Thermodynamic analysis of a novel pumped hydro compressed air (PHCA) energy storage system

Energy storage systems have a wide range of applications one of the most important of which is to facilitate the uncertain renewable energy sources. In this research, a new energy storage system is proposed named Pumped Hydro Compressed Air (PHCA) system. A comprehensive thermodynamic model is developed to assess its efficiency and reliability under different physical situations. The effect of key parameters including storage pressure, water-to-air volume ratio and pump/hydroturbine efficiencies on the system performance is studied. The results show that the storage pressure has a significant effect on the amount of energy consumed by the pump and power generated by the hydroturbine. The results also reveal that the overall energy conversion efficiency of the PHCA is dominated by the efficiency of the pump and hydroturbine. As efficiencies of both components increase from 65% to 95%, efficiency of the PHCA system is improved from 42% to 90%.