Department of Civil, Faculty of Technology Engineering, Universiti Malaysia Perlis, Malaysia

Transcription

1 Site Planning and Orientation for Energy Efficiency: A Comparative Analysis on Three Office Buildings in Kuala Lumpur to Determine a Location for Building Shading Device Nurul Akmam Naamandadin 1,3,a, and Abdul Razak Sapian 2,b, Siti Nur Aishah Mohd Noor 1,c 1 Department of Civil, Faculty of Technology Engineering, Universiti Malaysia Perlis, Malaysia 2 Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, Malaysia 3 Centre of Excellence Geopolymer and Green Technology, School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), Taman Muhibbah 02600, Jejawi, Arau, Perlis, Malaysia a nurulakmam@unimap.edu.my, b arazaks@iium.edu.my, c sitinuraishah@unimap.edu.my Keywords: Building Orientation, Energy Efficient Design, Green Building Abstract: A well-designed energy efficient building provide long term building optimisation while minimising the energy. Site planning and orientation of the building plays an important factor at the early stage of any development. Especially to determine the best location for the building opening and windows and also the suitable materials to enhance comfort to the occupants and reduce the energy consumption. Thus, the aim of this study was to identify the site planning and orientation of the selected office building. The benchmark for the analysis will be based on the architectural and passive design component provided in MS 1525:2007 for the site planning and orientation through comparative analysis. Three energy efficient office building in Kuala Lumpur were selected in this research. This case study is important in helping to understand the relationship between site planning, building orientation, energy efficiency and cost effectiveness. Introduction Refer to the Malaysian Standard code of practice on Energy Efficiency and Use of Renewable Energy for Non-residential Building, MS1525:2007, it was stated in the guideline for site planning and orientation as said; For climate zones nearer to the equator, generally the best orientation for the buildings are with the long directional axis of building facing North-South, minimising the East- West orientation. Technically the buildings longitudinal orientation should be on an axis 5 Northeast. On narrow sites this may not be possible, here the solutions may require circular, square or octagonal, or other building geometries. In this case, the shading devices recommended may differ according to orientation or building may also contribute to immediate microclimate of open spaces through the provision of shading to the immediate surroundings that will turn benefit the indoor areas adjacent to it. The microclimate information (temperature radiant temperature, wind direction and precipitation, etc) should be analysed for locally in making decision for design tradeoffs. Literature Review Site Planning and Orientation Building orientation and site planning are amongst the important factor in determining the building eco-friendliness [1]. Accordingly they can help the designers to determine which area will be affected by receiving direct sunlight to the building façade or atrium design. An important clue in

2 developing energy efficient facades for energy efficient building is the knowledge about the distribution of solar radiation due to orientation. It is not only that when refer to Yeang statement s [2], This can be reflected, for example, in the plan configuration, the building's depth, the position and layout of entrances and exits, the means of movement through and between spaces, the orientation and views as interpreted in the plan. The plan should also reflect air movement through the spaces and the provision of sunlight into the building. It can be conclude that the site planning has a relationship with orientation of the building. The orientation of the building should be accumulated with sun path. Sun path is the sun s position on the sky hemisphere [3]. It can be specified by two angles: i. Solar attitude angle (y). e.i. the vertical angle at the point of observation between the horizon plane and the line connecting the sun with the observer. ii. Solar azimuth angle (a). e.i. the angle at the point of observation measured on a horizontal plane between the northerly direction and a point on the horizon circle, where it is intersected by the arc of a vertical circle, going through the zenith and the sun s position Koenigsberger et. al [3] added, to find the angle of incidence of solar radiation, the position of sun in relation to the building elevation must be established for the specified point of time. The data then will help the designer to arrange the building orientation and determine which side can give the greatest advantages in reducing insulation (and the resulting air-conditioning load). To get the accurate results, the data must be collected in frequently. Friedrich and Michael [4] mentioned that, while the trajectory of the sun can be accurately calculated, the incoming radiation depends very much on the actual sky condition: while solar radiation with clear sky and sun can be easily predicted, a cloudy sky complicates this prediction, due to quite different kinds of clouds. To resolve the problem measurements were carried out on horizontal frame for many years in many locations at the same region. In order to obtain an idea about the average solar radiation, which is of the utmost importance for the economic analysis of solar systems, the results were interpreted via statistic programs [4]. While Yeang [2] mentioned tall buildings are exposed to the full impact of external temperatures and radiant heat. Accordingly, the overall building orientation has an important bearing on energy conservation. In general, arranging the building with its main and broader openings facing north and south gives the greatest advantages in reducing heat insulation (and the resulting air-conditioning load). It frequently happens that the geometry of the site does not coincide with sun path geometry. In these cases, the other built elements may, if expedient for planning purposes, follow the site geometry (for example, to optimize basement car-parking layouts). Typical floor window openings should generally face the direction of least insulation (north and south in the tropics). Cornershading adjustments or shaping may need to be done for sites further north or south of the tropics or for non-conformity of the building plan to the solar path [2]. Building orientation affects the air-conditioning or heating energy requirements in two respects by its regulation of then influence of two distinct climatic factors [5]. i. Solar radiation and its heating effects on walls and rooms facing different directions ii. Ventilation effects associated with the relation between the direction of the prevailing winds and the orientation of the building. From the above two, solar influence on energy is the most significant in the tropics and is extensively covered by many others [5]. Window Openings Generally, window openings should orientate toward north and south unless important views require other orientations. If required for aesthetic reasons, curtain walling may be used on non-solar-facing

