AUTHOR=Zhang Jiansong , Liu Yongsheng , Qin Xing , Dou Zijun , Meng Qingsheng , Xu Xiaonan , Lv Jianguo TITLE=Optimization design and drag reduction characteristics of bionic borehole heat exchanger JOURNAL=Frontiers in Energy Research VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.1024623 DOI=10.3389/fenrg.2022.1024623 ISSN=2296-598X ABSTRACT=

As a renewable energy source, geothermal energy has drawn attention because it is clean, low-carbon, resource-rich, stable, and sustainable supply. In the mining and operation of a geothermal energy system, there is a certain amount of fluid resistance in the borehole heat exchanger where the fluid flows. As the resistance in the conventional borehole heat exchanger (CBHE) accumulates with the length increase, the pumping power increases, resulting in energy loss and affecting the operation of the entire geothermal system. A bionic borehole heat exchanger (BBHE) is designed using a circular groove as a bionic unit based on the bionic non-smooth surface hypothesis. Its structural characteristics are the circular groove’s depth, width, and slot pitch. Where the fluid faces the least resistance, minimization of the pressure drop was the optimization goal. Based on the outcomes of a CFD numerical simulation and genetic algorithm optimization study. These are the BBHE’s ideal structural parameters: diameter is 60 mm, 66 mm for the groove width, 418 mm for the slot pitch, and 80 mm for the groove depth. Compared to the CBHE, under identical numerical simulation settings, the fluid resistance reduction rate of BBHE can reach 13%. Increasing fluid velocity in the BBHE can increase the temperature transmission rate. The study’s findings can serve as a reliable source of scientific information for the use and management of geothermal energy.