Mark wrote:

Paul,
    - No offense taken if you deem this one too far off topic but:

   - I've been wondering if there's not some way to get some cool air into
the cockpit without the weight and complexity of a conventional
automobile-style A/C system.  It's moist where I am in the southeast, so
evaporative cooling is out.  I've been wondering if using ice might not
work.  Bring about 5 lbs of ice cubes with me to the airplane in a cooler.
Dump them in a hopper in the cocpit followed by a cup or two of water.

The

water is cooled by the ice, flows into a heat exchanger in my cockpit
vent/blower system, the water keeps recirculating around and melting the

ice

while the air passing through cools down and blows on the pilot/passenger.
I wonder if this might not bring down the temps a noticable amount during
those hottest minutes of taxi and climbout to altitude.
   - I can work the numbers on how much heat the phase change would

"drain",

but the real question is how cool the air would be coming out of the vent.
If we figure the water is approx 34 deg F. and the ambient air is 100
degrees, is it reasonable to think there's a way to get 75 deg F. air from

a

reasonable size heat exchanger?

Mark

Gordon Robertson wrote:

I dont think this idea would work too well.   In my car, I put a block of
soft chocolate in the outlet of the air conditioner, and in about 1 minute
it was as hard as if it had been in the freezer.   I think the outlet
temperature of a car air conditioner is much colder than 32 deg F.

Gordon Robertson

Gordon,
 The actual evaporator temperature of any automotive A/C system MUST stay at or above 32 degrees. Below this point, the condensate water will freeze and block airflow through the evaporator. Most systems have a sensor which will shut down the compressor if the evaporator temp drops below 32 degrees Fahrenheit.

R-12 Freon will drop the temperature of the ambient air approx. 20 degrees in a well designed system. With the A/C system set to Max (or recirculate) the same interior air gets passed through the system again and again. This is how the temperature in the car will drop from 140 degrees ( here in S. Fla.) of a parked car, to a comfortable 65-75 degrees.

Charlie Kuss
RV-8A fuselage
Boca Raton, Fl.

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