A hot water tank test bench with phase change material (PCM) of sodium acetate trihydrate was built. The thermodynamic characteristics of the water tank were tested under the conditions of an initial water temperature of 80 °C and an inlet water temperature of 5 °C. The analytical method and the enthalpy efficiency analysis method were used to analyze the thermal stratification characteristics of the hot water storage tank with PCM when the influent flow rates were 1 L/min

3 L/min

5 L/min

7 L/min

and 9 L/min

respectively. The experimental results show that when the water tank temperature was 80 ° C

the energy of the ordinary water tanks

PCM48 and PCM58

were 18.81 MJ

19.34 MJ

and 19.07 MJ

respectively. When the inlet flow rate was the same

the closer the heat storage ball with PCM is to the water tank inlet

the better the heat stratification effect of the water tank. As the influent flow rate increased

the stratification effect decreased. The number of Ri in different water tanks reached a maximum at t*=0.5; the number of Ri decreased with the lower position of the heat storage ball with PCM. The Ri number of the PCM48 and PCM58 in the fourth layer were 7.569 and 7.78

respectively. The Ri numbers at the layer were reduced to 7.03 and 7.145

respectively

indicating that the degree of thermal stratification of the tank decreased with the higher position of the heat storage ball with PCM.