Potential of shallow aquifers in the plain sector of Piemonte region (NW Italy) for groundwater heat pumps diffusion

The study focuses on the potentiality of the low-enthalpy open-loop GroundWater Heat Pumps (GWHP) diffusion in the alluvial plain aquifers of the Piemonte region (NW Italy). The use of low-enthalpy open-loop GroundWater Heat Pumps (GWHP) could in fact contribute to the reduction of regional greenhouse gas emissions. GWHP could be used only with shallow groundwater, to avoid potential alteration of the deeper aquifer so the hydrogeological plain setting and the spatial distribution and temporal variability of the shallow groundwater temperature have been analyzed. Low annual and seasonal variability of the shallow groundwater temperature confirmed the potentiality of the low-enthalpy open-loop GroundWater Heat Pumps (GWHP) diffusion. The distribution of mean groundwater temperatures have been considered and differences among different areas were slight according with the modest variations in the general climatic condition in different areas. Higher temperature values recorded were typical of summer months and on the opposite lower values were measured in January and February. Besides air-temperature influence (seasonal variability) seemed strictly connected to the depth to groundwater in the measure point and it was negligible when the value was over 9.5 m. For the application of the open-loop systems, extensive examinations of the hydrogeological local conditions should be conducted at site scale and groundwater heat transport modeling should be developed. Geographical distribution analysis showed that technical and economic efforts should be made by public authority to implement the monitoring network and reduce the lack of information about groundwater temperature at a regional scale.