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for math types
Aug. 10th, 2005 12:44 am "So we're planning on building a vent fan for our office, something semi-permanent, for the one window that actually opens, to pull air out of the office (which with three computers running in it and crap airflow is always hot, and stifling).
A trip to Home Depot found an electric fan designed to augment forced hot air systems. Its a 6" fan mounted in a piece of galvanized steel ducting, I figured I can easily fab a mount with a piece of 3/4" plywood and some other bits of ducting to have it pull air out of the top of the window and direct it out (and down so rain can't get up into the fan).
The math bit is that the fan flows 250CFM[1]. The room is roughly 10' x 15' with a 10' ceiling. I get 1500 cubic feet for the room size, which means the fan should be capable of exchanging all the air in the room in about 6 minutes. Does that seem right or am I making a dumb error somewhere?
If it is right, I'm going to wire it through a dimmer switch so we can calm it down when we don't need it roaring full blast."
[1]the 8" model flows 500CFM, which is just nuts. I got this mental image of using it as an intake fan and having it sucking small birds right out of the air as they fly past.
A trip to Home Depot found an electric fan designed to augment forced hot air systems. Its a 6" fan mounted in a piece of galvanized steel ducting, I figured I can easily fab a mount with a piece of 3/4" plywood and some other bits of ducting to have it pull air out of the top of the window and direct it out (and down so rain can't get up into the fan).
The math bit is that the fan flows 250CFM[1]. The room is roughly 10' x 15' with a 10' ceiling. I get 1500 cubic feet for the room size, which means the fan should be capable of exchanging all the air in the room in about 6 minutes. Does that seem right or am I making a dumb error somewhere?
If it is right, I'm going to wire it through a dimmer switch so we can calm it down when we don't need it roaring full blast."
[1]the 8" model flows 500CFM, which is just nuts. I got this mental image of using it as an intake fan and having it sucking small birds right out of the air as they fly past.
