|How Refrigerant Flows Through the System
The following explanations
that describe the flow of refrigerant were taken from the bulletin
board. They were all good, and each describe the flow accurately with
different emphasis. The original discussion question with follow-up
threading appears at:
Refrigerant flow as descibed by Prof.
(1) compressor draws LOW PRESSURE HOT VAPOR refrigerant from the
evaporator (suction port - large line), and compresses the vapor.
(2) HIGH PRESSURE HOT VAPOR from the compressor goes into the
condensor. The vapor gives up its latent heat to the cooler outside air
through the condensor and changes back to LIQUID (like steam back to
water). Now its a HIGH PRESSURE LIQUID.
(3)The HIGH PRESSURE LIQUID now encounters an orifice (small opening)
either an orifice tube or expansion valve. When the liquid squirts
through this opening, its pressure is reduced and it gets very cold.
(4) The now LOW PRESSURE COLD LIQUID absorbs heat from the cab through
the evaporator and the liquid inside turns into vapor (boils) (like
water absorbing heat and turning to steam)except refrigerants boil at
veeery low temperatures.
(4a) Note: If the orifice is an O-tube, under some conditions too much
refrigerant might get into the evaporator and not all boil. An
accumulator is hooked on the evaporator output to "accumulate" this
excess liquid and prevent the liquid from reaching the
(5) This LOW PRESSURE HOT VAPOR from the evaporator is now drawn into the compressor. Back to step 1.
Refrigerant flow as descibed by Chris Bede
Hot compressed gas leaves the compressor via the small hose (aka high
side hose) and enters the top of the condensor where it will cool off a
little and "condense" from a hot gas to a high pressure liquid
Refrigerant exits the bottom of the condensor, and heads towards the
evaporator as a high pressure liquid. To get the refrigerant to boil,
and absorb the heat from the inside of the car, we need to turn that
high pressure liquid into a low pressure boiling liquid. That
refrigerant pressure drop happens right before the refrigerant enters
the evaporator via an expansion valve or an orifice tube. This is the
pressure split. The refrigerant enters the evaporator as low pressure
mix of boiling liquid and vapor. Heat load on the evaporator changes
the liquid to a gas vapor. This low pressure vapor then returns to the
compressor(via the suction hose) to start the cycle over again.
Comment #1 (Posted by kevin stark)
very good and easy to under stand
Comment #2 (Posted by Wade Clarke)
Very well said.The easiest way to understand I've heard yet.Great job.
Comment #3 (Posted by Daniel Parker)
The most comprehensive explanation for understanding automotive ac systems ever.
Comment #4 (Posted by Adam Shepherd)
This really helped with a paper that im doing for school thanks a million.
Comment #5 (Posted by Mirek)
Yee it is very easy to understand if you saw polish books about air-conditioning you would have headache :)
Comment #6 (Posted by Ben)
Um, you all clearly already knew how it worked. I work on cars, and I still am a little hazy on this. It fails to account or where the cool air comes from.
Comment #7 (Posted by jeremy)
agree with comment # 6
Comment #8 (Posted by B Denson)
I agree with #6 and #7; Some pictures may help as the explanation progresses
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