A promising solar heat pump system for cold climates

In an article published in volume 261 of Applied Thermal Engineering ^[1], a team of researchers simulated the performance of a solar ground source heat pump system designed for cold climates. The system, which integrates a solar heat exchanger with a foundation-based slinky ground heat exchanger, demonstrated promising results in reducing soil freezing risks and improving energy efficiency for buildings.

 

The researchers developed a 3D numerical model to simulate the thermal behaviour of the system, accounting for the energy loads of a building as well as variations in temperature and solar radiation over time. The simulation showed a significant reduction in soil freezing, from 58.3% to 32.4% of the year. Moreover, heat pump shutdowns caused by low fluid temperatures dropped dramatically, from 38.9% to just 5.8%.

 

This promising approach offers potential energy efficiency gains by reducing reliance on external energy sources. It could lower heating costs while also decreasing the carbon footprint of buildings by combining solar and geothermal energy for better management of renewable resources.

 

Finally, long-term simulations conducted for different locations in Minnesota revealed that the system could meet a significant portion of a building’s energy needs while mitigating soil freezing and heat pump shutdowns.

 

Source

^[1] Davani, Shayan, Darbandi, Amirhossein, Gruenes, Jordan, Hoxie, Alison, Mwesigye, Aggrey. "Thermal performance of a solar-assisted slinky foundation heat exchanger coupled with a heat pump in a cold climate." Applied Thermal Engineering, vol. 261, 15 février 2025, https://doi.org/10.1016/j.applthermaleng.2024.124986. Also available in FRIDOC.

Picture: Experimental Investigations and Numerical Simulation of Thermal Performance of a Horizontal Slinky-Coil Ground Heat Exchanger. https://www.mdpi.com/2071-1050/9/8/1362