Classic Mustangs List Archive

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Mail From: deo1929 (Dennis Ouellette)

You're on the right track with the fan speed and AC compressor running.? They are connected as the evaporator has a thermocouple that measures the temperature of the evaporator as the air flows across it.? When more air flows across the evap, the temp goes up, which in turn causes the compressor clutch to engage.? Likewise, when the compressor has run and dropped the evap temp to its low temp limit, the compressor kicks off.? The outside temperature will also play a role.? So...there you go...Temperature, and fan speed both will determine when and how long the compressor runs.?

An interesting note...most cooling systems in cars are rated around 5 tons of cooling.? The average 2500 square foot house usually has a compressor for AC that's rated around 3-4 Tons.? So your car AC is cooling the equivilant of a 4400 square foot house!





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Mail From: Andre.Pollard (Andre.Pollard


That seemed very high to me. 5 tons of cooling is 60,000 BTU/hr or ~24 hp.
Since you can't get something for nothing, the energy input will exceed the
energy removed (ie, the cooling). No single standard automotive v-belt that
I know of will handle 24+ hp, and most compressors I've seen use single
belts.

A quick google search shows it's more like 1.5 tons for auto air
conditioners:
heco.net/maincat/compressors.pdf
"Air conditioners used in buildings are normally rated in
terms of the number of BTUs of heat they can remove per
hour. The typical automotive air conditioner falls in the
18,000 BTU/hour range using that system."

Sanden compressors which are widely used on cars today are rated at
14-18,000 BTU/hr. Larger ones are used on trucks, but the largest I found
on thier website was 26,000 BTU/hr.

I'd suspect the old compressors used on Mustangs use the same power from
the engine, but provide less cooling. Something running with that much
vibration can't be efficient.



classic-mustangs-bounces at lists.twistedpair.ca wrote on 12/16/2009 08:50:20
AM:

> An interesting note...most cooling systems in cars are rated around
> 5 tons of cooling. The average 2500 square foot house usually has a
> compressor for AC that's rated around 3-4 Tons. So your car AC is
> cooling the equivilant of a 4400 square foot house!

>
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> Classic-mustangs at lists.twistedpair.ca
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>
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