Using outside air for AC into tent?

[uraceulose]

I'd like to run 2-3 600 watt bulbs inside a 5x10 foot tent.

Lights on at night so temps outside are between 45-60ish degrees.

Questions..

1) Using bare bulbs...run a duct to the outside window for intake, put a filter over the duct to keep dirt/bugs out. Then just pump cold outside air into the tent with about a 190 cfm 4 inch inline fan...while exhausting with a 6 inch 440 cfm fan up into the attic through another duct.

2) OR use is this way..Using sealed hoods. Same cooling setup as above but completely seal the hoods and then add another small fan with filter and a duct coming from outside...then also vent the hot air from the hoods separately and outside?


I'm just really trying to get away from running a portable AC even if it means only growing in the winter time.

Thanks,

Donnie

 

[uraceulose]

One more question..

Is it more advantageous to run the sealed hoods with Co2 and give up the bare bulbs OR

Better to run bare bulbs with the ventilation and then just give up the C02?

I'm thinking that sealed hoods with outside air ventilation and NO AC in anyway may keep it cool enough if I use Co2???

Thanks,

 

[Green lung]

Do number two it works great.





.

 

[uraceulose]

GL,

How is yours setup?

What are your temps outside?


Do you have the hoods vented AND the outside air pumping in or just the vented hoods?

Are you running Co2?

Thanks

 

[Stonefree69]

I'd like to run 2-3 600 watt bulbs inside a 5x10 foot tent.

Lights on at night so temps outside are between 45-60ish degrees.

Questions..

1) Using bare bulbs...run a duct to the outside window for intake, put a filter over the duct to keep dirt/bugs out. Then just pump cold outside air into the tent with about a 190 cfm 4 inch inline fan...while exhausting with a 6 inch 440 cfm fan up into the attic through another duct.

2) OR use is this way..Using sealed hoods. Same cooling setup as above but completely seal the hoods and then add another small fan with filter and a duct coming from outside...then also vent the hot air from the hoods separately and outside?


I'm just really trying to get away from running a portable AC even if it means only growing in the winter time.

Thanks,

Donnie

You lose a good 10% light intensity from hood glass and the ducting can get expensive and messy, especially with more than 2 lights. I'd run bare bulbs (and practice what I preach) and use this thermostst you can plug your fan(s) into to keep a precise temp range you want (I like 75-85 w/some CO2 @ 800 ppm). You want to cool the whole room not just the light hoods... much more efficient and direct this way.

"The TMP-DNE allows you to control the temperature within your growing environment. You can set the day and night temperaute independently. The TMP-DNe can be set to either heat or cool. Just connect your equipment, then set the temperature that you wish to maintain. If the temperature varies from your setting, the outlet on the front is activated. The temperature differential can be set at 3, 5 or 7 degrees.

You can set the day and night temperature independently
It has 50 to 100 degrees F Temperature range"

 

[uraceulose]

I definitely prefer going bare bulbs and already ordered one of those controllers. The one that I was using is called a 'ductstat' same price but doesn't allow separate night/day temps.

Just more needing to know how much intake I need vs. exhaust if I DON'T want to use a passive intake?

The "double the area of intake compared to exhaust" doesn't work very well when you're trying to filter the air for bugs.

My plan is to exhaust via a 10 inch inline 800 cfm fan with a filter...tent is 350 cubic feet.

If I want to filter the intake...how much area do I need or how much CFM when running a forced intake?

I'm willing to compromise and run passive intake but am confused as I think I'll need a HUGE intake filter to run passive with so much exhaust CFM??

Thanks again for any advice

 

[Stonefree69]

With a carbon air filter you usually derate the actual cfm by 20% due to resistance by the filter. So 800 - (800*20%) is 740 cubic feet, still plenty for 350 cubic feet tent. I heard passive intakes should be as much as 6x the area of fan

A bug screen should only drop cfm by 10% as it would seem to have less air resistance than a carbon filter (rated 20% drop). One guy suggested pantyhose. The CAP Valuline fans that I use are pretty powerful for their size - my 8" is rated 750 cfm and should work. I use speed controllers on them set to about 60-80% output (depending on stage of grow). Real quiet too and they are pretty inexpensive as far as good centrifugal fans go.

I should go at least 12" myself as my room is 9x15x8 feet or 1,080 cubic feet. I use the rest of my place (or residence) as a lung room with CO2 so in my case it's being recirculated. I suspect when I get a CO2 monitor it might be a good 600-800 ppm, then supplemet a bit with those CO2 shroom buckets. The general rule is air exchange every 2-3 minutes, but some growers here have said as much as 2x per minuite is very beneficial.

 

[uraceulose]

Thank you. I just need to figure out what size intake I should go with now..

It's a 10 inch diameter exhaust oulet. So double that would be 2 ten inch ducts for intake...

Just have to figure out away to connect these to a window and then filter it and I'll be good.

(6) 10 inch diameter holes just seems like overkill for 350 cubic feet especially with twice the CFM in exhaust fan output??

I just want to be fairly sure that I'm not going to have to add ports for intake to keep up with the exhaust...but the tents only have so many intake vents