Cooling an 8Kw Grow

[New Holland]

I'm trying to decide weither I should keep the room cool with ventilation alone, or go the "Sealed Room" route . I didn't consider the sealed room route before because I thought it would be to expensive.

I've discovered that I can buy an A/C unit for the same price as my big ass fans. Only problem is I don't know how big a A/C I need, all you yanks talk BTU's etc. Here in Australia we use Watts or Horse Power.

I don't think 8 Kw of lighting emits 8Kw of heat,...Soooo,....I'm thinking an A/C with 8Kw of cooling will do the job. What do you guys think?.

Here's the unit I'm thinking of http://www.aircondirect.com.au/Prod...7&fromUrl=Brand&fromType=Product&fromCmd=view

 

[icdog]

3kw of light and a 12000 btu 800w portable AC wasn't enough.

 

[New Holland]

ICDOG: Was it 800 watts of cooling power,...or does the unit draw 800 watts from the wall socket?

 

[icdog]

It used approx 800w of power from the wall, 12000 btu of cooling.

 

[Guest]

Could you give us a lil more info on your room ?.....I`m salivatin on 8k watts and what could be done with it ....Need length,width,and height........Anyways dewd ,I like your style and tell us more!...........50 watts per sq.ft. is ideal coverage and more if you can work it out with intake ,exhaust, or sealed room with the proper equipment.............PEACE...........DHF.........

 

[New Holland]

Hi Fred,

The room is 12'x14'x8',...but I'm only gonna use 8'x14'x8' to grow. The rest of the space I need as room to move around and place my nutrient tanks. I'm going to use 240 Litre garbage bin for nutrient tanks. Coco as my growing medium.

I'm thinking 8x 1Kw HPS lights, or 13 600 watters. I'm waiting for a friend to get back to me on a price to see which is more cost effective. I'm thinking the 600's would be better becuase I can spread the light out better, less hot spots that way.

Was investigating 2 Centrifugal fans and scrubbers to cool the room, I'd get away with this during winter without any problems. Temps of a night get down to 2 Deg Celcius. Summer is a problem, temps usually average 20 Deg Celcius of a night, and 30-40 during the day. I'm going to use lights on of a night, but even then with ventilation only and no A/C I don't think that's enough to keep the room cool, night or day.

I never considered Sealing the room before because I thought A/C would be to expensive. But going the Vent only route I'm looking at 2 fans @ $500 each, 2 Scrubbers @ $600, a shit load of accoustic ducting 2 duct mufflers. On top of this, to keep the sound of that air moving through the ducts and the fans roaring away, I'd have to frame the whole room, put sound insulation in the walls and buy sound check dry wall to keep it all quiet.

It'd be better to just seal the room and A/C it, and maybe air cool one row of lights. Co2 Gens cost fuck all. It'd be quiter, I'll be able to control the humidity tempreture etc alot easier. Other people told me that Humidity is a big problems in large grow. A/C eliminate this problem straight away.

BTW: This isn't going to happen over night, I've been planning this for the last 3 months, and I'll probably be another 3 months planning. If I jumped in head first I'd be in the middle of a grow with severe temp problems right about now!. It's all In the planning.

A smart man learns from his own mistakes, a fuckin genious learns from other peoples mistakes! C'mon fellas, give me some feed back!. What mistakes did you make planning a mega grow?.

 

[RUDEBOI]

I've run exactly that same amount of watts numerous times. I was running aircooled silverstar reflectors and had 4 12" Vortex fans used to cool them off. I had central a/c running into the room with an additional line of Central air run into the room. I used the fans with a push/pull method to maximize the cooling effect. This set-up when properly dialed in was able to achieve light on temps of mid to high 70's, and to be able to work in the summer time in the southeast is pretty damn good!LOL I have never tried to do over 4k without it being air cooled so I have no idea how a scenario would work with large amounts of A/C without it being aircooled. Good luck

 

[New Holland]

Thanks for your Input Rudeboi

 

[RUDEBOI]

Oh I forgot to tell you to always remember the time of the year you set up the room cuz many people set up inthe fall/winter and forget that what was adequate for the fall/winter months is often times lethal in the late spring/summer months. Had to learn that one the hard way. Also don't bring your plants in untill you have the wiring set up properly and I suggest you use some type of "control center for your ballasts. I opted to run mine 24/7 on a flipbox but you may decide that 8 is enough, if so a green air type timer box will make life simpler, although there may seem like there are cheaper alternatives insuring that your lights are going on/off in unison is priceless IMO. Plenty of air circulation is the key. Even though I used aircooled reflectors the room is sealed therefore it is important to bring in fresh air sources as well as utilize oscillating fans to move the air around the room.

 

[polski007]

Hey New Holland
I was reading an article that was saying that 3000BTU's is good for every KW of light that you use. So in your case something around the 21-24,000 BTU would be good.
If you have a look in a Harvery Norman Catalouge you will find some of the Air conditioners say it in KW output and BTU's
on average a 7KW output aircon - which is the 2.5HP one will do 24,000BTU's
so perfect for your room.
There is a Kelvinator reverse cycle with big LCD display
on special for $1200 in there

Im in the middle of designing a rather large room so maybe we can help each other out a bit with some ideas.

