A Study on Passive Design Strategies Used for Climate Control in Traditional Malay House by zhenxiang98

Asian Architecture

Abstract Energy crisis have become a serious global issue, more and more so in todayâ&#x20AC;&#x2122;s world that we live in. In the Residential Energy Consumption Survey (RECS) done by EIA in 2015, the data concludes that 56% of the energy usage is for Heating, Ventilating, and Air-Conditioning (HVAC) systems. That is why passive design is vital in the role of building design.

Our study is directed to traditional malay houses based in Malaysia, which has an equatorial climate, being hot and humid throughout the year. The local climates are affected by mountain ranges and the sea, thus it could be divided into that of lowland, highland, and coastal climate. Traditional malay houses are generally built in lowland areas, which is relatively hotter compared to highlands, and has high humidity levels. Therefore it is crucial to include passive design strategies in designing the house, to ventilate the interior, and to shade or daylight the house, to reduce energy consumption and to provide thermal comfort. Our research or study scope will include a few building related factors or elements that contributes to the thermal comfort and climate control of the traditional malay house, in accordance to the MS 1525:2014, which are its strategic orientation and spatial organization of the house, its building material that relates to thermal insulation, building elements which are part of the facade design that provides shade and affects daylighting, and roof design and openings that relates to natural ventilation.

BUILDING ELEMENTS OF TRADITIONAL MALAY HOUSE Figure 1.2 Large Roof Eaves, (therewillbeasia. 2015)

Large Roof Eaves / Overhang Roof

Figure 1.3 Ventilated Roof Space, (mtc, n.d)

Ventilated Roof Space

Figure 1.5 Stilted House Design, (terrapuri, n.d)

Stilted House Design Figure 1.4 Louvered Windows (mejakomputer, 2018)

Louvered Windows

Figure 1.1 Building Elements of Traditional Malay House, (roy, 2018)

Research Question 1. How does the orientation and spatial organization of traditional Malay house relate to thermal comfort and ventilation? 2. How building materials used can affect the thermal comfort in the building? 3. How does the roof design of traditional malay house related to the indoor air quality of the house? 4. How does the openings in traditional malay house and its stilted design contributes to the ventilation of the house? 5. Which are part of the facade design is related to daylighting, shading and glare control?

How does the orientation and spatial organization of traditional Malay house relate to thermal comfort and ventilation?

Spatial Orientation The orientation of the traditional malay house is designed specifically to control direct exposure to sunlight. They are traditionally oriented to face Mecca, which is in an east-west direction, for religious reasons. This east-west orientation of the house minimizes the amount of area exposed to direct solar radiation during the day, and thus reducing heat gain in the house from the sunlight.

Figure 2.1 Spatial orientation (Google Maps, 2018)

Typical Spatial Organization -The porch was designed as the lowest space in the house to make sure the largest amount of wind can be catch. Veranda is usually a rectangular space connecting the porch and main house. This space is usually one step down from main house around 15 centimeters. The opening of veranda can catch more wind into main house by using the pressure difference between the outside atmosphere and the inside atmosphere of the Rumah Ibu (Main House) and Serambi Gantung (Veranda).The core part of the vernacular Malay house is the main house which is used for official events and will be the place for treating guests or relatives, therefore the space needs to be in a good condition. To effectively cool the space, the strategy used is to design the main house as the largest area of the entire building and to have the highest floor level. As the roof level of the main house is the highest among all the spaces, air will flow into the main house thus cooling the space within.

Platform

Kitchen Entrance

Main House

Veranda

Porch Entrance Figure 2.2 Bubble diagram for traditional malay house, (khoo, 2018)

Typical Spatial Organization The core part of the vernacular Malay house is the main house which is used for official events and will be the place for treating guests or relatives, therefore the space needs to be in a good condition. To effectively cool the space, the strategy used is to design the main house as the largest area of the entire building and to have the highest floor level. As the roof level of the main house is the highest among all the spaces, air will flow into the main house thus cooling the space within. A similar space arrangement is applied from the main house to the kitchen. A roofless rectangular platform known as the closed pathway will be another entrance for females which is an open space that allows hot air from the kitchen to flow out, and cool air to go in to the main house and kitchen. The last space of the building is the kitchen which is the place to prepare food. Kitchen is designed as the second highest space of the building as kitchen produce a lot of heat, which needs to be well ventilated to prevent any fire events from happening.

en h c Kit Pla tfo

rm M Ho ain us e

ran

Po rch

Figure 2.3 Typical space planning for traditional malay house, (khoo, 2018)

Malay House in Johor Malay House in Johor also known as Rumah Limas. The main space of the building located in center of the house which the wind can directly come into space from veranda and the platform connecting the center space and kitchen. Kitchen is separated from the main activity block which the heat of kitchen will not be transfer to other activity space. The platform in between provides the fresh air into the main space and kitchen.

