Geothermal heat pumps in regions with continuous permafrost – Are they feasible?

Geothermal heat pumps could be an alternative to oil furnaces in remote communities worldwide. However, in Arctic locations, such as Baker Lake (NU, Canada), where permafrost is thick and continuous and heating needs are high, the implementation of these systems may be challenging. Numerical models were developed in FEFLOW to simulate the operation of borehole heat exchangers with 100 and 300 m depth considering the entering source temperature of commercially available heat pumps. The simulations suggest that, because of the 320 m thick permafrost and thermal disturbances of the shallow ground temperature, 100 m-deep borehole heat exchangers inject more energy into the ground than they extract. The results for 300 m-deep borehole heat exchangers are more promising, but the heat pump must be operated within its entering source temperature limit. The outcomes of this work suggest that geothermal heat pump systems with 300 m deep boreholes can realistically be developed in different Arctic regions to offset diesel consumption for residential heating. However, in areas where ground temperature is colder and permafrost is thicker than in Baker Lake, the development of geothermal heat pumps may be even more challenging. The findings of this study helped to determining a limit to the operation of geothermal heat pumps in regions with continuous permafrost.