21k Tabled Scrog Setup Design. Opinions on cooling/air cooled hoods.

[jimbobthe3rd]

Hi guys, it's been a while since i've posted up on the farm. I'm venturing into new territory with 21 x magnum xxl 8"s. I've never had air cooled hoods before, i've had setups the same size as my new project, but normally i split them up into 2-3 smaller rooms to make cooling alot easier.

This time i want to do one large sized room, with 7 5'x15' tables on wheels(3x1k per 5'x15' table), that i can move each way 1.5-2 feet to get in and work on the girls. It'll be coco 60%/hydroton 30%/perlite 10% mix. 21 plants, 21k of wattage, some cooling & intake and exhaust.

Now, the real question i have for you farmers, is how to best air cool my 21 magnum hoods. I've heard it takes 250-300 cfm to cool each 1k light, and i'd assume the number increases the farther the distance from the fan the light is (as the fans cfm drops with distance).

Below i have uploaded schematics of my room design, as you can see its a 7 rows of 3 lights. What would you opinion be towards the best action of cooling these hoods? 7 x 750-900 cfm 8" fans for each vertical row of three lights? Or 3 big max can fans 2100-2600+ cfm for the 7 lights in each 3 rows horizontally.(would have to go up from 8" to 12" i think and reduce it? i heard reducing can cause stress on the fan and not work as good.)

Any other ideas/input towards cooling/room schematics is very welcome as i know there are some very learned cultivators on the farm here :).

Sincerely
Jimbob.

 

[purpleberry]

Id just run 6" fan and hoods and put 1 fan per row, with only 3 hoods i dont think you need 8" hoods unless you tried to cool 7 lights in a row and i think thats going to make your room hotter, Ive ran 4 in a row and the last light heats up. Or change the design and run 5 rows of 4 hoods and you dont have to run so many fans.
Do you have cool air coming in all the time? The 24k btu ac isnt going to cool your room, Maybe it will help if you live in a cool climate and always have cool air coming in?

 

[jimbobthe3rd]

So you reckon doing the air cooled hoods in 7 vertical groups of 6" fans? I was gonna use 8" ones incase i change the setup later on etc. It'd be 3 in a row each then.

I will have constant cool air coming into the room yes, and the room will be incredibly well insulated & the room itself is inside another insulated room.

The 24k btu ac is just for supplemental cooling/heating, as i was trying to make it so there would be no heat projected from the 1k lights as i'd be doing some extreme air cooling of them. Regardless of the outside temperature, the room will be about 70F due to insulation. If the lights are really well cooled, i don't think their radiant heat should build up at all?

Also my exhaust fan will be rated at 2500-3000 cfm (gonna buy a big huge bastard xD).

Purple; when you ran 4 lights in a row and the last one heated up (this was 6" yes?) what was your fan's CFM rated at?

 

[bobby]

1. We need to know the exact ambient air temperatures at all times to make sure it is going to work. I doubt it will work if your outside temps go above 85.
2. You should use the 10 inch Max Fan with a fan speed controller on each fan. It's rated at 1019 cfm and you can turn it down if you need. But it's really efficient at 1.9 amps. Use 7 of them, 1 for each row of 3 lights. Only 13.3 amps at 120v...you could put it all on 1 20 amp breaker.
3. I don't know how secure your location is, but 1 major factor to take into consideration is the odor that leaks through the lights and ducting. So you can either push your air though your lights, or pull your air through your lights through a custom filter box with a can 100 filter. Or you can just risk it and pull it through with no filter. However, I'd advise against it. We are in the business of eliminating odor issues, so you want to make sure any air coming from your place is filtered. Remember, when you use a can filter, you have to calculate the true CFM with appropriate sized fan with filter on.

For an operation that large, I don't think it's worth the risk of not using an AC. You can properly cool your place with 2 5 ton AC's for $8-10K (8k if you use a Goodman AC). Cooling your hoods properly with fans is going to cost you this much:

7 Max Fans (1019 CFM) $350 x 7 = $2450
7 Fan Speed Controllers $20 x 7 = $140
7 Dust Shrooms $130 x 7 = $910
7 Can 100 Filters $282 x 7 = $1974
7 Filter Flanges $16 x 7 = $112
Ducting = $50
Zip Ties and Foil Tape = $50
7 Filter boxes who knows, maybe $100 each = $700
=$5686 plus tax is $6197.74 plus 700 for filter boxes = $6897 With $1100 bucks more you could air condition your spot and eliminate all doubt and odor concerns. Yes your electricity is like 1/2 lb of product per month, but having a closed/sealed environment is amazing.

If you cannot add air conditioning, make sure you go higher on your fan estimates with the ability to turn down. I wouldn't go the horizontal way because it's simply too many lights.

You can change your lighting arrangement, but you want to make sure to get 300 cfm per light....so you can try all the different lighting layouts to minimize equipment costs.

 

[Element]

Im guna have to agree with Bobby. Runnning your lights like that is going to be a huge headache and keep you playing $ catch-up. But it is possible if your set on it. Ive learned that rooms over 25x20 are not worth the trouble of cooling (or dealing with rh), even with air cooling the hoods. Maybe split the room in two?

I myself have two insulated rooms (480 sqft combined), both with 10k of vented hoods and I live wear my outside temp never goes over 90. The heat from the hoods will still build up, enough to raise the temp and thats only 10 lights. Also, your gunna need an ac or your ladies will not have the looking you are going for. Hope this helps
element

 

[evu80]

I second that. Also consider the what if and the cost associated with fixing the problem should the initial set up does not work as planned. I've spent more money on chasing solutions on a 10 light setup that would not cool right than the cost of buying a 5 ton unit and done with it.

 

[Nobodynobody]

If it were I, take all glass off hoods. Do industrial 3 phase 15ton should do the job. Or several 5 tons if power is not 3 phase.

Other things that I came across over the years. 8-10" fan with 600-1000CFM to cool a 1000w lamp. 600w can get away with 8" fan with 600CFM.

 

[norm]

Can't use a speed controller with the max fans

 

[swisscheese]

Seems like it's better to air condition a room that large rather than mess with air cooling the lights.

 

[sebastien420]

id use a 12inch max fan to cool down my shades , you'll never run out of power with this fan...
on another note i hate air cooled shades and find they cut lumens down by 5-10%...just my opinion anyways... cheers

 

[sebastien420]

Can't use a speed controller with the max fans

they have speed controllers for max-fans at 300 a piece ,lol...