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AG 31-011 • REFRIGERANT PIPING DESIGN
Suction Line:
A refrigerant line that carries low pressure
refrigerant vapor from the evaporator to the compressor.
Superheated Vapor:
A vapor that has been heated beyond
the saturation condition resulting in increased temperature
and enthalpy. This is done to make sure the refrigerant in the
suction line entering the compressor is truly a vapor.
Temperature (T):
Represents the average motion of the
molecules in the fluid. It is measured in °F (Fahrenheit) or °C
(Celsius).
Thermal Expansion (TX) Valve:
A pressure regulating valve
used in refrigeration systems to lower the liquid refrigerant
pressure from the condensing pressure to the evaporation
pressure. Thermal expansion valves modulate refrigerant flow
based on superheat in the suction line.
Trap:
A “P” shaped piping fitting that holds either liquid
refrigerant or oil.
Venturi:
An alternative device to a distributor for feeding two
phase refrigerant flow into each tube of a DX evaporator. It is
usually part of the coil and is directly down stream of the TX
valve.
Volume (V):
The geometrical space occupied by a fluid. It is
measured in cubic feet (ft³) or cubic meters (m³)
Volumetric Efficiency (ŋ
va
):
Measure of compressor
performance defined as actual volume flow rate/ideal volume
flow rate.
Zeotropic Refrigerants:
Refrigerant blends where the
components do not behave asone substance. Zeotropic
refrigerants experience glide. An example is R-407C.