10
3-10. Refrigerant Operation System
When the air conditioner is turned ON, the compressor starts to work. The compressor absorbs low-temperature and
low-pressure refrigerant from the evaporator; the refrigerant is then compressed into high-temperature and high-
pressure refrigerant gas and goes into the condenser (COMPRESSION). This high-temperature and high-pressure
refrigerant gas is condensed into liquid refrigerant; during the CONDENSING process, heat is released to the out-
doors through the condenser.
High-pressure and high-temperature liquid refrigerant goes into the capillary tube to reduce the pressure and to
lower the temperature (PRESSURE REDUCTION). The low-pressure liquid refrigerant passed through the capillary
tube is sent to the evaporator for evaporation. In this EVAPORATION process, heat in the room is absorbed. This
cycle is repeated until the room temperature is lowered to the target level.
During the heating cycle, the direction of refrigerant flow is reversed by a 4-way valve. As a result, the condenser
draws heat from the outdoor air and the evaporator supplies hot air to the room.
Service valve on
wide tube side
Service valve on
narrow tube side
Compressor
Strainer
Muffler
Muffler
Sub-
accumulator
4-way valve
When cooling
When heating
When defrosting
Outdoor
heat
exchanger
Solenoid valve
for hot gas bypass
Electric expansion
valve
Electric
expansion
valve
Main
accumulator
Receiver tank
Indoor unit
Fig. 19
Unit: mm
4-Room Multi Refrigerant Tubing System Diagram
