Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

For reducing the initial GSHP investment, heat transfer efficiency of borehole exchange (BHE) system can be enhanced to reduce number or depth drilling. This paper proposes a novel and simple BHE design by changing cross-sectional shape U-tube increase BHEs. Specifically, in this study, we (1) verified reliability three-dimensional numerical model based on thermal response test (TRT) (2) compared inlet outlet temperatures different U-tubes at 48 h under premise constant leg distance fluid area. Referent circular tube, increases efficiencies curved oval flat semicircle sector tube were 13.0%, 19.1%, 9.4%, 14.8%, respectively. (3) The flux heterogeneity tubes sides BHE, decreasing order, is oval, semicircle, sector, circle shapes. (4) temperature wall order circle, (5) Under maximum distance, referent resistance with h, increased 12.6%, 17.7%, 10.3%, 7.8%, (6) We found that adjustments affect about 25% 12%, (7) flat-oval-shaped was best for