venting question

[moonmist3207]

how powerful of a fan do i need to take the hot air out of a 2 1/2 by 2 1/2 by 6ft closet, looking into a computer fan, Need some help thanks!

 

[Hogdady]

depends on how hot your gonna get it.......

 

[moonmist3207]

well a 250 watt hps will be in use

 

[moonmist3207]

moreless how many CFM's do i need

 

[Hogdady]

120 to 200 cfm. what kinda intake of fresh air will you have?

 

[ChicagoJoe]

no no no,

Your cab at 2.5*2.5*6 = 37.5 cubic feet.
So a 40 CFM fan is plenty to completely exchange the air in the cab every minute.

I recently installed an 80 cfm fan and carbon filter in my cab (1.5 x 3 x 6 feet) and the fan is too powerful. I need to get a fan controller to slow it down.

 

[Hogdady]

the desired air ventilation rate is 3-5 times the room volume per minute....

 

[ChicagoJoe]

the desired air ventilation rate is 3-5 times the room volume per minute....

After looking up the info.
I found (on this site) that air should be exchanged "move the volume of your area 2 to 3 times every minute" from this post How Do I add Ventilation to my Grow Area, What Can I Do about Smell?

But some of the other references say once every 5 minutes is fine.
They take the grow area volume and divide by 5.

Seems to be different schools of thought on this. I will look into it further.


Edit:
In this thread: How Much Ventilation Do I Need in My Grow Room? ,
"When dealing with above average temperatures you will want your fan to exchange the grow room air 3-5 times in one minute, ... ... If you only want to replace depleted levels of co2 and are growing in a closet using fluorescents, one room change per five minutes (divide room size by 5) will be adequate."

So it really depends on your application. If you are trying to bring down temps, then more air exchange is recommended. But if just replacing depleted CO2 levels, one exchange every 5 minutes is recommended.