2200w, do I need AC?

[MedScience]

I have another thread where I kind of asked this already, but thought it appropriate to make a new thread since the first is a diary and not specifically about this topic.

I currently have 2200w in an 8x8 room, two 600w HPS and one 1000w HPS. The room is basically a wooden frame wrapped in poly inside a garage. I have an 8" Vortex 747cfm fan exhausting through vented hoods. The ducting is fairly long (about 25' total) with a 180 deg bend and a few 90 deg bends, finally exhausting into the attic.

My problem is my temp is sitting at 81 deg, and RDWC reservoir temp is at 82 deg. I added a 4" blower to exhaust out the side of the room but that does not seem to have changed anything.

Do I need an AC unit to effectively cool this area? Or does the problem lie in inefficient ducting? I cant think of a better way to vent these lights, and the room is not sealed so if I ran AC I would need to cool the entire garage, which seems even more ineffective.

Any suggestions would be greatly appreciated, heres a quick pic of the hoods, I can take more if needed.

 

[Mr. Hugeblunts]

What is the ambient temp outside the box? If it's like 78 you won't get any colder fixing the ducting. What's wrong with 81 anyway? Get a res chiller and you will be fine; cheaper than AC.

 

[globel]

here in so cal you need an ac for 600 watts. In summer at least.

 

[MedScience]

Ambient temp outside box is about 75, so yes I suppose I don't have much room to work with. Res chiller cheaper than AC? The 1/3hp chillers I have looked at are $600+. At what point do res temps slow down growth?

 

[Leemer2t8]

pythium

pythium

Hey med....it's not so much stunted growth that's the core problem. Stunted growth is a symptom (amongst others!!) of Pythium (better known as root rot).
Just google the term. you'll get a few trillion results.

a cool rez...between 68F and 72F is ideal. A rez 1/4HP res chiller will easily achieve that for a 100GAL (400L) rez.

you don't have to buy a chiller...there are many homegrown solutions...however as I'm no HVAC tech...I'd suggest letting an expert build one for you!

HTH.

L2

 

[MedScience]

Yeah I really should have taken this all into consideration and bought the chiller instead of another ballast. Will cooling the water have any effect on ambient temps?

 

[Securityfirst]

Ambient temp outside box is about 75, so yes I suppose I don't have much room to work with. Res chiller cheaper than AC? The 1/3hp chillers I have looked at are $600+. At what point do res temps slow down growth?

Go with the A/C, fuck a res chiller. The plants will love you for controlling the temperature of the air, not so much the water. Actually come to think of it, let money be no object and get both. Nothing like dialing it in.

Have you ever considered pulling your air into rigid metal ducting then thru the lights into rigid metal ducting and then exhausted? Not expensive at all to buy the rigid ducting at home depot.Little trick grownerd taught me. What are you thinking maybe a 5000 btu?

 

[MedScience]

I considered rigid ducting but thought that air flow might be lower and the insulation seemed like a good idea. It was also cheap so I would have no problem trying something else.

I really cant afford to get both AC and a chiller. A $300 portable AC would be cheaper than a $600 chiller but my problem is the room is not 100% sealed so it seems very inefficient. I want to go all out and do it right, just don't have the resources at the moment.

 

[deepforest]

hey bud

since summer is basically over, you can for sure find a cheap portable a/c on craigslist or something. i cool 2400w (non-air cooled) with a 13k btu unit and it handled it in summer just barely and now its doing a more than ample job keeping temps in line. when you get the flow you can totally seal your room off and get a better unit cause any portable a/c you will buy at a retail store (ie not an industrial model) dont work in sealed rooms cause they exhaust out room air. plus it doesnt sound like you are running co2 at the moment. i would definately not use co2 with a portable a/c . basically it will cool your room, recirculate alot of air, and vent out a bit of air. my guess is that most units would be exhausting out the equivalent of a ~200 cfm fan every time the compresser kicks on.

i was a bit concerned that id be stuck between not having it sealed enough to use co2 and not having enough vents to bring in enough fresh air but im in the last week of flowering and they look crystally and stinky and decent sized so i assume it was enough fresh air!!!

 

[MedScience]

Ok, so I can still go with a portable AC even though the room is not sealed. The only concerns that I have are that the room is inside a garage, so wouldn't I have to cool the entire garage? Also, I currently have the 8" fan inside the room, if I add AC should I move the fan outside the box so it doesn't suck out all the cool air too quickly?

I was talking to the guy at the hydro store yesterday and he thought that I had way too many 90 deg bends and too long of a run in my ducting. He suggested getting a separate 6" fan to cool the 1000w and use the 8" to cool the two 600w. This would be a cheap solution, but he was kind of an idiot, he didn't even know how a res chiller worked. This is also the same guy that keeps telling me that an 8" Organic Air filter is good enough for my entire grow. I don't believe him.

