Grow Room A/C

ttystikk · Mar 25, 2012

CannabisJohn said:
Would have to get full load amp draw and figure kw/hr usage with amt of time unit runs per hour. With this you could get a close est of kw/ton. Then do the math on a 3 ton good quality inverter mini split. I have a feeling if the math is done right your savings may be less than what you imagine because your unit runs at full load when ever it runs and an inverter mini can match the load very precisely.

I'm sorry, I think I was being unnecessarily confusing with all that- I didn't ask about the power consumption difference between a chiller cooling an airspace and a minisplit doing the same thing. That's a good question and I'll have to answer it sometime, but what I really want to know is how much the venting system that's cooling my hoods is saving me in cooling capacity- or cost, whichever. It occurs to me that I should just measure how much my chiller runs with it on, and then with it off, and subtract the two?

blazer · Mar 25, 2012

Got a small room with 1k ran a unvented hood last run and my temps were about 5-6 degrees hotter.example used to set at 76° then with a unvented hood i would set at 70° to keep temp around 76° vented hood definitely removes some decent heat load for sure!

CannabisJohn · Mar 25, 2012

Schwoop said:
What up CJ? Miss ya Bro! Good to see ya around! Props on all the AC knowledge you drop Dawg! Much Respect!

Thank you.

CannabisJohn · Mar 25, 2012

ttystikk said:
I'm sorry, I think I was being unnecessarily confusing with all that- I didn't ask about the power consumption difference between a chiller cooling an airspace and a minisplit doing the same thing. That's a good question and I'll have to answer it sometime, but what I really want to know is how much the venting system that's cooling my hoods is saving me in cooling capacity- or cost, whichever. It occurs to me that I should just measure how much my chiller runs with it on, and then with it off, and subtract the two?

It may be impossible to do that. Sorry for misreading the initial question. Let's put it this way if your venting wasn't proper than you wouldn't cool correctly. Are your ice boxes inline with hood venting or do they just cool the room?

CannabisJohn · Mar 25, 2012

Could someone sticky this thread?

ttystikk · Mar 25, 2012

I second the motion to sticky this thread! This info is way too useful to be allowed to slide down into obscurity.

ttystikk · Mar 25, 2012

CannabisJohn said:
It may be impossible to do that. Sorry for misreading the initial question. Let's put it this way if your venting wasn't proper than you wouldn't cool correctly. Are your ice boxes inline with hood venting or do they just cool the room?

I'm glad you sked that question, because the single thing that bugs me the most about people trying to build a sealed room is when they try to cool their HID lighting directly, and wonder why they then need HUGE AC capacity, and spend HUGE amounts of money running it! And if that weren't enough, they spend a lot of time dealing with indirect effects of such overcapacity, like hot and cold spots, low humidity and electrical problems.

I run an aircooled setup to cool my lights; the air comes from outside the growroom, is ducted to each light (in this case two rows of four Ochos each), PULLED through the hoods, and then sucked out of the room. The fan that pulls the air through the hoods is sited as close to the exit as possible, as this drastically reduces heat buildup. There is no active cooling other than air to cool the lights, and none is needed because this air never mixes with the sealed room environment. Even if the air leaves the room at 120 degrees it's okay since... well, since it's leaving, right?

The working air in the room is then cooled by 2 maxfans each blowing through its own Ice Box, which removes residual heat from the hoods, radiant heat (the part the plants actually use), heat from fans, electronics, dehuey, CO2 burner, etc. These units are taped together and hung from the ceiling, so they just suck air in at one end and blow it back out into the room. I aim them down somewhat so they can blow cooled air down towards the plants and create a nice breeze while they run. Again, these fans are thrmostatically controlled by my environmental controller and run about half time when all the gear is on full blast. That warmed water then mixes with warmed water from my RDWC units and continues on to my chiller, where the heat is removed. My chiller is set for 52 with an 8 degree rise before it kicks on. Keeping the relative humidity in the growroom below 60% prevents condensation issues on waterlines and Ice Boxes.

When I asked you about sizing cooling capacity for this room originally, I remember your calculations were based on 8kW of unvented lighting in the room and you suggested that a 2 ton chiller might or might not quite keep up, but it would be close. With the aircooling, the chiller runs about half time, and it's cooling all the other loads I mentioned above as well. Therefore, it works, and it works very well.

