house in the city with high ceilings, deep eaves with large windows, etc. but come summer, due to the extreme temperatures caused by the urban heat island effect, the occupants may not be able to withstand the heat and eventually install air-conditioning systems. Thus, more resources will be expended in the end. On the other hand, in a sustainable design, we want to lessen the negative impact of development so we respond by incorporating into our designs the local climate conditions, low carbon footprint materials and construction systems, culturally-responsive design, and energy efficiency in buildings. Urban Heat Island Effect Urban Heat Island (UHI) is the phenomenon where the temperatures in the city are higher than those in the suburban rural areas. Figure 32 : How the urban heat island (UHI) occurs Image source: https://www.skepticalscience.com/graphics.php?g=251 Credits: Heat in the City, with Kevin Cowtan ARC 1435 50 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ The causes of Urban Heat Island (UHI) are primarily the absorption of solar radiation by building/urban materials that is subsequently re-radiated to the surroundings. In addition, the anthropogenic heat generated from the combustion process and air-conditioning coupled with the greenhouse effect of pollutants also contributes to the increase in temperatures. Figure 33 : Sketch of an urban heat island profile Image source: Fuladlu, Kamyar & Riza, Müge & Ilkan, Mustafa. (2018). THE EFFECT OF RAPID URBANIZATION ON THE PHYSICAL MODIFICATION OF URBAN AREA. Temperature distribution in urban areas is highly affected by the urban radiation balance. Solar radiation incident on the urban surfaces is absorbed and then transformed to sensible heat. In densely built up urban areas, most of the solar radiation impinges on roofs, and the vertical walls of the buildings, and only a relatively small part reaches the ground level. Walls, roofs and the ground emit long wave radiation to the sky. The intensity of the emitted radiation depends to the view factor of the surface regarding the sky. Under dense urban conditions, most of the sky dome viewed by walls and surfaces is blocked by other buildings and thus the long wave radiant exchange does not really result in significant losses. Factors Contributing to the Heat Island Effect Thermal properties of materials that may increase storage of heat in the fabric of the city during the day time and release their stored heat into the urban atmosphere after sunset. The replacement of natural soil or vegetation by materials used in cities like concrete or asphalt reduces the ability to decrease ambient temperature through evaporation and plant transpiration. Anthropogenic heat released from combustion of fuels either from mobile or stationary sources and animal metabolism. Urban greenhouse, that contributes to increase the incoming long wave radiation from the polluted urban atmosphere. This extra radiative input to the city reduces the net radiative drain. Reduction of evaporating surfaces in the city putting more energy into sensible and less into latent heat. ARC 1435 51 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Figure 34 : Factors contributing to the UHI Image source: https://www.publichealthnotes.com/urban-heat-island-effects-mitigation-measures/ Strategies to decrease Urban Heat Island (UHI) The more sustainable and easy to use renewable energy source in the urban environment is the use of vegetation and water bodies. Vegetation and water bodies for cooling purposes can be considered as a renewable heat sink, in a similar way that the sun is a renewable heat source for heating purposes. Strategies to decrease UHI Use of light colored roofs and walls Afforestation and plantation in city areas Rooftop farming and agriculture Green parking lots Implementation of heat reduction strategies Lesser use of vehicles Car pooling Promotion of greener lands and parks in urban areas Grassy lands promotion Eco-roofing Vegetation The microclimate within and near green areas differs from unplanted, built-up areas. The main differences are in the temperature, wind velocity and turbulence, air and radiant temperatures, humidity, and air cleanliness. The leaves of plants absorb most of the solar radiation which strikes them. They transform a very small part of the radiant energy by photosynthesis into chemical energy, and in this way reduce the rate of heating of the urban space slightly. Landscaping and vegetation require to serve different purposes in different climates. In cooler regions it is necessary to utilize as much heat as possible in order to cut down energy consumption for mechanical heating. In hot climate it is desirable to modify climate to provide cooling. In arid areas existing moisture has to be maximized or moisture may have to be introduced by means of natural process in order to make the climate more habitable. ARC 1435 52 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Figure 35 : Greening of the cities can help reduce the impact of UHI Photo credit: Dr. L. De Viana, photo taken at Mehan Garden, City of Manila Promoting green spaces in densely populated and highly urbanized areas can help lessen heat concentrated during the day. Places with plants and vegetation have different thermal properties as compared to built-up and hard- surfaced unplanted areas. The main differences are: Plants have lower heat capacity and thermal conductivity than building materials and hard surfaces. Solar radiation is mostly absorbed in the leaves, so that the reflected radiation is very small. Rain water is absorbed in the soil. Water is later evaporated from the soil and mainly from the leaves. The evaporation rate is much higher in green areas than in unplanted, hard covered areas. Plants reduce the wind speed and its fluctuations near the ground. Figure 36 : Ecological qualities of trees Image source: CLEAR Comfortable Low Energy Architecture ARC 1435 53 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Trees have great potential to cool cities by shading and by "evapotranspiration." Evapotranspiration occurs when plants secrete or "transpire" water through pores in their leaves--in a way, plants sweat like people do. The water draws heat as it evaporates, cooling the air in the process. In hot and dry regions, this cooling indirect effect can reach 3 to 6°C in the daytime in areas with mature trees compared to areas with no trees. How important and desirable this is depends on the prevailing humidity and temperature conditions. Trees besides controlling the precipitation also control the seasonal and annual temperature variations. The effectiveness of specific plant in climate control depends upon the form and character of plant, the climate of the region and the specific requirements of the site. Correct selection and location of trees is important to achieve the best results. Two proven methods to maximize its benefits: 1. Deciduous trees shading the south and west sides of a building block the summer sun. These trees cool by shading urban spaces and buildings during overheated periods whilst allowing radiation transmission in underheated seasons. Also, evergreen trees and bushes to the northwest can protect buildings from cold winter winds and snow. 2. Trees grouped together create a refreshing park or oasis in a city and also cool nearby neighborhoods. Grouped trees can protect each other from the sun and wind, making them more likely to grow to maturity and live longer. Trees also have other important ecological qualities (sound absorption, blocking of rainfall erosion, filtering of pollutants, reduction of ozone, etc.) which interact positively with the microclimatic qualities mentioned giving urban trees a very high environmental-economic value. Water bodies Although water absorbs a lot of