quote:Well from time to time it helps to introduce some humidity to the system to helps the evaporator.
Originally posted by Ray H: Someone would have to take me by the hand and gently walk me through the "logic" that recirculating already chilled interior air* past the evaporator to maintain the desired cabin temperature is more energy inefficient than constantly bringing in HOT outside air to achieve the same comfort level. Think about it - do you leave your windows open in your house when you run your air conditioning on a hot day? Why would you do essentially the same thing by drawing in hot outside air in your car on a scorching day? I reject the argument that bringing in outside air to the evaporator is somehow more physically efficient than the recirculation of interior air - the blinkin' fan motor is drawing the same amperage off the alternator, regardless. *Even recirculated air contains at least a minimum amount of outside air if for no other reason that car bodies are not absolutely air-tight.
quote:I recall reading that now they delibertly include about 10% outside air for safety reasons. It used to be just leakage that let any outside air in some cars on recirculate Protection from Carbon monoxide, Blue flame special lunches, etc.
Originally posted by Ray H: *Even recirculated air contains at least a minimum amount of outside air if for no other reason that car bodies are not absolutely air-tight.
quote:How did you make this observation? How do you know it moved to outside air?
Originally posted by Alan: Ever notice on most cars when you put on the defrost it automatically goes to outside air to remove humidity in side the vehicle?
quote:The evaporator works off the humidity in the air. Ever notice on most cars when you put on the defrost it automatically goes to outside air to remove humidity in side the vehicle?
Originally posted by Kestas: Yes, recirculate mode will lower the demand on the air conditioning system..... not just because the incoming air is cooler, but it's drier. Alan, how does introducing humidity help the evaporator? Forcing the a/c system to squeeze humidity out of air puts a big load on the system.
quote:Yeah my 94 s10 did disengage when the throttle was wide open but the 00 s10 I have now doesnt. Guess it has the varible thing youre talking about
Originally posted by eljefino: Below 40'F the air runs very little to none anyway, which is when I use defrost the most in the northeast. It still bothers me to be forced to use it though. Therealdeal700, you might have a CCOT compressor, which if I had to explain it, would be a continuously variable load that doesn't quite freeze up. So when your AC has to work less the clutch stays engaged but it isn't as much of a drag. Floor the gas (most 4 bangers) and the A/C clutch cuts out for max acelleration. That, you should feel.
quote:I can tell you that the more humidity in the air, the less efficiently the evaporator can cool it, and the warmer the air coming out of it. When I turned on my home A/C unit for the first time this year, the air coming out of the vents really wasn't that cool. As several days passed and it got a lot of the moisture out of the house, the air coming out of the vents got noticeably colder and it cools down the house faster.
Originally posted by Alan: The evaporator works off the humidity in the air.