New Room Build - How do I size a lung room?

[500lbs Guerilla]

I'm potentially moving to a new home with a four car garage that measures roughly 23'x33' (minus a 7'x3' bathroom in one corner). I would like to build two sealed 8k rooms, probably 12'x20' each, on a flipbox. I'd like to purchase as little new equipment as possible, as the move and build will stretch me a little thin. I have about 150 amps to use at my disposal.

Here are some items I have laying around which I assume will come in handy.

(2) 24k btu dual zone mini splits
(2) 12" Max fans
(2) 8" Max fans
(1) Phoenix Max 200 Dehumidifier
(1) 8 Burner C02 Generator.

I've heard of lung rooms, but have never used or seen one. I assume I have plenty of space for one, but aren't sure how big they need to be, or how small of one I can get away with. I'd like to save some garage space if possible, at the very least for a few racks of T5's for vegging.

Although I think my dehumidifier can handle both rooms, I'm also not sure how to set it up to do so. Should it be on a separate timer to only run in the rooms whose lights are off? Or should I plan on purchasing a second dehumidifier so I can have one running 24/7 in each room.

Any input would be appreciated.

 

[toquer]

i tried this without much success at my old building. some things i learned in the process...

i had a 5 ton ac in my lung room open on the bottom and ducted out the top, it went into each room with 10" hard ducting and had 1 drop per 100 sqft. There were a total of three room, one of them 500sqft the other two were 300sqft and 200sqft. I had 20 lights flipping from one room into the other 2 smaller rooms of 12 and 8 lights respectively. Inside the lung room were a few propane burners to maximize co2 for the room needing the ac the most. that in theory would have been the room with the lights on. 5 tons should have been enough for 500sqft with 20 lights all ducted but it wasn't. so we enlarged the ducting to 16" and instead of allowing the lung room to breath freely through the walls we then ducted that as well directly to the lung room and put in motorized dampeners on the entire operation and zoned it into 3 rooms. still didn't work. moved the co2 burners into the individual rooms and still had problems. our lung room could not breath enough to handle the volume of 8000cuft. i had low ceilings at the place to start. finally we closed off the lung room and moved the ac above the rooms ducted directly to the return of the ac again using more dampeners. this worked to a degree. but that's not the point... what i learned...

i believe the lung room has to have a tremendous amount of negative pressure
at nights plants need the ac just as much as they do during the day as when the lights turn off it takes a few hours for the entire room to cool down
the ac acts as a dehu all night long as well
the lung room should be as small as physically possible as it is adding volume of air to maintain
i'd say get a second dehu as it's the first 2 or 3 hours of darkness where humidity spikes,

if you're building a lung room purely for the sake of saving on propane burner and dehumidifier i'd scrap the lung room idea and get the additional components to make each room ideal and just use the flip for the sake of lighting. perhaps for moving the air through the lights you could devise a flip system or plenum so that you maximize airflow through the lights and not duct 4 of them in a row. from my experience 2 lights in a row max otherwise you're just blowing hot air on a hot light bulb.

just a few thoughts from my experience

 

[500lbs Guerilla]

i tried this without much success at my old building. some things i learned in the process...

i had a 5 ton ac in my lung room open on the bottom and ducted out the top, it went into each room with 10" hard ducting and had 1 drop per 100 sqft. There were a total of three room, one of them 500sqft the other two were 300sqft and 200sqft. I had 20 lights flipping from one room into the other 2 smaller rooms of 12 and 8 lights respectively. Inside the lung room were a few propane burners to maximize co2 for the room needing the ac the most. that in theory would have been the room with the lights on. 5 tons should have been enough for 500sqft with 20 lights all ducted but it wasn't. so we enlarged the ducting to 16" and instead of allowing the lung room to breath freely through the walls we then ducted that as well directly to the lung room and put in motorized dampeners on the entire operation and zoned it into 3 rooms. still didn't work. moved the co2 burners into the individual rooms and still had problems. our lung room could not breath enough to handle the volume of 8000cuft. i had low ceilings at the place to start. finally we closed off the lung room and moved the ac above the rooms ducted directly to the return of the ac again using more dampeners. this worked to a degree. but that's not the point... what i learned...

i believe the lung room has to have a tremendous amount of negative pressure
at nights plants need the ac just as much as they do during the day as when the lights turn off it takes a few hours for the entire room to cool down
the ac acts as a dehu all night long as well
the lung room should be as small as physically possible as it is adding volume of air to maintain
i'd say get a second dehu as it's the first 2 or 3 hours of darkness where humidity spikes,

if you're building a lung room purely for the sake of saving on propane burner and dehumidifier i'd scrap the lung room idea and get the additional components to make each room ideal and just use the flip for the sake of lighting. perhaps for moving the air through the lights you could devise a flip system or plenum so that you maximize airflow through the lights and not duct 4 of them in a row. from my experience 2 lights in a row max otherwise you're just blowing hot air on a hot light bulb.

just a few thoughts from my experience

Awesome, thanks for your advice. I'm having a little trouble picturing your setup. So you had one room with 20 lights, which flipped into two rooms of 8 and 12. All lights were ducted, and you had 5 tons of A/C plumbed through the rooms through 16" ducting with a drop every 100 ft2. What were you using to draw the air from the A/C into the rooms?

You mentioned that the lung room should have negative pressure. Would it be better to be pulling air from the lung room, and the lung room would have a passive intake?

The lung room is really to utilize the A/Cs for both rooms. A second co2 burner is really not a big deal, but if the room is already exchanging air with a lung room, I don't see any reason why the co2 generator couldn't be in the lung room. I can justify buying a second dehumidifier, although I'd rather try and figure out a way to utilize the one I have since I know it can handle the humidity for both rooms combined. I'd rather not spend 1 to 2 grand on a capable dehumidifier if I don't need to.

