An automatic thermal cycling based test platform for thermoelectric generator testing

Abstract

Abstract-Thermoelectric (TE) modules are solid-state devices that convert directly thermal energy in electrical energy. However, they can undergo performance degradation due to thermal cycling. In the present study, a control-based test platform that is capable to apply specific thermal cycling pattern at periodic intervals is presented in order to evaluate performance degradation that influence the TE module lifetime. Using this test platform, some parameters and the figure of merit ZT of a commercial TE module are measured before and after thermal cycling application. An important feature of the proposed platform is that the applied thermal cycling is bipolar, that is, it is possible to apply positive or negative temperature difference and, through this, performance degradation would be observed after only 548 thermal cycles much lower than previous works.

An Extensive Unified Thermo-Electric Module Characterization Method

“…Another interesting setup is proposed in [27], where both the heat produced by an electrical resistance and the cooling capacity provided by a TEM, are controlled by a proportional-integral controller. Other propose the use of one or two opportunely driven auxiliary TEMs to set the temperature gradient on the TEM under test [2,28,33]. For example, in [28], ${\mathsf{\Theta }}_{IN}$ is obtained measuring only one heat flux induced into an aluminum block with a known thermal conductivity, interposed between the module under test and an auxiliary TEM used to set the average temperature, hence requiring only three temperatures to be measured.…”

“…In the first case the Seebeck effect is predominant to convert temperature gradient $\mathrm{sans-serif\Delta }T$ into electrical energy, whereas, in the second case, the dual effect—the Peltier effect—is exploited. TEMs’ several positive features make them reliable [1,2], and thus their use is appealing for both academic and industrial researchers.…”

“…The focus is on using an appropriate procedure and suitable hardware to investigate the underlying relationship between both the operating temperature, the temperature difference and the parameters of the electrical and thermal equivalent model for commercial modules. The novelty consists in applying a proper current stimulus (for which two alternatives are discussed) to the TEM under test and simultaneously acquire both thermal and electrical data to automatically derive all parameters in a single test, without using either a discrete load [9,23,24] nor hot plates or auxiliary TEMs [2,11,17,24,25,26,27,28,29]. Unlike other approaches, the developed testbed permit, using a very simple configuration, to quickly obtain all relevant parameters, making possible an extensive TEM characterization over a wide range of temperature differences, ambient temperatures and electric loads.…”

Fuzzy Controller Applied to a Remote Energy Harvesting Emulation Platform

“…The emulation platform was firstly proposed in [ 24 ], the diagram and the physical structure of the platform is shown in Figure 2 and Figure 3 , respectively. This platform features a symmetrical structure composed by two fans, two modules (TEC and TEC ), acting as thermoelectric coolers (TEC), and a module acting as a thermoelectric generator (the TEG-under-test or just TEG).…”

Thermal cycling of thermoelectric generators: The effect of heating rate

“…The authors concluded that the degradation of the TEG was mostly due to the degradation of the thermal contact. Unlike many of the studies mentioned above, the experimental rigs constructed by de Cerqueira Veras et al [18] and Tenorio et al [19] can vary the temperature on both sides of the TEG, which, according to the authors, enables the evaluation of TEGs under more realistic operational conditions. The test platform consists of a TEG positioned between two other thermoelectric modules acting as heater and cooler periodically.…”