Extension

Kitchen

Platform

Bedroom Centre Bedroom Space

Veranda

Figure 2.5 Rumah limas in Johor (mapsight, n.d)

Porch

Figure 2.5 Plan for traditional malay house in Johor, (lokalocal, 2017)

Malay House in Pulau Pinang Malay house in Pulau Pinang is known as Rumah Gajah Menyusu. For traditional Malay house in Pulau Pinang, main space also surrounded by other spaces such as porch, bedroom and platform. Although the kitchen is attached with main house but there is one platform to separate kitchen and main house which similar to other Malay house. In conclusion, the spatial organization of Malay house will change according to their status and culture however there is still a certain pattern in their organization. For example, there will be a transition space between kitchen and main space.

Kitchen Platform

Centre Bedroom Space

Porch

Figure 2.5 Rumah Gajah Menyusu in Pulau Pinang, (myMetro , 2016)

Porch

Veranda

Figure 2.5 Plan for traditional malay house in Johor, (lokalocal, 2017)

How building materials used can affect the thermal comfort in the building?

The traditional Malay house is a timber house raised on stilts. It is basically a post-and-lintel structure with wooden and bamboo walls and a thatched roof. It uses lightweight construction materials with low thermal capacity which are easily available from the tropical forests such as timber, bamboo, rattan, tree roots and leaves. The structural, non-structural and roof parts of a traditional Malay house are constructed out of different types of woods.

Construction Parts

Types of Woods

Structural (Columns, Beams, Joists, Girts)

Cengal, Merbau, Damar Laut and Petaling

Non-structural (Walls, Windows, Doors)

Meranti and Bamboo

Roof (Roof finishes)

Nipah, Rumbia, Bertam and Kabong

Table 3.1 Construction material for traditional malay house (Chung, 2018)

The using of natural materials will affect the thermal comfort in the building because of the different unit of thermal mass and thermal conductivity of the materials.

Thermal Capacity

Thermal capacity is the numbers of heat units needed to raise or lower the temperature by one degree.

Thermal Mass

Materials with low thermal mass holds little heat, therefore the heat transfer between the material and the atmosphere is fast, and the heat energy could be easily dissipated to the atmosphere by natural ventilation. Thus only little heat will be transmitted into the house.

Thermal Conductivity

Thermal conductivity is the ability of a material to conduct heat. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity.

Table 3.2 Definition for thermal properties term (Chung, 2018)

How thermal comfort is achieved ? Meranti and bamboo are the materials which are used to construct the non-structural parts of the building which are the walls, windows and doors. Meranti has low thermal capacity so it can absorb and release heat easily. In a tropical country, materials with higher thermal mass and thermal capacity are normally used as construction material to insulate the house from the strong sunlight. However in kampong areas, materials with lower thermal capacity and thermal mass could be used as the radiating heat will be dissipated to the atmosphere by constant currents of strong wind. The good natural ventilation allows the heat of the building to be carried away, and only a small amount of heat will be transmitted into the house. The main material of roof finishes is palm tree leaves. It has low thermal conductivity and it can reflects the heat energy, therefore the heat from atmosphere will not transfer into the interior space of the house through the roof.

Figure 3.1 Thermal properties of Meranti and Palm Leave (Chung, 2018)

How thermal comfort is achieved ? Bamboo also has low thermal capacity which can help in absorbing and releasing heat quickly. Bamboo has air gap in internodes, it is great at reducing the heat gain because air is a bad conductor of heat. Apart from that, there is a layer of lignin, which is a dead-cell-layer surrounding the bamboo surface that can prevent heat from passing into the bamboo. A layer of natural wax lies on the lignin of bamboo which helps in reflecting heat waves from the atmosphere. In a nutshell, traditional Malay house utilize local natural material to achieve thermal comfort by minimize the heat gain of the interior space.

