Energy performances of a ground-source heat pump system

Some results from an experimental study of a ground-source heat pump system (GSHP) using mixed energy sources (geothermal, electricity, solar, internal gains, combustion heat recovery, natural gas) located in a new institutional building in Canada are presented. This system consists of 35 electrical water-to-air heat pumps (between 8,8 and 21 kW cooling capacities) connected to a heating transfer medium closed-loop, which in turn is attached to a horizontal geothermal heat exchanger. A water storage tank allows the thermal storage of internal gains (alternating with the ground heat exchanger) and heat recovery from the cooling circuit of an oil-fired backup generator. The outdoor fresh air required is first preheated by a solar wall and then by natural gas, if necessary. After a brief system and experimental approach description, some preliminary results concerning duty cycle of heat pumps, system energy balance, heat pump and system energy performances, consumption and power demand profiles achieved in a Nordic climate were evaluated.