Search

Abstract  In this paper, the averaged reentering rates of the densely built cooling towers, which form banks on the building roof in Seoul, Korea have been predicted by a numerical method according to various summer wind conditions and roof wall types. The averaged reentering rates of all the cooling towers are compared according to two wall types to study the effect of the intake outdoor air louver on the reentering rates. Consequently, two findings are drawn as follows. (1) With a curtain wall, the averaged reentering rates of the total cooling towers against the west and the south wind at ν = 5 m/s are 13.3 and 24.4%, respectively. Therefore, it is strongly needed to find a method to reduce the reentering of the discharged air from the cooling towers. (2) In the case of a louver wall, the averaged reentering rates of the cooling towers with the west and south wind at ν = 5 m/s are 2.5 and 9.74%, respectively, which have been estimated to be lower than those of the curtain wall. Therefore, the louver wall can be suitably adopted to reduce the reentering of the discharged air from the cooling towers in the present study. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]