Exergoeconomic assessment of a high-efficiency compressed air energy storage system

Abstract

Energy storage systems have a critical part in enabling greater use of intermittent energy resources. For a sustainable energy supply mix, compressed air energy storage systems offer several advantages through the integration of practical and flexible types of equipment in the overall energy system. The primary advantage of these systems is the management of the duration of the peak load of multiple generation sources in ‘islanded operation’ without connection to the electricity network. Here, research introduces and analyzes a novel multigeneration system for electrical power, cooling, heating, potable water, sodium hypochlorite, and hydrogen production to improve the industrial aspects of the system for more profitability and efficiency with lower environmental impacts. The system involves three main sub-systems: CAES, combined cooling, heat & power, and a desalination unit. To assess the performance of the system, technical, economic, exergoeconomic, and exergoenvironmental studies are conducted. The results regarding the energy and exergy studies reveal that the system presents great potential for reliable operation during peak demand hours. The round-trip efficiency is 74.5 % producing 1721 kW of electrical power with concurrent cooling and heating loads at 272.9 and 334.6 kW, respectively. Economically, the levelized costs of heating/cooling, clean desalinated water, and electricity are 26.4 US$/GJ, 2 US$/lit, and 4.5 cents/kWh, respectively. Finally, the outcomes of the exergoenvironmental study display that the sustainability index for the system is 1.7.