heat, water bodies are good heat sinks because the heat does not produce a significant increase of water temperature because of the water bodies’ thermal inertia and evaporation at its surface. The inertia of a water body is directly proportional to water mass and therefore to its depth. With increasing water body inertia, the water temperature decreases. The daily range of water temperature (difference between maximum and minimum) is reduced and there is a phase shift between air and water temperatures. When the water body is in shadow (for instance a pond in a courtyard), the incoming solar radiation is reduced, with a further reduction in water temperature. Compared with land surfaces water bodies exhibit very little change in surface temperature during the day. Water is different because: Solar radiation can be transmitted deep within it and then absorbed. Heat can also pass deep within the water by convection and mixing. Water loses heat by evaporation. Specific heat of water is very high (high inertia) when compared to that of building materials. Figure 37 : Evaporative cooling in hot-humid climates has always been contested in the past, but more recent studies show that it can in fact be a heat mitigating technique even for humid environments Image source: CLEAR Comfortable Low Energy Architecture ARC 1435 54 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ The use of water bodies such as ponds, streams and cascades for evaporative cooling is best suited to warm and dry climates. However, more recent studies have shown that it has a great potential for passive and low energy solutions for buildings and cities for the majority of the hot humid areas of the world, particularly those with less developed economies (Sandoval, 2015). Outdoor evaporative cooling mechanisms can help to provide outdoor comfort and to lower indoor cooling costs by lowering the air temperature surrounding the building. The landscape techniques include the use of pools or ponds, fountains or sprays cascades or falls, drip or mist irrigation and surface or subsurface irrigated areas such as rock and pebbles. The proximity of a site to the sea or other large water bodies also affects the climatic conditions in and around the site. Wind movement from the water body during the day, and towards it at night, is caused by temperature differences of the air close to the surfaces of the soil and water. The relative humidity of air is also affected, since the air coming from a water body is more humid. Such phenomena are stronger close to water bodies, but may also affect the regional climate by creating strong air movement reaching large distances. This is mainly affected by the physical characteristics of the region, such as topography and vegetation. Figure 38 : Sea breeze vs Land breeze Image source: https://www.freepik.com/free-vector/science-infographic-land-sea-breeze_6408010.htm Take note… Land breeze and sea breezes take place near large bodies of water. The key difference between the two is caused by the property of water to retain and warm up longer. The differences in the temperature of land and water causes respective changes to the densities of the air above them. The resulting low pressures then cause alternating air movements which are manifested as breezes. Individuals situated near coastlines (within 50 kilometers from the oceanfront) experience cool sea breezes during the day and warm land breezes at night. Furthermore, these winds are instrumental in humidity and temperature levels, and precipitation rates. Source: http://www.differencebetween.net/science/difference-between-land-breeze-and-sea-breeze/ ARC 1435 55 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Topography The landform or topography of a site and its surroundings could either be flat, sloping or undulating (mounds etc.). If the land is flat, similar conditions would prevail over the entire site. The location of the building in such a case is not dictated by climatic concerns. Topography or modulations of earth either in natural undisturbed or manmade conditions has the ability to modify, ameliorate or accentuate climatic variations in different ways. Mountain ranges are diverters of air masses. They affect the flow of moisture-laden air and cause rain shadows for the areas on the leeward side. Temperature decreases with the rise in height and cold air flows downhill and settles in valleys. As a result, the air temperature is lower in such areas. Also air speed increases up the windward slope. Air speed is maximum at the crest and minimum on the leeward side. Some facts… Cool air has a higher density than hot air. As a result cool air is heavier and tends to settle down in depressions while hot air rises. On the other hand, air movement is also affected by pressure difference. Airflow normally takes place from high-pressure zones to low pressure zones. Obstacles in the path of airflow cause an air-buildup and therefore a high pressure area on the windward side. Similarly, direction of the airflow would now depend on the shape of the obstacle and the magnitude of the pressure difference. These phenomena would have an implication on our building design. In hot climates, building in a depression implies relatively lower air temperatures. When building on a slope, the leeward side is preferable, as long as the orientation is acceptable. In both cases warm breezes would be minimized. The collection of water in a depression might allow for a water body. This would also be beneficial in cooling the place. In cooler climates, not only do we not place our building in the depression we also avoid the path of the cool air down the slope. Here again, vegetation could help in protecting from cool breezes. In humid climates, our primary concern is maximizing air movement. We must, therefore, place our building on the top of the windward slope where the air speed would be the highest. Figure 39 : Influence of topography to climate Image source: http://www.ricksci.com/atm/images/atmi_orographic_lift.jpg ARC 1435 56 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Influence of Topography on small scale, air movement can be generated in the following examples: between a lake and its shores between a quarry and a nearby forest between a town and surrounding countryside between sunny and shaded sides of large buildings Ground character The color and texture of a material surface determines its reflectivity. The lighter the color and smoother the surface, more the reflectivity of the material. The darker the surface and rougher it is, the lower the reflectivity. Such materials would store more heat during the day and reradiate it at night. Black surfaces in the sun can become up to 40°C hotter than the most reflective white surfaces. Roads and parking lots are frequently paved with black asphalt concrete (commonly called "asphalt") and other dark materials that absorb most of the sunlight that falls upon them. The energy of the sunlight is converted into thermal energy and pavements and roads get hot, heating the air around them and contributing greatly to the urban heat island effect. In hot climates ground surfaces preferably should be green in order to minimize heat gain. Trees, shrubs, plants and grass utilize sunlight for photosynthesis. They absorb and consume the radiation. In this case the heat is neither reflected nor reradiated. Where hard surfaces and paving are unavoidable they should be rough but not very dark. This would make the ground less reflective but not very absorptive. Trees with a wide canopy can be used to shade the paved surface. In cold climates heat gain would be maximized by reflecting the heat or storing it. Reflective ground surfaces could be used to reflect solar radiation into the buildings. Dark surfaces that would absorb heat during daytime