Abstract: The phase change heat storage tank can effectively adjust the contradiction between the supply and demand of the collector and the load end. The water inlet structure and heat storage tank of the annular water distributor are designed,and the performance test platform of the phase change heat storage tank is built. The temperature stratification of the direct type heat storage tank and the heat storage tank of the annular water distributor are compared,and the thermal stratification of the phase change heat storage tank and the heat release performance of the phase change ball under the variables of porosity,water inlet velocity and variable temperature water inlet are explored. The experimental research shows that the annular water distributor can effectively suppress the disturbance of the inlet water flow to the temperature field,maintain good temperature stratification,make the phase change ball release heat layer by layer,increase the temperature difference between the phase change ball and the heat transfer fluid,improve the heat release efficiency,and ensure that the high-temperature water can be continuously provided to the user;The smaller the porosity,the better the delamination effect;The higher the flow velocity is,the worse the stratification effect is,but the heat release efficiency is improved; The heat release time of variable temperature influent is about 40% longer than that of constant temperature influent.