Accurate and simple measurement of power generation efficiency and figure of merit of thermoelectric modules based on optical heating and non-contact temperature detection methods

In this study, we propose an accurate, simple, and versatile measurement method for power generation efficiency and device figure of merit <i>ZT</i> of thermoelectric devices. Toward the energy harvesting applications of thermoelectric generators, the performance characterization under low heat inflow and temperature difference is crucial. However, when the conventional solid-state heat flow meter is used, the uncertainty of power generation performance increases as heat input decreases. We have solved these problems by using a laser for heat input, improving the simplicity and accuracy of power generation efficiency measurements, especially at low heat flow. The direct and non-contact measurement of the temperature difference by using a thermography allowed us to determine <i>ZT</i> as well as power generation efficiency. The obtained mean power generation efficiency and <i>ZT</i> values are consistent with the values obtained by the conventional method within the error range, thereby validating the reliability of the proposed method. The relative uncertainties of the efficiency and <i>ZT</i> were estimated to be less than 3% and 12% for our method, respectively, whereas those were 19% and 24% in situations where the temperature difference was less than 6 K for the conventional method.