Heat pump evaporator coil - grabbing heat from the outside air

Air Conditioning and Heat Pumps · Heat Pumps in Theory · printed page 226 (PDF page 227)

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Evaporator Coil – for Heat Pump Heat Pump – Evaporator Coil

Text in the illustration

refrigerant into a low temperature, low the refrigerant from a liquid into a gas the warmed refrigerant (now a gas) heads cold refrigerant gas refrigerant boils
when the heat pump is running in heating mode, the expansion device turns the refrigerant into a low temperature, low pressure liquid that enters the outside coil
outside air blowing across the coil boils the refrigerant from a liquid into a gas
in the conversion from liquid to gas, heat is absorbed from the outside air
the warmed refrigerant (now a gas) heads back to the condensing coil
flow direction
cold refrigerant gas (e.g., 35°F) at low pressure
evaporator coil
refrigerant boils
outside air blown across coil at 45°F
cold air discharged into outside atmosphere at 30°F
expansion device
cold Refrigerant liquid (e.g., 20°F) at low pressure

Generated explanation

The diagram depicts an outdoor heat pump evaporator coil operating in heating mode. Low-pressure liquid refrigerant, illustrated at 20°F, passes through an expansion device and enters the bottom of the coil. Outside air at 45°F flows across the coil, transferring heat to the refrigerant and causing it to boil from liquid to gas. Low-pressure refrigerant gas, illustrated at 35°F, leaves the top of the coil, while the cooled air is discharged outside at 30°F. Arrows indicate refrigerant and airflow directions; no defects are depicted.

Components

outdoor evaporator coil expansion device refrigerant tubing coil fins

Materials

refrigerant liquid refrigerant gas

Related illustrations

1271

Heat pump schematic - summer mode

· p. 227

This schematic shows a heat pump operating in summer cooling mode, with an indoor furnace blower and plenum coil connected to an outdoor compressor, reversing valve, and coil. Arrows show indoor air moving upward through