ABSTRACTIn order to meet both economic and energy requirements, this study has proposed an optimal design to minimize the sum of the initial and operation energy costs for a 1200 refrigeration ton chiller and 12 water storage tanks in an absorption chilled water storage air conditioning system. Various power consumption calculation methods for the main devices are included to predict the performance of this equipment under different operating conditions. In addition, the performance curves of the water storage tank under the storage and discharge modes are calculated using Fluent software. The article uses five control strategies for a cooling tower along with three hot water inlet temperatures of a generator to simulate the optimal design of a system. The results show that the least power (10,336 kWh) is consumed when the cooling tower’s outlet temperature is 32°C and the generator’s inlet hot water temperature is 105°C.