Evaluating the improvements of thermal comfort by different natural elements within courtyards in Singapore

Abstract

Heat mitigating natural elements such as trees, shrubs, grass and water have been broadly studied, while their effects on semi-open spaces have been almost ignored. This paper aims at measuring and comparing the heat mitigating effects of four natural elements in Singaporean courtyards. Four typical courtyard scenarios (each featuring a natural element) are simulated in Envi-met and a comprehensive analysis of air temperature, mean radiant temperature, wind velocity and relative humidity is done to clarify the respective advantages of each natural elements. Daily variation of climate indicators reveal that swimming pools and grass have similar effects on air temperature, mean radiant temperature, wind velocity, relative humidity, and on Physiological Equivalent Temperature, with their differences only being 0.1 °C, 0.3 °C, 0.1 m/s, 0.3%, and 0.3 °C, respectively. Compared with grass, trees do slightly reduce wind velocity by 0.1 m/s, still they significantly reduced the daily Physiological Equivalent Temperature by 2.1 °C. Fountains are better at reducing air temperature by 2.1 °C, compared with swimming pools, but because they also increase relative humidity by 12.8%, they end up performing not so differently from swimming ponds and grass in terms of Physiological Equivalent Temperature.