First grow, Air cooled light questions

[Doobie Snax]

Hi,

I am using a Secret Jardin Dr120. (4x4x6'7) I am going to use 2 x 400w lights with air cooled hoods that have a 6' duct vent. I am currently using a 171CFM 4 inch inline fan for air exchange.

What size fan would i need to cool the 2 400W lights?

Also what would be the optimal set up for cooling and light footprint?

Parallel

----------0-<===>------
ducting , fan, splitters, lights, splitters

OR

Inline

------0===-====-------

ducting, fan, light, light, ducting

I am going to be using switchable digital ballasts, what would you recomend for veg IE 1 400w MH, and what for flower IE 2 x 400W HPs or using a MH and HPS?


Right now I have 1 Super silver haze, 2 purple killer, 2 trainwreck (from 80s) 1 Blue Bud, and 1 God bud under 4 42w CFLs. I recieved these clones about 8 days ago. They are doing great and growing quite well. My first light will be here in 5 days or so.

Thanks for the sageness,

Doobie

 

[Jnugg]

Your grow tent is about 112 cubic feet and you have a 4" 172cfm inline exhuast fan.

I see you plan on using the 4" 172cfm inline as the tents fresh air/air exchange...good job.

I would purchase a 6" 440cfm inline for cooling two 400w HPS.

But what about smellies?Are we going to be using a carbon scrubber,negative Ion,or nothing to take care of the smellies?

I'd setup as so:

Air exchange:

outside tent > passive itake(s) > carbon scrubber > ducting > 4" 172cfm inline > out of tent and out of room tent sits in (like into an attic or out a window).

Light cooling:

Outside tent > ducting > Light 1 > ducting > light 2 > ducting > 6" 440cfm inline > ducting > outside of tent and room tent sits in.

or

Outside tent > ducting > 6" 440cfm inline > ducting > light 1 > ducting > light 2 > ducting > outside of tent and room tent sits in.

 

[LlamaSchool]

A DR120 (with a single 600w) works quite well with a 6" on a speed controller used both for cooling and air exchange. A good way to route air is (starting from inside the tent):

carbon filter hung from bars->ducted to light/hood->ducted out of the tent to your fan hanging directly outside->ducted out of the room somewhere

With this setup, you use a single fan to both exchange air and cool the lights.

 

[Doobie Snax]

Your grow tent is about 112 cubic feet and you have a 4" 172cfm inline exhuast fan.

I see you plan on using the 4" 172cfm inline as the tents fresh air/air exchange...good job.

I would purchase a 6" 440cfm inline for cooling two 400w HPS.

I was hoping to use a bit smaller fan for the lights, trying to keep quiet.

But what about smellies?Are we going to be using a carbon scrubber,negative Ion,or nothing to take care of the smellies?

I am using a 4'diameter, 11' long core scrubber I built. No smells here.

I'd setup as so:

Air exchange:

outside tent > passive itake(s) > carbon scrubber > ducting > 4" 172cfm inline > out of tent and out of room tent sits in (like into an attic or out a window).

That is exactly how it is set up, minus ducting out of the room. Currently the tent is ducting into the room it is in. During the day the room is locked with the window open and shades shut.

After I get home the door gets left open. So far It seems to get pretty good airflow, I get even feel vacuum of air rushing through the door edges when shut. My temps stay between 68 and 79 at the canopy.

Light cooling:

Outside tent > ducting > Light 1 > ducting > light 2 > ducting > 6" 440cfm inline > ducting > outside of tent and room tent sits in.

or

Outside tent > ducting > 6" 440cfm inline > ducting > light 1 > ducting > light 2 > ducting > outside of tent and room tent sits in.

The second one is the one I was going to do, just hoping I can use a smaller amount of CFMs.

A DR120 (with a single 600w) works quite well with a 6" on a speed controller used both for cooling and air exchange. A good way to route air is (starting from inside the tent):

carbon filter hung from bars->ducted to light/hood->ducted out of the tent to your fan hanging directly outside->ducted out of the room somewhere

With this setup, you use a single fan to both exchange air and cool the lights.