Anyone else use rigid ducting? I like flexible because I can still adjust the height of the hoods. Think it makes much of a difference? I am planning on building a screen so there wont be much light movement after things get going a bit.

 

[deepforest]

i think if your room is within the garage you should place the portable a/c in your actual grow room, but make sure you put the a/c exhaust venting outside the garage. you might need a duct booster or something on your duct run depending on how far it is. or, you could cool the entire garage and have your room on a thermostat to turn the intake and exhaust fans on and off when you reach a set temp. personally id go with the first option as then you can avoid installing exhaust and intake fans. i dont think the portable a/c provides an IDEAL amount of exhaust and room air replacement (ie co2) but it will do. i think portable a/c is more of a temp solution until you can get enough cash to do it right. in my mind air conditioning and unsealed rooms = waste of money cause you are venting out air you just paid to cool



and while rigid ducting is awesome, i simply wouldnt use it with air cooled hoods because it seems like a pain in the ass. however you could probably make it work if you are working with one strain and you can keep your canopy even. yah that guy sounds like a tard, ive seen pics here of people with crazy duct runs with bends ups and downs and they seem to do fine. i wouldnt get a second fan.

 

[MedScience]

So even with a portable, Ill still need to vent that hot air outside, which really isnt an option unless I build some kind of box over the window, or just vent up into the attic.

 

[deepforest]

well, any a/c is going to create heat. if you can't easily vent , maybe you should look into water cooled a/cs and heat exchangers

 

[Mickymouse]

Go with a chiller root rot can kill a crop in no time.heres best price I found.I run a 24 bucket RDWC.2400w of light there not cooled just hanging temps get in mid 80s.this is in a 2x4 stud polly room.plants do great.leaves can take some heat.good roots means good plants.I have an ac barely ever use it.

http://www.plantlightinghydroponics.com/14-hp-ecoplus-water-chiller-p-1894.html

 

[NiteTiger]

Get ya a $25 dollar window A/C (craigslist) and build a duct box if you need to. Your setup is almost exactly the same I run, and A/C, while not strictly necessary, will make your life a LOT easier. Definitely the cheaper option by a very very long shot.

And portable A/C's suck ass, most folks who try them report that they don't handle the grow room environment well, and they're not as effective as a decent window unit.

Or, make it even easier - Window A/C through the poly (I upgraded mine a pod for better control), and then vent the garage to prevent a huge build up of heat. I just used a dual window exhaust fan sitting in the attic access for mine.

KISS

 

[MedScience]

Go with a chiller root rot can kill a crop in no time.heres best price I found.I run a 24 bucket RDWC.2400w of light there not cooled just hanging temps get in mid 80s.this is in a 2x4 stud polly room.plants do great.leaves can take some heat.good roots means good plants.I have an ac barely ever use it.

http://www.plantlightinghydroponics.com/14-hp-ecoplus-water-chiller-p-1894.html

What is the sq footage of your room? I am considering taking out the ducting and just venting the ambient air with the 8" vortex. Thanks for the link that is the cheapest I have been able to find that chiller so far when you add in shipping.

Or, make it even easier - Window A/C through the poly (I upgraded mine a pod for better control), and then vent the garage to prevent a huge build up of heat. I just used a dual window exhaust fan sitting in the attic access for mine.

Do you have any pics of this setup?

 

[MedScience]

Side note: that chiller says it needs a MINIMUM 633 GPH pump, is this true? If so... I dont think you can even get that high of a flow rate on the 1/2" feed tubing I have now. Would I install a separate cooling loop in the controller or would I need to increase the flow capacity on my feed tube to 3/4" to compensate?

 

[NiteTiger]

Do you have any pics of this setup?

Not the poly, but my newest grow is a pod using the same theory. Hit the link in my sig

 

[REZDOG]

Generally speaking,use 5500 rated BTUs of A/C per 1000w of light,to keep the environment plant friendly.
A "roller",or portable A/C unit,loses about 20% of its stated output,due to lack of efficiency,versus a window-mounted A/C-so figure accordingly before you buy.
Never buy a used A/C,would you bet your garden to save a few bucks?

My two pence and a farthing.

 

[NiteTiger]

Generally speaking,use 5500 rated BTUs of A/C per 1000w of light,to keep the environment plant friendly.
A "roller",or portable A/C unit,loses about 20% of its stated output,due to lack of efficiency,versus a window-mounted A/C-so figure accordingly before you buy.
Never buy a used A/C,would you bet your garden to save a few bucks?

My two pence and a farthing.

I can see why you'd say that about the used, but I'll have to disagree to a certain level. For less than the cost of a new 5000BTU a/c, I was able to get used 3 5k, 1 10k, and one 12k. Of course I checked them out rigorously, but with that kind of savings, I was able to have back up units on hand.

Overall, I think the money I invested in that situation left me in a better position for the continued health of the garden than if I'd spent that money on a new a/c.