Multiobjective Optimization of a Combined Heating and Power System Based on Compressed-Air Energy Storage and Thermochemical Technology

Abstract

Compressed-air energy storage has been considered as a promising technology to smooth the fluctuations of renewable energy sources and improve the peak-shaving flexibility capacity of power systems. In order to improve the energy degree of compression heat and enhance the system performance, the current paper described a novel combined heating and power system that integrates compressed-air energy storage with thermochemical technology. In the proposed system, the compression heat is coupled with methanol decomposition reaction to convert the thermal energy to chemical energy (H2 and CO). A sensitivity analysis was carried out to investigate the effects of five key parameters on the system performance. The results indicated that higher values of air-to-methanol ratio, pressure ratio, and isentropic efficiency of gas turbine have positive influences on the thermodynamic performance of the proposed system. In addition, the multiobjective optimization was implemented to ascertain the optimum performance from the aspect of thermodynamics and economics. The optimal condition selected using the technique for order preference by similarity to an ideal solution (TOPSIS) method demonstrated that the exergy efficiency and levelized cost of energy of the proposed system are 39.42% and $96.58/MWh, respectively.