Good luck bro!!

 

[New Holland]

POLSKI!!!! I love you man!. That's the exact info I was after. Plenty of people on these boards can tell me in great detail with mathamatic formulas etc how many BTU's I need. But BTU's are useless to me here in Aus. How big is a 25,000 BTU airconditoner?, well I know now, it's 2.5 HP or 7Kw.

I wonder if it's lineal, i.e 3Kw A/C for 3Kw lighting, 4Kw A/C for 4Kw Lighting etc etc.

 

[Guest]

No,its 3000BTU per 1K light,I have 3 1K vertizontals and a 12,000BTU window AC,this will get temps down good enough if you are using co2.If not you may want tyo go 4 or even 5000BTU per 1K light

 

[mrgrowmez]

hey new holland,
dude i havent got any handy info for you, just sympathies. sometimes i spend half my time on these sites converting everything so can understand what the hell is going on with measurements hehehehe ive got all the online converters in my favourites.
best of luck man,
from an aussie a long way from home(but with much freindly growing temps)
MR.G

 

[New Holland]

Hey MrGrowMez!, where can I find some of this online converters?. Especially Litre/Sec to CFM.

 

[Guest]

NewHolland........What`s probably gonna bust your bubble is grams per watt performance in a that`s harder to control light performance in a 7800-8000watt room with MAJOR $ spent with no results behind it to pay for initial equipment expenditure ....Keeping the perfect environment is first and foremost in quality and yield,......Smaller manageable rooms are the wave of the future,but let`s think about this for just a second and wonder.........With all those lumens ,can you hope to get even close to 1 gram per watt?..........It`ll never happen........Why?...... MJ Plants will only use what they can uptake and repel and or suffer from the rest .........Albeit light saturation and or nutes shoved up their ass........I mean 8x14 isn`t that big but saturating it with MEGA-WATTS with all the bells and whistles it takes to control that type of heat and environment won`t give you the yields,It`ll only drain your wallet...8000 watts will never give you over 17 lbs in that room without vegging fewer plants for quite a while and growing trees with whole lotta maintenance....Been there and done that in 10x10 room with 3400 watts and NEVER got more than 10 lbs after 1 month veg and 3 month flower.....8000 watts will never double that.........Check your PM`S..........PEACE..........DHF.........

 

[mrgrowmez]

hey man,
this is the page I use for any kind of length, weight or volume http://www.onlineconversion.com/
I dont know about litres per sec though, over here they count in CubicMetresperHour and I thought that they used that back home as well. To convert CFM to CMH use the following formula CFM X 0.03 X 60 = CMH
I just checked the conversion site and 1 liter = 0.001 cubic meter. Dont know if you've seen this page,overgrow faq ,before but it has some great info etc on it
so hope that all helps man.
MR.G

 

[New Holland]

DHF: I've currently got a grow in a 10x5x7 shed with 1.8Kw of light and 2 x 160litre/sec fans. Temps are usually 8-10 deg C over ambient, which is usually around 20-22 deg of a night. I was just getting away with it temp wise.

I had 12 Noerthern LightsxBigBud in there and pulled just on 3lbs. I was stoked. I was planning on making my next grow about 4 x the size if this one. The room is 4 x bigger + 4x the light + 4x Vent= 12lb I didn't think it would be possible to get 15lb.

How do you think I should go about it?. I don't like the idea of breaking the area up. I gotta buy say 3 scrubbers 3 fans etc etc etc

 

[Guest]

You always want to oversize your a/c or otherwise it will be constatly running to try and keep the room cool, which in turn will make your humidity drop to around 20% which is not good, but you are going to need a hydrofogger humidifier for that room anyway. so if you were going to need 24000 btu, you will really need around a 36000 btu or 3 ton. good luck with your new room 8k is a lot different than 2. peace

 

[TGT]

Might be a good idea to start with 4 1000 watters and see how things go. Buy cooling as if you were doing the 8 lights so that when you want to go bigger you can. I have found in the past jumping in too fast with both feet can sometimes be a little more trouble than I can handle. Going smaller first and then expanding might allow you to ease yourself into this and things might appear clearer when not dealing on such a large scale all at once. Just a suggestion.

This is what I have done and am now going to expand. I'm using 4 1000 watters and going to move up to 6 in the bud room. My yeilds have been a little less than 2 pounds bone dry per 1000, so in total I get about 7 pounds. In the summer It gets down to around five and a half pounds. What I am going to do very soon is set up two other rooms and have a perpetual garden. My goal is to get 7 pounds every 6 to 8 weeks. Sounds crazy but I believe I can do it. I'll have a thread here detailing the rooms when I get the new place and start the build.

TGT

 

[New Holland]

bumpity bump bump