The question of thermoelectric devices (TEDs) in/efficiency - a practical research considering thermoelectric generators (TEGs)

Abstract

Thermoelectricity is a versatile clean energy technology; however, its in/efficiency has been a question of debate. Thus, this practical study focuses on thermoelectric devices' (TEDs') performance when operated as thermoelectric generators (TEGs). Sixteen identical TEDs (TEC-12706 of the same made and model) were operated as TEGs under the same experimental setup and test modalities with a hotside temperature between ∼20°C and ∼100°C and a coldside temperature of ∼20°C, to practically and comparatively examine the TEGs voltage production and energy conversion in/efficiency. The findings revealed that, while it's already common knowledge that a TEG output voltage is proportional to its temperature difference as evident in all the TEGs used in the study; however, as the TEGs temperature difference proportionally increases, some of the TEGs relatively produced less, the same and more output voltages at certain temperature differences compared to others. For example, TEG1 and TEG3 produced almost the same output voltages throughout; however, at ∼100°C hotside temperature, TEG3 produced 3.16 V, whereas TEG1 produced 2.90 V. While such widespread TEGs discrepancies can be mostly attributed to bad manufacturing/poor workmanship, they are usually misconstrued by some as a generic inherent thermoelectricity technology limitations which this study highlights.