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Glossary of
Terms A|
B|
C| D|
E|
F| G|
H|
K| L|
M|
O| P|
R|
S| T|
W|
Z
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A
Absolute Humidity
Amount of moisture in the air, indicated in grains per cubic foot.
Active Cooling
Compressor driven air-conditioning.
Air Washer
Device used to clean air, which may increase or decrease humidity.
Anemometer
Instrument for measuring the rate of flow of air.
Aquifer
A large body of underground water.
Attenuate
Decrease or lessen in intensity.
B
Baffle
Plate or vane used to direct or control the movement of fluid or air
within a confined area.
BTU
British Thermal Unit
The amount of heat required to raise the temperature of one pound of
water, one degree Fahrenheit.
C
Carbon Filter
Air filter using activated carbon as an air cleaning agent.
CFM
Cubic feet per minute of air flow.
Check Valve
A check valve is a mechanical device normally applied to a piping system
which allows fluid to flow in only one direction.
Closed Loop
An underground heat exchanger piping system usually of polyethylene or
polybutylene designed to allow the extraction or rejection of heat to the
earth by the circulation of fluid within the tubing.
Coefficient of Performance (COP)
Heating capacity divided by electrical energy consumed. ( e.g.15 kW output
/ 4.5 kW input = COP of 3.3)
The coefficient of performance of a heating system is the electrical ratio
of the heat we get out divided by the heat we put in.
Comfort Zone
Area on the psychrometric chart that shows conditions of temperature,
humidity, and sometimes air movement in which most people feel
comfortable.
Compressor
A refrigeration component which increases the density, temperature and
pressure of entering refrigerant through compression and discharges a hot
dense gas.
Condenser
The heat rejecting mechanism in a heat pump usually in the form of a
refrigerant-to-air coil or a refrigerant-to-water coil. Refrigeration heat
exchanger where the refrigerant gives up its heat during condensation from
a vapour to a liquid.
Condenser Types
air-cooled and water-cooled. An air-cooled condenser is a heat exchanger
that transfers heat to the surrounding air.
A water-cooled condenser is a heat exchanger that transfers heat from a
hot gaseous refrigerant to water.
Critical Vibration
Vibration that is noticeable and harmful to a structure.
Cupro-Nickel
90% copper / 10% nickel alloy which has high corrosion resistance to water
containing salt, sulphur, chlorides and other dissolved minerals.
D
Damper
Device for controlling air flow.
Decibel
Unit used for the measuring the relative loudness of sounds. One decibel
is equal the approximate difference of loudness ordinarily detectable by
the human ear, the range of which is about 130 decibels on a scale
beginning at one, for the faintest audible sound.
Degree Day
The number of degrees that the mean temperature for that day is below 65°
F.
(eg. mean temp. of 40° F for the day--65-40=25 degree days)
Dehumidifier
Device used to remove moisture from the air in an enclosed place.
Desuperheater
A heat exchanger and pump system which removes a small portion of heat
from the compressor discharge gas and typically transfers it to a domestic
hot water tank.
Dewpoint
Temperature at which vapour (at 100 percent humidity) begins to condense
and deposit as liquid.
Direct Expansion Heat Pump
A geothermal heat pump system whereby the liquid refrigerant is sent
directly out into copper coils buried in the ground where it is vaporised
or condensed by contact with the earth.
Drip Pan
Pan-shaped panel or trough used to collect condensation from an evaporator
coil.
Dry Bulb
An instrument with a sensitive element that measures ambient (moving) air
temperature.
Dual Condenser
A heat pump system that has the capability to switch, usually
automatically, between an air and a water heat exchanger.
Full capacity hot air or hot water output is available.
Duct
A tube or channel through which air (heated or air-conditioned) is
conveyed or moved.
Dynamometer
Device for measuring power input or output of a mechanism.
E
Effective Temperature
Overall effect on a human of air temperature, humidity and air movement.
Electrostatic Filter
A filter that gives particles of dust an electric charge. This causes the
particles to be attracted to a plate so they can be removed from the
air-stream or atmosphere.
