Thermodynamics analysis of multi-cycle performance of an integrated concentrated solar power, calcium looping and methane reforming system based on exergy approach

Abstract

The integration of concentrated solar power (CSP) and calcium looping (CaL) systems serves to tackle the issue of instability in solar power generation. However, there is relatively insufficient research on the impact of the decline in sorbent activity on the performance of CSP-CaL systems. In this study, the exergy flow of the novel system integrated with the CSP-CaL and methane reforming (MR) subsystem over multiple cycles under mild and severe conditions are analyzed. The results show that using pure CaO under mild conditions results in the power generation efficiency dropping sharply from 37.32 % to 27.90 % over 19 cycles, and the exergy efficiency of the heat exchange network is consistently below 89.8 %. Compared to pure CaO, using CaO/Ca₃Al₂O₆ sorbent decreases slightly the power generation efficiency from 37.49 % to 37.32 %, and improves the exergy efficiency of the heat exchange network by at least 0.5 %. Compared to mild conditions, severe conditions for CaO/Ca₃Al₂O₆ sorbent slightly increase the H₂ production efficiency and the exergy efficiency of the heat exchange network in the first 15 cycles, but reduce the power generation efficiency by >3.4 %. Nevertheless, the stability of the system is higher than that of the system using pure CaO under mild conditions.