Study on optimal ice storage capacity of ice thermal storage system and its influence factors

This paper explores the impact of different control strategies and electric tariff structures on the optimal ice storage capacity in relation to system economy for four typical buildings of hotel, restaurant, mall and office. The ice storage rate and electric price ratio are introduced to denote the various ice storage capacities and the different electric tariff structures, respectively. Then the chiller capacity and economic evaluation index value corresponding to each typical building with various ice storage rates and electric price ratios under three control strategies (chiller priority, storage priority, and optimizing) are calculated. The results indicated that there is respective optimal ice storage rate corresponding to both the minimal chiller capacity and the minimal economic evaluation index value. The optimal ice storage rate in relation to minimal chiller capacity is constant value under each control strategy. Such optimal values under both chiller priority and optimized control strategies are equivalent and less than that under storage priority control strategy. However, the optimal ice storage rate in relation to minimal economic evaluation index value under each control strategy is significantly affected by the electric tariff structures. The corresponding optimal ice storage rates under both chiller priority and optimized control strategies are equivalent and increase to a definite value with the increase in the electric price ratio. While the optimal ice storage rate under storage priority control strategy will appear when electric price ratio is greater than 3. The results also showed that, when electric price ratio increases to a certain value, the optimal ice storage rates corresponding to both minimal economic expense and minimal chiller capacity under each control strategy for the four typical buildings are equivalent.