Analysis of thermal and dynamic comportment of a geothermal vertical U-tube heat exchanger

This paper presents a computational analysis on the turbulent flow and heat transfer for water flowing in a geothermal vertical U-tube heat exchanger (GHE). The governing equations, based on the k–ɛ model used to describe the turbulence phenomena, are solved by using finite volume method. The velocity and pressure terms of momentum equations are solved with SIMPLEC algorithm. The simulation of the dynamic and thermal behavior of the geothermal vertical U-tube heat exchanger was carried out under Fluent software. Results are compared with recent work from the literature and good agreement is obtained. The evolution of temperature and the heat transfer according to time (700 h) and position, have been fixed, as well as the influence of fluid flow on the dynamic and thermal behavior of the heat exchanger.

► The U-tube's form (smoothes tube) used until now in the installation of ground-coupled heat pump (GCPH) in building.
► The temperature distribution in a perpendicular surface of the U-tube shows the soil capacity to store heat.
► The distribution of the temperature around the U-tube decreases according to the depth.
► Water velocity in a U-tube with 32 mm of diameter should be between the value of 0.3 and 0.4 m/s for GCHP performance.