Replacing commercial thermoelectric generators with a novel electrochemical device in low-grade heat applications

Abstract

A thermoelectric generator (TEG) is a solid-state electronic device. The main defect of a commercial TEG, which makes it useless for most of practical applications such as solar energy harvesting, is its very low power production when the difference of temperature between its two surfaces ranges below 50 °C. The traditional solution is to add some relatively expensive devices such as concentrator, evaporator, condenser and cooling system to TEGs that there is often no technical and economical justification for it. This study provides a new solution by presenting a novel electrochemical device operating based on the thermally regenerative electrochemical cycle (TREC). The proposed device is first analyzed in detail to provide theoretical concepts. A prototype of the device has been constructed, and experimental verifications are given that substantiate the capability of the device in precisely mapping temperature difference between its two cells to its output electric power. A comparison between the proposed electrochemical device and a commercial TEG module TEG1-1263-4.3 is also performed that demonstrates the power production of the electrochemical device is extremely more than that of a commercial TEG module, in particular, in the temperature difference range of 0–50 °C. For instance, 54.5 W of electric power is produced by the device at the temperature difference of 50 °C, while it is only 0.3 W for a TEG module TEG1-1263-4.3. This point explicitly verifies the superiority of the proposed electrochemical device in low-grade heat harvesting. The novelty and originality of this study can be summarized as follows. First, presenting and constructing a novel electrochemical device operating based on the TREC with the size and weight of, respectively, 50×30×32cm3 and 3.1 kg that makes it portable and suitable for industrial applications. Second, the power production of the constructed electrochemical device is extremely greater than that of TEG modules that considering size, weight and portability is the only alternative technology in low-grade heat harvesting applications. Third, this work presents an electrochemical device which is an industrial TREC based system applicable to industrial applications that is clearly different from small-scale TREC cells reported in the literature, which are only applicable to small-scale experimental applications.