Experimental Study on the Influence of Urban Water Body on Thermal Environment at Outdoor Scale Model

Abstract

Urban Heat Island (UHI) has become a common urban problem that may lead to human health issues and increase in air-conditioning energy demand due to increase of air temperature. In order to reduce the UHI effect and improve the outdoor thermal environment is necessary to assess the effect of various measures. Water bodies’ ability to regulate the microclimate arguably has the potential to mitigate the effect. Water bodies commonly found in urban area are usually described as a permanent or temporary collection of water in form of small stationary water or pond. These water bodies contribute to altering the surrounding thermal environment due to its cooling effect, either by evaporation or transfer of heat between air and the water. In real urban condition, however, the heterogeneity makes it difficult to assess the cooling benefits and to isolate the effects of individual parameter (such as shape, surface area, wind condition or solar radiation) under the complex physic process involved in the urban meteorology. As an alternative method, an outdoor measurement on a physically reduced scale model was conducted in summer. The outdoor-scaled model consists of an array of 1.5m concrete cubes and able to recreate thermal pattern similar to the actual urban condition. A typical of commonly found water bodies in urban areas, pond, was installed in the scale model to have a better understanding on potential benefits of water bodies in urban area. In this paper, the author present initial findings on the characteristic of surrounding microclimate and its influential factors, particularly ambient air temperature near urban water body derived from the proposed approach. The experiment result shows interesting patterns, which generally shows cooling effect during the day and even though is limited it also happen during the night. Moreover, the present of more solar radiation and low wind conditions are found further enhance the cooling effect.