Improvement of thermal comfort in naturally ventilated classrooms by phase change material roofs in Taiwan

Abstract

This paper researched the effects of different types of insulated roofs, PCM roofs, and composite roofs on the overheating risk (Ihot ) in the naturally ventilated classroom in Kaohsiung, Taiwan. The EnergyPlus was applied to simulate the hourly operative temperatures in the classroom. The optimal melting temperature (tmp ) and thickness of the PCM roof, as determined from design day, were 36°C and 26mm, respectively, which are consistent with the results from year-round simulations. The design PCM roof could decrease the Ihot by up to 64%, leading to an effect equivalent to the decrease by 25mm insulation. However, with thickness of PCM>26mm or insulation>25mm, their effect on the Ihot was not significant. The changes of Ihot was insignificant while tmp of PCM roof in the range of 34-40°C, and Ihot increased rapidly when tmp >40°C. The effect of tmp of composite roof on the Ihot was not significant.