Webasto Thermosysteme
Roof-top air-conditioning system CC4E
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2.4.
Design, purpose and principle of operation of the assemblies
Condenser
The condenser (3, Fig. 2.2) consists of a continuous pipe coil and fins interconnected to form a large heat
exchanger surface.
It cools the hot refrigerant gas so that the latter liquefies and undercools. At the same time, it transfers the
condensation heat to the outside air flowing through it via the fins.
Receiver-drier
The receiver-drier with viewglass (13, Fig. 2.2) is an expansion and storage reservoir for refrigerant. Its
lower part contains a granulated desiccant which extracts and chemically binds small amounts of water from
the refrigerant. This reduces the risk of ice forming on the expansion valve and protects the compressor
against damage. During operation, the level can be checked in the viewglass (14, Fig. 2.2) to ensure that
there is sufficient refrigerant in the circuit.
Thermostatic expansion valve
The thermostatic expansion valve (11, Fig. 2.2) regulates the flow of refrigerant to the evaporator as
required and in accordance with the temperature in the evaporator. The thermostatic expansion valve
represents the control element between high and low-pressure part of the refrigerant circuit.
Evaporator
The evaporator (6, Fig. 2.2) is basically of the same design as the condenser. The refrigerant flowing
through the pipe from the expansion valve changes from the liquid to the gaseous state and superheats in
the evaporator.
The required evaporation heat is extracted from the cabin air flowing through the fins and is transmitted
through the pipe to the refrigerant. The air dries as it cools and condensation water is drained overboard.
The mist separator (7, Fig. 2.2) prevents droplets of condensation being drawn in by the radial fan and
entering the interior of the vehicle.
Fig. 2.5
