CanSIA 2012-Integrating Solar Thermal with Geothermal | Photovoltaic Innovation Network Blog
"Using the geothermal loop field as a storage tank to absorb the excess solar energy in the summer. This advantage allows you to oversize the solar thermal system and increase the solar thermal contribution to the winter heating.
A study has been done [3] for the viability of a combined system in Milton, Ontario. This study shows that a combined system is feasible for space conditioning. For the house in this study, the seasonal solar thermal energy storage in the ground was sufficient to offset the large amount of Geo-thermal pump system length that would have been required in conventional systems. They showed that the economic benefit of such system depends on climate, as well as borehole drilling cost.
To conclude, a hybrid Solar-Geo-thermal system could be an outstanding solution to the high demand of energy in today’s world. It has a lot of benefits like sustainability, being clean (non-polluting) and having the ability to work all year round. Another important benefit is the possibility of using this system for all kinds of applications such as residential, commercial and industrial."