would give off warmth at night. Note that… Ground surface whether natural or man-made, its characteristics of reflectance, permeability and soil temperature influence the microclimate. Depending on the ground surface, incident radiation can be absorbed, reflected or stored and re-radiated later. In other words, radiative heat gain could be decreased or increased during the daytime. Emissivity of a surface depends on its texture. During night time, rough surfaces would re radiate the heat absorbed during the day faster than smooth surfaces. Based on the climatic context this could be used to our advantage. Laws Related to the Use of Resources and Sustainable Design Sustainable building design is about reducing the impacts of our actions towards the environment by designing and constructing buildings that are appropriate for the climate, with minimal environmental impacts, and are healthy and comfortable for users. Sustainable building design for the tropical regions would be considerably different from sustainable building design for temperate areas. That is why it is relevant to understand the principles of tropical design in the context of sustainability. ARC 1435 57 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ We have seen in the previous sections how our vernacular structures have adapted to the local climate. However, are the conditions in the present context the same as before? Today, we design our indoor living conditions with low ceilings and add air- conditioning systems to make them more comfortable. The element of energy has now been added variable on the equation in designing our structures to adapt to the climate conditions. There are now regulatory bodies for more sustainable practices in building. And with electricity being our main source of energy for our buildings today, it is also imperative that there are governing bodies that intervene to regulate its use. The following laws were crafted to help regulate development and the proper use of resources. PD 1152: Philippine Environment Code The Code covers regulations for the: Air quality management Water quality management Land use management Natural resources management and conservation Waste management PD 1067: Water Code of the Philippines To appropriate, control and conserve water resources to achieve the optimum development and rational utilization of these resources To define the extent of the rights and obligations of water users and owners To adopt a basic law governing the ownership, appropriation, utilization, exploitation, development, conservation and protection of water resources. RA 6969: Toxic Substances, Hazardous and Nuclear Waste Control Act of 1990 The law aims to regulate restrict or prohibit the importation, manufacture, processing, sale, distribution, use and disposal of chemical substances and mixtures that present unreasonable risk to human health RA 8749: Philippine Clean Air Act of 1999 The law aims to achieve and maintain clean air that meets the National Air Quality guidelines values for criteria pollutants. RA 9003: Ecological Solid Waste Management Act of 2000 The law ensures proper segregation, collection, storage, treatment and disposal of solid waste through the formulation and adaptation of best eco-waste products. ARC 1435 58 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ RA 9275: Philippine Clean Water Act of 2004 The law aims to protect the country’s water bodies from pollution from land-based sources (industries and commercial establishments, agriculture and community / household activities). PD 1096 Referral Code: Philippines Green Building Code of 2015 This referral code aims to: Provide for the protection of the people from the harmful effects of climate change Improve the efficiency of building performance through a framework of standards Efficient use of materials, site selection, planning, design, construction, use, occupancy, operation and maintenance, without significant increase in cost PD 1586: Establishing an Environmental Impact Statement system, including other environmental management related measures and for other purposes Sustainable Tropical Building Design Principles Energy and emissions Passive design is design that works with the environment to exclude unwanted heat and take advantage of sun and breezes, thus avoiding or minimizing the need for mechanical cooling. Passive design in the tropics means designing a building to make the most of natural light and cooling breezes, and using shading, orientation and appropriate building materials to reduce heat gain and storage. The use of passive design principles in the tropics results in a building that is comfortable, energy efficient and results in substantial savings in running costs of both cooling and lighting. The main principles of passive design for buildings in the tropics are the following: Avoid heat gain o Orient the building to reduce exposure to midday sun, particularly summer sun. o Use materials with low thermal mass. o Shade walls and windows, particularly any walls with high thermal mass. o Use glazing on windows that cannot be effectively shaded. o Use insulation, light colours and heat reflective surfaces. Encourage natural ventilation o Orient the building and windows towards prevailing north-eastern winds. o Include operable windows and ceiling vents that enable the building to naturally ventilate. ARC 1435 59 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Make use of natural light o Install shaded windows. o Install shaded skylights, light tubes and other natural lighting devices. Create cool outdoor areas o Use verandahs and deep balconies to shade and cool incoming air. o Use landscaping to provide shade without blocking cooling breezes and use planting to reduce ground temperature and minimize reflected heat. The elements to consider for implementing these principles are orientation, thermal mass, insulation, ventilation and lighting. These elements will be discussed in the next module. Figure 40 : Passive design for a Filipino home Image source: www.realliving.com.ph, photo by Paolo Feliciano, Energy efficient systems and appliances. In fitting out the building, efforts should be made to install the most energy efficient systems and appliances available to reduce operating costs of the building. Air-conditioning, lighting and hot water systems will have particularly significant implications for reducing a building’s energy requirement. Efficient air-conditioning: Wherever possible air-conditioning systems should incorporate zoning controls which enable the system to be adjusted to different heat loads in different parts of the building and to be shut off when areas are not in use. This reduces the amount of energy used in cooling or heating air unnecessarily and improves the comfort of building users. Efficient lighting: Lighting is directly responsible for most greenhouse gas emissions. The most efficient way to reduce lighting in a building is to maximize the use of natural light. Use of lighting zones and switching, efficient bulbs, and automatic shut off systems can all help to further reduce lighting energy use and costs. Hot water: Supplying hot water in large facilities can be expensive and energy intensive. The type of water heater used, where the unit is installed, and how the water is used all affect the costs and emissions associated with supplying hot water. A good way to save money and reduce greenhouse gas emissions is to use solar heaters, when the location makes it possible. Solar hot water systems generally have the lowest greenhouse gas emissions of available system types. Hot water storage systems should be located as close as possible to the point of water use. This helps ARC 1435 60 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ to keep pipe lengths short, which minimizes