Numerical analysis on the thermal performance of a novel PCM-encapsulated porous heat storage Trombe-wall system

Phase change material (PCM) applied in the architectural equipment can decrease building energy consumption and ameliorate thermal comfort by heightening its thermal energy storage capacity, and it has been a research hotspot in recent years. For the purpose of saving building energy in a simple and effective way, a novel solar composite wall with a porous heat storage layer in the present paper, and its matrix consists of the PCM encapsulated granular capsules, so the phase change occurs in the encapsulated capsules when the temperature reaches the melting point. The unsteady numerical simulation is conducted to analyze the performance of passive solar heating room. In the daytime, a large amount of heat can be stored in the porous layer due to the occurrence of phase change in the capsules, once the temperature of porous layer is above a certain value. The heat can be released at night or in a cloudy day when the temperature is below the solidification temperature, thus, the overheating can be avoided in the room and the heat can be fully utilized. The comparisons are conducted between the porous layer with and without PCM encapsulated granular capsules in the composite wall for heating. And in comparison with the granular capsules-consisted porous layer which without PCM, approximate 20.2% increment of average temperature at night can be achieved in the heating room when the PCM is packaged in the porous layer. The thermal efficiency of the PCM heat storage wall is 76.2%. Besides, the structure parameters and combined modes in the porous composite solar wall are analyzed. For instance, the porous storage wall with a porosity of 0.1 and a thickness of 6 cm are reasonable choices in this model.