N
NoThc4me
- 32
- 8
... Where does the existing air in the room go? This is a basic question but I'm not sure of the answer. I know that a room (box) can only hold so much air. But if you have an intake fan blowing or sucking air in, theoretically no more air could enter the room without air being displaced or leaving the room.
So let's say you have a room with only a central air duct blowing air in....
Assuming the room is air tight, wouldn't the duct only be able to blow the air in if there was someplace to displace the air already in the room? Of course you would still expect to feel air blowing in if the fan was strong and yet the room is already 'full' of air?
My intuition is that air must actually be moving both ways- into and out of the room through the fan, even though you only feel it blowing one direction. This must happen because of a temperature difference in the air. Yet it sells seems logical that if you have air moving into a sealed room at 40cfm, that air would also have to be leaving the room at 40cfm (same rate). Can someone clarify this?
Edit - - I didn't think about air pressure. Of course more air can enter the room until air pressure raises enough to force it back. So then the question is how much new air can you provide a sealed room with only an intake fan (per minute). There must be a way to figure this out with an equation which accounts for air pressure?
So let's say you have a room with only a central air duct blowing air in....
Assuming the room is air tight, wouldn't the duct only be able to blow the air in if there was someplace to displace the air already in the room? Of course you would still expect to feel air blowing in if the fan was strong and yet the room is already 'full' of air?
My intuition is that air must actually be moving both ways- into and out of the room through the fan, even though you only feel it blowing one direction. This must happen because of a temperature difference in the air. Yet it sells seems logical that if you have air moving into a sealed room at 40cfm, that air would also have to be leaving the room at 40cfm (same rate). Can someone clarify this?
Edit - - I didn't think about air pressure. Of course more air can enter the room until air pressure raises enough to force it back. So then the question is how much new air can you provide a sealed room with only an intake fan (per minute). There must be a way to figure this out with an equation which accounts for air pressure?
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