New grow cupboard - how do i cool it tho using pc fans?

whitewidow2

whitewidow2

Well-Known Member
Ok... so ive started posting on here and im already growing as some of my previous pics have shown. Probelm is my setup isnt exactly ideal at the moment - i have a cupboard 50cm x 80cm x 165cm with swing open doors at the front and a stand alone fan inside to circulate fresh air.

What i WANT to do is have an inlet and outlet using pc fans to circulate the air and the reason this hasnt been done yet is it involves some modification to the unit.

I understand that fans have a CFM rating (cubic feet per min) and with the help of

https://www.rollitup.org/view.php?pg=...article&id=227

https://www.rollitup.org/view.php?pg=...article&id=229

i have worked out that my cupboard has a cubic volume of 21.62 cubic feet (bit of maths involved 1cm = 0.032ft) so basically i have worked out that i need a fan with a rating of approx 65 (multiplied the cubic volume by 3 assuming it needs 3 changes per minute) ie a 65CFM fan and from my research i see that the 120mm 12v fans have the highest CFM ratings so ill probably go for one of them.

Now im gonna put this fan at the bottom of the grow cupboard to let the air out and eventually carbon filter it...

Whats confusing me is it talks about passive intakes (ie no fan reqd.) i would have thought you needed a fan to push air in to the grow room as well?

And also - once this is done, will i still need my oscillating stand alone fan in the grow room for circulation or will the new setup be enough?

Please anyone who has any experience can you lend me a hand - thank you.

The cupboard http://www.ikea.com/gb/en/catalog/products/14903207
 
whitewidow2

whitewidow2

Well-Known Member
Im also taking it that when you buy a pc fan and you reverse the direction that it blows and mount it inside to blow air out you are exiting air from the grow room?
 
godbox

godbox

Active Member
whitewidow2 said:
What i WANT to do is have an inlet and outlet using pc fans to circulate the air and the reason this hasnt been done yet is it involves some modification to the unit.
Click to expand...
Turning PC fan into exhaust/intake: https://www.rollitup.org/do-yourself/8402-how-turn-pc-fan-into.html

whitewidow2 said:
Whats confusing me is it talks about passive intakes (ie no fan reqd.) i would have thought you needed a fan to push air in to the grow room as well?
Click to expand...
if u have en exhaust it should automatically create some kind of flow with out a fan, but adding an intake fan will increase the airflow rate and more fresh air will be pulled into your grow box. i think i said that right. :bigjoint:

whitewidow2 said:
And also - once this is done, will i still need my oscillating stand alone fan in the grow room for circulation or will the new setup be enough?
Click to expand...
Yes, Fans blowing on your stems/leafs etc helps stems to get stronger and hold its weight. so that is a must.

well that's my attempt to help, hope it makes sense :)
 
whitewidow2

whitewidow2

Well-Known Member
Can someone confirm that if i get a fan with a 65CFM rating that it will clean the air 3 times per min and is this what i need for a CFL grow in a cupboard???

Im still a bit confused as to the air intake, whether it should be passive or whether i should put another fan in there to bring in some fresh air...

Also where should the air intakes be located - ive heard that the bottom of the cupboard is the best place for it, should i have an exit at the bottom and an intake located directly opposite it???
 
godbox

godbox

Active Member
whitewidow2 said:
Can someone confirm that if i get a fan with a 65CFM rating that it will clean the air 3 times per min and is this what i need for a CFL grow in a cupboard???
Click to expand...
no idea.

whitewidow2 said:
Im still a bit confused as to the air intake, whether it should be passive or whether i should put another fan in there to bring in some fresh air...

