BUILDING SCIENCE 1 PTM GEO 2
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The document summarizes the passive design features of the GEO building in Malaysia that improve thermal comfort and reduce energy usage. The building is oriented with its long facades facing north and south to minimize direct sunlight. It has a stepped design that becomes wider at higher floors to provide self-shading. Double glazed windows, overhangs, and internal reflectors are used to maximize daylight while minimizing heat gain. Insulation is used extensively in walls and roofs. Together, these passive design strategies maintain indoor temperatures close to outdoor conditions without excessive energy use.
BUILDING SCIENCE 1 PTM GEO 2
- 1. Page | 13 Passive Design Feature 1 - Basic building design A. Building Orientation According to the Malaysian Standard 1525 (MS1525), one of the passive design strategy is orientation of building. The GEO building is considered well orientated because its long facades are facing north and south, and short facades are facing east and west. (Department of Standards Malaysia, 2007, p. 5) With this orientation direct sunlight only shines at the shorter facades in the morning and evening. West Facade N North Facade South Facade East Facade Figure 1 Floor Plan Figure 2 Geo building Sun Path
- 2. Page | 14 To avoid the entering of direct sunlight into the facades facing east and west, the building is designed to have minimal windows at these two short facades. On the other hand, the longer facades are filled with windows to allow maximum amount of daylighting to enter the building. Natural lighting that enters the building through the long facades are diffused light, not direct sunlight. Diffused light has lesser thermal impact compared to direct sunlight. Hence, with this design strategy, the building is able to achieve higher thermal comfort. (Ng & Akasah, 2011, p.) Figure 4 the north and south facade is filled with windows to allow daylighting (Source: http://www.greenbuildingindex.org/why-green-buildings.html) Figure 3 The east and west facades have minimal window (Source: http://wikimapia.org/619168/PTM-GEO-Building)
- 3. Page | 15 B. Building Configuration Another passive design strategy mentioned in the MS1525 is the configuration of the building. (Department of Standards Malaysia, 2007, p. 4) The GEO building has a “step-in” design. The step-in design enables the building to be self-shaded by its own structure. (Ng & Akasah, 2011, p. 221) In the section, it can be seen that the width of the floor increases as we go up the floors. This is done to control glaring from direct sunlight. There are also extended walls that creates a vertical shading system. Overhangs are also installed to aid the shading and glaring control. The extended walls and the overhangs create an egg-crate-like design which helps the building to be well- shaded. Figure 5 Section of the building Figure 6 Extended vertical walls at the North Facade North South
- 4. Page | 16 The images below are created using Ecotect. The date was set to be 22nd September and the façade used is the North facade. From the images, it can be seen that the GEO building is well- shaded throughout the day. The orientation of the building and the building configuration had contributed to the success of the shading system. Figure 9 Shading at 6pm Figure 8 Shading at 2pm Figure 7 Shading at 10am
- 5. Page | 17 C. Insulation Referring to the MS1525, the general requirement of the building envelope is to be able to block out heat gain into buildings via conduction and solar radiation. (Department of Standards Malaysia, 2007, p. 10) To achieve this, insulations are installed in the walls and the roof of the building. The internal walls are installed with a layer of rock wool whereas the external walls are installed with two layers of rock wool. This is because the external walls receive greater thermal effects compared to the internal walls. (Ng & Akasah, 2011, p. 215) The roofs are also insulated to reduce thermal transfer. The slanting roofs are insulated with Mineral wool due to its excellent thermal insulation. However, mineral wool is vapour-permeable causing it to be unsuitable for flat roof insulation. Hence, Styrofoam insulation is used in flat roofs. (Ng & Akasah, 2011, p. 215) With the roof and wall insulations, the overall thermal transfer value (OTTV) of the building can be reduced, hence achieving better thermal comfort. With the aid of air-conditioning and the radiant cooling, the average temperature of the interior of the building is 24°C to 26°C. (Ng & Akasah, 2011, p. 225) Rock wool insulation Wire Mesh Cement mortar Figure 10 internal wall insulation Rock wool insulation Wire Mesh Cement mortar Figure 11 external wall insulation Figure 12 installation of Styrofoam during construction of the roof (Source: Malaysia Green Technology Corporation, 2010) Figure 13 Mineral wool layer is installed on the slanting roof (Source: Malaysia Green Technology Corporation, 2010) Figure 14 Indoor temperatures (Source : Yoong, 2008, p. 67)
- 6. Page | 18 Passive Design Feature 2 - Windows and Roof Light To minimize the use of artificial lighting, windows are placed along the long facades and roof lights are placed on the top floor for natural lighting to reach the interior. The GEO building uses an open space concept where the workstations are placed near the windows and use of partition is minimal to enable light to reach all workstations. (Pusat Tenaga Malaysia, 2008) The MS1525 also touched on the daylighting. It is mentioned that when designing with the emphasis of natural daylighting, the solar gain has to be considered. (Department of Standards Malaysia, 2007, p. 5) This can be controlled by using windows with suitable solar and thermal properties and external and internal shading devices. A. Windows Double glazed windows are used to reduce heat gain in the interior. These windows reflect ultraviolet and infrared radiation from the building’s exterior surface, reducing the heat transfer by 25%. With the use of radiant cooling through the floor slab and air-conditioning, there is a maximum difference of 7°C between the indoor and outdoor temperatures. (Yoong, 2008, p. 67) The windows also use a unique system to avoid emission of direct sunlight into the building. Overhangs are installed for shading purposes. On the overhangs, there are Double pane glass Argon Gas Gap Indoor Figure 16 Double Glazing Window Reflected Heat Outdoor Figure 15 Floor Plan: Workstations are placed near windows. N
- 7. Page | 19 reflective mirrors to reflect the diffused daylight into the building. Blinds are installed on the upper windows to direct the light upwards to the internal daylight reflector. These reflectors enables diffused daylight to be thrown deeper into the building. The blinds also act as a barrier direct sunlight which comes from the above. By preventing direct sunlight from entering the interior, heat gain in the building can be reduced greatly. The lower surface of the blinds are white with low gloss whereas the upper surface of the blinds are reflective aluminium to allow reflection. (Muhammad, 2014) Blinds Internal daylight reflector Reflective mirror Outdoor Indoor Figure 17 pathway of diffused light through window Figure 18 Overhangs from the exterior Figure 19 Internal Daylight Reflector (Source: Green Tech Malaysia, 2014)
- 8. Page | 20 B. Roof Light On the highest floor, roof lights are installed to distribute diffused natural lighting which carry less heat energy compared to direct sunlight. This is achieved through the installation of mirror reflectors on the insides of the structure which serve to magnify light. A better thermal comfort is achieve as direct sunlight do not enter the building. (Muhammad, 2014) Direct Sunlight Diffused Light Mirror Reflector Figure 20 Pathway of diffused light from Roof light Figure 21 Roof light from the roof (Source:http://www.uniten.edu.my/newhome/uplo aded/coe/arsepe/2008/UNITEN ARSEPE 08 L24.pdf) Figure 22 Roof light from the resource centre