heat loss from pipes, reduces installation costs, and reduces water wastage as users wait for water to heat up at the outlet. Hot water pipes should also be insulated to minimize heat loss from pipes as hot water travels to the taps. Monitoring energy use: The ability to monitor energy use assists in reducing energy waste and assessing the effectiveness of energy efficiency measures. Smart meters can be installed to keep track of energy used in a building, which can record consumption in intervals of an hour or less and communicate that information at least daily back to the utility (or information system) for monitoring and billing purposes. Home energy monitors can also be installed for residences. Renewable energy. In the current context of rising electricity prices and the ongoing issue of energy security, investing in renewable energy generation systems is increasingly appealing. These systems help to reduce greenhouse gas emissions and improve energy security. If possible, incorporate considerations for solar panel installation at the design stage, as this ensures that roof aspect and slope angle can be designed for maximum power generation. When designing a building for solar power generation it is important to consider solar access for the panels and the slope of the roof. Transport. A sustainable building is designed to encourage public transport use and active transport (walking, cycling, etc) by building users. This helps to reduce the carbon footprint of the building and its workers and visitors, and also encourages a healthy lifestyle. The elements of designing a building for low- or zero-carbon transport by building users are the following: Situate building close to public transport routes. Provide safe, user-friendly walking and cycling access to the building. Provide showers and lockers in commercial buildings to encourage cycling or walking to work. Provide bike parking facilities. Water and waste water Treating and pumping water uses substantial amounts of electricity. Over 50% of annual electricity consumption is used by water pumping stations and water and wastewater treatment plants. Reducing the amount of potable water used, and reducing the amount of wastewater going to treatment plants will reduce greenhouse gas emissions as well as reducing building electricity costs. The water that comes out of our taps has undergone a high level of treatment and disinfection to render it suitable for human consumption. This level of treatment is not required for the majority of water uses associated with a building. Thoughtful building design can greatly reduce demands on potable (drinking) water sources. Water consumption can be reduced within buildings through a combination of water efficiency, rainwater capture and storage and water reuse. Water efficiency. All fixtures and fittings should be highly water efficient. Rainwater tanks. Rainwater can be collected for indoor and outdoor use depending on the building location and roof condition. Rainwater can be collected for toilet flushing within the building. The overflow from the tank should be directed so that it does not adversely affect adjoining land areas or buildings. When possible, the overflow should be connected to the stormwater system or an on-site filtration system. Mesh should be placed over all openings to prevent mosquitoes from breeding in the tank. ARC 1435 61 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Recyled water. Recycled water can be used instead of drinking quality water for non-potable uses such as irrigation, air- cooling towers and toilet flushing. Installing a recycled water supply is an effective method for reducing potable water consumption and reducing environmental impacts. Greywater (waste water from fixtures such as showers, basins and taps) can be treated and used for toilet flushing and for the irrigation of landscaped areas. Managing stormwater. The Philippines experiences periods of heavy rainfall during the wet season, with large volumes of water falling on urban areas. In urban areas we have replaced vegetation with non-porous surfaces such as concrete and metal. The majority of rain falling on urban areas cannot soak into the soil and is instead diverted into stormwater drainage systems which speed up the flow of the water and do not allow for sediments and nutrients to be removed. Reducing stormwater runoff by capturing this water for use, or by filtering it through vegetation and soil, improves reef health and also decreases our dependence on the mains water supply. To most effectively manage stormwater on site, efforts should be made to minimize the amount of impervious (non-porous) surfaces and maximize the potential for filtration, storage and infiltration, so that the least amount of water flows off-site into the stormwater system. Retaining stormwater onsite temporarily stores surface runoff and releases it at a reduced rate to receiving waters. This reduces peak storm flows through natural drainage systems and minimizes flooding potential. The following design principles can be incorporated to reduce stormwater runoff and limit a building’s impact on water quality: Avoid changes to topography, vegetation and landforms. Most disturbances to a site, and removal or disturbance of vegetation, will compact soils and increase stormwater flows by reducing the ability of soils to absorb water. Preserving the original topography and drainage channels is generally recommended. However if changes are unavoidable, re-contouring the land, if carefully planned and executed, can also slow water runoff and improve infiltration in some cases. Minimize impervious areas. The negative effects of impervious surfaces on a site can be minimized by: o Limiting the clearance of vegetated areas o Installing porous pavements (e.g. gravel or permeable paving) on low traffic areas such as driveways, car parks and footpaths o Reducing the sealed area to the minimum required to accommodate an activity o Building pedestrian surfaces, such as walkways and patios, with loose aggregate, wooden decks, or well- spaced o Separating impervious surfaces with turf, gravel or vegetation to increase infiltration between the areas o Redirecting runoff from impervious surfaces on to vegetated areas or gardens designed for water capture Use green walls and green roofs. A green roof is a vegetated roof system consisting of an impermeable membrane, insulation, gravel, soil and plants. Typically, green roofs range from 5cm to 15cm in soil depth and are planted with a variety of low growing ground cover plants. Vegetated green roofs on conventional buildings such of offices now account for 20% of the new roofs in Germany, and Tokyo has mandated them on all new commercial buildings over 1000m2. Green roofs are also increasingly popular in Singapore, experiencing high temperatures and humidity, where research is being conducted into effective green roofs for the tropics. Green roofs result in significant energy savings by providing insulation as well as reducing water runoff by retaining and slowly releasing water. They are attractive natural features that also help to reduce the urban heat island effect in larger cities (re-radiated heat from concrete and other building materials that creates a hotter environment in heavily built-up areas). ARC 1435 62 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Figure 41 : Roof garden at the Trinoma Mall (left) and the Sky Garden SM North (right) Image source: Flickr, https://www.flickr.com/photos/m-aero/3550286783, www.dreamstime.com. Copyright © Junpinzon Use Water Sensitive Urban Design. Water Sensitive Urban Design (WSUD) is an approach to stormwater management that replaces in-ground stormwater pipes with drains, swales and detention areas that mimic natural Key components of WSUD: Infiltration