Sizing optimization of thermoelectric generator for low-grade thermal energy utilization: Module level and system level

Abstract

With the significant improvement of thermoelectric material properties, the thermoelectric generator is attracting more attention in heat recovery. The geometric parameters and design parameters have a significant effect on performance of TE module and system. Counterintuitively, for a fixed heat source condition, integrating more thermoelectric modules would reduce the overall economic performance, output power, and energy efficiency. In fact, there exists an optimal size of thermoelectric module number and geometry. In this study, a novel sizing method is proposed to find the optimal size parameters, which can be applied on both module and system levels. As a case study, exhaust gas from a truck engine of 708 K is considered as the heat source. Both technical constraints and economic indicators, such as NPV, IRR and payback period are analyzed. To maximize the TEG net present value, the optimal module height is found to be 1.5 mm and the module number is 144, under the studied thermal boundary condition. The analytical results in this study could provide guidance for thermoelectric generator system designs and help the realization of large-scale industrial applications.