Heating storage performance of a water tank–combined phase change material:An experimental case study

Water tank is a commonly used unit which has been frequently applied for thermal energy storage units. In order to enhance the thermal performance of the water tank, the phase change material is utilized by embedding paraffin into water tank. But the key question is whether a competitive charging could be achieved. Therefore, an experimental system has been constructed. In this article, two key indices, the energy storage capacity and the energy storage intensity, are investigated. The performances of the phase change material–thermal energy storage tank during the heat charging processes are investigated experimentally, and a series of experiments are carried out under different heat transfer fluid flow rates and distance between phase change material plates. The temperature evolutions of the phase change material plates and heat transfer fluid are obtained during the experiments. The thermal performance of the phase change material–thermal energy storage tank was observed to be more effective than the conventional sensible thermal energy storage tank. It is found that water flow rate of 1.3 m³/h is taken as the optimal working condition, and the 3-cm plate distance is considered as the optimal design.