Numerical Simulation of a Novel Spiral Type Ground Heat Exchanger for En-hancing Heat Transfer Performance of Geothermal Heat Pump

The spiral type one is more prominent, of which the vertical type ground heat exchange (GHE) is the most common in ground source heat pumps (GSHP) and on the purpose of this study as well. The present paper provides numerical simulation for 1D-3D model of the ground source heat pumps in cooling mode by using COMSOL environment. In contrary to popular spiral models, this model is designed with a low depth and high diameter with special metal rods (Fins). The simulated spiral pipe has 10 m in depth and 1 m in diameter. In order to compensate for the reduction in heat transfer due to the lower depth, the effect of different parameters such as velocity, pitch, thermal conductivity, and specific heat capacity in backfill material and ground on the heat performance is investigated. Furthermore, different velocity range is recommended for several pitches. In addition, as a novelty, an innovative design is modeled consisting of diverse type of horizontal aluminum rods (Fins) in the soil connected to the pipe completely (Finned pipe). The fins not only hold the pipe inside the ground firmly but also improve the heat transfer rate due to the area increase and the high thermal conductivity system up to 31%.