audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

ABOUT US
Refrigerant circuit with restrictor and reservoir > < Pressures and temperatures in refrigerant circuit

A1

Refrigerant circuit with expansion valve
Refrigerant circuit with expansion valve
HP – High-pressure side of refrigerant circuit
LP – Low-pressure side of refrigerant circuit
   
ComponentState of refrigerantPressure (bar)Temperature in degrees centigrade
-1- Evaporator, from inlet to outletVapourapprox. 1.2 bar → Remark1approx. -7 °C → Remark2
-2- Expansion valveLiquid, expanded to vapourapprox. 14 barapprox. +55 °C (high-pressure end), reduced to -7 °C (low-pressure end)
-3- High-pressure switch / high-pressure senderLiquidapprox. 14 barapprox. +55 °C
-4- Service connection/high-pressure end
and
-5- Receiver 		Liquidapprox. 14 barapprox. +55 °C
-6- CondenserFrom gas (at inlet) via vapour to liquid (at outlet)approx. 14 barFrom approx. +65 °C (at inlet) to approx. +55 °C (at outlet)
-7- High-pressure safety valve
and
-8- Air conditioner compressor (HP side)		Gasapprox. 14 barapprox. +65 °C
-9- Air conditioner compressor/low-pressure endGasapprox. 1.2 bar → Remark1approx. -1 °C → Remark2
-10- Damping chamber (not fitted on all vehicles) and
-11- Service connection/low-pressure end		Gasapprox. 1.2 bar → Remark1approx. -1 °C → Remark2

1)  1 - The pressure in a refrigerant circuit with a regulating air conditioner compressor is maintained at approx. 2 bar absolute (corresponding to approx. 1 bar gauge) despite varying heat transfer and fluctuating engine speeds. This however only applies within the output range of the air conditioner compressor. If the output limits of the air conditioner compressor are exceeded, the pressure will increase → Chapter.
2)  2 - The temperature in a refrigerant circuit with a regulating air conditioner compressor is maintained within the regulating range of the air conditioner compressor despite varying heat transfer and fluctuating engine speeds. This however only applies within the output range of the air conditioner compressor. If the output limits of the air conditioner compressor are exceeded, the temperature will increase → Chapter.
  Note
t  Non self-regulating air conditioner compressors are switched off by the relevant control unit via the air conditioner compressor regulating valve -N280- at evaporator temperatures below 0 °C.
t  On vehicles with air conditioner compressor regulating valve -N280- the pressure on the low pressure end is altered by actuating the valve.
t  On vehicles with two evaporators and two expansion valves, the temperature and the pressure in the refrigerant circuit correspond to those on vehicles with only one evaporator and one expansion valve (parallel connection).
t  Depending on the design of the refrigerant circuit, a component with an internal heat exchanger may be fitted (e.g. on the Audi A4 2008 > and the Audi A5 Coupé 2008 > a refrigerant line with an internal heat exchanger). In the internal heat exchanger, the hot refrigerant (liquid) flowing through the high-pressure side gives off energy to the cold refrigerant (gaseous or vaporous) flowing through the low-pressure side, thus enhancing the efficiency of the air conditioner → Chapter.
Arrows show direction of refrigerant flow.
HP – High-pressure side of refrigerant circuit
LP – Low-pressure side of refrigerant circuit
   
1 - Evaporator
2 - Expansion valve
3 - High-pressure switch / high-pressure sender
q   Different versions depending on vehicle
4 - Service connection/high-pressure end
5 - Receiver
q   Different versions depending on vehicle
6 - Condenser
7 - High-pressure safety valve
8 - Air conditioner compressor/high-pressure end
9 - Air conditioner compressor/low-pressure end
10 - Damping chamber
q   Not fitted on all vehicles
11 - Service connection/low-pressure end

   

Refrigerant circuit with restrictor and reservoir > < Pressures and temperatures in refrigerant circuit