An investigation of microclimatic impact of cool coating for buildings in low-latitude and tropical climate

This study investigates the impact of cool coating on airconditioning energy savings and micro-climate of buildings in low-latitude and tropical climate by performing a computational study. The computational study was carried out using Integrated Environmental Solutions (IES) software which is plugged in with Computational Fluid Dynamics (CFD) program [1]. IES simulations (which uses the heat balance equations at building envelope surfaces and in indoor environment) were performed to investigate the roof surface temperature, while CFD simulations (which uses the Finite Volume Method) were performed to investigate the impact on micro-climate above a real-size single storey air-conditioned building. The computational models in the software were validated by comparing the simulations results against the experimental results obtained from the test building in the industrial area of Nanyang Technological University (NTU), Singapore. Results showed that by applying a cool coating having solar reflectivity of 0.8 on the concrete roof with original solar reflectivity of 0.27, the surface temperatures of roof and ceiling can be reduced by up to 17.5°C and 1.2°C respectively in an air-conditioned room maintain at 22°C. In addition, after applying this high solar reflectance coating, a maximum reduction of 1.0°C, 0.7°C and 0.6°C for air temperature at a height of 0.5 m, 1 m and 1.5 m above the roof surface could be achieved.