Also where should the air intakes be located - ive heard that the bottom of the cupboard is the best place for it, should i have an exit at the bottom and an intake located directly opposite it???
Click to expand...
if u don't want any smell, i suggest you have an intake fan( down the bottom) with no passive vents, and your exhaust fan located at the top of your cabinet(hot air rises) sucking though carbon filter.


i would suggest Centrifugal Fan as your exhaust and inline duct fan as your intake.

i made this little diagram i made for myself. it might help with understanding some stuff

hope it helps :)
 

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whitewidow2

whitewidow2

Well-Known Member
godbox said:
no idea.



if u don't want any smell, i suggest you have an intake fan( down the bottom) with no passive vents, and your exhaust fan located at the top of your cabinet(hot air rises) sucking though carbon filter.


i would suggest Centrifugal Fan as your exhaust and inline duct fan as your intake.

i made this little diagram i made for myself. it might help with understanding some stuff

hope it helps :)
Click to expand...
I see what you are saying but i really just want to keep it pc fans to keep the noise down, so do you think i should have a pc fan near the bottom for intake and the other one at the top with a carbon filter... i was thinking of using a diy one like someone posted on here earlier
 
whitewidow2

whitewidow2

Well-Known Member
This is kinda contradicting the stuff in the article... can anyone confirm whats the best method for a cupboard grow like mine?
 
SWIMoryou

SWIMoryou

Active Member
s long as your lights dont over heat and burn the plants or the house down you are good. Personally I use both methods but in different ways, I have a fan blowing air across the MH bulb on the cieling of my vege room and another forcing air out of the room from above, while an 8" fan blows fresh air into the box and 2 4 " passive exhausts to the outside allow the heated air not to build up and naturally escape. For my flowering room I have and 8" fan blowing airconditioned air into the box and an 8" passive exhaust as well as a 4" fan blowing across the HPS and another 4" sucking heated air away from it to the outside. Then I have an 8" sucking air out of the closet that the rooms are located in so that does not over heat. Over kill? who knows it does get to be 120 deg F in the shade here a lot of times most of the year.
 
whitewidow2

whitewidow2

Well-Known Member
Lol fair enough, i still need to get a temp guage in my grow space. I just wanna use pc fans for airlflow and its a relatively small space as described earlier, just want to know where to put 'em, how many i need, do i need passive or not etc. - so many questions.
 
N

needhelp

Well-Known Member
putting the measurement of your cab in cm sucks... what are you trying to do to me...

get 2 fans for exhaust and 2 for intake.. seperate them into 2 different sets up plugs.. have 1 exhaust and 1 intake on one plug and have the other 2 wired to another plug... the reason... because of your sucky ass measurements, that i can't calculate at this moment, one set of fans might not be enough... as the plant grows and the more bulbs you add, the higher the temps will be and the more ventilation you have, will come in handy.....place the exhaust high up so it can release heat from the bulbs... place the intake somewhere lower so it helps blow on the plants and give them fresh air at the same time... also placing a glass of water in each corner for humidity would help....

if you don't want to use oscilating fans.. you can use pc fans also.... just have them angled in a way that they can blow on your plants... wire 2 of them on another seperate plug or however you want it to be.. you can have 4 fans on one plug if you want... but all i'm saying is, instead of those other fans, you can also use pc fans to blow on your plants....
 
whitewidow2

whitewidow2

Well-Known Member
Cool but whats the problem with my measurements???

Surely they can be converted to give a cubic capacity which i already worked out anyway of just over 20 cubic feet.

It states in the article that a hot room should have its air changed 3 times per min (ie a 60CFM fan 3x20) and in a cupboard grow if its just to replace lost CO2 then the air only needs changed once per 5 min (ie a 4CFM fan 20 divided by 5 ) - can someone clear this up for me and tell me what the CFM rating of my fan should be for the room and how often the air should be changed per minute - im thinking more along the lines of the first one but the article has got me confused. Thx.
 
whitewidow2

whitewidow2

Well-Known Member
needhelp said:
don't worry about the CO2... they'll get it when you shut off everything for the night
Click to expand...
i got some good answers on the growroom design section of the website, basically they said have a fan at the top which is extracting with a carbon filter and a passive inlet at the bottom to let air in. The cfm rating should be between 40 and 65 - think im good to go 8-) gonna use a homemade carbon filter too and stick a tub of ona inside.
 
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