Trenches: an infiltration trench is a shallow trench filled with gravel, rock or porous material, which is placed to collect stormwater runoff. Stormwater slowly filters from the trench through the surrounding soil, while particulate and some dissolved pollutants are retained in the trench. The trench discharges the treated stormwater into a conventional pipe system. The trench is lined with a layer of geotextile fabric, to prevent soil migration into the rock or gravel fill. The top surface of the fill is also covered with a layer of fiber fabric, then finished with a shallow layer of topsoil. The trenches can increase the soil water levels, groundwater flow rates and can reduce stormwater flow velocities. Swales: are deliberately formed undulating terrain creating raised banks and open channels that are designed to slow water flow and allow plants growing in the channels to take up nutrients and filter the water. Soil micro- organisms also help to remove some pollutants from the water. Swales also help with the screening or removal of gross pollutants, such as litter and coarse sediment, from stormwater runoff. Swales may be used as an alternative to the conventional street nature strip or in central median strips of roads, through to runoff collection points in car park areas. Hydraulically swales can reduce run-off volumes and peak flows. Current designs involve the use of grass or other vegetation (such as rushes) to carry out this function. Bio-retention systems: combine various WSUD treatment types in one system. They are designed to carry out primary and/or secondary treatment of stormwater and to slow flows. The current types of treatments used include grassed swales (primary treatment) in combination with infiltration trenches (secondary treatment). Reducing velocities and retarding water reduces the flow of stormwater during the infiltration process. Source: www.melbournewater.com.au ARC 1435 63 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ processes. The purpose of WSUD is to improve absorption of rainwater into the soil and to slow and filter any water which is not absorbed so that high quality water leaves the site. Create rain gardens. Rain gardens are designed to retain runoff from the site and can be used in conjunction with WSUD or as a stand-alone design response. They may be container gardens, or sunken pits, generally formed on a natural slope, that are filled with gravel, sand, soil and native shrubs perennials, and flowers. It is designed to temporarily hold and soak in rain water runoff that flows from roofs, driveways, patios or lawns. Depending on the amount of water entering, these gardens may need to be fitted with a low flow outlet and an overflow device for high flows. Rain gardens are effective in removing up to 90% of nutrients and chemicals and up to 80% of sediments from the rainwater runoff. Compared to a conventional lawn, rain gardens allow for 30% more water to soak into the ground. A rain garden is not a water garden. Nor is it a pond or a wetland. Conversely, a rain garden is dry most of the time. It typically holds water only during and following a rainfall event. Because rain gardens will drain within 12-48 hours, they prevent the breeding of mosquitoes. Rain gardens will require periodic maintenance to remove sediment that has built up in the gravel and plants need to be cut back to encourage new growth. Figure 42 : A rain garden is a planted low area that allows rainwater runoff from hard surfaces (like roofs, driveways, walkways and parking lots) to soak in. Image source: https://extension.umn.edu/landscape-design/rain-gardens Indoor environment quality Creating an enjoyable and comfortable environment creates a healthier and more productive space. On the other hand, poor indoor environmental quality is considered to be the main cause of Sick Building Syndrome, (a common worldwide health concern, where people in a building suffer from symptoms of illness or become infected with chronic disease from the building in which they work or reside). A healthy indoor environment incorporates good air and light quality, views to outside, comfortable temperatures, minimal noise pollution and a low-toxicity environment. Waste and construction materials Reducing waste. Waste from the building can be divided into two categories: waste generated during construction waste generated during subsequent operation or habitation of the building ARC 1435 64 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ It is important to reduce the amount of waste going to landfill as this reduces the need for more landfill sites; also the production of new materials consumes natural resources and produces greenhouse gas emissions. Reducing, reusing and recycling waste materials is therefore the most sustainable option. Simple steps you can take to minimize waste from the building site during construction: Reuse or recycle as many of the unwanted materials as possible. Use building designs that are designed to minimize off cuts. Avoid over ordering and materials being damaged onsite. Return over-supplied quantities to the supplier. Create an area within the site for the storage and removal of different waste types. Ensure waste is clearly separated into recoverable and non-recoverable streams. Keeps records of movement of waste and recovered waste materials on and off site. Store off-cuts that are of a reasonable size and condition for use in maintenance. Organize with suppliers for pallets to be returned with follow on deliveries. Crush large quantities of concrete, bricks and hard materials and use for road base, retaining walls, drainage etc. Design and select materials for ease of deconstruction, reuse and recycling, either upon major refit or demolition. Source: Cairns Regional Council, 2011. Selecting low impact construction materials. Careful choice of building materials can greatly improve energy efficiency, increase the comfort and health of building users, and reduce overall environmental impacts of a building. For best environmental outcomes, construction materials that have the below characteristics should be prioritized. Sustainable construction materials are: Manufactured from renewable or recycled resources. Energy efficient and have low embodied energy. Non-polluting. Manufactured using environmentally acceptable production methods. Durable and have low maintenance requirements (painting, re-treatment, waterproofing etc), or whose maintenance will have minimal environmental effects. Recyclable. All materials have embodied energy and emissions. The embodied energy is the energy used in the extraction and processing of raw materials to make building materials and transport and processing of those building materials. The embodied energy per unit mass of materials used in building varies enormously, from about two gigajoules (GJ) per tonne for concrete to hundreds of GJ per tonne for aluminum. However, other factors also affect environmental impact, such as differing lifetimes of materials, differing quantities required to perform the same task and different design requirements. ARC 1435 65 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Selecting materials with low embodied energy greatly reduces the greenhouse gas emissions associated with a building project. Recycled materials generally have much lower embodied energy levels. For example, aluminum from a recycled source will contain less than ten per cent of the embodied energy of aluminum manufactured from raw materials. The figures in the table below are estimates only, and do not include transport emissions. Therefore these materials used at sites near production will have lower embodied energy than the same materials used at sites further away. Table 3 : Embodied energy of building materials. MATERIAL PER EMBODIED ENERGY