Thermodynamic analysis of an energy storage system based on pumped hydro combined with compressed gas for use in a solar powerplant

摘要

In this research, an energy storage system is proposed for Jarghooyeh's 10 MW photovoltaic solar powerplant. This powerplant is located on a flat plain with dry and warm climate. Therefore, conventional methods for energy storage based on pumped hydro is not suitable in this case. Hence a pumped hydro combined with compressed gas (PHCG) is used to design an energy storage system. Determination of proper values of the design parameters of the PHCG system, including volume ratio of water to gas and pre-set pressure of the pressurized vessel is conducted by investigation of the effects of different values of these parameters on the performance of the system. Using determined design parameters the PHCG system is proposed for the considered powerplant. Obtained results showed that proposed PHCG energy storage system comprising 23 high pressure vessels with a volume of 1000 m(3) could supply up to 68% of energy demand of Jarghooeyeh-Olya city with 14,100 populations during peak load demand or night hours. Efficiency of charge and discharge cycle of the proposed PHCG energy storage system is found to be 79.1% and achieved overall efficiency of the system is about 42%.