Energy analysis and evaluation of an innovative hybrid compressed air and pumped hydroelectric energy storage system

Concerning the limitations and environmental problems of fossil fuels, the use of renewable energy systems is necessary and inevitable, but the development of the use of these systems due to their unsustainable nature requires energy storage systems. Compressed air energy storage systems and pumped hydroelectric have a high potential for applying renewable energy systems in terms of power and storage time, but both have environmental and site limitations. The hybrid system of compressed air energy storage and pumped hydroelectric with the advantages of both systems is suitable for wide application. So far, less research has been done to analyze this hybrid system, and therefore the relationship between system parameters and system efficiency required further investigation. Also, the combined systems presented in previous research have two problems; Water evaporation and limitations in system operating pressure. In this paper, a new hybrid system is presented in which the rate of water evaporation is minimized by modifying the structure of the previous systems, and also the limitation of the operating pressure is determined by the existing compression technology. The present study showed that the ratio of air volume to high-pressure tank volume has the greatest effect on system efficiency and is a determining parameter. The amount of energy saved in the current research system is significant compared to previous researches and a roundtrip efficiency of 90% can be obtained. The energy analysis of the present paper determined the parameterchr('39')s interaction and their limitations in order to pave the way for design and feasibility.