Competency G1: Geothermal Systems

Over the last number of decades, geothermal (earth or ground source) systems have emerged as a viable source for providing the heating and cooling that we all need for comfort in our homes and buildings. The heart of any of these systems is a heat pump. This term is used to describe a device that uses the refrigeration cycle to convert low-temperature heat from a source into higher-temperature heat which is imparted to a load. When used to heat buildings, heat pumps can gather low-temperature heat from sources such as outdoor air, groundwater, lakes or ponds, or from tubing embedded in the ground. All of these sources provide “free” low-temperature heat. Some heat pumps also have the ability to reverse the direction of the refrigerant within them, so they can use those sources as a heat sink (place to dispose of unwanted heat) if cooling is what the heat pump circuit is trying to achieve on the load side. No matter what the source or load, the refrigeration cycle is at the core of the operations of any heat pump.