A trigeneration application based on compressed air energy storage integrated with organic Rankine cycle and absorption refrigeration: Multi-objective optimisation and energy, exergy and economic analysis

Abstract

Compressed air energy storage (CAES) has attracted worldwide attention due to the advantages of dealing with the intermittent problem of renewable energy. However, CAES is plagued by inadequate utilisation of the compression heat and waste heat in flue gas, and requires further improvement. In this study, a combined cooling, heating, and power (CCHP) system based on the CAES, organic Rankine cycle (ORC), and absorption refrigeration system (ARS) is comprehensively investigated. From the view of thermodynamic and economic performances, a multi-objective optimisation is performed to maximise the round-trip efficiency (RTE) and minimise the total investment cost per output power (ICPP) based on the rigorous model simulated in Aspen plus. The results show that the optimal CCHP system has the advantages of high efficiency of 68.38 % RTE (increased by 3.05 %) and low cost of 0.1984 $/kWh ICPP (decreased by 2.68 %). Additionally, the impact of different working fluids is investigated. Compared with different working fluids, the results show that R601 performs better from the system efficiency perspective (68.38 % of RTE), while R600 has an advantage over ICPP of 0.1977 $/kWh. The results indicate that the decrease in combustion chamber temperature benefits the system by generating more electricity power and cooling capacity. The discharging process accounts for the largest proportion of the exergy destruction and equipment costs. This research can help explore the potential of improving system efficiency and economy, and guide practical application in the area of CCHP.