Operation: refrigeration – Scotsman NME454 User Manual
Page 15
OPERATION: Refrigeration
Beginning at the compressor, the refrigerant is
compressed into a high temperature gas. The
discharge line directs this gas to the condenser. At
the condenser (air or water cooled) the gas is
cooled by either air or water and it then condenses
into a liquid. This high pressure liquid then goes
through the liquid line to the expansion valve.
The thermostatic expansion valve meters liquid
refrigerant into the evaporator, the volume of liquid
refrigerant depending upon the temperature of the
evaporator.
At the evaporator, the refrigerant enters an area of
relatively low pressure, where it can easily “boil off”
or evaporate. As it evaporates, it absorbs heat
from the evaporator and whatever is in contact with
it (such as the water inside it). After the evaporator,
the refrigerant, now a low pressure vapor, goes
through the suction line back to compressor, where
the cycle is repeated.
NME454, 654 & FME504, 804
January 2007
Page 15
CONDENSER
FAN
MOTOR
LIQUID
LINE
THERMOSTATIC
EXPANSION
VALVE
SUCTION LINE
GEAR
MOTOR
COMPRESSOR
DISCHARGE
LINE
Refrigeration Schematic
EVAPORATOR