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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.

Indoor air temperature, RH and moisture content in a enclosed space with / without HCM were simulated using the effective moisture penetration depth model under typical climate of Nanjing in winter and indoor periodic moisture load boundary conditions. The results show that HCM can effectively weaken the influence of outdoor climate fluctuation and indoor periodic moisture load change on indoor air temperature and RH. HCM can not only make indoor air temperature change slowly and uniformly in winter but also control indoor air humidity parameters in a narrow range. The thickness of HCM should be equal to the optimum thickness (0.002 m).When the thickness of HCM is 0.002 m, natural ventilation space has more ways to gain heat than enclosed space, and thus the temperature in natural ventilation space is higher than that in enclosed space.

For lots of areas in the world, the indoor thermal environment is terrible both in summer and in winter. The thermal environment needs to be improved for both the two seasons. A new type of phase change material (PCM) room is proposed in this paper. That is to lay two different kinds of PCM on room envelopes of different orientations. In this paper, the new PCM room and room without PCM are all built. Experiment is done for the two rooms under actual climate condition. Indoor air temperature, wall internal surface temperatures are measured. Results show that the new type of PCM room can improve indoor thermal environment in summer and winter.

A new type of phase change material (PCM) room was proposed in this paper to control the indoor air temperature for a better thermal comfort for human beings. That is to place two different kinds of PCM into room envelopes of different orientations. Both experimental and numerical studies were carried out for rooms with/without PCM. Indoor air temperature and interior surface heat flux of the two rooms were studied in typical summer and winter climate of Shanghai (31.2N, 121.5E). Important factors that affect the thermal performance of the PCM were studied, such as phase change temperature, thickness of the PCM and the arrangement of the two kinds of PCM in the room. Results showed that this new type of PCM room can decrease the indoor air temperature fluctuation by 4.3 °C in summer and 14.2 °C in winter. Different arrangements of the two kinds of PCM in the room can cause an indoor air temperature difference to be 6.9 °C in summer and 2.7 °C in winter.

The thermophysical properties of the wall can greatly affect the thermal performance of the buildings. When design the thermophysical properties, the choice of object function is important. In this paper, two new objective functions (heat insulation factor η1 and heat absorbing factor η2) were proposed to evaluate the thermal performance of the phase change material (PCM) wall. The two objective functions can describe the heat transfer of both the external and inner surface of the PCM wall. The heat transfer of the PCM wall was solved by the thermal-resistance method. The effect of different factors to the objective functions was analyzed. Such as melting temperature, latent heat and the position of the PCM layer in the wall. The model and objective functions are expected to be helpful for the design of PCM wall in active and passive room.