MJ/kg Kiln dried sawn softwood 3.4 Kiln dried sawn hardwood 2.0 Air dried sawn hardwood 0.5 Hardboard 24.2 Particleboard 8.0 MDF 11.3 Plywood 10.4 Glue-laminated timber 11.0 Laminated veneer lumber 11.0 Plastics – general 90 PVC 80.0 Synthetic rubber 110.0 Acrylic paint 61.5 Stabilized earth 0.7 Imported dimension granite 13.9 Local dimension granite 5.9 Gypsum plaster 2.9 Plasterboard 4.4 Fiber cement 4.8* Cement 5.6 In-situ Concrete 1.9 Precast steam-cured concrete 2.0 Precast tilt-up concrete 1.9 Clay bricks 2.5 Concrete blocks 1.5 AAC 3.6 Glass 12.7 Aluminium 170 Copper 100 Galvanised steel 38 Source: Lawson Buildings, Materials, Energy and the Environment (1996) You may read this online article: Embodied Energy of Materials, https://www.pmcarchitects.com/sustainability-information-blog-content/embodied-energy-of- materials Local environment The level of impact that a construction project has on the natural environment can be greatly reduced by adopting simple measures such as locating the building away from ecologically sensitive areas, protecting topsoil, landscaping with local native plants, revegetating areas of the site to create habitat, minimizing soil runoff during construction, and landscaping to slow water flow across the site. Social and visual amenity can also be improved by allocating space for community gardens if the site is appropriate. Effective landscaping can also influence the indoor environment by channeling cool breezes into the building and shading sun-exposed walls. ARC 1435 66 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Sustainability Benchmarks According to International Social and Environmental Accreditation and Labelling (ISEAL Alliance), the global membership organization for credible sustainability standards, sustainability benchmark is a way of systematically evaluating the sustainability performance of voluntary standards, certifications, companies or other entities that aim to implement sustainability measures or create positive impacts. Using a set of criteria or reference points, a benchmarking process provides its users with comparable information about the benchmarked entities. In Architecture, benchmarking is the tool used for measuring the sustainability and monitoring the performance of a building. There are three steps in using this system: (1) based on sustainability principles, define and rank the values of a building; (2) establish partnerships with outside building research sources that endorse sustainability principles; (3) adopt a procedure that ensures a comprehensive comparison (Hasan, 2006). Stakeholders using sustainability benchmarks: Government Private sectors like companies, business platforms and associations Non-Government Organizations ARC 1435 67 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Figure 43 : Sustainable design benchmarks and examples Green building case studies Zuellig Building The Zuellig Building in Makati City is the first development in the Philippines, and among the first in Asia, to earn the highest level in the LEED rating system for “green” architecture, sustainable construction methodologies and resource-efficient building operations. Figure 44 : Zuellig Building in Makati City, the first development in the Philippines to earn the highest level in the LEED rating system for “green” architecture. Image source: http://www.asiagreenbuildings.com/6524/philippines-zuellig-building-earns- platinum-leed-certification/ ARC 1435 68 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ It was awarded a certification at Platinum level under its Leadership for Energy and Environmental Design (Core and Shell) (LEED-CS) program by the the US Green Building Council (USGBC). Green principles were integrated in the plans of the architects and design consultants, W.V. Coscolluela & Associates, and Skidmore Owings & Merrill (SOM, New York), while adherence to LEED requirements was monitored throughout the construction process by the project’s sustainability consultant, Langdon & Seah. Among its sustainable features are the following: 1. Energy savings. The green technologies employed in the Zuellig Building achieve significant energy savings (at least 15 percent compared with a base building built to conventional US standards), thereby reducing greenhouse emissions and energy costs. It uses: a. sensor-controlled lighting system to reduce electric lighting based on the intensity of daylight b. efficient HVAC system to regulate temperature and humidity, using fresh air from outdoors 2. Renewable energy source. The building has an on-grid photovoltaic solar power system to generate renewable energy. 3. Water efficiency in the building will save approximately 29 million liters of water annually that result in over 70 percent water savings through water conservation by capturing rain and condensate water and recycling grey water for watering plants. 4. Transport. The location of the Zuellig Building allows tenants easy connectivity and access to public transportation. Bicycle stands and showers are provided for office users who choose to pedal to work instead of burning fuel. 5. Daylighting. Uses double-paned, low-emissivity glass curtain wall, with its ceramic "frit" pattern minimizing solar heat gain and energy loss. a. allows 90% of the interior office space to have natural light b. low-E glass is designed to reflect infrared and ultra-violet radiation to protect people and assets within the building from sun damage c. designed to support the wellbeing and productivity of occupants 6. Air quality. The indoor air quality (IAQ) plan controls the choice of construction materials to eliminate the health risks of volatile organic compounds, and carbon dioxide sensors control and modulate the airflow. 7. Green spaces. The building has three gardens in different locations: A 2,500-square meter private garden at ground level with Zen-like water features and fragrant champaca floral trees; open air terraces on the second and third level of the retail annex; and a futuristic Sky Garden on the 32nd floor with bamboo trees and a breathtaking panorama from Laguna Bay to the Montalban Hills and the Manila Bay. 8. Waste management practices. The building has waste collection and proper disposal of used mercury and bulbs, and waste paper. Sources: Malaya Business Insight and www.bworldonline.com/ ARC 1435 69 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ Sun Life Centre Sun Life Centre is an office building in Taguig, Metro Manila which has achieved the first LEED Gold Certification from the US Green Building Council. The building is home to Sun Life Insurance and other multinationals. It is a 14-storey building with a typical floor plate of 1,657 sqm. per floor. Figure 45 : Sun Life Centre, Taguig, received the first LEED Gold Certification in the Philippines from the US Green Building Council. Image source: https://kmcmaggroup.com/building/Sun-Life-Centre/ Among its green features are the following: 1. Energy savings. Installed with motion-sensors to regulate electricity consumption lead to valuable energy savings 2. Daylighting. Glazed windows block heat but let in sunlight, while the use of zero CFCs prevents further ozone depletion. 