Depletion and Regeneration Behaviour of a Large Solar-Assisted Ground Source Heat Pump System (SAGSHP) for 156 Units Multi-Dwelling.

Abstract

Geothermal heat pumps can contribute to the transition to 100% renewable energy. Thermal depletion of the soil can be a constraint to this application for large heatingdominated buildings. A large solar assisted ground source heat pump system (SAGSHPS) is analysed for an apartment building located in Belgium. For this specific case a simulation set-up of the system (SAGSHPS) is developed in the software environment TRNSYS. All the components of this system have been dimensioned by hand and then tested in the simulation set-up in order to validate the sizing. No sustainable large heating system can be designed without regeneration of the soil. Geothermal storage with a volume 30% above the calculated volume still encounters thermal depletion problems. Solar collectors to inject solar heat into the ground is a proven technology to reduce depletion of the soil. A SAGSHPS containing 390 boreholes of 107 m deep combined with 100 solar collectors with an absorber area of 303m² is the sustainable set-up calculated at first in this research. The last system SAGSHPS resulted with 48 boreholes of 107m deep combined with 450m² solar collectors. Furthermore, this research encloses few design guidelines. This leads to a conclusion that a SAGSHPS can be a sustainable heating system for large buildings in specific cases.