Heat problem, wlc to share hints!

[Terramoto]

i have a 90x71x43cm closet with a 125w CFL (also have a 400w i want to put but thats another story), currently 5 fans blowing air in and a hole on top of the closet (10cm diameter), my ambient temps are 27-29ºC and inside the closet 30-35ºC (normal temp around 32ºC). And my problem as you can see is the heat, i thought having hot air would go up and with the pressure of fresh air it would go out by the top hole, and the problem is it keeps getting hotter like a hooven.
would turn the 5 fans blowing out, help lowering the heat?

If you have any hint please share it.

 

[infinitylimit]

It really depends on the fans, but generally a small space is easy to pull the air out of thus turning the fans to blow out would be a good idea.

This thread has alot of great ideas
Ventilation 101

 

[Zest]

It's likely that a air circulation happens inside instead of hot air pushed out. Like infinitylimit said, try to suck out air (ie turn the fans).

 

[smokinweedgi]

yeh u will def do better with the fans at the top of your grow space sucking the air out and with a passive intake near the bottom of grow space ,make sure passive intake is bigger siz than the fans are , ie u could use 2 fans both sucking air out at top and have a hole the size of 3 or 4 fans at bottom

ps make sure to lightproof the passive intake hole easy done with a box upside down over the hole

 

[StealthDragon]

yeh I think you wil have much better airflow if you try to suck the hot air out instead of push cool air in. The general rule of airflow is that you want your intake 2x the the size of your exhaust. So if you have a total of 6 equal sized holes in your box 2 should be for exhaust and 4 should be for intake. If it's still a little warm try 3 and 3 or get stronger exhaust fans.

 

[Terramoto]

here's my setup:

i had the 3 fans in and the top fans out but it wasnt working so i changed all to in and opened the hole still not working. I guess im going to put them all out to give it a try.

 

[FreezerBoy]

You've built a positive pressure machine that everyone in your neighborhood will be able to smell. Air is coming in faster than it can escape. Pressure and temperature climb. You want the opposite, or negative pressure, where air exits as fast as it enters, thus allowing air exchange, cooling and scrubbing.

Intake fans are the fastest way to achieve positive pressure. Unless you're a pro, you don't want anything to do with them. Remove the intake fans and get a proper exhaust fan up top to achieve negative pressure. A decent scrubber will choke such small axial fans and, your heat problem will come right back.

 

[Terramoto]

tyvm for the info, now i understand whats the problem. tomorrow im gonna buy an exhauster, change the fans, but now to live through tonight i had a 12v motor here and build this mini fan that is blowing so much air from the closet that its maintaining the temps at a 30ºC.

 

[Dimebagg]

Gotta jump in and agree with everyone here, you want fans pulling out, not pushing in. BUT, not sure with the way youve worded, but you dont want to simply flip your fans and reinstall at the same place theyre at. Youre on the right track man, but you'll want to reinstall your fans in the top of your cab as well, and just leave your intake ports passive. That will give you the most efficient cooling in your setup

 

[cyberwax]

and if i can add; that box of yours doesnt look very light tight, looking at the fan picture.

 

[Terramoto]

behind the closet i have more of those black things to filter light i've already checked, no light inside
i have two fans on the top (third photo), the thing is they are together on the first photo you cant see because they are behind the reflector.

Maybe let the bottom fans blowing in and split the two top fans on different corners to pull air out plus the exhauster on the top hole would do the work? it would be like having 3 fans in at the bottom and 2 fans+exhauster out on the top.

 

[le crunch]

Dude seriously forget the intake fans. In a small cab like yours you don't need them. Leave them open as passive intakes and use 2 exhaust fans in the top. That will pull plenty of air through.

 

[LoKey]

i dont even know where this photo is, (seeing your reflector i presume top back left corner, but i cant see it in your other photo, but it looks like you have one fan blowing in and one fan blowing out right beside each other with the one side being partially blocked by the wall ??????

But as said seriously ditch the intake fans, you dont need them (but keep the intake holes open of course), and have your exhaust fans blowing out the top of your closet, as in the air goes up and out around your reflector.

dont see why you seem so confused on this

also your talking about two fans and an exhaust at the top, please clarify ??? and maybe a better pic of the top of the closet showing all your holes and fans

 

[blwd67]

Hey, LowKey, is that just a reflector over your exhaust or does it serve another purpose? Don't see how it could help with light, but maybe so as to draw air more from the center of cab instead of just up the backwall? Both intake and exhaust are on the same wall in my cab and I have a sneaking suspicion that air is only being circulated along that wall, not throughout the cab.

OP, duct booster fans would do you well, two stacked or one on either side can handle a small scrubber (or so I'm told).

Not sure yet, I'll be going to the store tomorrowish, but from what I'm told they come in atleast 4" and 6".

 

[FreezerBoy]

Both intake and exhaust are on the same wall in my cab and I have a sneaking suspicion that air is only being circulated along that wall, not throughout the cab.

It's not as though air has brakes. It can't come in, stop, turn 90º, flow up the back wall and stop again before exiting. You can always throw in a small fan simply for circulation.

 

[Terramoto]

k, just bought a 15w exhauster, closed the top fans holes and turned all fans off it gets the closet temp to ambient temp (33ºC today), i turned on only the bottom fans and it got to 31ºC

 

[grouchy]

I am not sure what a 15w exhauster is but it does not sound up to the task.

I would use four fans for exhaust only and one to just circulate. You can stack fans to get more pulling power and use the two top holes with two fans on each hole.

Do you have plans for a carbon scrubber? Your plants will start to get stinky soon and a scrubber will make sure no one finds them like parents or neighbors.

These are just suggestions and you can always keep using intake fans instead but its not the right way to do it.

 

[Terramoto]

the exhauster its a wc exhauster, im planning on buying a net basket from the chinese store and put inside some activated carbon, since the exhauster is on the top it will be easy to install.
the exhauster's caudal is 98m3/h
Ok, now i have only one fan for circulation 2 fans on the top extracting and the exhauster, it seems to be cooler now.

 

[infinitylimit]

k, just bought a 15w exhauster, closed the top fans holes and turned all fans off it gets the closet temp to ambient temp (33ºC today), i turned on only the bottom fans and it got to 31ºC

With the way that is built your air circulation will be along that one wall like you mentioned. Without moving the holes you will need a internal fan to circulate your dead spots on the other side; or you can just use a larger exhaust fan. Also note that your large reflector in such a space creates a large block for airflow, try removing it and your will see a great decrease in temps.

A 125w CFL isn't going to throw enough light to require a reflector, what your creating is more ambient heat and blocking airflow in this situation.

 

[Dimebagg]

so now that your temps are coming down, your can tell your headed in the right direction. I also dont know what a 15w wc exhauster is, but I gotta say it doesnt sound up to the task. Im not sure why you seem to be so set on keeping the intake fans. Double stack your fans as exhaust, and pick up one more to circulate air in the cab. That will help with moving air around since you have the intake and exhaust on the same wall.