Energy Efficiency Ratio (EER)
Cooling capacity in BTU/hr divided by electrical energy consumed in watts.
EWT
Entering water or fluid temperature.
Evaporation
The term applied to the changing of a liquid to a gas. Heat is absorbed in
the process.
Evaporator
The heat absorbing mechanism or heat exchanger in a heat pump. Refrigerant
changes state from a liquid to a gas in this exchanger, absorbing heat
energy from the surrounding media in the process.
Expansion Valve
A device in a refrigerating system that reduces and maintains a pressure
difference between the "high side" and "low side" operated by pressure.
F
Fan
A radial or axial flow device used for moving or producing artificial
current air.
Flash Gas
Instantaneous evaporation of some liquid refrigerant in the evaporator,
which cools the remaining liquid refrigerant to the desired evaporation
temperature.
Flow Meter
Instrument used to measure the velocity or volume of fluid movement.
Forced Air
A heating/cooling system that uses a fan to circulate air or cause air
flow.
Freezing Point
Temperature at which a liquid will solidify upon the removal of heat. The
freezing temperature for water is 32 degrees Fahrenheit (zero degrees
Celsius).
Freon
Trade name for a series of man made chemicals or refrigerants used in
refrigeration systems. Each refrigerant is designed to change phase at
specific temperatures and pressures that will produce the desired cooling
effect required for a specific job. The refrigerant absorbs energy as it
evaporates and releases energy during condensation.
Frost back
Condition in which liquid refrigerant flows from the evaporator into the
suction line; usually indicated by sweating or frosting of the suction
line.
Full-Condensing Heat Exchanger
A heat exchanger with enough surface area to condense all the hot
refrigerant gas produced by a heat pump to its liquid state thereby
transferring the all the heat produced by the unit.
G
Geothermal Energy
Heat energy stored in the earth's crust by the absorption of solar energy
and by conduction with the earth's hot interior. This underground or
underwater temperature source is used for the operation of a heating and
cooling system - heat pump.
Geothermal Heat Pump
A heat pump that uses the constant underground or underwater temperatures
as supply.
Ground Loop
A series of heat exchange pipes containing an antifreeze solution buried
either vertically or horizontally in the earth.
Ground Source
A heat pump that utilizes the earth as it's source of energy.
H
Heat Exchanger
A component or components that transfers heat energy from one medium to
another. For example heat could be transferred, in a geothermal heat pump
system, from water-to-air or from water-to-water and visa versa.
Heat Load
Amount of heat, measured in BTU's, that is removed during a 24 hour
period.
Heat Loss
A measure of the amount of heat that escapes from a material or substance,
measured in BTU's for hours.
Heat Recovery System
Produces and stores hot water by transferring heat from a condenser to
cooler water.
Heat Source
The area or media from which heat is removed. (water, air, etc.)
Heat Sink
The area or media to where heat is deposited. (For instance, inside a
home.)
Heat transfer
Movement of heat from one body or substance to another. Heat may be
transferred by radiation, conduction, convection or a combination of these
three methods.
Humidistat
An electrical control that is operated by changing humidity.
K
KWh
Kilowatt-hours, an electrical term where 1 kWh equals the use of 1000
watts for one hour.
L
Liquid-to-Air Heat Pump
A heat pump that absorbs heat from a liquid and distributes the energy in
the form of hot forced air.
(Generally called Water to Air Heat Pump)
Liquid-to-Liquid Heat Pump
A heat pump that absorbs heat from a liquid and distributes the energy in
the form of hot water.
(Generally called a Water to Water Heat pump)
M
Mechanical Cooling
Conventional cooling provided by a compressor operated refrigeration
device.
Term can be interchanged with "active cooling".
O
Open Loop
A system where water is pumped from a water well, pond, lake or other
surface source for use in a heat pump.
Oversized Evaporator
A technique of employing a larger than normal evaporator (heat absorption
device) in a geothermal heat pump in order to obtain greater heat exchange
and thus better performance from the unit.
P
Passive Cooling
A process whereby cold well water (less than 50° F.) is pumped directly to
a finned air coil (much like the radiator of a car) so that when the heat
pump fan is operated, cooling and dehumidification are provided without
the operation of a compressor driven refrigeration system.
