Experimental Study on the Strengthen Heat Transfer Performance of PCM by Active Stirring

Abstract

Latent heat storage has higher energy density, but most phase change materials (PCMs) have low thermal conductivity. Current research focuses on conduction dominated heat transfer mechanism to increase the heat transfer performance. However, convection also has important effects on promoting PCM melting and solidification processes. Therefore, an active stirring method with conduction dominated heat transfer mechanism was studied. A shell storage with stirrer inside was constructed and tested. Paraffin was selected as the PCM; the heat transfer fluid (HTF) was water. The results show that average charging rate increased by 32.23 J/s than that without stirring, and the average discharging rate increased by 47.39 J/s. Completion time for charging/discharging with stirring was shortened by 9.61% and 48.61% than that without stirring. In the charging process, the average power of motor was 16.08 W, and the average discharging rate was greater than 500 J/s, accounting for less than 3.2%. In the discharging process, the average power consumption of the motor accounted for less than 5.2% of the discharging rate. It may be considered that convection dominated heat transfer mechanism can effectively improve phase-change heat transfer performance with lower active power consumption