Numerical Simulation of Ground Heat Exchange System with Water Injection or Pumping

Abstract

In Ground Source Heat Pump (GSHP) systems, reduction of initial and running costs are important. Previous studies show that groundwater flow around the well would enhance heat exchange performance and is expected to reduce initial costs and running costs of GSHP systems. Either water injection into or pumping from the heat exchange well induce flow of water in the well and the flow may enhance heat exchange performance. In Akita University, Japan, Thermal Response Tests (TRT), a common method to determine effective thermal conductivity of ground and thermal resistance of borehole. These basic parameters are necessary to study heat transfer mechanism and to design sustainable closed GSHP systems. Some researchers reported that are effective to improve BHE characteristics. In this research, a numerical model of heat exchange well drilled in Akita University was developed and numerical simulations were carried out for the modeling of TRTs either with water injection or water pumping case. In addition, characteristics of the system were investigated through numerical simulations.