Study on the simplified model of vertical double U-pipe ground heat exchanger

Abstract

A simplified semi-analytical model of vertical double U-pipe ground heat exchanger (VDUGHE) was established. The validity of the established model is examined by contrasting the figured outcomes with experiment data, emulation results of 3D numerical model and calculation results of infinite line-source model (ILSM) for different inlet boundary conditions and configurations. After 1 hour, the semi-analytical model?s relative error is less than 0.32% under the boundary condition of given inlet fluid temperature. Under the boundary condition of given total heat input rate, the semi-analytical model?s relative error after 10 hours is less than 0.11%, while the ILSM?s relative error is less than 0.60%. The semi-analytical model is in good agreement with experiment and numerical model, and has higher calculation accuracy than ILSM.