The reason I asked the question I did is so that I can quantify how much cooling I'm gaining with this aircooled helper setup. Just telling people they will save an unspecified but 'large' amount of power isn't as convincing as saying something specific , such as they're looking at saving some 2/3 of their total bulb cooling requirement. As it stands, two-thirds is my best guess on how much heat the aircooled system removes from the lights. Combined with other energy saving strategies I'm working on, as discussed elsewhere in these forums, I'm trying to reduce a given grow's energy consumption footprint by a solid 50% per unit of output produced over currently practiced methods.

El Cerebro · Mar 25, 2012

New readers please know we've hardly done justice to re-starting this thread compared to the previous one. Kind of makes me want to go dig through web archives to look for an old version..

So boxing in a condenser for ventilation, what would be a good thumb-rule for minimum interior volume per ton/12k?

CJ, did you notice my other question about inverters a few posts back? Just wondering if there are any downsides or contraindications compared to using regular mini?

Bobby_604 · Mar 25, 2012

Hello,

Thanks for having this thread for all us AC illiterate growers.

Quick question:

I have a 12k, bare bulb room going up. It will have a CO2 burner. Is this a good unit for me? 48,000 btu. I would put one handler on each wall.

I want to buy these cause the distributor is local.For repairs and warranties and such.

Many thanks.

CannabisJohn · Mar 26, 2012

ttystikk said:
I'm glad you sked that question, because the single thing that bugs me the most about people trying to build a sealed room is when they try to cool their HID lighting directly, and wonder why they then need HUGE AC capacity, and spend HUGE amounts of money running it! And if that weren't enough, they spend a lot of time dealing with indirect effects of such overcapacity, like hot and cold spots, low humidity and electrical problems.

I run an aircooled setup to cool my lights; the air comes from outside the growroom, is ducted to each light (in this case two rows of four Ochos each), PULLED through the hoods, and then sucked out of the room. The fan that pulls the air through the hoods is sited as close to the exit as possible, as this drastically reduces heat buildup. There is no active cooling other than air to cool the lights, and none is needed because this air never mixes with the sealed room environment. Even if the air leaves the room at 120 degrees it's okay since... well, since it's leaving, right?

The working air in the room is then cooled by 2 maxfans each blowing through its own Ice Box, which removes residual heat from the hoods, radiant heat (the part the plants actually use), heat from fans, electronics, dehuey, CO2 burner, etc. These units are taped together and hung from the ceiling, so they just suck air in at one end and blow it back out into the room. I aim them down somewhat so they can blow cooled air down towards the plants and create a nice breeze while they run. Again, these fans are thrmostatically controlled by my environmental controller and run about half time when all the gear is on full blast. That warmed water then mixes with warmed water from my RDWC units and continues on to my chiller, where the heat is removed. My chiller is set for 52 with an 8 degree rise before it kicks on. Keeping the relative humidity in the growroom below 60% prevents condensation issues on waterlines and Ice Boxes.

When I asked you about sizing cooling capacity for this room originally, I remember your calculations were based on 8kW of unvented lighting in the room and you suggested that a 2 ton chiller might or might not quite keep up, but it would be close. With the aircooling, the chiller runs about half time, and it's cooling all the other loads I mentioned above as well. Therefore, it works, and it works very well.

The reason I asked the question I did is so that I can quantify how much cooling I'm gaining with this aircooled helper setup. Just telling people they will save an unspecified but 'large' amount of power isn't as convincing as saying something specific , such as they're looking at saving some 2/3 of their total bulb cooling requirement. As it stands, two-thirds is my best guess on how much heat the aircooled system removes from the lights. Combined with other energy saving strategies I'm working on, as discussed elsewhere in these forums, I'm trying to reduce a given grow's energy consumption footprint by a solid 50% per unit of output produced over currently practiced methods.

The problem with you are doing is that some people don't want to pay for hoods, ducting, and fans to vent lights. Also some people are running vertical lighting. I think the bottom line is everyone wants something different so I try to give them what they want.

CannabisJohn · Mar 26, 2012

El Cerebro said:
New readers please know we've hardly done justice to re-starting this thread compared to the previous one. Kind of makes me want to go dig through web archives to look for an old version..

