On Jan 13, 2011, at 9:15 AM, Fred Sturm wrote: > It would take an enormous output of moisture to counteract having > the entire volume of air in a room replaced at the standard rate, > which I think is as high as three times an hour. Does somebody know? > My memory is not clear on that, but I remember being astonished when > I first came upon the figure many years ago. I did some extensive research <G> (looked at HVAC and some related articles in wikipedia) and found that, first, wiki has great info on these systems. Bottom line for air exchange rate seems to be 3 - 6 times per hour for classrooms. They acknowledge that 100% of the air doesn't get exchanged due to air flow and the shape of the room, and expect something like 2/3 to be exchanged actually each time there is a theoretical complete change. In any case, the air is always moving, in and out, faster than you think (assuming the system is working). I also found that ASHRAE has a committee dedicated to humidity issues, and that it met here in Albuquerque last summer. Regards, Fred Sturm fssturm at unm.edu "Travel is fatal to prejudice, bigotry, and narrow-mindedness." Twain
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