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Refrigerant Circuit Function - GF83.40-P-2001RF

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Model 205, 253 

G14547377Courtesy of MERCEDES-BENZ USA

Model 205 (except 205.012/013/047/053/147/212/213/247/253), 253 (except 253.353/354/953/954/99) 

G14547378Courtesy of MERCEDES-BENZ USA

Model 205.012/212 

G14547379Courtesy of MERCEDES-BENZ USA

Model 253.353/953 

Function requirements, general 

Refrigerant circuit in general 

The refrigerant circuit is regulated by the A/C control unit (N22/1).

The refrigeration circuit basically consists of the following components:

The individual components of the refrigerant circuit are interconnected through hoses and pipelines and form a closed system.

The refrigerant circuit consists of the following functional components:

IMPORTANT The separation points for this are the valve plates at the respective refrigerant compressor and the injection valve at the expansion valve.

High-pressure side 

The respective refrigerant compressor draws in the cold, gaseous refrigerant from the evaporator and compresses it, whereby it is heated, and delivers it to the condenser. The compressed hot refrigerant is cooled in the condenser by the blow-by air or the outside air sucked in by the fan motor (M4/7).

On reaching the dew point dependent on the pressure, the refrigerant condenses and changes in terms of its physical state from gaseous to fluid.

The refrigerant then flows into the accumulator (drier). While it is flowing through the fluid reservoir, moisture is removed from the refrigerant, vapor locks are separated and any mechanical impurities are filtered out in order to protect the downstream components from these. The cleaned refrigerant flows onto the expansion valve (except model 205.012/013/047/053/147/212/213/247/253, 253.353/354/953/954), to the front evaporator shutoff valve (model 205.012/013/047/053/147/212/213/247/253, 253.353/354/953/954) or to the high-voltage battery cooling shutoff valve (model 205.012/013/047/053/147/212/213/247/253, 253.353/354/953/954).

The liquid refrigerant which is under high pressure is injected into the respective evaporator there.

IMPORTANT Model 205.012/212

Through actuation of the high-voltage battery cooling shutoff valve the refrigerant flows through the evaporator integrated into the high-voltage battery module. This serves to remove heat from the high-voltage battery.

IMPORTANT Model 205.013/047/053/147/213/247/253, 253.353/953 The refrigerant circuit is extended to include the cooling circuit of the high-voltage battery by actuation of the high-voltage battery cooling shutoff valve. This means that the high-voltage battery can be cooled by refrigerant. If the high-voltage battery is cooled, the cleaned refrigerant flows through the heat exchanger and cools the high-voltage battery cooling system's coolant flowing through the heat exchanger.

Low-pressure side 

The liquid refrigerant decompresses in the respective evaporator and changes again in terms of its physical state from fluid to gaseous. The evaporation heat required for the evaporation is removed from the blow-by air at the evaporator fins, cooling it down in the process. The refrigerant, which is completely gaseous once more, is drawn in again and compressed by the respective refrigerant compressor. The cooled air is led to the vehicle interior via the blower motor (A32m1).

IMPORTANT Model 205.013/047/053/147/213/247/253, 253.353/953 If the high-voltage battery is cooled, the refrigerant changes its aggregation state from liquid to gaseous when flowing through the high-voltage battery cooling shutoff valve. The gaseous refrigerant is then sucked in by the A/C compressor and compressed again.

IMPORTANT The refrigerant compressor is switched off by the control unit for climate control to prevent the evaporator from icing up when a specific evaporator temperature is undershot on model 205 (except 205.012/013/047/053/147/212/213/247/253) and 253 (except 253.353/354/953/954). The control unit for climate control actuates the shutoff valves accordingly on model 205.012/013/047/053/147/212/213/247/253, 253.353/354/953/954.

This enables the electrical A/C compressor to continue to be operated. This is necessary to ensure that the high-voltage battery can also be operated at outside temperature of T < 10°C.

  Overview of system components for climate control   GF83.40-P-9994RF 
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