Refrigerant Circuit Component Allocation, Influence On High And Low Pressure Sides: Evaporator
There are different versions of the evaporator. Depending on the design and the function, the necessary heat energy of the flowing air (for example, an evaporator in the A/C unit or in the battery cooling module) or flowing coolant (for example near the high-voltage battery heat exchanger) is extracted for refrigerant evaporation. Refer to Refrigerant Circuit (vehicle-specific repair information).
Two versions of the evaporator are described in the following.
Evaporator in A/C Unit (or in Battery Cooling Module)
The liquid refrigerant evaporates in the evaporator pipe coils. The heat required for this is extracted from the air flowing on the evaporator ribbing. The air cools off. Refrigerant evaporates and is extracted with the absorbed heat by the A/C compressor.
A defined amount of refrigerant is supplied to the evaporator by a restrictor or expansion valve. In systems with an expansion valve, the flow rate is regulated so that only gaseous refrigerant escapes the evaporator output.
Evaporator / High-Voltage Battery Heat Exchanger (Chiller)
The liquid refrigerant evaporates in the evaporator (heat exchanger). The heat required for this is extracted from the coolant flowing through the evaporator. The coolant cools, the refrigerant evaporates and is extracted with the absorbed heat by the A/C compressor.
A defined amount of refrigerant is supplied to the evaporator by a restrictor (or expansion valve) and a shut-off valve. The flow rate of the refrigerant (or the coolant) is regulated so that only gaseous refrigerant escapes the evaporator output. Refer to Refrigerant Circuit (vehicle-specific repair information).