PCM thermal energy storage tanks in heat pump system for space cooling

• The use of PCM in a thermal energy storage tank when coupled to a heat pump system is experimentally evaluated.
• The PCM tested is a salt hydrate with a phase change temperature of 10 °C and macro-encapsulated in plastic flat slabs.
• The thermal behaviour of the PCM TES tank is compared to the same tank when water is used as storage medium.
• The PCM tank was able to supply 14.5% more energy than the water tank.
• The system maintained the indoor set temperature by 20.65% longer time when the PCM tank was used.

A heat pump coupled to thermal energy storage (TES) tanks is experimentally tested under simulated summer conditions and the results are presented in this paper. The cold TES tank is used for shifting the cooling load of a small house-like structure. The study evaluates the thermal behaviour of the TES tank for cold storage and the application of the system for space cooling. For the analysis, two different configurations of the tanks are compared: a water tank and a PCM tank. The PCM tank is filled with a commercial macro-encapsulated PCM, which has a phase change temperature of 10 °C. The results point out that the PCM tank is able to supply 14.5% more cold and to maintain the indoor temperature within comfort 20.65% longer than the water tank. However, it needs 4.55 times longer to charge the tank.