recirculating sealed grow room with co2

[applepoop911]

hello i would like to start by saying a common problem with rooms running constant exhaust is a lower concentration of co2, not as low as a room with no exhaust but not as good as a sealed room with co2. he problem some people have with sealed rooms with co2 is excessive temperatures. i believe plants can utilize up to 7500-10000 footcandles at 90-85 farenheit co2 with a ppm less than 1200 at a relative humidity below 50% but above 40%. with a sealed grow room all of these factors are much harder to control, while maintaining a consistent level of co2

i think i have a solution and it is a sealed grow room with recirculating exhaust.

1st make sure to seal up your grow room completely. a good way is with duct tape. i envision this in a 3x3x6 ft grow box with three walls and the front being a sheet of pandafilm/mylar/reflectix etc. on one side will be the intake fan or pusher fan, not the most efficient design as far as air movement but necessary to recirculate exhausted co2 rich air. this fan will be on the lowest part of the pusher fan side as this will provide colder air by the means of the exhaust duct acting as a heat sink.

cut a hole in the pusher fan side and install the fan and seal around with duct tapemaking sure there are no leaks.

next we install the puller fan side. install puller fan on the side that is opposite the pusher fan and at the highest pointof the box, even the ceiling of the box is acceptable and preferred as this will be the highest point of the box allowing the most heat to be able to escape and be cooled. secure the puller fan on ceiling or wall opposite the pusher fan and make sure it wont fall duct tape is good for sealing but may need other support such as hooks etc.

now we install the recirculation duct. install ducting the exact diameter of both fans so that the puller fan connects to the pusher fan so you have one fan pushing air into the room and another pulling that same air out of the room in a constant loop.i find its best to run the exhaust duct from the puller fan, behind the box and around to the pusher fan.

now you are done. it is important to be able to control at least one of the fans speeds for most control how ever if you can only use one fan controller make it for the pusher fan as the puller fan will always be limited by the rpms of the pusher. it is even possible to use one fan but make sure it is the puller fan up to to increase upward air movement maximizing co2 uptake

no you have much more control as opposed to running a fan timer in your grow room plus these added benefits:

1 less wasted co2
2 more consistent level of co2
3 ability to control humidity more easily
4 easier temp control
5 less risk of outside pests entering
6 increased air movement in the grow room, co2 is very dense and tends to pool on the bottom so upward air movement and negative pressure are helpful
7 reduced odor

i hope someone found this useful i will be implementing it soon

a side note this setup is intended for co2 only, without co2 enrichment the plants would use up available co2 as well as recirculate hotter air since it is a sealed system

i am still working on how the fan speeds will affect temp humidity etc any insight would be appreciated

 

[applepoop911]

any thoughts?

 

[applepoop911]

poke

 

[Tonygreen]

What kind of co2 generator are ya usin bro?

 

[applepoop911]

What kind of co2 generator are ya usin bro?

i am using nothing as of now but plan to use either yeast reproductive method or yeast fermentation method. another option that woudl work is baking soda vinegar or a 12 oz co2 container with on off valve. i have a co2 ppm meter to measure if it will work the main problem with a sealed recirculating setup is the humidity and heat can accumulate as well as ethylene accumulation, all which are not good. in a normal sealed co2 setup the use of a dehumidifier and air conditioner is used to eliminated heat and humidity problems at the cost of so many hundreds of watts of electricity , making it not worth while. another way is through timed fan cycles running once per minute. the way i have devised to eliminate humidity is to have an intermediate box or cylinder in the middle of the ducting to remove moisture and or heat. to combat humidity you would find a suitable cylinder or even box, make it so the ducting attaches to each side, and fill it with silica beads, 900 grams of silica for 25$ shipped on amazon. 450 grams should do the trick and once they are full of moisture and you notice humidiy rising, you can remove them place them on a baking tray and leave them in the oven for 1 hour on 150-200 degrees farenheit. whilst they are drying replace the cylinder with the other 450 grams silica.
now that only leaves us with ethylene build up and heat. temps should be at 85-90 for an 1100 ppm co2 concentration, which contrary to popular belief, is the preferred level of enrichment seeing as over 1200 ppm will inhibit rubisco.
onto heat. to combat heat im somewhat stumped. my main thoughts are using the ducting as a heat sink but i am not sure abotu how to do this to keep levels below 90 degrees. im thinkin keeping it on the floor should lower temps 1 degree,another would be , and i think this may be the best idea, is to have a small fan mounted on the top of the box pulling both heat and ethylene out. having this fan have less cfm than the puller fan mounted on the top of the box would be best so that it wont pull dense co2 particles out of the room while pulling rising heat out and possibly ethylene

density of co2= 1.98 kg/m cubed
density of ethylene= 1.18 kg/ m cubed
density of air= 1.225 kg/m cubed

so ethylene, being lighter than air, should be getting pulled out readily , and co2, if getting pulled at all should hit the puller fan below the ethylene and heat extractor fan since it is much denser.

now the only problem left is positioning of the heat and ethylene extracting fan, and the recirculating co2 puller fan.

if placed on the ceiling of the box it should leave co2 to recirculate, especially if it has a lower cfm than the recirculating fan.

next would be to mount the fan just above the point where the top of the canopy is . i think this solves all problems
so basically here is a short synopsis:

1 seal box
2 install pusher fan at bottom of the box on one of the 3 walls
3 install puller fan on wall opposite of the pusher fan, just inches above wear you estimate the top of your canopy will be
4 install puller fan with lower cfm than other fans on ceiling of box, opposite the wall of the recirculating puller fan
5 connect ducting to puller fan with dehumidifying cylinder in the middle
6 connect dehumdifying cylinder to pusher fan with ducting

 

[applepoop911]

update update update!

now with picture!

how ever, to fully utilize ethylene/ heat exhaust fan a hole must be cut in the "sealed grow room" this hole will be a few inches under the exhaust fan and will be relatively small, to reduce negative pressure slightly o as not to create leaks through the pressure. cut small hole size of a baseball near top of the plant parallel with your light but at least 6 inches above the canopy on the same wall as the pusher fan.

 

[Dabstronaut]

Instead of using a separate space to have the air passively cool down in, why not build something to actively cool the air within the recirculating duct? You could potentially rig a mini fridge and run air through there to cool it down. Or a through a container with water (or a more efficient cooling liquid though it would be more expensive) and a small aquarium chiller...
This would of course cost you extra electricity, though a large enough water container might not need a chiller.
Just a suggestion

 

[applepoop911]

Instead of using a separate space to have the air passively cool down in, why not build something to actively cool the air within the recirculating duct? You could potentially rig a mini fridge and run air through there to cool it down. Or a through a container with water (or a more efficient cooling liquid though it would be more expensive) and a small aquarium chiller...
This would of course cost you extra electricity, though a large enough water container might not need a chiller.
Just a suggestion

great suggestions however i have installed a 50cfm fan on the ceiling fo the grow box to vent any and all hot air. this might not sound like alot but my goal is 85-90 farenheit so if it doesnt cut it i can go bigger or add a second 50 cfm fan for only 16$ more

 

[applepoop911]

also it is not exactly a seperate space btu a means to recirculate the co2 rich air already in the grow room to pass throw a silica gel type filter to pull moisture out of the air