Evaluation of Thermoelectric Generators by I–V Curves

Abstract

A recent theoretical study proposes a new way to evaluate thermoelectric devices by measuring two I-V curves-one obtained under a constant temperature difference and the other obtained for a constant thermal input. We report an experimental demonstration of the feasibility of this novel technique. A measurement system was designed and constructed, which enables both types of I-V curves to be obtained automatically. The effective ZT values of a thermoelectric module were determined using this system and compared with those measured by an impedance spectroscopy technique. The results confirm the validity of the proposed technique. In addition, the capability of measuring ZT under a large temperature difference was also investigated. The results show that the ZTs obtained for a large temperature difference are significantly smaller than those for a small temperature difference, providing insights into the design and operation of thermoelectric modules in realistic applications.

Thermal contact resistance evaluation of a thermoelectric system by means of three I-V curves

“…Notice that the module zT=RTE/RΩ, can thus be obtained from these two I-V curves, as previously reported [14].…”

“…On the other hand, an I-V curve performed waiting for different steady state I and V values allows the temperature variations induced by the Peltier effect to contribute to the response. These different I-V curves have been demonstrated to be useful for the determination of the figure of merit zT of a TE device [14], and the total thermal parasitic resistance [15,16]. However, none of these methods allowed the independent determination of the thermal contact resistance.…”

Measuring Device and Material ZT in a Thin-Film Si-Based Thermoelectric Microgenerator

“…Several techniques have been developed to evaluate the performance of a TEG [20,21], measuring the efficiency and the figure of merit (ZT), while avoiding some of the side effects, such as the Thomson effect. However, an alternative means of characterization consists of separately measuring the three extrinsic parameters related ZT: the total heat conductance from the hot side to the cold side, the electrical resistance (produced by the active material plus the contact resistances), and the total Seebeck coefficient produced by all of the TEG legs.…”

A Flexible Thermoelectric Generator Worn on the Leg to Harvest Body Heat Energy and to Recognize Motor Activities: A Preliminary Study

“…However, since the F-TEG is a non-linear device, the value of R L is shifted to a larger resistance value, which is usually estimated to be ~1.4 R ′ [28], but it can also reach the value of ~1.8 R ′ [29]. For that reason, the formula for the calculation of the power generated by the F-TEG is as follows:…”