Thermally regenerative electrochemical cycle (TREC) is a novel and effective heat-to-electricity technology for harvesting low-grade heat. Currently, reported TREC analyses have been based on the Stirling cycle of ideal infinite heat source and infinite time for heat transfer. However, this will lead to inaccuracy when the scenario deviates from the ideal case. In this study, a systematic thermodynamic analysis on TREC is performed to address this problem. Based on different heat transfer situations, the description of thermodynamic processes and the corresponding mathematical models are established. At the same time, the TREC system, with the solar collector as the high-temperature heat source and the environment as the low-temperature heat source, is employed as a case. And the study delved into discrepancies arising from incongruences between the practical operational process and the traditional ideal analytical methodologies, along with an investigation of the different thermal environment impact on system performance. The findings suggest that the finite analysis method should be used when the actual operating time of the system is shorter than the desired equilibrium period. On the contrary, the use of the infinite analysis method, in this case, produces an error, the magnitude of which is directly related to the operating time, whereas when the time reaches 80% of the equilibrium time the error can be controlled to less than 2%. The influence of the heat source on the operating phase of the system is mainly in the temperature equilibrium and the rate of temperature equilibrium. This effect is proportional to the thermal capacitance and is also positively related to the system performance. Therefore, to improve system performance, it is recommended that a high-temperature heat source with a high ratio of thermal capacitance to system thermal capacitance should be selected and that the response time should slightly exceed the system equilibrium duration.
FU Shen
,
TANG Xin
,
LIU Penghui
,
LI Guiqiang
. A Systematic Thermodynamic Analysis of the Thermally Regenerative Electrochemical Cycle[J]. Journal of Thermal Science, 2025
, 34(2)
: 389
-399
.
DOI: 10.1007/s11630-025-2094-5
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