The question of thermoelectric devices (TEDs) in/efficiency - a practical examination considering thermoelectric coolers (TECs)

Abstract

Thermoelectric devices (TEDs) are clean energy devices with diverse applications; however, the question of their energy in/efficiency and how to improve it, has been a subject of research/debate among many researchers and non/users. In an effort to contribute to this quest/scientific discourse, this paper focuses on energy in/efficiency in TEDs when operated as thermoelectric coolers (TECs) for cooling purposes. A practical research was performed using sixteen identical TECs operated in the same performance test conditions and powered in turns using 12 V, 10 V, 8 V, 6 V and 4 V, with a 5 A current limit, to investigate TECs in/efficiency inconsistency. It was found that the TECs (TEC-12706 from the same manufacturer) used in the study all performed differently under identical test setup; however, they all performed optimally at 8 V, with the best (TEC3) attaining a cooling of −4.81 °C with an input power of 21.09 W and the worst (TEC9) attaining a cooling of 12.63 °C with a power input of 45.52 W. From our findings, TECs in/efficiency can therefore be summarily attributed to five fundamental factors and though TECs efficiency is well known to be limited by 1) its intrinsic p-n junction semiconductor chemistry and physics at materials level; however, we can conclude that given the same semiconductor technology, TEC inefficiency is further exacerbated by 2) low-quality manufacturing/assembly at module level, 3) inadequate designs at application/system level, 4) substandard system construction/workmanship at implementation level and 5) general lack of theoretical/physical knowledge of TECs operation at users’ level.