Evaluation method for assessing heat transfer enhancement effect on performance improvement of thermoelectric generator systems

Abstract

The total power output of a thermoelectric generator system can be increased by enhancing the heat transfer performance of its hot-side heat exchanger. However, heat transfer enhancement is usually accompanied by the consumption of additional pump power. Therefore, it is unclear whether the net power output, that is, the difference between the total power output and the pump power, increases. Developing a comprehensive evaluation method based on the net power output is necessary to determine the heat transfer enhancement effect on performance improvement of the system. In this paper, the concept of net power ratio which integrates the total power output and the pump power consumption was proposed to evaluate the heat transfer enhancement effect on the performance improvement of a thermoelectric generator system. Based on a ring-shaped thermoelectric generator, the analytical solution of the net power ratio was theoretically derived. Compared with the numerical and experimental methods, the proposed net power ratio in a thermoelectric generator system is convenient and time-saving with adequate accuracy for engineering applications. Moreover, the application of net power ratio in a real thermoelectric generator system was investigated by case studies. Results show that both the inlet fluid temperature and the mass flow rate affect the net power ratio. When using net power ratio to evaluate the performance improvement of a thermoelectric generator system, net power should also be considered to obtain optimal working conditions for a thermoelectric generator system.