Maximal continuous power output and parametric optimum design of an electrochemical system driven by low-grade heat

Abstract A new model of the electrochemical system consisting of multiple thermally regenerative electrochemical cycles (TRECs) working in different states is proposed to solve the problem of discontinuous power output. This system can efficiently harvest low-temperature waste heat and realize the continuous power output. Based on the performance of a single TREC, the power output and efficiency of the system are analytically derived. The effects of the electric current on the power output and the upper and lower boundaries of the efficiency are discussed. The general performance characteristics of the system at the maximum power output are revealed. Moreover, it is expounded that when the system is operated at the state of the maximum efficiency-power product, the systemic performance relative to the state of the maximum power output may have an obvious improvement. For example, when the Carnot efficiency of the system is smaller than 0.2, the improvement ratio of the systemic performance is larger than 16%. The results obtained here show that the system should be operated between the maximum power output and the maximum efficiency-power product. Consequently, the optimal criteria of the parametric design are provided and the rationally operating region of the system is determined.