Ground Source Heat Pump Glossary

Borehole - Holes drilled into the Earth, 50m deep and filled with a loop of pipe that collects the energy from the Earth. Boreholes are usually drilled when there is no land area to dig trenches.

Closed-Loop Heat Pump System - A heat pump system that uses a loop of buried plastic pipe as a heat exchanger. Loops can be horizontal or vertical.

Open-Loop Heat Pump System - A heat pump system that uses groundwater from a well or surface water from a lake, pond, or river as a heat source. The water is returned to the environment.

Compact Collector - A plastic collector that can be used to collect energy from the ground when used with a heat pump. The Compact Collector is used when the garden/land area is too small to install a "Slinky" ground loop system.

CoP (Coefficient of Performance) - The ratio of heating provided by a heat pump to the energy consumed by the system under designated operating conditions. The higher the COP, the more efficient the system. i.e. 1kW in to the Heat Pump 4kW out, COP = 1:4.

Compressor - The central part of a heat pump system. The compressor increases the pressure and temperature of the refrigerant and simultaneously reduces its volume while causing the refrigerant to move through the system.

Condenser - A heat exchanger in which hot, pressurized (gaseous) refrigerant is condensed by transferring heat to cooler surrounding air, water or earth.

Cycling Losses - The actual efficiency of a heating or cooling system is reduced due to start-up and shut-down losses. Over-sizing a heating or cooling system increases cycling losses. buffer tank or weather compensation on an open zone on the underfloor heating system reduces cycling.

Geothermal Heat Pump - A heat pump that uses the earth as a heat source.

Heat Exchanger - A device designed to transfer heat between two physically separated fluids or mediums of different temperatures.

Heat Pump - A mechanical device used for heating and cooling which operates by pumping heat from a cooler to a warmer location. Heat pumps can extract heat from air, water, or the earth. They are classified as either air-source or geothermal units.

Heat Source - The medium of air, water or earth from which heat is extracted by a heat pump.