Evaluation of a trigeneration system based on adiabatic compressed air energy storage and absorption heat pump: Thermodynamic analysis

Compressed air energy storage can be a promising application to meet diversified energy needs of cooling, heating and power supplies through mutual conversions among electrical, thermal and potential energies. A novel trigeneration system based on adiabatic compressed air energy storage is thus proposed for efficient allocation and utilization of the heat of compression. An absorption heat pump is also integrated in the system to improve the heat capacity of the proposed system. A steady state thermodynamic model of this system is then established with the focus on the energy conversion variation principle for changing key physical parameters. It is demonstrated that increasing storage pressure from 3 to 8 MPa can enhance the system round trip efficiency and exergy efficiency about 20.57–31.69% and 23.64–30.62%, respectively. Larger charge-discharge pressure difference has a negative effect on the two indicators. Minimal exergy efficiency can be found with the ratio of thermal oil allocation located at about 0.8. Lower vapor generator temperature and evaporation temperature can achieve higher system round trip efficiency and exergy. However, the influence is minor when evaporation temperature is higher than 283.15. In brief, this study represents detailed guidance for the design of the proposed system, which has a promising prospect in intermittent renewable energy storage and management.