Abstract
The paper presents results of the analysis and comparison of the hot-side heat exchangers (HHXs) dedicated for the thermoelectric generators (TEGs). Efficient operation of TEG depends on, i.a. proper design of the HHX. Six geometries of the heat exchangers’ cross-section have been investigated and analysed in view of heat transfer effectiveness (ηTH) and pressure drop (ΔP). As an assumption, useful heat exchange surface has been set up as 2400 cm2 , maintaining heat exchanger (HX) length as 30 cm, which is enough for the placement of the 32 thermoelectric modules able to generate at least 160 W of the electrical power. The source of waste heat are flue gases, in the analysis approximate as an air. Cold-side heat exchanger (CHX) has been simplified and calculated as a water flow around the casing of the HHX to achieve comparable results. As a base, circular profile has been presented. Numerical calculations provide results suggesting which shape is most suitable for specified application. Results could be the first guidelines for selecting and designing the HX for the TEG. Further investigation will focus on optimization of the chosen HX in view of increasing ηTH and minimizing ΔP.
Highlights
Increasing awareness of waste energy losses, especially waste heat, causes constant development in the recovery solutions
Flue gases were simulated by hot air, whole lateral surface has been cooled by water flow around the casing to avoid dissimilarities caused by the design and mismatching of the Cold-side heat exchanger (CHX)
The net generated power, taking into account losses due to pressure drop is presented for varied mass flow rates
Summary
Increasing awareness of waste energy losses, especially waste heat, causes constant development in the recovery solutions. As a result of Seebeck phenomenon, due to temperature difference between hot and cold sides of thermoelectric module, heat flux is converted into electrical energy with the defined efficiency. The efficiency of a TEG as a whole device depends on both, the efficiency of the thermoelectric modules and the effectiveness of the HXs on the cold and on the hot sides. Location of the TEG varies from its usage for supplying residential boilers in electrical energy [1], projects of wood stoves able to generate heat, electricity and hot water [2], through cement rotary kilns with energy recovery unit [3], to automotive applications [4,5,6].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
