Study of the thermal behavior of the composite phase change material (PCM) room in summer and winter

The thermal behavior of the PCM in one season has been studied by many researchers. However, more and more attention was paid to the thermal behavior of new types of PCM room in several seasons. In this paper, the concept of composite PCM room was proposed, that is to place two PCMs of different melting temperature in one room. A composite PCM room and an ordinary room (room without PCM) were built. The indoor air temperature, thermal load leveling, standard deviation of the inner surface temperatures were tested and analyzed for both summer and winter. The thermal behavior simulation platform of the PCM wall was established by sensible heat capacity method together with TRNSYS. On this basis, the influence of melting temperature and thickness of the PCM layer to the heat absorbing/releasing performance were simulated. Results showed that (1) In summer, as compared to ordinary room, the PCM room can bring a temperature drop of about 4.28-7.7 °C during the day and reduce the indoor air temperature fluctuation by up to 28.8-67.8% during sunny days. The combined PCM room can significantly increase the heat absorbed from the room and decrease the heat released to the room. (2) In winter, the temperature rise was 6.93-9.48 °C for PCM room at winter night. The indoor air temperature fluctuation decreased 17.7-25.4% during sunny days. The combined PCM room can significantly increase the heat released to the room and decrease the heat absorbed from the room. In conclusion, the composite PCM room performed a better thermal behavior in both summer and winter.