Discharging strategy of adiabatic compressed air energy storage system based on variable load and economic analysis

Abstract

It is promising to match the variable loads of the supply objects in different seasons by adjusting the trigeneration of the adiabatic compressed air energy storage system (A-CAES).. In this paper, the thermodynamic model of the A-CAES system was developed to investigate the characteristics of the A-CAES system for trigeneration combined cooling, heating and electric supply. The cooling, heating, and electric load of a typical residential area in different seasons was analyzed. Then the load of residential area and trigeneration of system was matched to increase the efficiency of energy utilization. Finally, the new energy supply method by the A-CAES system for the residential area was compared with the traditional approach through economic analysis. The simulation results show that households' cooling, and heating load vary greatly in different seasons, but the difference in electric load is insignificant. For A-CAES, the mass flow rate of chilled water in the charging process has little effect on the cooling, heating, and electric output, so the minimum value is suggested to improve the thermal storage temperature of chilled water. The ratio of compression heat distributed for preheating the air in the discharging period can greatly change the cooling, heating, and electric output of the system. From the perspective of meeting the hot and cooling load as much as possible, the optimal heat distribution ratio for summer, spring/autumn, and winter were selected as 36.0%, 94.1%, and 36.0%. However, according to the economic analysis, the optimal heat distribution ratio was selected as 94.1%, 94.1%, and 67.5% to maximize daily profit. The economic analysis also found that the annual energy supply cost of the residential area with the A-CAES system is 24% lower than that of the traditional method. The annual energy supply cost decreases by 254.5 thousand dollars. Given the cost of devices, the static investment payback period of the system was calculated as 15.4 years.