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Just a quick question. It's insanely hot here in Oklahoma, reaching 105+ degrees. I was just wondering, does having recircualted Air on in your car put more of a load on it? Does it put more load on the Air-condishoner? How does this work, does anyone ahvea diagram they can show me? Thanks Alot.
 

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I just uses cabin air, for the intake, instead of the outide air.

A/C lower the temperature by a certain amount, say 20 degrees. Using outside air at 100 degrees, it's going to output air at 80 degrees. If you have the recirc on, and the air in the cabin is 80, it outputs 60. The system works the same either way, in terms of load.
 

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No, if anything, it would be putting a very slightly lower load onto the A/C. Heat flow is roughly proportional to the temperature difference between the evaporator core and the air flowing past it, e.g., the greater the temperature differential, the greater the heat flow. So if you are sucking outside air at 105 past the evaporator core, vs. the cooler air from inside the vehicle (after the A/C has been running a while), the A/C system will be taking the maximum amount of heat and be at its maximum loading of the engine. And if the outside air is very humid, this will be even greater, as turing water vapor into liquid takes a lot of heat removal (engineers call it "Latent Heat of Vaporazation," if I recall correctly).

Of course, if the A/C system is maxed-out at both incoming air temps, it will make no difference. But, as I said, if anything, recirc takes less power to run, not more.

P.S. To put it another way, when you are running with recirculated air, the auto A/C is working like your home A/C, sucking air from inside the house, cooling it, and returning it to another part of the house via ductwork. When you're running you vehicle A/C without recirc on, it is as if you modified your home A/C system to take hot air from outside the house, cool it, and blow it into the house. Clearly the recirculate which cools previously cooled air take less energy. Since vehicles are much more "leaky" than houses when it comes to air tightness, the difference is not as large, but the concept is still valid.
 
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