Experimental Study on Heat Storage and Release Processes of Composite Phase Change Wall under Short Intermittent Heating Conditions

Abstract

During intermittent heating, the short intermittent conditions are common in meeting rooms of office buildings and school classrooms. The thermal process of building envelope has coupling effects on the indoor thermal environment in the frequent start-stop of heating equipment. This paper integrated phase change materials (PCMs) with building envelope to improve its thermal performance. Measurements were carried out to study the dynamic thermal process of composite phase change wall (composite-PCW) in case 1 (heating 1h + suspension 1h) and case 2 (hating 2h + suspension 2h). Results showed that: 1) the indoor air temperature fluctuations were around 14°C and 18°C respectively for case 1 and case 2 when the indoor thermal processes reached relatively stable. 2) The heat storage of composite-PCW could maintain the inner surface temperature relatively constant, so that the inner surface temperature fluctuations were only 5°C and 6°C respectively for case 1 and case 2. 3) The heat storage utilization rates of the last cycles were 5.08% and 14.86% for case 1 and case 2. Thus, the heat transferred into the wall during the heating period was stored inside the wall to improve the indoor thermal environment by rational use to maintain the inner surface temperature during the cooling-down period.