The room the equipment is being pulled from is an 8k bare bulb sealed room with the dehumidifier, ballasts, and co2 burner all in the same room. The room had low 6.5 foot ceilings and measured 12x24. The A/C could keep the room at 80 without working too hard, probably due to the fact I had a blower in each corner of the room (two dual zone A/Cs).

So I'm not sure if I really need to duct the lights, especially if the rooms are going to have more cubic space than the one they came from. The A/C, dehumidifier, and co2 burner should be able to supply both rooms adequately. I'm hoping its just a matter of designing the lung room properly. I could put the reflectors sideways and duct 2 lights at a time, which I might do. I'm sure a lung room is less efficient than having the A/C handlers directly inside the flower room.

I do have a third, single zone 2 ton mini split I can use, but I don't think I have the amperage available to run it.

 

[toquer]

It looked like this. Sorry not to scale. The lung room passively received air from both rooms through wall registers. The 200sqft room was ducted passively since it wasn't adjacent. So the AC drew in air from the lung room fed from the flowering rooms. It actively blew into each room. Supply side.

The negative pressure draws the air into the lung room.

Id like to know how to make it work. I've got the room to build another 16 light room but not the amperage so flip is the way to expand. I also built my place to allow for another room.

Good luck! I'll respond again when I got more time.

 

[CannabisJohn]

i tried this without much success at my old building. some things i learned in the process...

i had a 5 ton ac in my lung room open on the bottom and ducted out the top, it went into each room with 10" hard ducting and had 1 drop per 100 sqft. There were a total of three room, one of them 500sqft the other two were 300sqft and 200sqft. I had 20 lights flipping from one room into the other 2 smaller rooms of 12 and 8 lights respectively. Inside the lung room were a few propane burners to maximize co2 for the room needing the ac the most. that in theory would have been the room with the lights on. 5 tons should have been enough for 500sqft with 20 lights all ducted but it wasn't. so we enlarged the ducting to 16" and instead of allowing the lung room to breath freely through the walls we then ducted that as well directly to the lung room and put in motorized dampeners on the entire operation and zoned it into 3 rooms. still didn't work. moved the co2 burners into the individual rooms and still had problems. our lung room could not breath enough to handle the volume of 8000cuft. i had low ceilings at the place to start. finally we closed off the lung room and moved the ac above the rooms ducted directly to the return of the ac again using more dampeners. this worked to a degree. but that's not the point... what i learned...

i believe the lung room has to have a tremendous amount of negative pressure
at nights plants need the ac just as much as they do during the day as when the lights turn off it takes a few hours for the entire room to cool down
the ac acts as a dehu all night long as well
the lung room should be as small as physically possible as it is adding volume of air to maintain
i'd say get a second dehu as it's the first 2 or 3 hours of darkness where humidity spikes,

if you're building a lung room purely for the sake of saving on propane burner and dehumidifier i'd scrap the lung room idea and get the additional components to make each room ideal and just use the flip for the sake of lighting. perhaps for moving the air through the lights you could devise a flip system or plenum so that you maximize airflow through the lights and not duct 4 of them in a row. from my experience 2 lights in a row max otherwise you're just blowing hot air on a hot light bulb.

just a few thoughts from my experience

5 tons on 20 vented lights is pushing it hard. Even vented lights I recommend 4000 btus per hour per 1 kw which means u need 80k not 60k in cooling. Minimum is 3413 per 1 kw ( number used for heat load calcs). Which means you need 69k or so. That number allows for no other heat loads such as dehumidifers, and any other loads. That is why I use 4k

 

[CannabisJohn]

I'm potentially moving to a new home with a four car garage that measures roughly 23'x33' (minus a 7'x3' bathroom in one corner). I would like to build two sealed 8k rooms, probably 12'x20' each, on a flipbox. I'd like to purchase as little new equipment as possible, as the move and build will stretch me a little thin. I have about 150 amps to use at my disposal.

Here are some items I have laying around which I assume will come in handy.

(2) 24k btu dual zone mini splits
(2) 12" Max fans
(2) 8" Max fans
(1) Phoenix Max 200 Dehumidifier
(1) 8 Burner C02 Generator.

I've heard of lung rooms, but have never used or seen one. I assume I have plenty of space for one, but aren't sure how big they need to be, or how small of one I can get away with. I'd like to save some garage space if possible, at the very least for a few racks of T5's for vegging.

Although I think my dehumidifier can handle both rooms, I'm also not sure how to set it up to do so. Should it be on a separate timer to only run in the rooms whose lights are off? Or should I plan on purchasing a second dehumidifier so I can have one running 24/7 in each room.

Any input would be appreciated.

I honestly never have installed a lung room. If the room is too small the units will cycle too much. I think you would better served to do a single room or get more a/c. If you get a 5 ton a/c installed with zone dampers for a flip flop then you would be set. The reason why I say 5 ton is so you have some air for off cycle room because 4 tons is really only enough for 8k of unvented lights. Trust me with a dehumidifier running the off cycle room will need a/c sometimes. Sell the minis to help with 5 ton costs. Then you will not need wasted inefficienct space for a lung room.

 

[Jalisco Kid]

Grow one crop with no flip then upgrade a/c and service panel. If this is your house you do not want to make it harder to grow/play with your girls. 4k btu/1k is not enough for me. JK

 

[Chance Last]

I am trying like hell to keep my co2 in the room but no matter how hard I work at this with lights being sealed and intake and exhausted heat from lights never entering room. My burner is CONSTANTLY running it seems. I feel the air dumping out from under door but not really an ac guy that knows how to build a return correctly to keep co2 in..ANY ADVICE IN LAMENS TERMS APPRECIATED! Thanks for any advice