Economic, exergoeconomic analyses of a novel compressed air energy storage-based cogeneration

In this paper, the performance of a compressed air energy storage system is improved by an ejector refrigeration subsystem with zeotropic working fluid. According to the results, Pentane/Trans-2-Butane is found as the best zeotropic mixture. To obtain the proposed system's optimum performance, an optimization analysis is conducted based on multi-objective particle swarm optimization algorithm. Based on optimization results, the optimum round trip efficiency and exergetic round trip efficiency are 52.04% and 58.70%, respectively, and the exergy destruction rate reduces by about 8.3% at charging time and 2% at grid peak time. Also, the coefficient of performance for the ejector refrigeration subsystem is improved from 0.22 at the base case to 0.25 at the optimum conditions. Moreover, economic analysis is considered to analyze the profitability and availability of the system for possible establishment. Therefore, when the selling prices determined for the power in the charging and discharging periods and cooling load are respectively taken into account 0.022 $/kWh, 0.20 $/kWh, and 0.15 $/kWh, the system has good economic feasibility and reaches the payback period of 5.24 years. In this conditions, a profitability of 2.5 $M can be obtained at the end of system lifetime.