Package Heat Pump
A heat pump that has all components (compressor, blower and heat
exchangers etc.) in one cabinet.
R
Rankin Scale
Name given to the absolute (Fahrenheit) scale. Zero () degrees Rankin) on
this scale is -460 degrees Fahrenheit
Refrigerant
A naturally occurring or man made liquid which absorbs and releases heat
energy in a refrigeration device by changing phase from a liquid to a gas
and visa versa in response to the influence of a refrigeration compressor.
Refrigerant Charge
Quantity of refrigerant in a system
Relative Humidity
Ratio of (difference between) the amount of water vapor present in the air
to the greatest amount possible at the same temperature.
Reversing Heat Pump
A heat pump in which the condenser and evaporator coils of the unit
reverse roles in response to a reverse in the direction of the flow of
refrigerant in the machine.
Reversing Valve
Device used to reverse the direction of the refrigerant flow, depending
upon whether heating or cooling is desired.
Radiant Floor Heating
Process of embedding tubing (cross-linked polyethylene, polybutylene etc.)
directly in a concrete floor so that hot water can be pumped through the
tubing for the purpose of heating the floor and thus the building.
S
Seasonal Coefficient of Performance (SCOP)
The average COP over the entire heating season.
Seasonal Energy Efficiency Ratio (SEER)
The average cooling efficiency over an entire cooling season.
Simple Pay back Factor (heating)
Subtract the installation cost of the least expensive (less efficient)
system from the installation cost of the more expensive (more efficient)
heating system. This value is the increased cost of installing the more
efficient system. Calculate the yearly energy savings in dollars by
installing the more efficient system. Take the increased cost to install
divided by the yearly energy savings and your result is the number of
years required for the more efficient system to pay for itself.
Sink Temperature
This is the temperature of the media (water or air) into which the heat
pump must reject it's heat.
Source Temperature
This is the temperature of the media (water or air) from which the heat
pump extracts its heat.
Split System
Split heat pumps are two (2) part refrigeration systems which have
separate evaporator / air handler and compressor / condenser sections.
Commonly employed in air-to-air systems where the condenser section is
located outside the home while the evaporator / air handler is located
inside the conditioned structure.
Suction Line
Tube or pipe used to carry refrigerant gas from evaporator to compressor.
Suction Side
The Low-pressure side of the system extending from the refrigerant control
through the evaporator to the inlet side of the compressor.
Super Heat
1) Temperature of a vapor above it's boiling temperature as a liquid at
that pressure.
2) The difference between the temperature at the evaporator outlet and the
lower temperature of the refrigerant evaporating in the evaporator.
Superheater
Heat exchanger arranged to take heat from liquid going to the evaporator
and use it to superheat vapor leaving the evaporator
TX Valve.
T
Thermo Expansion Valve
A temperature and pressure controlled device for metering refrigerant in a
heat pump or other refrigeration device.
Also known as a "TEV"
Ton (of refrigeration)
The amount of energy it takes to convert 2000 lbs. of water at 32° F. to
ice at 32° F. during a 24 hour period. Calculation: 2000 lbs. (H2O) x 144
Btu/lb. = 288,000 Btu's in 24 Hrs. Divide by 24 hrs = 12,000 Btu/hr.
Therefore a "ton" of cooling is a measure of heat energy which is roughly
equivalent to 12,000 BTU's.
W
Water Well
A vertical hole drilled into the earth’s crust usually to a depth of less
than 300 ft. for the purpose of accessing an underground water supply
(aquifer). A pumping system generally of the submersible type is normally
installed to bring the water to the surface under sufficient pressure to
be used in a home.
Water-to-Water
A heat pump which extracts heat from water in one area and transfers the
heat usually at a higher temperature to another body of water. E.g.
Extracting heat from a 50° F well and using it to heat domestic hot water
at 120° F.
Z
Zone Controls
Controls used to maintain each specific area or zone within a building at
a desired condition. This is a type of distribution control often used in
a hydronic heating system.
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