3. Air quality. CO2 sensors flush out pollutants inside the building, improving the distribution of fresh air. 4. Water efficiency. Rainwater harvesting collects rainwater for watering the vegetation in the green roof. 5. Green roof. A green roof provides relief and a refreshing view of the BGC skyline for cubicle-stuck employees. Source: https://www.philstar.com/business/real-estate/2012/11/02/862420/sun-life-centre-story Formative Assessment 5: What is sustainable tropical design? Readings in Sustainable Tropical Architecture This compilation of articles written by architects and academicians on sustainable tropical architecture are included to provide us a better understanding of the various concepts on sustainable tropical architecture as observed in different cities within the tropical regions. Below is an overview of the articles which you can read in full in the Reading Materials folder under the Course Learning Module. ARC 1435 70 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ 01 Green Design in the Hot Humid Tropical Zone by Ken Yeang Already well-argued elsewhere is the case for architects and engineers to design our man-made environment with sustainable and “green” (ecologically responsive) design objectives. Simply stated here, the approach is to build with minimal impact on the natural environment, to integrate the built-environment and its systems with the ecological systems (ecosystems) of the locality and if possible, to positively contribute to the ecological and energy productivity of the location. For many designers today, these objectives are regarded as pre-requisites for all their design endeavors. 02 Socio-environmental dimensions in Tropical semi-open spaces of high-rise housing in Singapore By Joo-Hwa Bay, Na Wang, Qian Liang and Ping Kong What are the relationships of community, tropical environment and semi-open spaces in the high-rise high-density housing? The social and environmental aspects of the veranda spaces of the traditional kampong (village) houses in the tropical regions are integrated and sustainable. Is it possible to have community living in semi-open spaces such as entrance forecourts and corridor spaces in high-rise apartments? What are the environmental conditions that permit this? What are the relationships of socio-climatic aspects with plants in sky-gardens and sizes of semi-open spaces? All these are discussed in the case of Bedok Court condominium, with comparison with a typical public housing block in Singapore. 03 Policy and evaluation system for green building in subtropical Taiwan By Hsien-Te Lin Sustainable development has been a worldwide concerned issue in many aspects. However, most of the existing Green Building assessment tools such as BREEAM, GBTool, CASBEE, and LEED are established for developed countries with cold climates, and many of them are difficult to be directly applied for those with tropical climates. For example, there are great differences between residential energy usages for the diverse climates, which may greatly influence the technology of building envelop design. Furthermore, the buoyancy ventilating method is applied well in south European countries, but is not suitable for tropical climates due to the warm outdoor temperature and high humidity. This essay will discuss different aspects of green building technologies for various climates by analysing the building energy simulation of 300 Asian cities by using two energy- consumption distribution maps in a whole Asian scale. The discussion is specifically focused on different green building design strategies such as shading, insulation and ventilation for the climate between tropical and subtropical zones. This essay will also introduce an unique Green Building Labelling System in Taiwan – EEWH system, which mainly concerns about four topics, Ecology, Energy conservation, Waste reduction and Health, comprising nine environmental indicators. This system has been maturely developed, simplified and adapted for the subtropical climate and acknowledged by the Ministry of the Interior of Taiwan as the standard method for Green Building evaluation since 1999. From 2005, a new rating scheme will be brought in the EEWH system. The ratings are classified into four levels ranking from diamond, gold, and silver to bronze, which respectively represent the top 5, 15, 30, and 50% of the score percentage. In the near future, the EEWH system with new rating scheme will become a more important index in a government-led program encompassing long and lasting development in the technology and promotion of green buildings. Finally, some Green Building promotion programs, such as mandatory Green Building Green policy, Green Remodelling project, Green Building Award competition, and Green Building Expo will also be introduced in this essay. 04 In search of a habitable urban space-built ratio: A case study of building and planning regulation in Dhaka City By Q.M. Mahtab-uz-Zaman, Fuad H. Mallick, A.Q.M. Abdullah and Jalal Ahmad Building and planning regulations in Dhaka are weak instruments for designing and managing urban space and built form. Ambiguities in the existing regulations result in the scarcity of open space mainly in residential areas since residential ARC 1435 71 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ development occupies majority of urban space in order to cater for the growing urban population. The tropical climate suggests the need for sufficient open space with the building forms, to bring about a habitable environment. This chapter highlights the limitation of the existing building regulations, which allow less open space in Dhaka. Case study-based comparison between previous building practices and current standards reveal that certain building regulations have the potential to be revised for better living environment. Some proposals are made emphasizing the need for introducing FAR (Floor Area Ratio); and simulated to suggest a change in the contemporary building practice in order to (a) achieve a comfortable indoor and outdoor environment; (b) create more green areas to reduce urban heat island effect; (c) create a better ecological balance; and (d) preserve low lying areas for water retention as flood protection mechanism –all of which collectively have potentials to enhance social and environmental qualities of the city. 05 Designing high density cities - parametric studies of urban morphologies and their implied environmental performance By Edward Ng, Tak-Yan Chan, Vicky Cheng, Nyuk-Hien Wong and Meiqi Han Cities of tomorrow must embody the concept of sustainability. Urban design is not about drawing patterns on paper and its architectural studies could not be merely spatial, formal or geometrical. Urban design of the next millennium is about providing and optimising an infrastructure for the enjoyment of its inhabitants while at the same time minimising energy and resources needed, and maximising the benefits of the natural environment. An important consideration of urban design is to provide natural outdoor conditions that are pleasant to human activities. A well-designed outdoor urban environment will also make the design of individual buildings within it easier. Hong Kong and Singapore share common climatic and environmental conditions. Both are cities with limited land resources with a growing and more demanding population. Planning the cities to cope with needs is an important task for their planners. There are many design parameters, for example: Development Density, Plot ratio, Site Coverage, Skyline, Building to Space Ratio, Permeability, Building Shapes and so on. This chapter reports a study based on “skylight” as a design parameter, and how it affects daylight and natural ventilation performances. Experiments were conducted with physical models in wind tunnel and artificial sky, as well as using CFD and computational lighting simulation. The study establishes that, for example, by varying the skylines of the city, the overall daylight and natural ventilation performances could be improved when compared to a city with a uniform skyline. A key message of the chapter is that, through a better understanding, high density cities could be planned and optimised environmentally without losing the development efficacy of the land. 06 Urban Heat Island Effect in Singapore By Wong Nyuk-Hien and Chen Yu Urban Heat Island is the phenomenon where the temperatures in the