PCM cool roof systems for mitigating urban heat island - an experimental and numerical analysis

Abstract

The purpose of this study is to develop a “PCM cool roof system”, and to evaluate its performance by applying the PCM cool roof system to the roof envelop. The study methods and procedures are as follows: First, the optimal PCM and finish materials were selected utilizing the indoor artificial climate chamber. Second, the PCM cool roof system was applied to the testbed, and the changes in surface temperatures were measured to determine the effect on the reduction of the heat island phenomenon. Third, the air currents in Gangdong-gu Seoul Korea were analyzed through a numerical analysis based on the data derived from the testbed to verify the reduction in the UHI. The experimental groups were set to A: WPC, B: WPC+PCM, and the control group to C: PCM cool roof system in the testbed experiment. The experimental environments were divided into winter, intermediate, and summer periods to increase the performance evaluation reliability in Seoul, where there are four distinct seasons. The study results showed that all seasons saw an effect of a reduction of roof surface temperatures when using the PCM cool roof system. The maximum temperature difference for each season was 2.5 °C in winter, 4.7 °C in intermediate season, and 5.7 °C in summer. The a numerical analysis results showed that the reduction in roof surface temperature due to the PCM cool roof system was effective in the mitigation of the heat island phenomenon. © 2019