Thermodynamic analysis and multi-objective optimization of a trigenerative system based on compressed air energy storage under different working media and heating storage media

To meet the diverse energy requirements of clients, a trigenerative system based on advanced adiabatic compressed air energy storage is established. To investigate the thermodynamic performance of systems adopting different working media and heating storage media, four combination modes are proposed and studied. The results indicate that the exergy efficiency and energy density of mode 1 (air as the working medium, and water as the heating storage medium) exceed those of other modes. Among all modes, the maximum exergy destruction emerges in the second heat exchanger. For the system adopting therminol 66 as the heating storage medium, the gas storage chamber has great potential in improving system performance. Moreover, parameter analysis and multi-objective optimization are conducted. As a result, ambient temperature, cold tank temperature and convective heat transfer coefficient are of massive influence on system performance. Under certain optimal conditions, the optimal energy densities of the four modes are 5.28, 4.33, 4.81 and 3.84 MJ m⁻³, respectively, and the optimal exergy efficiencies are 53.51%, 46.43%, 50.19% and 42.59%, respectively.