city are higher than those in the suburban rural areas. The causes of Urban Heat Island (UHI) are primarily the absorption of solar radiation by building/urban materials that is subsequently re-radiated to the surroundings. In addition, the anthropogenic heat generated from the combustion process and air-conditioning coupled with the greenhouse effect of pollutants also contributes to the increase in temperatures. With the current trend of adopting high-rise and high density strategy, as well as the increasing and extensive usage of air- conditioning, UHI effect becomes an unavoidable issue during the rapid urbanization in Singapore. From the social point of view, UHI effect may have some negative impacts on urban environments, urban dwellers, and energy use. Some related social issues include atmospheric pollution, heat-stress related injuries, increased energy use for cooling and water use for landscape irrigation, etc. Singapore is a tropical country and all these social issues occur more frequently as compared to countries with warm or cold climate. Therefore, this research carried out to explore the severity of UHI and potential mitigating strategies, is meaningful for Singapore. ARC 1435 72 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ This research was sponsored by the Building and Construction Authority and National University of Singapore. At the macro level, the severity of the UHI was studied through remote sensing technology, mobile survey, as well as comparison of historical meteorological data. At the micro level, the tangible measures are explored through field measurements conducted in big parks and surrounding developments, rooftop experiments, wind tunnel testing, and CFD simulations. This chapter provides a broad perspective of some of the key findings of this UHI study in Singapore and discusses the potential mitigation measures. 07 Tropical Urban Street Canyons By Elias Salleh Urban canyons represent important urban open spaces in between buildings, having various microclimates which influence the resulting thermal environment, including the formation of “cool islands”. Thermal environment is of prime importance, influencing people’s use of urban outdoor spaces. Generally, a deeper urban canyon will result in less penetration of direct solar radiation to the street level, while reducing the sky radiant field and increasing air flow within the urban canyon. These are potentially favourable for mitigating outdoor thermal discomfort in highly developed tropical urban areas, and for promoting better utilisation of urban spaces for outdoor activities. An attempt to study Kuala Lumpur urban street canyons has been made, using Fanger’s PMV comfort index and Terjung’s URBAN3 climate model. The study confirms that a shallow urban canyon is warmer than a deeper one, and that shallower urban canyons experience higher cumulative energy fluxes than deeper ones. In shallower urban canyons small increases of air velocity have little influence on thermal comfort level. On the other hand, a deeper urban canyon with lower air velocities can maintain tolerable PMV levels, mainly because of the cooling effect from the reduction in solar penetration to the street level and the reduced sky view. For optimum shading the best street orientation for urban canyons in such locations is north/south, and the northeast/southwest and northwest/southeast orientations are good compromises. An urban canyon height/width ratio of 3:1 represents the threshold of optimum urban canyon shading and surface temperature control. These design guides are critical for designing better urban environments. 08 Tropical and traditional: Inventing a new housing model for the old 36 Streets Quarter in Hanoi, Vietnam By Shoichi Ota Hanoi’s old quarter, also known as the “Old 36 Streets Quarter,” composed of extremely long and narrow tube-like houses, is nowadays regarded as a historic district with its traditional way of life. On the other hand, the quarter holds the commercial core of the city as well, and is exposed to the pressures of urban development. The Quarter is essentially a high-density populated area full of urban and environmental problems. Existing houses in the quarter are already fully used and have been modified ad hoc to meet ever-changing residential needs during last several decades. This shows the gap between structure and usage. The poor infrastructure is insufficient to accommodate the increasing population of the city, and their increasing energy demands such as for air-conditioning. The Hanoi Experimental Housing Project was started to resolve these difficulties, by introducing a novel housing model based on the study of existing urban fabrics. The architect Kazuhiro Kojima introduced an important idea, “space block,” to the project. Space block is an architectural design methodology, using some basic space blocks (BSBs) as constitutive elements, which form a whole porous structure. This idea is well-matched to the required building performance. BSB is equivalent to housing in a tube-like house. The porous structure creates wind corridors connecting several inner void spaces or courtyards, which encourages natural ventilation and is effective in reducing energy consumption. The experimental construction was completed in 2003. The model is designed to accommodate local lifestyle and to ensure comfort in the tropical climate. For “sustainable development”, we have to consider how to co-exist with conventional urban contexts, in historic and environmental terms. The Hanoi experimental house is not merely a new architectural model, but also takes in old elements of the site and surroundings. This merging of old and new is a key characteristic of the project. ARC 1435 73 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts ___________________________________________________________________________ 09 ECOPET 21: An innovative sustainable building system for ecological communities in tropical regions By José Roberto García Chávez During the last fifty years, an inappropriate use of energy and natural resources on our precious planet has been a common pattern, associated with an explosive population growth and an accelerated intensity of industrial activities, based on an irrational exploitation and burning of fossil fuels, and these include intense energy use in cities and buildings, which are responsible for about one half of total energy consumption in the world. All these trends have provoked a severe damage on the planet’s ecosystems. Nowadays, it is not only necessary, but urgent to modify these trends and to apply corrective actions. In this work, an innovative sustainable construction system called ECOPET 21, has been applied in a house prototype and integrated with the application of bioclimatic design principles and sustainable technologies as well as environmental planning, aimed at the development of ecological sustainable communities, particularly for tropical regions. The principles and benefits of this approach are presented and their benefits demonstrated. The main objective of this project is to implement ECOPET 21 with the integration of sustainable technologies into bioclimatic architectural design and rural planning actions in tropical regions, based on the use of renewable energies, taking into account and emphasizing the economic and social issues, aimed at promoting a multiple effect and a consistent sustainable development with local and global benefits. Formative Assessments 6: How do other cities in tropical regions respond toward urban climate issues and contribute to sustainable tropical architecture through their design responses? Summative Assessment 1: Energy-efficient Design Case Study ARC 1435 74 Far Eastern University 1st Semester SY 2021 - 2022 Institute of Architecture and Fine Arts
