What It Is: Glossary
Btu (British thermal unit):
The amount of heat needed to raise the temperature of one pound of water one degree Fahrenheit. Btu is used to signify the heating and cooling capability of a system and the heat losses and gains of buildings and homes. Btuh is the number of Btus produced in one hour.
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.
COP (Coefficient of performance):
The ratio of heating or cooling provided by a heat pump (or other refrigeration machine) to the energy consumed by the system under designated operating conditions. The higher the COP, the more efficient the system.
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 or shut-down losses. Oversizing a heating or cooling system increases cycling losses.
Desuperheater:
A device for recovering superheat from the compressor discharge gas of a heat pump or central air conditioner for use in heating or preheating water.
Fossil fuel:
Any of several types of combustible fuels formed from the decomposition of organic matter. Examples are natural gas, propane, fuel oil, oil and coal.
Geothermal heat pump:
A heat pump that uses the earth as a heat source and heat sink.
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 extract heat from air, water or the earth. They are classified as either air-source or geothermal units.
Heat sink:
The medium - air, water or earth - which receives heat rejected from a heat pump.
Heat source:
The medium - air, water or earth - from which heat is extracted by a heat pump.
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.
Rule
Learn more about:
Resources: Incentives & Financing
Rule
Brochures and fact sheets:
Geothermal: Bringing Comfort to Your World
By Alliant Energy
[PDF format – 7 pages, 174kb]
