Receiver-Drier; Evaporator; Expansion Valve - Aston Martin DB7 Workshop Manual

Air Conditioning
Compressors
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Evaporator
Figure 3.
Receiver-Drier
The receiver drier (Fig. 1) accepts high pressure
warm refrigerant liquid from the condenser and
del ivers it via an expansion valve to the evaporator.
It contains a quantity of molecular sieve desiccant
to remove moisture from the refrigerant, and a fi Iter
to removecontaminants.lt also a providesa reservoir
of refrigerant for the evaporator under varying
operating conditions.
The evaporator consists of a refrigerant coil mounted
in a series of thin fins to provide a maximum
amount of heat transfer in a minimum amount of
space. It is housed in the air conditioning unit and
all air entering the system passes across its coil.
The evaporator receives refrigerant from the
thermostatic expansion valve as a low pressure
cold atomised liquid. As this cold liquid passes
through the evaporator coils, it absorbs heat from
the surrounding air and changes into a low pressure
warm vapour.
Expansion Valve
The expansion valve is the dividing point between
the high and low pressure sides of the system. It
automatically meters high pressure, warm liquid
refrigerant via a metering orifice into the low
pressure, cold side of the evaporator matrix. The
valve senses outlet pipe temperature, inlet pipe
pressure and regulates the flow of refrigerant into
the evaporator to ensure that only vaporised
refrigerant appears at the outlet.
Figure 1.
8-36
May 1996