Scotsman NME1250 Service Manual page 14

NME1250
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; warmer evaporators get more
refrigerant and colder evaporators get less.
AIR COOLED
CONDENSER
REFRIGERATION SYSTEM SCHEMATIC
FAN MOTOR
LIQUID LINE
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.
DISCHARGE
LINE
COMPRESSOR
June 1994
Page 14
SUCTION LINE
THERMOSTATIC
EXPANSION
VALVE
EVAPORATOR