RETA Terms
DISPLACEMENT Correct Answer - The cubic feet or cubic
inches of vapor per minute pumped by a compressor. This is the
actual (not theoretical) displacement of the compressor.
DISTRIBUTOR Correct Answer - A device between the
expansion valve and the coil that splits the flow of liquid refrigerant
into equal parts to feed a multi-circuit coil.
DOUBLE ACTING COMPRESSOR Correct Answer - A
compressor where suction vapor is admitted to both sides of the
piston so that there are two compression strokes per revolution.
Most common form is the horizontal double acting (HDA)
compressor.
DOUBLE PIPE CONDENSER Correct Answer - See "tube in
tube" condenser
DRIER Correct Answer - A small vessel containing a desiccant
for the removal of moisture from a refrigerant system.
DRY AIR Correct Answer - Air in which there is no moisture
(water vapor).
,DRY BULB TEMPERATURE Correct Answer - The air
temperature as measured by the thermometer where there is no
evaporation of water from the bulb.
DRY EXPANSION Correct Answer - A system in which just
enough liquid is fed to the evaporator to be completely evaporated
so that the suction vapor to the compressor is dry and contains no
liquid. Also known as Direct Expansion.
DRY ICE Correct Answer - See "carbon dioxide ice".
DUCTWORK Correct Answer - An enclosure (usually sheet
metal) to convey air or fluids from one location to another. Not
usually liquid tight. Most common applications are found in air ducts
in air conditioning systems both for supply and return.
DUNNAGE Correct Answer - Strips of wood or other material
placed between packages, boxes or cartons of material in storage to
allow air circulation to all parts of the stored material.
ELECTRIC DEFROST Correct Answer - The removal of ice and
frost from a refrigeration coil by means of heat supplied by electric
heating elements.
, ELECTROSTATIC AIR CLEANER Correct Answer - An air
cleaner using high voltage electrostatic charges to precipitate out
very small particles from the air stream when cleaner air is desired
than possible with ordinary glass or felt media filters.
ENERGY Correct Answer - The capacity for doing work.
ENTHALPY Correct Answer - It is the total energy in a fluid
often measured in BTU/lb.
ENTROPY Correct Answer - A relationship between heat and
temperature that is useful in determining discharge temperatures. It
is the heat moved into or out of the process divided by the absolute
temperature. BTU/lb. / 'R
EQUALIZER Correct Answer - Any piping arrangement made
to maintain equal pressures in different vessels, or between
different points in a system.
EVACUATION Correct Answer - Emptying a system by placing
a vacuum on it to remove foreign and non-condensable gases from a
system prior to installing the refrigerant charge.
DISPLACEMENT Correct Answer - The cubic feet or cubic
inches of vapor per minute pumped by a compressor. This is the
actual (not theoretical) displacement of the compressor.
DISTRIBUTOR Correct Answer - A device between the
expansion valve and the coil that splits the flow of liquid refrigerant
into equal parts to feed a multi-circuit coil.
DOUBLE ACTING COMPRESSOR Correct Answer - A
compressor where suction vapor is admitted to both sides of the
piston so that there are two compression strokes per revolution.
Most common form is the horizontal double acting (HDA)
compressor.
DOUBLE PIPE CONDENSER Correct Answer - See "tube in
tube" condenser
DRIER Correct Answer - A small vessel containing a desiccant
for the removal of moisture from a refrigerant system.
DRY AIR Correct Answer - Air in which there is no moisture
(water vapor).
,DRY BULB TEMPERATURE Correct Answer - The air
temperature as measured by the thermometer where there is no
evaporation of water from the bulb.
DRY EXPANSION Correct Answer - A system in which just
enough liquid is fed to the evaporator to be completely evaporated
so that the suction vapor to the compressor is dry and contains no
liquid. Also known as Direct Expansion.
DRY ICE Correct Answer - See "carbon dioxide ice".
DUCTWORK Correct Answer - An enclosure (usually sheet
metal) to convey air or fluids from one location to another. Not
usually liquid tight. Most common applications are found in air ducts
in air conditioning systems both for supply and return.
DUNNAGE Correct Answer - Strips of wood or other material
placed between packages, boxes or cartons of material in storage to
allow air circulation to all parts of the stored material.
ELECTRIC DEFROST Correct Answer - The removal of ice and
frost from a refrigeration coil by means of heat supplied by electric
heating elements.
, ELECTROSTATIC AIR CLEANER Correct Answer - An air
cleaner using high voltage electrostatic charges to precipitate out
very small particles from the air stream when cleaner air is desired
than possible with ordinary glass or felt media filters.
ENERGY Correct Answer - The capacity for doing work.
ENTHALPY Correct Answer - It is the total energy in a fluid
often measured in BTU/lb.
ENTROPY Correct Answer - A relationship between heat and
temperature that is useful in determining discharge temperatures. It
is the heat moved into or out of the process divided by the absolute
temperature. BTU/lb. / 'R
EQUALIZER Correct Answer - Any piping arrangement made
to maintain equal pressures in different vessels, or between
different points in a system.
EVACUATION Correct Answer - Emptying a system by placing
a vacuum on it to remove foreign and non-condensable gases from a
system prior to installing the refrigerant charge.
