Performance analysis of combined cooling power based on small-scale compressed air energy storage system

Abstract In order to overcome the limitations of geological conditions, a test bench of small-scale compressed air energy storage (CAES) system based on pneumatic motor (PM) is proposed in this paper. As a key component of CAES system, the PM serves as an expander with the advantages of small size, lightweight, low cost, and convenient operation. The effect of the rotation speed, regulated pressure, and current on the key performance parameters (power output, compressed air consumption rate, and energy efficiency) are tested through experiments. In addition to the resulting output performance of the PM and generator, the energy efficiency of the PM, generator, and CAES system is analyzed. Given that the exhaust air from the PM has a refrigeration potential, the cooling power, cooling efficiency, and combined cooling power efficiency are also examined to improve the comprehensive energy utilization efficiency of the CAES system. The power output and energy efficiency of the PM and generator increase but eventually decrease with the rise of current and rotation speed. Under the lab-scale conditions, the maximum power output of the PM and generator are 989.21 W and 862.35 W, respectively. The maximum efficiency of the PM and generator is 9.83% and 87.19%, and the cooling efficiency and combined cooling power efficiency of the CAES system are 11.77% and 17.25%.