The
following is an alphabetical list of terms that are commonly
used in association with Geothermal H.V.A.C Systems as well
as conventional systems, and may be found throughout our website.
BTU
(British Thermal Unit)
The
amount of heat needed to raise the temperature of one pound
of water by 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.
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 and shut-down losses. Over-sizing 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
can 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.
Payback
A
method of calculating how long it will take to recover the
difference in
costs of two different heating and cooling systems by using
the energy and
maintenance cost savings from the more efficient system.
Supplemental
heating
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.
Tonnage
This
is a measurement for cooling capacity of a system. One ton
is equal to 12,000 British Thermal Units (BTUs - see above).
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