Applicability of the pipe structure and flow velocity of vertical ground heat exchanger for ground source heat pump

This paper builds three-dimensional heat transfer model of single- and double-U type vertical ground heat exchanger (GHE). The heat transfer and pressure loss of vertical GHE is simulated with different flow velocities, pipe diameters and well depths. Moreover, the value engineering (VE) is used to evaluate the tech-economic performance of the buried pipe. The value coefficient of each scheme is compared with selecting five functional indicators. The objective of this paper is to obtain the recommended structures for the GHE in engineering applications. The results show that single-U32, double-U25 and double-U32 have their own advantages in the aspects of the heat transfer, outlet temperature, pressure loss and material consumption. The recommended velocity ranges of single-U32, double-U25 and double-U32 are 0.4-0.6, 0.4-0.5, 0.3-0.4 m/s respectively. Finally, the recommended well depth ranges of double-U25 and double-U32 are 80-100 m and 90-110 m respectively.