Scoping Study of Integrated Geothermal CO2 Heat Pump and Water Well System in Cold Climate Region

This study evaluates the feasibility of using ground-source heat pumps (GSHPs) integrated with water wells for residential heating demands in cold regions of the United States. Four different heat pump systems were evaluated and compared: a CO2 air-source heat pump (ASHP), a R-410A ASHP, a CO2GSHP integrated with well water, and a R-410A GSHP integrated with well water. Simulations were conducted at both equipment and building integration levels, followed by a nationwide analysis across 10 selected cities. Results indicate that integrating GSHP technology with existing water wells (e.g., artesian, bedrock, drilled, and collector wells) is a feasible heating solution because of their high flow rates, good water quality, stable temperatures, and low environmental impact. Although R-410A systems demonstrate higher efficiency, CO2 systems are more suitable for heating from contamination-free and energy security perspective. The CO2 GSHPs maintain better performance in colder climates compared with that of ASHPs, providing higher coefficient of performance and environmental benefits because CO2 refrigerant leakage would not contaminate well water. A national analysis confirms that CO2 GSHPs outperform furnaces, especially in cold climates, making them a promising solution for residential heating.