Water-air heat transfer

Nov 2018
2
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Experiment: The air currents of two large domestic fans were directed toward the water surface of a 50-gallon tank while the ambient temperature was 88°F. If at the beginning of the experiment the water was at 77°F, why did this temperature drop? Shouldn't it have been the other way around? Since the forced air temperature was higher than the water temperature, shouldn't that air have transferred heat to the water causing its temperature to rise?
 
Last edited:
Apr 2017
528
130
It's all about the Humidity of the air...

If the air is @ 100% humidity then it's fully saturated with water vapor and the warm air will cause the tank temperature to rise ....

If not , then water will evaporate from the surface , causing the water to loose heat , and if it looses heat quicker than it gains heat from contact with the warm air then it will cool.
 
Nov 2018
2
0
So evaporation is the key, the loss of heat from the water is directly proportional to the amount of humidity absorbed by the forced air. I think I got it right, thank you very much!