Modelling of flow and heat transport in vertical loop ground heat exchangers

The performance of ground source heat pumps relies greatly on the heat transfer efficiency throughout the ground loop configuration. Vertical ground loops can employ a U-Bend or a Coaxial pipe configuration which generates vortical structures and turbulence, enhancing the heat transfer process. For the U-Bend, the Dean Number (radius of curvature) and the Reynolds Number (inlet velocity) are tested. For the Coaxial, the inner pipe offset, and the Reynolds Number (inlet velocity) are tested for improved configurations. For the U-Bend, it was found the Reynolds Number dominates. In the Coaxial system, it was found that inner pipe offset destroys the heat flux of the system. Comparing the two systems, the Coaxial pipe shows both lower pressure loss and increased heat flux at equivalent inlet flow rates