Air Cooled Hoods when its snowing outside?

[Green Mopho]

We are running a 24kW room in a commercial warehouse space in Colorado. We just got a nice temp drop and a few inches of snow. I'm getting condensation on my hoods and and ducting since I'm pulling air from outside through my hoods. I am working on rerouting to pull air from the inside of my warehouse, that is warmer and dryer than the outside air. This will also help control odor, as I will have some negative pressure in the ambient space within the warehouse (but not in the grow room, which is sealed).

I seem to be getting puddles of moisture on the ground from the build up of condensation on the ducting and manifolds coming in. In fact, the manifolds were damn near frozen over tonight. I have about 3 tons of dehumidifiers running and 5 tons of A/C in the room. Now I'm wishing I went open bulb for the winter! LOL!

Anyone got any suggestions as how to reduce the humidity in the room and/or get rid of the condensation, other than what I stated above?

 

[Green Mopho]

Let me show an example.

Intake Manifold (the one freezing over)
http://i905.invalid.com/albums/ac257/iamgreen420/IMG_5051.jpg

Exhaust Manifold
http://i905.invalid.com/albums/ac257/iamgreen420/IMG_5054.jpg

Air Conditioner
http://i905.invalid.com/albums/ac257/iamgreen420/IMG_5097.jpg

Ducted Room
http://i905.invalid.com/albums/ac257/iamgreen420/IMG_6009.jpg

 

[FLB]

The only way to get rid of all the condesation is to throw down for an air handler/air exchanger. It takes all your exhaust and runs it by all the fresh air coming in. This pre-heats the air coming in and most of the condesation takes place in the unit which has drains built into it. One big enough to handle your op would probably run somewhere around 8-10 g's. Might want to look at upsizing your AC and go bare bulb. I'm in the same battle right now

 

[Green Supreme]

You could make a lung room, to condition the air before it hits the grow room. Good luck. Peace GS

 

[leadsled]

yes agree lung room would also do it.

Another option:
re-route the intake to pull inside air. Otherwise due to the temp diff, no way to avoid condensation. I tried warming the intake but was not enough. I had to reroute the intake to pull air from inside rather than outside.

Rather than re-route your ducting for each season. Can add a motorized duct damper with a y. Then can choose to pull air from inside or outside.

Wintertime pull in air from inside. When not freezing out, pull air from outside.

Here is a pic of what worked for another member. he needed 2 duct dampers so he could exhuast inside the room to heat it, and then in the summer direct the heat outside. (may be able to use one duct damper)


Same concept, just slightly different for you. Hope that helps and make sense.

Can also use duct dampers to make sure the air flows where you want it.

 

[Green Mopho]

Yea, I have those dampers in a few spots. I just don't have holes cut in my ducting for the intakes and exhausts. My HVAC guy said he can set me up with holes where I want em on slide gates, that I can manually adjust. I hope that does the trick!

Question about Lung Rooms:

I've done quite a bit of research, and I was actually planning on having a lung room for this grow, but I was tight on space and there wasn't even space left over for a closet sized room after building the bloom room.

When you setup a lung room, you have your AC return and supply both going only to that room, right? And you also put a fresh air intake on a HEPA in the room, passive or with fan? But your deheuys would still need to be in the bloom room to offset plant transpiration, right? You are just ducting from the lung room to cool both your environment and your lights....clear me up on this a bit, please...

 

[weedfarm]

Is the ceiling of the room, the ceiling of the warehouse? I grew in a warehouse where we had rooms built inside the warehouse. I also had manifolds in each room. But I pulled from inside the warehouse, and exhausted into the warehouse. Then luckily already installed was a big 36" fan in one corner and a power vent on the other corner. In winter we shut off the fan (which closed the vent), and in summer we turned on the fan. This helped keep the warehouse at 80ish outside the rooms, and my hoods stayed cool enough to keep your hand on.

Try to pull from inside the warehouse. Or you can try to keep the air cooling in a loop to warm up the air, then have a system that allows cool outside air to mix in as the temps go up. Maybe a damper on a temp controller set around 50 that will open and close as the temp changes.


BTW is the intake and exhaust of your manifold in the center? How does it stay balanced? I had mine intake on one end, and exhaust fan on the other end and it created equal airflow through all the hoods.

 

[Green Mopho]

Is the ceiling of the room, the ceiling of the warehouse?

No, its exactly as you described, a room in a room.