3 facades. On the other faces of the building, some form of solar shading is required; while the quality of light entering the spaces should also be considered. In temperate zones, transitional spaces can have adjustable glazing at the other face so that balconies or recesses can act as 'sun spaces', collecting solar heat, like a greenhouse or conservatory [2]. The flow of air can be influenced by topographical features, by the orientation of the building and the position of the surrounding buildings and other obstructions. All these factors must be considered carefully, as the openings should be free from the effect of outside obstructions. The air flow should not pass over hot surfaces (such as asphalt) before reaching the building [3]. In fulfilling the human requirement, designers should minimise energy consumption. As for an example, the use of air-conditioning system will require a high-energy expenditure [6]. Highenergy expenditure must be considered in planning spaces to ensure compact plans which minimise external surfaces for example, from which heat can escape from hotter climates. This factor must be considered to make sure that the location of heat sources can be of maximum benefit [6]. The location and orientation of a window or skylight, therefore, can be more important than its size in determining the quality of daylight room receives. Direct sunlight provides a high degree of illumination, especially during mid-day. Designers should take benefit on this situation in minimizing energy consumption for example by developing solar system for water heating and also electricity to generate the electrical instruments. Yeang [7], clarified that typical floor window openings should generally face the direction of least insulation (north and south in the tropics). Corner-shading adjustments or shaping may need to be done for sites further north or south of the tropics or for non-conformity of the building plan to the solar path. Double Skin Facades Pomponi et.al [8] explains the definitions of Double Skin Façade (DSF) systems as said: A glazed double skin façade is a hybrid system made of an external glazed skin and the actual building façade, which constitutes the inner skin. The two layers are separated by an air cavity which has fixed or controllable inlets and outlets and may or may not incorporate fixed or controllable shading devices. Double Skin Façades (DSFs) are said can introduce significant benefits in reducing the energy demand of a building [8]. It has gained much popularity in prevalent time for its ability to reduce solar heat gain or losses in buildings. It has been developed and widely used in order to increase human comfort and decrease energy consumption. DSF systems give a lot of advantages include good acoustics, ideal thermal insulation and wind pressure effect reduction when compare to normal façade window [9]. Research Methodology In order to find out the architectural and passive design strategy those have been applied to the office buildings (in the reduction of the overall energy consumption), case studies had been carried out to discover the site planning and orientation for the selected energy efficient buildings in Malaysia. A comparative analysis was done based on the secondary data collected from the buildings owners. In this research, the measures are; i) Securities Commission Malaysia, ii) Mesiniaga and iii) LEO Building.

4 Data Analysis Buildings Description a) Building 1 ~ Securities Commission Malaysia This building is situated near to Pusat Sains Negara. It was built on 4-ache site was a deep ravine of cleared land bounded by roads to the North-South, and open car park to the west and a rubber estate to the east. The original base ground level was approximately 13 meters difference to the surrounding entry road. Several site analyses were made to determine solar path patterns, orientation and traffic access to match Clients own design brief. The design solution optimised to fit the existing valley topography minimising the removal of earth for the construction of the basements car parks and facilities that did not require natural daylight i.e. auditorium, lecture theatre and squash court were placed in the basement. A 12 meter wide moat runs around the building to bring natural daylight into the spaces below ground that require natural daylight like Child Care centre, Surau and Cafeteria. Figure 1 Site Planning of Securities Commission Malaysia According to MS1525:2007, generally the best orientation for the buildings are with the long directional axis of building facing North-South, and minimising the East-West orientation. But, this building was design based on an equilateral triangle shape. To create an immediate microclimate, the entire building facade has hollow double skins (shows in Figure 3), which form a buffer between indoor and outdoor temperatures and climatic condition. This hollow double skins is called as thermal flue facade which is a double-glazed facade provided with 1.2 m air gap. The air gap serves as a multipurpose maintenance walkway, ventilated air gap and an acoustic buffer zone. Besides that, the walkaway also is installed with louvered panels as horizontal solar- shading to the building.

