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Home >> Volvo >> 2002 >> V70 XC >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Alarm System, Control Modules, Engine Management Systems - Design And Function >> Climate Control (2001-2007) >> Function >> Air conditioning >> Refrigerant
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Air conditioning: Refrigerant

Fig 1: Principle Sketch Of Climate Control System
GLL145808Courtesy of VOLVO CARS OF NORTH AMERICA.
  1. Compressor
  2. Condenser
  3. Engine cooling fan (FC)
  4. Receiver drier
  5. Expansion valve
  6. Evaporator
  7. Blower fan.

Explanation: 

A - High pressure, warm fluid

B - Low pressure, cold fluid

C - Low pressure, cold gas

D - High pressure, warm gas

Dark arrow - Warm air

Light arrow - Cold air

By allowing the refrigerant to circulate in the closed system and changing the pressure and volume it will change temperature and boil (evaporate). At the pressure found in the system, approximately 170 - 320 kPa (1.7 - 3.2 bar), the refrigerant boils at approximately 0 °C to +4 °C.

A condition of the refrigerant boiling is that the heat is accessible. This heat is taken from the air around the evaporator (6) where boiling occurs. When the heat is taken up by the refrigerant the surrounding air becomes cooler. It is this cooled air that is blown into the passenger compartment by the climate control system blower fan (7). The heat taken up by the refrigerant in the evaporator (6) is transported out to the engine compartment, where it is transferred to the air by the condenser (2). The condenser is cooled by the airflow and the engine cooling fan (FC) (3).