|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 capacity of a system and the heat losses
and gains of buildings and homes.
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
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.
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
A heat exchanger in which hot, pressurized
(gaseous) refrigerant is condensed by transferring heat to cooler surrounding
air, water or earth.
The actual efficiency of a heating
or cooling system is reduced because of start-up and shut-down losses. Oversizing
a heating or cooling system increases cycling losses.
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.
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.
A device designed to transfer heat
between two physically separated fluids or mediums of different temperatures.
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.
The medium—air, water or earth—which
receives heat rejected from a heat pump.
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.
A method of calculating how long it will
take to recover the difference in cost between two different heating and cooling
systems by using the energy and maintenance-cost savings from the more efficient
A heating system used during
extremely cold weather, when additional heat is needed to moderate indoor temperatures.
May be in the form of fossil fuel or electric resistance.
| 1 gallon
|| .8 gallon (3.78 liters)
| 1 foot
|| .304 meter
| 1,000 feet
|| 304.8 meters
| 1 BTU
|| 252 calories (grams)
| Fahrenheit Celsius
|| = (F-32) * 5 \ 9
|| 40F = approximately 4.44C