POTENTIAL USE OF ABANDONED UNDERGROUND COAL MINE AS-029 AS A RESERVOIR FOR GROUND SOURCE HEAT PUMPS, ATHENS, OH

Ground source heat pumps (GSHPs) have been used for heating and cooling applications in areas where the thermal gradients are normal. Unlike conventional heating and cooling systems, ground source heat pumps rely on ground or underground water temperature which is more constant than air temperature. Flooded abandoned underground coal mines (AUMs) have been used as heat exchangers for ground source heat pumps in countries such as Nova Scotia, the Netherlands and states like Pennsylvania. Ohio has around 147 abandoned underground mines located close to towns and with sufficient water and heat available in the groundwater for heat exchange using ground source heat pumps.

This project characterized the potential of the AUM AS-029 located in Athens, Ohio, as a reservoir for GSHP technology in Ohio University or The Plains. Monitoring of the hydraulic and thermal response of groundwater wells around the mine was performed and a hydrogeological model was constructed using Visual MODFLOW to better determine the flow and velocity of water through the mine. Additionally, a thermal model of the mine was created considering the overburden thickness of the mine. Groundwater modeling and modeling of the heat absorbed by the mine shows that mine AS-029 can be used to receive heat, it cannot be used to give heat due to the low temperature of the groundwater in this area. For a change in temperature in the mine water of 10 °C, 0.23 MW of heat could be absorbed. The mine could theoretically provide 2.43% of Ohio University’s heating/cooling system with this increase in temperature. In conclusion, mine AS-029 may serve as a geothermal reservoir for a small number of buildings at Ohio University or for Athens High School in The Plains.