Conventional and advanced exergy-exergoeconomic assessment of pumped thermal energy storage integration in enhanced thermally coupled methanol decomposition reaction

In this paper, a thermochemical energy storage based pumped thermal energy storage system is proposed to address the efficient utilization of intermittent and fluctuant renewable energy sources. To enhance the thermodynamic performance of the proposed system, compression heat is employed as the heat source of endothermic methanol decomposition reaction, thereby upgrading thermal energy to chemical energy. The comprehensive performance of the proposed system is investigated by utilizing conventional and advanced exergy/exergoeconomic-based analyses for the first time, which could reveal the interactions among system components and identify the thermodynamic and economic improvement potential of each component simultaneously. The results indicated the system exergy efficiencies were 56.54 % and 64.32 % under real and unavoidable conditions, respectively. For conventional analysis results, the highest values of exergy destruction (1155.19 kW) and total cost rate (71.56 $/h) were in the combustion chamber, while considering the results of advanced exergy and exergoeconomic analysis, the combustion chamber gave the highest avoidable endogenous exergy destruction of 297.75 kW, and flue gas heat exchanger had the highest avoidable endogenous total cost rate of 22.82 $/h. Furthermore, the system exhibited 20.99 % avoidable exergy destruction, 13.12 % avoidable investment cost rate, and 28.42 % avoidable exergy destruction cost rate, demonstrating the significant optimization potential of the proposed system. Notably, the endogenous part dominates the avoidable exergy destruction cost rate for each component, indicating that enhancing the component efficiency is more effective for improving the thermo-economic performance of the system than optimizing the interaction among components.