That is what I originally had planned to do when I was planning on using a 1000 watter.

I believe with the 4x4 space however that running a filter and 2 light hoods off of one fan would not be possible with minimal bends or smallest fan size possible.

I decided to go with 2 400w lamps because I believe that 2 400w lights have only 3/8 of the heat output of a 1000w and a better footprint, also I am thinking of possibly running a 400MH and 400HPS for flower.

My main goal is to have an excellent light foot print along with using the smallest fans possible to keep the noise down.


Thanks a lot for the replies.

Doobie

 

[Jnugg]

I was hoping to use a bit smaller fan for the lights, trying to keep quiet.

.


That is exactly how it is set up, minus ducting out of the room. Currently the tent is ducting into the room it is in. During the day the room is locked with the window open and shades shut.

After I get home the door gets left open. So far It seems to get pretty good airflow, I get even feel vacuum of air rushing through the door edges when shut. My temps stay between 68 and 79 at the canopy.

The second one is the one I was going to do, just hoping I can use a smaller amount of CFMs.

Doobie

How about building a window box out of some 1/2"-3/4" MDF (medium density fiberboard,lining it with some foam padding or painting the inside of box black.Attach to the window frame using some industrial adhesive or caulk and some wood screws.Cut a hole with a circular saw close to the top of the box,and attach a flange of proper size then attach exhuast ducting to that...now all hot stale air is exhuasted out of the house and the room the cab sits in.You say using a 4" inline that your canopy temps stay at 68-79F lights on......that's a huge temp fluctuation.....5 degree fluctuation is alright but at most between lights on and lights off you want no more then a 10 degree temp change.

Get the 6" inline and build a fan box for it,that will silence the noise of the fan itself,then use insulated ducting that is bigger the the fan and run the longest length of ducting on the exhuast side....no more then 10' or you will experience pressure problems.Plus you never know,if it ends up that a 6" 449cfm inline is too much you can always slap a solid state speed controller on the fan and slow it's RPM down thus making the fan quieter as well.



Are we planning on using cooltubes or standard A/C hoods?

 

[Jnugg]

This "paint" is not to scale but you get the basic jist....I can draw this by hand much better and to scale or close to it if you like.

Here is the window box

As you can see the reason I mentioned the fact that you might want a 6" 449cfm Inline Centrifugal exhuast fan is because not only will you be trying to cool two lights,but you will be scrubbing the exhuast air via carbon scrubber (this DOES reduce cfm of fan) becuase you are also using the same fan for replenishing air in the grow room.


I live in Central Florida and in the summer it gets ungodly hot and humid and unless I run my central a/c 24/7 my 4" 172cfm inline centrifugal will not get the job done and I don't even use a carbon scrubber.....look at pics in my grow diary sigs.


Also what are the temps of the room the cab sits in?

What are the temps at your fresh air intake?

What are the temps at your exhuast?

Take a look and a good long read at the ventilation 101 link in my sig.

Also use this chart:

with this link as this is the original link taken from OverGrow FAQ;s (R.I.P. OG)
http://www.drugs-forum.com/growfaq/1635.htm



The rest of overgrow's FAQ's:
http://www.drugs-forum.com/growfaq/GrowFAQ Basic Topics.htm


Remember use the chart I provided with the info in the first link.

 

[Doobie Snax]

I already have the 171 CFM doing scrubber duty. So I only need to figure out what size fan to use for the 2 400w lights.

I read on another forum that to cool lights you need .3 CFMs per watt. For the 800w I plan on running the formula comes out to about 240 CFMs, does this sound about right?

They are regular A/c hoods not tubes. The room the tent is in does not get over 80 except about a week in the summer.

I am thinking about using 3 sheets of panda film black side out for my window box, Does this work OK? If not I probably will use some dense foam board.

I will be of course using insulated ducting to duct out of the window box, next run I will have a portable AC if I need it to cool the room the tent is in.

Thanks alot
Doobie