5 Figure 2 Securities Commission Building shape Source: Hijjaz Kasturi (2006) Figure 3 Securities Commission Building Double Skin Façade b) Building 2 ~ Mesiniaga This building is consisting 15-storeys and circular in plan (shows in Figure 4). It had been design with a sloping landscape base to connect the land with the verticality of the building, a circular spiraling body with landscaped sky courts that allow visual relief for office workers as well as providing continuity of spaces connecting the land through the building; and the upper floor provides a swimming pool and gym. Using sun-path, designer has determined the building orientation (shows in Figure 6(C)). All the window areas facing the hot sides of the building (i.e. east and west sides) have external louvers as solar-shading to reduce solar heat gain into the internal spaces. The louvers and shades relate to the orientation of the building. They allow or reduce solar gain. Those sides without direct solar insulation (i.e. the north and south sides) have unshielded curtain-walled glazing for good views and to maximise natural lighting (shows in Figure 4 and Figure 6(D)). Figure 4 Mesiniaga Floor Plan Source: Mesiniaga (2006)

6 Shading devices Figure 5 Shading devices for Mesiniaga Tower Source: Mesiniaga (2006) Figure 6 Mesiniaga Tower: Building orientation and site analysis Source: Mesiniaga (2006) c) Building 3 ~ LEO Building This building was design with L shape (shows in Figure 7). The windows are primarily orientated to the North and the South. This orientation receives less direction sunshine, and only shallow out shading is required to shade off the sun. East and west orientations receive more sun, and the sun is more difficult to shade off due to the low sun angles for the radiation in the morning and in the afternoon. The most efficient in this building is at the exterior shading. Two types of window façade are used with the concept of the sun is stopped before it enters the building. Lower floors area are being installed with the punch-hole window facades. Meanwhile upper floors are installed with curtain wall windows with shading louvers. The shading is deeper towards east in order to protect against the low morning sun. The windows constitute around 25 39% of the facade area, depending on orientation. Meanwhile, no window at the western facade.

7 Figure 7 LEO Building floor plan Source: Abd Khalid [10] Figure 8 LEO Building North Façade Source: Abd Khalid [10] Figure 9 LEO Building South Façade Source: Abd Khalid [10] Figure 10 LEO Building East Facade Source: Abd Khalid [10] Figure 11 LEO Building West Façade Source: Abd Khalid [10]

8 Findings From these three office buildings, the orientation of the buildings and the sites planning show the differences in shapes. Building Table 1 Buildings Shapes Shape N The best orientation for the building according to MS1525:2007 W N-E 5 E S Securities Commission Building equilateral triangle Mesiniaga Tower circular LEO Building L-shape These three buildings were not 100 percent follow the guideline proposed by MS1525:2007 as it says; in general, arranging the building with its main and broader openings facing north and south gives greatest advantages in reducing insulation. So, the designers have come out with the solutions to provide immediate microclimates for each building. Table 2 shows the solutions to reduce insulation from direct sunlight. Discussions From these three Energy Efficient office buildings, the orientation of the buildings and the sites planning show that the designers and the project teams are concerned about the aspects of reduction of energy usage in buildings. These buildings were built with the main objective: to deliver and achieve the target for minimising energy consumption in the buildings. Site planning and orientation were taken into account were they are not just to minimising direct sunlight heat the building but also to optimize the use of land topography. Refer to James [11], he said microclimate has particular important effect on two aspect of building environment: (1) energy consumption for the heating and cooling of buildings, and (2) the comfort of people in outdoor settings. He added that both microclimate and energy consumption are influenced, however, by the spatial organisation and orientation of the building, structures, and outdoor spaces [11]. Another matter should be taken into account is a tall building. Yeang [7] has had pointed out that the tall buildings are exposed to the full impact of external temperatures and radiant heat. Accordingly, the overall building orientation has an important bearing on energy conservation. In general, arranging the building with its main and broader openings facing north and south gives the greatest advantages in reducing insulation (and the resulting air-conditioning load) [7].

