| Title | Design of a compact flat heat exchanger for a modular thermoelectric stack towards geothermal power generation |
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| Authors | Entong Xia, Heping Xie, Licheng Sun, Xiting Long, Jun Wang, Cunbao Li, Mingzhong Gao, Tianyi Gao |
| Year | 2023 |
| Conference | World Geothermal Congress |
| Keywords | Geothermal power generation; Compact heat exchanger; Flow uniformity; Modular design |
| Abstract | Thermoelectric generators (TEGs) own advantages of no moving parts, scalability, and compatibility with different systems. Using of TEG technology for geothermal power generation has been of interest to many researchers in spite of its low conversion efficiency. As such, compactness of a thermoelectric device is of significance for a large-scale application, otherwise it would be too large to become impracticable. In the current work, a compact heat exchanger was designed for a modular thermoelectric stack on the basis of previous work of our research team with foremost aim at realizing large-scale geothermal power generation using of TEG technology. It realizes a uniform flow distribution among sub-channels for a better temperature uniformity across the contacting surfaces with the TEG modules. More importantly, relatively high compactness of the heat exchanger is not at the expense of increasing the flow resistance. Due to that the tapering inlet and outlet play a key role in regulating the flow distribution among the sub-channels, a CFD analysis is be carried out on the current design with modified inlet and outlet, aiming to find optimized design of the heat exchanger. Hence, a comparison of simulation results obtained under given various geometry of tapering inlet and outlet is analyzed, in order to determine an appropriate geometry to weigh the uniformity against flow resistance. Meanwhile, the flow distribution among sub-channels in the heat exchanger is assessed quantitatively. Finally, a compact heat exchanger is designed and optimized, hopefully it can provide a feasible approach to the design of heat exchangers for a large-scale thermoelectric system. |