Interior

Exterior

Figure 3.2 How bamboo reduces heat gains (Ang, 2018)

Thermal Mass and Thermal Conductivity of different material type

Material Type

Thermal Mass (J/Â°C)

Thermal Conductivity k(W/mK)

Timber

653

0.12

Clay

950

0.25

Concrete

2060

1.13

Bricks

1360

0.73

Aluminium

900

230

Table 3.3 Thermal mass and thermal conductivity of each material (Chung, 2018)

How does the roof design of traditional malay house related to the indoor air quality of the house?

Traditional malay house not only use their roof for sheltering and aesthetic purpose, they have also incorporated passive design strategies into their roof design. The roof space in a traditional malay house is ventilated through roof gap and joints. Most traditional malay houses’ roof is separated into two pieces, top and bottom with two different slopes and there are roof joints in between them which creates a gap. The degree of the roof slopes for top and bottom roof is 45º and 20º respectively and this helps to create a stack ventilation effect in the house. It forces hot air to flow upwards into the roof space created at the top roof which will cool down the room at the bottom. Air typically flows from high pressure area to low pressure area. The hot air in the roof space makes the roof space to have high pressure and the air will, therefore, flow out to the lower pressure area outside of the roof.

Figure 4.1 Hot air cycle of traditional malay house (Ang , 2018)

When there is air movement around the house, the hot air will be dragged out from the roof space by the air movement. Due to the different slope of the roofs, the air movement from one direction will partially crash into the top roof who has a steep angle as shown in Figure 4.2. The air which are pushed onto the roof will stay there for awhile and the air that is there will pull hot air out from the roof space as it flows into the roof space to equal out the temperature. This happens because the roof space which contains hot air in it has high pressure and the air movement outside the roof creates high pressure on the surface of the roof. As a result of this, both inside and outside of the roof have high pressure which causes the factor of air flowing from high pressure to low pressure cannot be consider. However, air typically also move from lower temperature area to higher temperature area and the temperature between them are still different, therefore the air will flow from the roof space who has a higher temperature compared to outside of the roof that has a lower temperature in order to achieve thermal equilibrium. This could then helps to cool down the interior of the house very quickly compared to when there is no air movement.

Figure 4.2 Stack ventilation of traditional malay house (Ang , 2018)

How does the openings in traditional malay house and its stilted design contributes to the ventilation of the house?

Openings in traditional malay house plays a big role in providing a good ventilation for the house and good ventilation is very important to the house because they do not have any active cooling system such as fan or air conditioning system back in the days. They rely mainly on ventilation to cool off the interior in order to provide thermal comfort to the occupants. They have quite a lot of openings in the house and some even have the whole facade as windows on all sides. This allows more ventilation into the house and bringing out the hot air from the house through the other side as shown in Figure 5.1. This effect is called cross ventilation where ventilation would come into the building from openings on one side and leaving from openings on another side. Allowing more ventilation into the interior is very crucial because while the material of the walls and floorings, which has low heat capacity, is releasing heat into the interior, the ventilation is needed to bring the heat out. With the cooperation between ventilation and building materials could lead to an even more effective and efficient way in cooling down the interior.

Figure 5.1 Cross ventilation of traditional malay house (Ang , 2018)

The stilted design of the house also helps a lot in providing ventilation to the house. As the house is stilted, It creates a pocket or a gap below the house which allow wind to flow right through with high velocity because of flowing into a smaller, compact space. With air movement beneath the house would also cool up the floor causing the occupants to feel cool while being in the space. Providing strong ventilation beneath the house could also helps removing trapped humidity that can encourage termites, dry rot in timber flooring structures, and an unhealthy environment within the home that can cause the occupants health problems.

Figure 5.2 Cross ventilation underneath of traditional malay house (Ang , 2018)

5. Which are part of the facade design is related to daylighting, shading and glare control?

What building elements which are part of the facade design relate to daylight, shade and glare control?

With a direct dependence on nature for its resources and embodying a deep knowledge of ecological balances, the house is efficiently designed to suit the local climatic requirements using various ventilation and solar-control devices, and low-thermal-capacity building materials. Besides being well adapted to the environment, the house has also evolved a prefabricated building system which is flexible and varied to suit the needs of the users. It has also developed a very sophisticated addition system which allows the house to be extended in line with the growing needs of the user. Shading is effectively controlled by the large thatched Malay house roof with large overhangs. The walls of the house are low, thus effectively reducing the vertical areas of the house exposed to solar radiation. The low walls also make the task of shading easier. The large overhangs which provide good shading also provide good protection against driving rain. They also allow the windows to be left open most of the time for ventilation, even during the rain.

