Trane TRG-TRC003-EN User Manual
TRG-TRC003-EN
37
period five
Review
notes
Refrigerant enters the evaporator as a cool, low-pressure mixture of liquid and
vapor. It absorbs heat—from the relatively warm air or water to be cooled—and
boils. The cool, low-pressure vapor is then pumped from the evaporator by the
compressor. This increases the pressure and temperature of the refrigerant
vapor. The resulting hot, high-pressure refrigerant vapor enters the condenser
where it rejects heat to ambient air or water that is at a lower temperature, and
condenses into a liquid.
vapor. It absorbs heat—from the relatively warm air or water to be cooled—and
boils. The cool, low-pressure vapor is then pumped from the evaporator by the
compressor. This increases the pressure and temperature of the refrigerant
vapor. The resulting hot, high-pressure refrigerant vapor enters the condenser
where it rejects heat to ambient air or water that is at a lower temperature, and
condenses into a liquid.
This liquid refrigerant flows from the condenser to the expansion device. The
expansion device creates a pressure drop that reduces the pressure of the
refrigerant to that of the evaporator. At this low pressure, a small portion of the
refrigerant boils off, cooling the remaining liquid refrigerant to the evaporator
temperature. The cool mixture of liquid and vapor refrigerant travels to the
evaporator where it absorbs heat and boils, repeating the cycle.
expansion device creates a pressure drop that reduces the pressure of the
refrigerant to that of the evaporator. At this low pressure, a small portion of the
refrigerant boils off, cooling the remaining liquid refrigerant to the evaporator
temperature. The cool mixture of liquid and vapor refrigerant travels to the
evaporator where it absorbs heat and boils, repeating the cycle.
Period Four discussed the use of the pressure–enthalpy (P–
h) chart to analyze
the refrigeration system.
The pressure–enthalpy chart plots the properties of a refrigerant—pressure
versus enthalpy. Enthalpy is a measure of heat quantity per pound [kg] of
refrigerant. The chart includes an envelope (curve) that indicates when the
refrigerant exists as a subcooled liquid (to the left of the envelope), a mixture of
liquid and vapor (inside the envelope), or a superheated vapor (to the right of
the envelope).
versus enthalpy. Enthalpy is a measure of heat quantity per pound [kg] of
refrigerant. The chart includes an envelope (curve) that indicates when the
refrigerant exists as a subcooled liquid (to the left of the envelope), a mixture of
liquid and vapor (inside the envelope), or a superheated vapor (to the right of
the envelope).
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Figure 56