Help with temps AND humidity

[DougV]

Morning all,

I’m going nuts trying to control temperature AND humidity during warmer months. In cold weather, no problem. This is for flower only.

Set up: 8x8 tent. One 4x4 space has 4 pot RDWC setup, one 4x4 space I’m using four 7.5 gallon smart pots. Each of these areas have 630 watt led lights. The remaining 4x8 area is used for equipment.

The tent is in a barn without heat or air. I have an 8” inline exhaust fan, two passive six inch ducts vent air directly on my lights when the exhaust fan is on. I’ve got a portable AC unit, a 50 pint dehumidifier with pump, a 16” oscillating fan, 16 inch box fan, five 6 inch clip fans for air circulation, and a water chiller. During winter a small 1000 watt heater keeps temps warm along with the heat from the dehumidifier and everything works great.

Summer months, I’m lost. Use a water chiller and the RDWC system sweats and drips water as the dew point rises. Turn on dehumidifier and temps climb into the 90’s. Use AC without dehumidifier and the walls of the tent sweat with condensation and I end up with a cold rain forest. Turn AC and dehumidifier on I end up with AC being unable to cool lights and dehumidifier, temps rise to the 90s. Bottom line, I can control temps or humidity, but not both. I can’t find an inline dehumidifier or AC so I can keep equipment outside the tent.

I live in central Virginia. Summers are hot, humidity ranges all over the place. Split AC units are way too big, as are most portable units, they cycle on/off way too rapidly. The only solution I can come up with is to build an insulated room, cool it with a window unit, and put my tent inside that. Hard to justify the costs and effort for a non-profit setup.

Am I overlooking something? Any wisdom would be much appreciated. I can’t be the only person running into this, but I have been unable to find a solution despite way too much time on the internet lookin for answers.

Thanks for yalls time.

Doug

 

[PooToe]

Until you're able to control the temp and humidity in the shed/lung room you won't be able to control the environmentals inside the tent.

Insulate and make controllable your shed and your tent will follow.

 

[DougV]

Until you're able to control the temp and humidity in the shed/lung room you won't be able to control the environmentals inside the tent.

Insulate and make controllable your shed and your tent will follow.

I had already reached that conclusion, but was hoping someone had an alternate. It’s not in a shed, it’s in a 2400 square foot uninsulated barn. It’s not cost effective to try and cool that. A shed big enough would cost 6k or more to buy and insulate, not including AC and power.

I should add, I do not sell any product. I think my most cost effective way is going to be buying another tent with a duplicate setup and only grow indoors in the winter.

Thanks for your response. It confirms my thoughts.

Doug

 

[SnappyJack]

Build something similar to what's in the link below

If it already in a barn... then it's out of the sun and wind... 2x3 poly in and out of frame... 2 -3 x volume of grow tent.. should be cheap to condition.

Got extra money?..... cover frame with poly carbonate panels

Here​

 

[DougV]

Build something similar to what's in the link below

If it already in a barn... then it's out of the sun and wind... 2x3 poly in and out of frame... 2 -3 x volume of grow tent.. should be cheap to condition.

Got extra money?..... cover frame with poly carbonate panels

Here​

That just might work. I can frame in a corner so I have access to a window for AC and only have to frame two sides. Good idea, thanks.

Doug

 

[PooToe]

Build something similar to what's in the link below

If it already in a barn... then it's out of the sun and wind... 2x3 poly in and out of frame... 2 -3 x volume of grow tent.. should be cheap to condition.

Got extra money?..... cover frame with poly carbonate panels

Here​

Not a bad idea as far as building a makeshift lung room that is smaller and easier to control. My thing is that room won't be insulated from the weather the barn is currently giving his tent. Not sure how truly effective it'll be but it might work.

 

[DougV]

I steal and modify ideas with no remorse whatsoever. (Thanks SnappyJack.)

So this makes a bit more sense I attached a couple of photos of my barn. The barn is two stories, each 1200 square feet. The exterior photo is the back, or east side. By the time the sun gets over the trees the attached shed roof blocks sunlight from the back wall of the ground floor. My tent is on the SE corner, but I’ll move it to the NE corner. On that corner there is no direct sunlight on any wall near the tent. For grins there is a shot of my current crop, Black Maple #22, about 5 weeks into flower.

I’m rebuilding an old wood farmhouse built three years before the end of the American Revolution. Thanks to the build I have six 4x8 foam board, R10, about 90 square feet of R15 rockwool insulation, a door, and a year old window unit. I can use the existing two walls with a window for two walls and a window. A ceiling can be both suspended from the floor above and supported on all four sides. I can seal both interior and exterior of the ceiling with 6mil poly and cover it with foam board and rockwool to get R25. Cinder block barn walls I’ll cover with two layers of R10 foam board for R20. I’ll frame the last two walls with 2x4’s, line inside with poly, fill with rockwool, and cover the exterior with poly again, for R15 walls. A single layer of R10 foam board should do for floors. 60 square feet of rockwool runs $80, and R10 4x8 foam boards are $40 each. Roof and floor, at 12x12 each are 144 square feet, each wall would be 12x8, or 96 square feet each.

So for a 12x12x8 room I’ll need 21 4’x8’x2” foam boards, or $880. Less $240 for what I have. I’ll need enough rockwool, R15 for two walls and the ceiling or 6 packs of 60sq. ft., $480, less $160 for existing leftovers. 6ml poly is $100 for 1000 square feet. I’ll need roughly 12 2x4x12 at $8 each and 16 2x4x10 at $6.50 each, about $200. I’ve got a framing gun, enough nails, Tapcons, and adhesive to put it all together. Little over a grand to effectively double indoor grow adding two more grows per year. Oh yeah, I’ll have to add CO2 but that’s not super expensive and should increase quantity a bit. Or I could go organic CO2 and line one wall with cages for rabbits, nah scratch that, my wife would name them all and not let me eat them.

I appreciate the help and ideas. Using poly sheet makes the whole thing much easier and more cost effective. Dang it, wish I had thought of it first.

Doug

 

[SnappyJack]

Hmm... a fellow homesteader kinda guy... Excuse the 60 sec sketch...... your after dead air space.. like a thermos... ..styro / insulation may not be necessary... can tack it on later if necessary.... keep construct wall away from masonry / block is heat sink.. will hit air temp (think 95 degrees) and give off heat to dusk..

Yup ... the ceiling should be double sheet poly​