Are you interested in the technology behind geothermal, you get a deeper explanation here.
Hoses buried on the land surrounding the house is filled with environmentally friendly alcohol or glycol. The fluid accumulating the heat, the sun is stored in the soil.
The evaporator transfers the heat to the heat pump’s refrigerantion
The compressor raises the pressure so the coolant temperature rises several degrees.
The condenser transfers the heat to the house’s heating and hot water tank.
Expansion valve lowers the pressure. The refrigerant is colder, so it can absorb as much heat in the evaporator.