So boxing in a condenser for ventilation, what would be a good thumb-rule for minimum interior volume per ton/12k?

CJ, did you notice my other question about inverters a few posts back? Just wondering if there are any downsides or contraindications compared to using regular mini?

Inverter type units are better. No downside I know of at this time. I would say that somewhere around 2-3 sq ft of space per ton but make sure box is same or bigger dimensions than condenser coil is.

CannabisJohn · Mar 26, 2012

Bobby_604 said:
Hello,

Thanks for having this thread for all us AC illiterate growers.

Quick question:

I have a 12k, bare bulb room going up. It will have a CO2 burner. Is this a good unit for me? 48,000 btu. I would put one handler on each wall.

I want to buy these cause the distributor is local.For repairs and warranties and such.

Many thanks.

If I'm running 12k bare bulb I would do 5 tons total in either 2-2.5 ton units or 1-3 ton and 1-2 ton unit. I think you maybe short of a/c with only 4 tons. Good luck.

El Cerebro · Mar 26, 2012

CannabisJohn said:
I would say that somewhere around 2-3 sq ft of space per ton but make sure box is same or bigger dimensions than condenser coil is.

You mean cu ft? Sounds like not much plenum space necessary with proper vent-fan match?

Are there any window or small all-in-one units available inverter style? (did a quick search and not seeing anything on retail mkt)

CannabisJohn · Mar 26, 2012

El Cerebro said:
You mean cu ft? Sounds like not much plenum space necessary with proper vent-fan match?

Are there any window or small all-in-one units available inverter style? (did a quick search and not seeing anything on retail mkt)

Best way to put it about box. I would build it the same dimensions as the condenser coil height and length and then build it minimum of 2 ft deep. No window units I know that are inverter.

fishwhistle · Mar 26, 2012

John,how are you bro?,Can you tell me what size the pads need to be for the mini condensers to sit on?should they be right in front of the disconnect or off to one side or the other?thanks FW

CannabisJohn · Mar 26, 2012

fishwhistle said:
John,how are you bro?,Can you tell me what size the pads need to be for the mini condensers to sit on?should they be right in front of the disconnect or off to one side or the other?thanks FW

Doing well. Hope you are too. Pads should be an 1-2 inch bigger than condenser. In most cases 36 in long by 18 in wide will be plenty big enough but check your unit. You want disconnect on right side of condenser as you face it.

fishwhistle · Mar 26, 2012

thanks bro!

CannabisJohn · Mar 26, 2012

fishwhistle said:
thanks bro!

No problem. Also you can buy outdoor pads pre-made for about $30 each or so.

ttystikk · Mar 27, 2012

CannabisJohn said:
The problem with you are doing is that some people don't want to pay for hoods, ducting, and fans to vent lights. Also some people are running vertical lighting. I think the bottom line is everyone wants something different so I try to give them what they want.

You're right, of course, and I don't want what I'm trying to say to come across as 'my growroom is more efficient then yours' or any variation of such a pissing contest. Lots of different ways to skin this cat and I'm not saying what I'm doing is better or worse than any other approach.

That said, I am researching something specific, which is how to reduce the electrical consumption (biggest variable cost of growing) per unit weight of finished product as much as feasible and cost effective with gear that's currently available, and that does invite some comparisons. Who knows? Maybe the vertical lighting rooms with bare bulbs are actually more efficient! All I'm trying to do is figure out how to measure and quantify what I'm doing, even roughly. Since cooling is the next biggest consumer of power after the bulbs themselves, I'm thinking this is information people will be interested in when making growroom design decisions.

One more point; even bare bulb rooms need fans and ducting, leaving the main cost difference to be the sealed and vented hoods. At a couple hundred bucks each full retail, they aren't cheap. Yet, if you're running 10kW and your cooling costs are halved, how long does it take at 15-30 cents a kWH for those hoods to pay for themselves? I'm betting only a few months... Food for thought.

fishwhistle · Mar 27, 2012

CannabisJohn said:
No problem. Also you can buy outdoor pads pre-made for about $30 each or so.

Im gonna pour em in concrete as i have a set of steps to do to.

Grow Room A/C

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