9 These variables can help to reduce the energy usage because air-conditioning load. Building orientation and site planning can help the designers to determine which area will be affected by receiving direct sunlight to the building façade or atrium design. This opinion can be strengthened when relates to Archit Jain [12] statement:..as the earth rotates around the sun and this causes the sun to "rise" and "set". The angle of the sun and its intensity on earth is affected by location of the place on the surface of the earth. The length of the atmosphere that the solar radiation has to pass through determines the amount of radiation that reaches the earth's surface. During the day, the sun is directly overhead and radiation travels through least amount of atmosphere enroute to the earth's surface. As the sun moves closer to the horizon (sunset), the path of the radiation through the horizon lengthens and the intensity of the radiation decreases. Also, at a high elevation, the amount of atmosphere that the solar rays have to travel through is lesser and therefore the energy content is somewhat higher (Archit Jain, USC School of Architecture, 1999). Refer to Yeang [7] a designer for Mesiniaga Tower, he wrote that it frequently happens that the geometry of the site does not coincide with sun path geometry. In these cases, the other built elements may, if expedient for planning purposes, follow the site geometry (for example, to optimize basement car-parking layouts). Typical floor window openings should generally face the direction of least insulation (north and south in the tropics). Corner-shading adjustments or shaping may need to be done for sites further north or south of the tropics or for non-conformity of the building plan to the solar path [7]. Conclusion Table 2 Design Solutions for minimising solar gain Building Orientation Securities Commission Malaysia East and west orientations receive more sun have automatic blind controlled via solar cell to limit excess solar gain to offices north and south orientation receive less direct sunshine and only shallow out walkway as a façade component provides principal solar shading Mesiniaga Tower East and west orientations receive more sun have external louvers as solar-shading to reduce solar heat gain into the internal spaces north and south orientation are not receiving direct solar insulation unshielded curtain-walled glazing for good views and to maximise natural lighting LEO Building East and west orientations receive more sun Difficult to shade off because of low sun angles for the radiation in the morning and in the afternoon north and south orientation receive less direct sunshine and only shallow out shading is required to shade off the sun Detail study and analysis on site planning and orientation have been made to determine a location of building shading device. Shading devices will contribute to the facade designs of the buildings. These three (3) buildings have used different type/design of shading devices. They may vary based on shading coefficient value. Land topography and surrounding area also contribute to the immediate microclimate.

10 From the above findings and discussion, here can be made another conclusion that site planning and building orientation are very important in order to allocate which side of the building façades or building atriums. References: [1] Fallahtafti, Reza Mohammadjavad Mahdavinejad, (2015), Optimisation of building shape and orientation for better energy efficient architecture, International Journal of Energy Sector Management, 9 (4) pp [2] Yeang, K. (1995). Designing With Nature: The Ecological Basis for Architectural Design. McGraw Hill Publication. [3] Koenigsberger O.H., Ingersoll T.G., Alan Mayhew and Szokolay S.V. (1978). Manual of Tropical Housing and Building: Part 1: Climatic Design. London: Longman Group Limited. [4] Friedrich W.G Wilhelm Grimme and Michael Laar. (2006). Solar Radiation & Orientation As A Key Information For Bioclimatic Design. [Online]. [Accessed on 16 th January 2016]. Available from World Wide Web: [5] Chan Seong Aun (2004) ENERGY EFFICIENCY: Designing Low Energy Buildings Using Energy-10. [Online]. [Accessed on 16 th January 2016]. Available from World Wide Web: [6] Young, M. (1986) Architectural and Building Design: An Introduction. London: William Heinemann LTD [7] Yeang, K. (1999) T.R. Hamzah & Yeang: Selected Works (Master Architect Series, 3). Japan: Books Nippan [8] Pomponi, F., Piroozfar, P.A.E., Southall, R., Aston,P., Farr, E.R.P., (2016) Energy performance of double-skin facades in temperate climates: A systematic review and meta-analysis, Renewable and Sustainable Energy Review, 54, pp [9] Shameri, M.A., Alghoul, M.A., Elayeb, O., Zain, M.F.M., Alrubaih, M.S., Amir, H. et al.(2013) Daylighting characteristics of existing double-skin façade office buildings, Energy Build, 59, pp [10] Abd Khalid, C.D. (2007) MEWC LOW ENERGY OFFICE BUILDING (LEO): A Showcase of EE in Buildings. Putrajaya: Ministry of Energy, Water & Communications Malaysia Department of Standards Malaysia (2007) MS 1525: 2007 Code of Practice on Energy Efficiency and Use of Renewable Energy for Non-Residential Buildings (1 st Rev.). (2007) Department of Standards Malaysia: SIRIM. [11] James A. LaGro. (2001) Site analysis linking program and concept in land planning and design. New York: John Wiley & Sons, Inc. [12] Archit Jain. (1997) Online Solar Position Calculator and VRML Builder VRSolar. [Online]. [Accessed on 16 th January 2016]. Available from World Wide Web: 00/dept/architecture/mbs/tools/vrsolar/Help/solar_concepts.html#apparent