The influence of macro-encapsulated PCM panel’s geometry on heat transfer in a ceiling application

Abstract

One of the deficiencies of using Phase Change Materials (PCMs) is the low conductivity, therefore, increasing the heat transfer from and to the PCM remains a challenge. The exposed surface area of the container can play a major role in the amount of heat transfer. Furthermore, building energy simulation always considers surfaces as slabs without shapes consideration. This paper aims to broaden the current knowledge of the relation between the exposed surface area of a macro-encapsulated PCM panel and the heat transfer with the environment. For this study, coconut oil was considered as PCM encapsulated in a thin plastic container, represents an aesthetic PCM panel attached to the ceiling. The results showed that an increase of 50% in the exposed surface area to volume ratio could lead to a 20% reduction of the time required to completely melt the PCM. Results also showed that the convective heat transfer coefficient is proportional to the exposed area to volume ratio, and for that an equivalent heat transfer coefficient is proposed to be used in building simulation tools when dealing with non-slab geometry.