Experimental investigation of latent heat storage in a coil in PCM storage unit

The thermal energy storage is very important because it provides the solution to problems related between the provided and the required energies. This work presents the experimental study of a PCM storage unit for storing latent heat thermal energy. Three different types of paraffin are tested as phase change material (PCM) and water is used as heat transfer fluid (HTF). The temperatures of PCM and HTF, solid fraction and thermal effectiveness are analyzed. The effects of inlet temperature of HTF, flow rate of HTF and the type of PCM used on the time for charging and discharging heat are discussed. The following conclusion can be drawn: (1) HTF flow rate does not have a great effect on the discharging phase compared to the charging phase. (2) Inlet temperature has a great effect on the exchanger performance. It can accelerate charging phase 54.5% and delay the discharging phase by 48.5%. (3) Adding the oil engine to the paraffin can improve the speed of the charging and discharging heat process by 42.4 and 66%, respectively. However, the latent heat of the PCM is considerably reduced.