The Question of Thermoelectric Devices (TEDs) Electrical Resistance: A Practical Research From a Seebeck Effect (TEG) Context

Thermoelectricity is an intriguing technology; however, though clean and flexible, its efficacy in converting heat to direct current (DC) electricity based on the Seebeck effect has been reportedly dismal. One key parameter that affects this, but often overlooked and less detailed in scholarly publications, is the intrinsic electrical resistance and most importantly how to determine it if unknown. This study is, therefore, conducted to share some insights on determining thermoelectric devices (TEDs) resistance and from a Seebeck effect perspective. The research employed 16 identical TEDs, operated as thermoelectric generators (TEGs), to study and estimate their electrical resistance by subjecting them to temperature differences (TDs) of approximately 10, 20, 40, 60 and 70–80°C, while connected to various electrical loads of 10, 8, 6, 4 and 2 Ω derived in turns from: (i) normal variable resistors, (ii) trimpots resistors and (iii) fixed value resistors. The findings revealed that determining the TEDs electrical resistance when operated as TEGs is varied, even though a sizeable amount of the TEGs resistance values under the different test conditions were between 3 and 6 Ω. The fixed value resistors load offered the most reliable measurements, with 10 out of the 16 TEGs under the 4 Ω load giving an internal electrical resistance between 4 and 6 Ω; with also a mean between 4 and 6 Ω and standard deviation <1 Ω as follows: TEG1, TEG3, TEG4, TEG6, TEG7, TEG8, TEG10, TEG11, TEG13 and TEG15, respectively, have a mean electrical resistance of 4.59, 4.62, 4.70, 5.05, 4.29, 5.05, 4.64, 6.03, 5.12 and 5.77 Ω; with corresponding mean standard deviations of 0.44, 0.27, 0.81, 0.98, 0.41, 0.63, 0.59, 0.62, 0.54 and 0.42 Ω. It was also noticed that regardless of the TDs and the electrical loads used, some of the TEGs electrical resistance was more or less the same throughout, while some of the TEGs electrical resistance highly fluctuated at a particular TDs and or with a particular electrical loads. In sum, though the electrical loads using fixed value resistors are definitive (since variable resistors loads drifts during testing), there was, however, not really a clear/ deterministic pattern in terms of the TEGs electrical resistance value proportionality, with respect to the TDs value and or the electrical loads value.