Principal Investigator: Prof Wong Nyuk Hien
With rapid urbanization, there has been a tremendous growth in population and buildings in cities. The high concentration of hard surfaces triggered many environmental issues. The Urban Heat Island (UHI) effect, one of these environmental issues, is a phenomenon where air temperatures in densely built cities are higher than the suburban rural areas. The primary root of UHI is the rapid urbanization which replaces natural landscape with enormous hard surfaces such as building facades, roads, pavements in cities. First, these hard surfaces in built environments re-radiate solar energy in the form of the long-wave radiation to surroundings. A lack of extensive vegetation further incurs the loss of a natural cooling means which cools surrounding air through evapotranspiration. Also, the UHI is aggravated by the lack of moisture sources due to the large fraction of these impervious surfaces in cities. The rain water is discharged quickly. Finally, the anthropogenic heat generated from the combustion process and the use of air-conditioning coupled with the greenhouse effect of pollutants also contributes to the increase in temperature. Such increase in temperature with the presence of air pollutants can result in the accumulation of smog, damage the natural environment and jeopardizes human health. It also costs consumers more money because it takes more energy to cool buildings.
A long term analysis of the Singapore weather data has shown that the ambient air temperature has increased by about 1 degree C over the past 20 years. A study of the Urban Heat Island (UHI) effect in Singapore has also revealed that Singapore has a UHI intensity (the temperature difference between rural and urban area) of about 5 degrees C. To combat such effect, it is essential that designers should be conscious of the inter-relationship between urban design and the climatic conditions.
This research entails a proposal to conduct studies on macro scale effects of wind, solar irradiance, shadow effects, etc. on town planning and development and vice versa. The studies should look at how existing developments affects local climatic condition (e.g. wind and solar irradiance) that can affect natural ventilation, and devise ways to promote/enable sustainable development by capitalizing natural climatic conditions to reduce energy usage, and encourage energy generation through clean, renewable means. A specific HDB township will be utilized as a test bed for this study and it is hoped that from the findings of this study, guidelines can be generated which can be useful for future township development.