Heating Systems 325
Figure 12-10. Cooling cycle operationthe outside air, is cooled, and is changed into a liquid state. It then returns
to the compressor, where it is pumped through an expansion device and
returned to the indoor coil. The process then repeats itself
Figure 12-10 shows an illustration of the heat pump during its air
conditioning cycle. At (1), heat is absorbed from the inside air and cool
air is transferred into the building. At (2), the pressure of the heat-laden
refrigerant is increased by the compressor and cycled into the outside coil
for transfer to the air. At (3), cool, dehumidified air is circulated through
the duct network as a result of passing through the cooled indoor coil. At
(4), the refrigerant condenses back into a liquid as it circulates through the
outdoor coil. At (5), the liquid refrigerant flows through the compressor
and expansion device, where it is vaporized and returned to the indoor
coil to complete the cycle.