Typical Refrigeration Cycles - Daikin VHF Installation And Maintenance Manual

Typical Refrigeration Cycles

Figure 58: Cooling mode – (single circuit only shown)
Coil – Air to Refrigerant
Heat Exchanger
Cooling Refrigeration Cycle
When the wall thermostat is calling for COOLING, the reversing valve directs the flow of the refrigerant, a hot gas, leaving the com-
pressor to the water-to-refrigerant heat exchanger. Here the heat is removed by the water and the hot gas condenses to become
a liquid. The liquid then flows through a thermal expansion metering system to the air-to-refrigerant heat exchanger coil. The liquid
then evaporates becoming a gas, at the same time absorbing heat and cooling the air passing over the surfaces of the coil. The re-
frigerant then flows as a low pressure gas through the reversing valve and back to the suction side of the compressor to complete
the cycle.
Figure 59: Heating mode – (single circuit only shown)
Coil – Air to Refrigerant
Heat Exchanger
Heating Refrigeration Cycle
When the wall thermostat is calling for HEATING, the reversing valve directs the flow of the refrigerant, a hot gas, leaving the
compressor to the air-to-refrigerant heat exchanger coil. Here the heat is removed by the air passing over the surfaces of the coil
and the hot gas condenses to become a liquid. The liquid then flows through a capillary thermal expansion metering system to the
water-to-refrigerant heat exchanger. The liquid then evaporates becoming a gas, at the same time absorbing heat and cooling the
water. The refrigerant then flows as a low pressure gas through the reversing valve and back to the suction side of the compressor
to complete the cycle.
IM 986-11 • Vertical Stack WSHP
Return Air
Blower
Conditioned Air – (Cooling)
Return Air
Blower
Conditioned Air – (Heating)
Thermal
Co-Axial Heat
Expansion Valve
Exchanger
Reversing Valve
Thermal
Expansion Valve
Reversing Valve
57
t
roubleshooting
Water In
Water Out
Sensing Bulb and
Capillary Tube
Compressor
Co-Axial Heat
Exchanger
Water In
Water Out
Sensing Bulb
and Capillary Tube
Compressor
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