In this study, the effects of peak shaving control of air conditioning systems using phase-change material (PCM) for ceiling board in an office building were examined. Rock wool PCM ceiling board (PCM ceiling board) was enhanced by adding microcapsulate PCM, whose melting point, at about 25°C, is close to room temperature. The load on the airhandling unit (AHU) can be reduced by using the thermal storage of the PCM ceiling board during the peak shaving control period. At the same time, the radiation field in the room can also be improved due to stabilization of the ceiling board temperature at the PCM melting point.

During overnight thermal storage, cool air from the AHU flows into the ceiling chamber space and chills the PCM ceiling board, storing the cooling thermal energy. During the peak shaving period, when the thermal load is at maximum, the air from the room returns to the AHU via the ceiling chamber space. As a result of passing through the cooled-down PCM ceiling board, the warm air from the room cools down before returning to the AHU. The maximum thermal load and the capacity of heat source can thus be reduced.

The results of this research were obtained by examining measurements of the thermal capacity of the PCM ceiling board and a numerical simulation. The maximum  thermal load was cut by 9.4% compared to conventional rock wool ceiling board. From this result it can be concluded that the PCM ceiling system acts effectively to enable peak shaving control.

Units: SI