TY - JOUR

T1 - Take it to the Carnot limit

T2 - Perspectives and thermodynamics of dual-cell electrochemical heat engines

AU - Bae, Dowon

AU - Bentien, Anders

N1 - Publisher Copyright: © 2022 The Author(s)

PY - 2022/11

Y1 - 2022/11

N2 - In electrochemical dual-cell heat engines, the conduction of heat and electricity are fully decoupled, allowing their independent optimisation to maximise the conversion efficiency. Despite this advantage, the dual-cell electrochemical heat engine has only been explored superficially in previous studies. Here we address the in-depth thermodynamic aspects of the heat engines integrated with two electrochemical flow cells and assess the route to achieve a high heat-to-electricity conversion efficiency and system's power output. Our theoretical analysis revealed for the first time that in the dual-cell electrochemical system, the flow rate must be controlled as a response to the electrical current, and conversion efficiency no longer depend on the conventional thermoelectric figure-of-merit. Based on established principles and considering tremendous advancements for the past 10 years within thermogalavic materials and flow battery systems, our analysis presents that it is realistic to develop dual-cell electrochemical heat engines that can be operated at conversion efficiencies approaching the Carnot limit, reaching 10.1 % and 19.3 % at maximum power point and maximum conversion efficiency conditions, respectively, under the temperature gradient of 80 °C.

AB - In electrochemical dual-cell heat engines, the conduction of heat and electricity are fully decoupled, allowing their independent optimisation to maximise the conversion efficiency. Despite this advantage, the dual-cell electrochemical heat engine has only been explored superficially in previous studies. Here we address the in-depth thermodynamic aspects of the heat engines integrated with two electrochemical flow cells and assess the route to achieve a high heat-to-electricity conversion efficiency and system's power output. Our theoretical analysis revealed for the first time that in the dual-cell electrochemical system, the flow rate must be controlled as a response to the electrical current, and conversion efficiency no longer depend on the conventional thermoelectric figure-of-merit. Based on established principles and considering tremendous advancements for the past 10 years within thermogalavic materials and flow battery systems, our analysis presents that it is realistic to develop dual-cell electrochemical heat engines that can be operated at conversion efficiencies approaching the Carnot limit, reaching 10.1 % and 19.3 % at maximum power point and maximum conversion efficiency conditions, respectively, under the temperature gradient of 80 °C.

KW - Electrochemical heat engine

KW - Heat-to-chemical conversion

KW - Redox flow cell

KW - Thermogalvanic effect

U2 - 10.1016/j.enconman.2022.116315

DO - 10.1016/j.enconman.2022.116315

M3 - Journal article

AN - SCOPUS:85139722183

VL - 271

JO - Energy Conversion and Management

JF - Energy Conversion and Management

SN - 0196-8904

M1 - 116315

ER -