Help with Heat

[kaze420]

I'm using 70W in CFLs (1-42, 2-14)
I converted 1 side of my desk to make the area. 10"W x 20"H x 20"D

Lights off temp are 75-80F
But lights on are 90-95F

I have pc fans. 1 exhaust at top, directly below 1 intake, directly below that 1 passive intake.

So I have 2 fans and 3 holes to work with. Without making anymore holes what can I do here??

 

[Fuzz420]

Im personally not a fan of the stacked intake/exhaust setup. Why not just make both fans exhaust to expel the heat

 

[FreezerBoy]

One intake won't feed 2 fans.

What size holes, what size fans? You can try a bigger fan or isolate the lamps from the grow chamber.

Note that intake fans are the fastest way to positive pressure which you want to avoid at all costs.

 

[geopolitical]

It sounds like you have two issues.

#1 You have nothing containing the heat from your bulbs. In very small grows often a tiny partition of glass will make a huge difference in heat at canopy level. But being CFL's you'd have to make sure they're definitely air cooled or their integrated ballasts will fail at an accelerated rate.

#2 Your intake/exhaust is undersized. If you can't get away with drilling any more holes stick to one exhaust and have the other two holes be intakes. Put a big old fan on the one exhaust and make both intakes passive.

 

[ScrubNinja]

You want intake holes at the bottom, exhaust at top.

 

[Aerohead]

You are really going to need to draw air across the case, not just for temps but for proper air circulation in the canopy. I don't think it will work out with three holes stacked on top of each other. You are going to need more exhaust power and a passive intake on the lower opposite side of the case..

 

[kaze420]

I now have both pc fans for exhuast and 1 passive intake
temps are 88-90F lights on

would adding 1 more passive intake do anything more for this?
I can only use the back side because of stealth. can you have proper circulation only venting intake/exhaust on the same side?

 

[grow1620]

would adding 1 more passive intake do anything more for this?

yes your intakes should be twice the size of your exhaust.

can you have proper circulation only venting intake/exhaust on the same side?

imo, not really...the ideal set up would be exhaust at the top, intake at the bottom...in opposite corners of the box....seems like all your hgoles are on the backside for stealth right?...well you could always add a tube on the inside from your intake...."relocating" the intake to the front side of the cab...just an idea that would still keep all the holes on the back wall of the box.

pics? if not pics...how bout a crappy paint drawing explaining hole sizes and location of the intake/exhaust? The more info you give the more we can help.

 

[kaze420]

Pic

Both fans are running exhaust, temp is 87.9F 5 hours into light cycle
Doing 12/12 from seed for heat/space reasons

 

[FreezerBoy]

Again, one intake will not feed dual exhausts. You're choking the cab. You want dual intakes. Preferably both at the bottom.

 

[grow1620]

k how bout something like this

you would have to create a sort of false floor to channel the air under to get it to the front, the intake would be the width of the whole back of the box, and about 2-3 inches high. You would lose about 2-3 inches vertical room though...does the bottom of the "box" rest directly on the floor? if not maybe there's room underneath to channel the air more towards the front so you wouldn't lose any vertical room. this would also properly trap light from your intake.

I just want to mention that I use this sort of intake and it works very well for circulation...so it's not purely in theory.

 

[kaze420]

Hmm looks like a perfect idea for my setup Grow16

I could get away with this even without losing any grow area because I'm growing in a converted desk so there is another false bottom that isn't being used under the panels I've installed as the base. About 2 1/4" of space

Thanks, I'm sure this will solve my problem

 

[grow1620]

awesome glad I could help!!.. the icmag community has been a huge help to me, it's nice to be able to give something back makes me feel all warm and fuzzy.

 

[ScrubNinja]

You know I'm a big fan of your ideas Grow, but the problem with that is that you have to take the dummies guide to intakes into account. How big will that floor gap be when you allow for 4 of those fan holes? Edit: sorry I just realised it's out of scale, lol. Beg your pardon.

 

[grow1620]

10 " x 2 1/4" gap = 22.5 sq inches of intake...assuming that he make the cut in his floor 2 1/4" wide as well....

"4 of those fan holes" I don't know what you mean

it looks to me that those fans are like 3 1/2" 12.25" sq. per... with 2 fans that's 24.5" sq using the dummies guide that would equate to 49 sq inches of intake right>? so the gap would need to be 2x as big right? sorry I was lazy and didn't do the math before, yer right Scrub if that's what you mean. but don't worry I have the fix! just do both. make the vent under the floor and if that doesn't help temps consideraby you can always add the false bottom to double the intake size. plus venting directly off the floor will suck in cooler "floor air" and might help enough with temps that only one fan would be needed..

...run some tests and let us know how it works out kaze.
*edit to your edit....ah ha!!

 

[noone4u]

Sounds like if you remove the intake fan youd be ok

just hve the exhaust pulling air into the 2 holes you got.

if that doesnt workout then make the intake larger it worked for me

 

[ScrubNinja]

LOL sorry grow it's late here and I'm jacked up on loco weed As long as someone allows for the blah blah blah whatever - it's all been said. Do that and everything will be ok or something

 

[kaze420]

Temps are good now
Lights on 75-80, highest ive seen is 84
Lights off 65-70

Will upload pics tomorrow
plants on 12/12 under 70W of CFLs
day 20 from seed

 

[Mk3Jetta]

Nice Kaze420! those are great temps.