BTW is the intake and exhaust of your manifold in the center? How does it stay balanced? I had mine intake on one end, and exhaust fan on the other end and it created equal airflow through all the hoods.

There are 2 separate manifolds, one on each side of the room. The exhaust manifold is powered by a 5000 CFM commercial fan, that I don't have much control over, other than ON/OFF and a timer.

The manifolds taper down, as you can see, from the middle, so the pressure stays equal throughout.

I'm opening my hoods until the HVAC guy comes. Hope that works!

I really, really, really don't like water dripping on my plants, especially 9 weeks into bloom!

 

[TurboAllWD]

Man that sucks Green Mopho, hope you get it figured out, looks like everyone has the right idea on fixing it. I kinda run the same design except without a dampner.

My A/C just froze up out of nowhere tonight, caught the room at 86 and I normally keep it 80-82 with co2, had an inch of ice covering 80% of the condenser. The drain hole was clogged, probably from the extremely cold air/high humidity and dust building up. Got lucky that it still works, thought I heard the pressure release valve go off once or twice while upstairs. It's a floor unit modified into a split unit both intake and exhaust go outside and the ducting is covered in ice and water thanks to the cold air and humidity from the snow.

My lights in the flower room have air blowing through them from the grow and into the "lung" room which has a passive intake for outside air. Most of it is recirculated back into the grow room but I'll probably end up routing it back outside in the summer. Or get a dampner so I dont have to keep switching it.

I bet the A/C in the lung room would work well and act as a good heater to warm up the cold air going into the grow or wherever it goes to cool the lights. If that makes any sense. I'm assuming you plan on pulling inside air and venting most of it if not all of it outside. Venting it back into the lung room with the a/c might get things too hot for the grow. But I don't know, i'm only playing around with 3k watts, I'm high as hell on this Golden Goat. haha Good luck getting it figured out.

 

[weedfarm]

I am not an HVAC expert by any means, but I do not think the tapering helps. Air takes the path of least resistance. So if the exhaust fan is in the middle, it is going to draw air from the center of the intake via the rows closest to the center.

I understand there are two manifolds, one on each side of the room. One is the intake, one is the exhaust.

By intaking from one corner and exhausting the opposite corner, the air path is exactly the same for each row of lights.



Maybe I am missing something and could be wrong. Obviously you know if all your hoods are cool



As far as your fan goes, it would be easy to put it on a temp controller


You have a few options on how to fix this, just a decision now which one you choose. Good luck

 

[Green Mopho]

Thanks for all the help guys! Got my HVAC guy coming soon to install the damper so I can pull in from inside. I understand what you mean now with the fan & intake on the corner of the manifolds. I'm not an HVAC guy myself, and I left that work to the experts! However, I often find things done by growers on these sites that is more well thought out than what my HVAC guy does....guess that's grower's experience.

For the weekend, its all opened hoods! I shoulda gone vert, I shoulda gone vert...LOL!

 

[mr. bojangles]

Glad you got that figured out, and yes, you shoulda gone vert :evilgrin0040:

 

[Green Mopho]

Glad you got that figured out, and yes, you shoulda gone vert :evilgrin0040:

LOL...my time with vert will come, soon enough....thanx to guys like you! SOG and big trees! :harvest:

And yea, I open some of the hoods, my RH dropped down to like 30% and no condensation. Quick temporary fix, but hey, it is what it is!

 

[xX Kid Twist Xx]

just a thaught but how about using regular 8 inch can fans to cool your lights instead of the a/c. you would need 6-8 of them. draw the air in from a lung room and exshaust as well like some have already said. either way seems it would be pretty easy to keep a lung room at 65 degrees in the winter.

 

[Green Mopho]

What up Twist! DryLttlFukr sez whats up! Wink, wink....

Yea, I literally have no room at this WH for a lung room. Gotta work with what I got!

 

[xX Kid Twist Xx]

What up Twist! DryLttlFukr sez whats up! Wink, wink....

Yea, I literally have no room at this WH for a lung room. Gotta work with what I got!

lol tell him i says what up as well. i hope u guys get the issues worked out your last run look great. i wish i could do it big like that

 

[Green Mopho]

lol tell him i says what up as well. i hope u guys get the issues worked out your last run look great. i wish i could do it big like that

Yea, just some bumps in the road. I have to say, I wouldn't of made it this crop if it wasn't for my Thermastor 2 ton commercial dehuey!