Analysis of Enhanced Heat Transfer Characteristics of Coaxial Borehole Heat Exchanger

Coaxial borehole heat exchangers provide a practical method for geothermal energy extraction, but transfer efficiency is low. In order to address this problem, three coaxial with vortex generators, based on the enhanced theory, are proposed in paper. The author compared and analyzed performance of generators those traditional structures, which explains why new exchanger’s mechanism enhanced. results demonstrated that generator can enhance fluid flow’s turbulent kinetic exchanger. This also improve mixing characteristics flow transfer. resultant increase inlet velocity decrease friction coefficient f, Nusselt number strengthen sleeve. As result, exchange tubular exchanger will be improved. thread (TVG) outperforms other terms performance, extraction temperature power. evidenced TVG better than smooth tube thermal PEC was improved by 1.1 times, heating power were increased 24.06% 11.93%, respectively. A solid theoretical foundation provided extracted outcomes designing selecting high-efficiency suitable extraction.