Shading Diagram Example Figure 6.1 Roof shading of traditional malay house (Roy , 2018)

The traditional Malay house with its large roof and low windows tends to be shaded most of the time. This gives a psychological effect of coolness as strong light is often mentally associated with heat. Indirect sources of light like internal and external reflected light are used in the traditional Malay house. They are the best forms of natural lighting for our climate as they minimize heat gain and glare. Direct sunlight should not be used for daylighting as it is accompanied by thermal radiation.

Figure 6.2 Lighting of traditional malay house (Roy , 2018)

Glare, which can be a major source of stress in the Malaysian climate, is effectively controlled in the traditional Malay house. This is done by excluding open skies and bright areas from the visual field. Windows are kept low and shaded by large roof overhangs to reduce glare from the open skies. Glare from the surrounding environment is lessened by the use of grilles and carved wooden panels which break up large bright areas into tiny ones and yet allow the interiors to be lighted up. Figure 6.3 Glare protection of traditional malay house (Roy , 2018)

Conclusion Generally, it can be concluded that the presence of passive design strategies in the building design of traditional malay houses are able to achieve thermal comfort in building spaces. The orientation of the building and its spatial organization ensures that it has maximum air flow over the house and into the interior spaces, to provide sufficient cross ventilation throughout its interior. The materials used are considered and are assured that it has good thermal insulation or could be ventilated easily to keep out heat from the house. The roof design of the malay house is also specifically designed to enhance the stack ventilation in the house when there is minimum air movement, and to draw out heat from the house very efficiently when air movement is present. To aid in shading and daylighting the house, several building elements and the building design are considered to significantly reduce the direct sunlight radiation on the house, and also to control glare from the environment. From our studies above, it could be proven and concluded that these passive design strategies are very effective in achieving thermal comfort and reducing energy consumption of the house. As an evidence, to further strengthen our conclusion above, there are no HVAC (Heating, Ventilating, and Air-Conditioning) systems ever being used in traditional malay houses. This proves that the passive design strategies discussed above are sufficient enough to cool down the house and provide thermal comfort to the residents without the aid of HVAC systems, thus reducing energy consumption required by the HVAC systems by 100%, solving the major issue of energy crisis in todayâ&#x20AC;&#x2122;s era.

Reference List Abd. Wahab, Izudinshah & Ismail, Lokman Hakim (n.d.). Natural Ventilation Approach in Designing Urban Tropical House. In: The International Conference on Civil and Environmental Engineering Sustainability (IConCEES 2011), 3-5 April 2012, Johor Bahru, Malaysia.

Architecture | Tourism Malaysia. (n.d.). Retrieved from http://www.malaysia.travel/en/my/about-malaysia/culture-n-heritage/architecture

Essays, UK. (November 2013). Passive Ventilation of Modern and Traditional Malay Houses. Retrieved from https://www.ukessays.com/essays/architecture/comparing-the-passive-ventilation.php?vref=1

Hashim, W., & Nasir, A. H. (2014). The traditional Malay house. Kuala Lumpur: Institut Terjemahan Negara Malaysia.

Lim, J. Y. (1987). The Malay house: Rediscovering Malaysia's Indigenous Shelter System. Pinang: Institut Masyarakat.

Malay Houses. (2012, January 02). Retrieved from https://vernaculararchitecture.wordpress.com/2011/12/30/hello-world/

Ramli, N. H. (2012). Re-adaptation of Malay House Thermal Comfort Design Elements into Modern Building Elements – Case Study of Selangor Traditional Malay House & Low Energy Building in Malaysia. Iranica Journal of Energy & Environment. doi:10.5829/idosi.ijee.2012.03.05.04

Sahabuddin, M. F., & Longo, C. G. (2015). Traditional Values and their Adaptation in Social Housing Design: Towards a New Typology and Establishment of ‘Air House’ Standard in Malaysia. International Journal of Architectural Research: ArchNet-IJAR, 9(2), 31. doi:10.26687/archnet-ijar.v9i2.493

Syahril Kamal, Kamarul, Abdul Wahab, Lilawati & Che Ahmad, Asmalia (n.d.). Climatic Design of The Traditional Malay House to Meet The Requirements of Modern Living. In: The 38th International Conference of Architectural Science Association ANZAScA “Contexts of architecture”, Launceston, Tasmania, 10–12 November 2004.

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