Investigation of Pcm Cooling Saving Potential Under Variable Building Envelope Structures and Chinese Climatic Regions

Abstract

The integration of PCM (phase change material) into building envelopes has been proven as an effective strategy for maintaining indoor thermal comfort and reducing building energy demand. In this study, the cooling saving performance of PCM for a two-story building in Hong Kong was optimized using Energy Plus, with a focus on the impact of envelope component materials and their optimal arrangement order. The unique passive cooling performance of PCM which differs from the other materials was outlined. The simulation results revealed that arranging the PCM layer on the interior side of the insulation layer effectively extends the phase transition time and enhances cooling saving performance. The application of PCM can increase the thermal mass of lightweight wallboards to yield significant cooling savings ratio up to 18%, while that is decreased to 2.5% in the heavyweight wallboards. Moreover, increasing the insulation thickness reduces the cooling energy-saving effect of PCM. However, PCM still retains a certain level of effectiveness, as it can absorb the heat gains caused by solar radiation and other internal heat sources. Additionally, the phase transition temperature was studied to optimize PCM performance. It was found that the phase transition temperature should align with the desired indoor thermostat temperature, regardless of ambient temperature. Besides, the cooling savings of PCM in different Chinese climatic regions was investigated. Cities with larger diurnal temperature ranges, such as Wuhan and Kunming, exhibit higher cooling energy savings potential. Coastal cities like Hong Kong and Shanghai showed less prominent cooling saving benefits.

Keywords: Phase change materials (PCM), Passive cooling technology, Building envelope structure, Chinese climatic zones