Experimental study on the melting behavior of a phase change material in a conical coil latent heat thermal energy storage unit

An experimental study on the melting behavior of paraffin wax used as a phase change material (PCM) in a conical coil latent heat energy storage unit (LHSU) was performed. The experiments were conducted concurrently for conical coil and normal coil LHSUs to compare their thermal performances. The effect of heat transfer fluid (HTF) inlet temperature was examined. The evolution of the temperature during charging, the spatial variation in temperatures and captured images of the melting PCM in both LHSUs were compared. The results indicated that the melting rate in the conical coil LHSU was enhanced by 20.97%, 22.13% and 28.32% in comparison with that of normal coil LHSU at HTF inlet temperature of 70 °C, 75 °C and 80 °C respectively. Moreover, the rate of energy stored in the conical coil LHSU was a notably faster than that of the normal coil LHSU. The HTF inlet temperature has a similar effect on both LHSUs by substantially decreasing their melting time.