Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Climate Control - Air Conditioning/ Operation

PRINCIPLES OF OPERATION

To accomplish the transfer of heat, the refrigerant is circulated around the system, where it passes through two pressure/temperature regimes. In each of the regimes the refrigerant changes state, during this process the maximum heat absorption or dissipation occurs.

The low pressure/temperature regime is from the TXV, then through the evaporator to the compressor. The refrigerant decreases in pressure and temperature at the TXV then changes state from a liquid to a vapour in the evaporator to absorb heat.

The high pressure/temperature regime is from the compressor, through the condensor and receiver drier assembly to the thermostatic expansion valve.

The refrigerant increases in pressure and temperature as it passes through the compressor; then releases heat and changes state from a vapour to a liquid in the condenser.

The operation of the A/C system is controlled by the ATCM.

For additional information, refer to: Control Components (412-01 Climate Control, Description and Operation).

NOTE:

NOTE: Due to a drop in performance of the R1234yf system when compared to the R134a system an Internal Heat Exchanger is installed

INPUT/OUTPUT DIAGRAM

System without an Internal Heat Exchanger (IHX)

NOTE:

NOTE: A = Refrigerant liquid; B = Refrigerant vapor; C = Air flow

System without an Internal Heat Exchanger (IHX)

  1. Evaporator
  2. TXV
  3. High pressure servicing connection
  4. Refrigerant pressure sensor
  5. Electric cooling fan
  6. Condensor
  7. Receiver/drier
  8. A/C compressor
  9. Low pressure servicing connection
  10. Blower

System with an Internal Heat Exchanger (IHX)

NOTE:

NOTE: A = Refrigerant liquid; B = Refrigerant vapor; C = Air flow

System with an Internal Heat Exchanger (IHX)

  1. Evaporator
  2. TXV
  3. High pressure servicing connection
  4. Refrigerant pressure sensor
  5. Electric cooling fan
  6. Condenser
  7. Receiver/Drier
  8. A/C compressor
  9. IHX
  10. Low pressure servicing connection
  11. Blower

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