Energy and exergy analysis of two modified adiabatic compressed air energy storage (A-CAES) system for cogeneration of power and cooling on the base of volatile fluid

A novel isobaric adiabatic compressed air energy storage (IA-CAES) system was proposed based on the volatile fluid in our previous work. At the same time, a large amount of waste heat should be employed, which may restrict its applications. Two modified A-CAES (configuration 1&2) without using waste heat are proposed in this work. The volatile fluid has two functions: driving the air out of storage vessels and evaporating in a heat exchanger to generate cooling energy. Carbon dioxide (CO2) is selected as the volatile fluid due to its environmentally properties and high saturation pressure at ambient temperature. The thermodynamic analysis is evaluated by using a steady-state mathematical model and thermodynamic laws. The calculation results show the configuration 1 has the same round trip efficiency (RTE) as conventional A-CAES, while 36.59% additional cooling energy can be obtained, and the total exergy efficiency (TEE) improves by more than 2%. Moreover, configuration 1 saves nearly 35% of the total volume of the air storage unit. Compared with conventional ACAES, configuration 2 has obtained 42.71% additional cooling energy, the RTE and TEE improve 0.14% and 2.83%, respectively. Meanwhile, parametric analyses are also carried out to evaluate the effects of several critical parameters on the system performance of two modified A-CAES systems.

Automated summary

Two new configurations of A-CAES systems are proposed in this study, which do not require waste heat and can generate higher cooling energy and total exergy efficiency.