Study on the influence of thermo-physical parameters of phase change material panel on the indoor thermal environment of passive solar buildings in Tibet

Abstract

In this study, an unsteady heat transport numerical model of phase change material (PCM) panel under indoor-outdoor dual thermal disturbance conditions was development by using the apparent heat capacity method, which was employed to evaluate the effect of thermal performance parameters of PCM on the heat storage and temperature regulation capability of PCM panel. Then, a single-space passive solar building located in Tibet was used as a basic building model to study the influence of thermo-physical parameters, such as phase change temperature, thickness and position of PCM panel in composite wall on indoor thermal environment. Meanwhile, the indoor discomfort degree hours and heating energy consumption of the passive solar building with composite wall containing PCM panel were quantitatively analyzed, and the dynamic payback period of PCM investment in Tibet was calculated for economic analysis. The results indicated that the phase transition temperature, thickness and position of PCM panel have a significant impact on its heat storage and temperature regulation capability, and the composite wall containing PCM panel with reasonable thermo-physical parameters could obviously damp indoor air temperature fluctuation and save the building heating energy consumption. Compared with the basic building, applying a 30 mm thickness PCM panel with phase transition temperature of 18 °C on the interior side of the composite wall could reduce indoor discomfort degree hours in studied period (Dec. 20 to Dec. 24) by 74.9% and reduce heating energy consumption in the whole heating period (Dec. 01 to Mar. 01) by 20.76%, respectively. Furthermore, the economic analysis results show that the application of PCM panels in passive solar buildings in Tibet has high economic value, and the dynamic payback period of PCM investment in Tibet with 3% discount rate is 41.29 years, which is lower than the usual service life of a building.