Study on thermal storage performance and heat transfer blind area of multi-tube phase change heat storage tank

Abstract

Phase change heat storage tank has application value in solar heating system and waste heat utilization. However, due to the different melting sequence of phase change units, there will be a heat transfer blind area, which greatly affects the heat storage performance of tank. In this paper, the experimental platform of multi-tube phase change heat storage tank was set up to investigate the melting sequence and characteristics of phase change material (PCM) under different working conditions. The results show that the inlet temperature of the heat transfer fluid increases from 55 °C to 70 °C, the flow rate increases from 0.1m³/h to 0.4m³/h, and the overall heat storage time of the water tank decreases by about 50 % and 53 %, respectively. In the standard arrangement, the PCM closer to the entrance in the X-direction melts slowly, and the PCM closer to the tank wall in the Z-direction melts slowly. In addition, reducing the tubes' distance of X and Z-direction will prolong the heat storage time and change the melting sequence of PCM. This study provides guidance for further heat transfer of uniform phase change water tank, and provides reference for design and application of tank.