Experimental and numerical study on thermal performance and inlet and outlet structure optimization of phase change heat storage tank

Abstract

Summary For the sake of enhancing the heat storage tank performance, the thermal characteristics and structural improvement of a water tank equipped with phase change material (PCM) were explored in this paper. The influence of PCM on the performance of the tank under conditions was experimentally analyzed, and the optimal working condition is determined by comparing the difference in effective heat storage rate under different inlet flow rates and the temperature of the water. The concept of “heat transfer blind zone” is introduced and analyzed, and the temperature and velocity field in PCM tanks with different structures are numerically compared. The results show that the addition of PCM makes the discharging time and effective water supply increase by 12.0% and the charging time increase by 6.0%. As the inlet flow rate and temperature of water rise, the thermal storage capacity reduces, and the effective heat storage rate rises first and then drops. The PCM tank has the optimum performance at the inlet water temperature of 70°C and the inlet flow rate of 15 L/h. The inlet and outlet setting up and down has the best effect on eliminating the “heat transfer blind zone” in the water tank. The research results have a good reference value for the design and realistic operation of the phase change heat storage tank.