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Design guidelines for indoor comfort in row houses in hot-humid climates.

Many countries in hot-humid regions cope with rapid urbanisation. Land cost becomes higher especially in high-density areas. There is a demand of residential and commercial buildings due to the economic growth in the cities. Row house became a popular building type since it combines both functions in one place. A large amount of row houses are found in Bangkok, Thailand. Despite their versatility, they are not properly designed for the climate and urban conditions. The occupants adopt air conditioning systems to control indoor comfort whereas row houses are not properly designed for the installation of the airconditioners. This increases the energy demand. This research aims to establish appropriate design guidelines and recommendations to ensure indoor comfort in urban row houses in hot-humid climates. Thermal comfort is the main concern apart from others such as visual, acoustic and indoor air quality. Thermal stress should be minimised by primarily passive means as long as possible and the building design should also provide the flexibility for operating active systems whenever they are required. To achieve this aim, it is important to assess indoor conditions in existing row houses to provide a basis of comparison. A case study in Bangkok has been selected for a field investigation during the hottest month of the year to examine how the case study responds to the critical condition. Flow visualisation tests have been conducted to compare the results of indoor air velocity to those of the field investigation. Computer simulations have been carried out to investigate and compare the performance of design variables affecting indoor comfort such as orientation, zone location, roof and wall materials, aperture schedules, and shading devices. Two blocks of 4-level row houses have been simulated and three units: an intermediate and two units at the both ends of the row have been examined. There are two sets of the simulations: naturally ventilated and air-conditioned cases. Then, the design guidelines and recommendations are developed based on the results from the two series of simulations. Results from the 3-day field investigation show that indoor conditions of the case study are overheated. The indoor temperatures are slightly lower than To during the day while they are higher than To during the night. These results correspond to those of simulation runs for a verification study. The wind tunnel test shows low indoor air velocities. It is recommended to install ceiling fans to increase the wind speed enough to generate cooling effect. The level of interior illuminance drops with distance from the window. It should be improved by installing artificial light sources in the area far from the opening. The sound levels exceed the noise control limit at all times. Results from the simulations for the naturally ventilated and air-conditioned row houses show some similarities. In the former, internal conditions of the occupied units are above the comfort limit almost all day. Orientation is a crucial factor affecting the indoor thermal condition. The front of a row house should face either north or south and the end unit with east-facing side wall performs better than that with west-facing side wall. The worst orientation is generally west but the east could be worse for the end unit with south-facing side wall at such an orientation. The effect of zone location is also related to the orientation. The intermediate unit is more sensitive to design variables since it generally shows the biggest T difference between the variants with the best and the worst design factors. Aperture schedule has a great effect on indoor conditions for naturally ventilated cases. Closing windows during the day could keep the zone cooler than opening the windows which would admit the hot air from the outside. Concrete flat roof with ceiling insulation gives the best results while metal sheet roof gives the worst. Concrete block with acoustic board performs best for both naturally ventilated and air-conditioned buildings while the worst wall type is aerated concrete in cases of the naturally ventilated buildings and common brick wall in cases of the air-conditioned ones. However, the results from the effect of roof and wall material study show that adding insulation could improve the indoor condition more effectively than changing the roof and wall materials. An additional height from the mezzanine floor only affects the thermal performance of the room on ground floor. In comparison to the row house without mezzanine floor, the presence of mezzanine slightly increases indoor temperature in naturally ventilated cases while increases cooling load of the room on the ground floor drastically in air-conditioned cases. Shading devices should be designed particularly for each orientation since their effects are tremendous once applied to the opening to protect it from solar radiation. The limited distance between the front of row houses and the street as allowed in the existing building regulations should be extended for the devices to provide enough shading for the building.

Identiferoai:union.ndltd.org:ADTP/253224
CreatorsTakkanon, Pattaranan
Source SetsAustraliasian Digital Theses Program
Detected LanguageEnglish

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