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Thread: Pot Farms

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    Pot Farms

    Now its CO2 control.
    No such thing as a modulating inert gas valve. They wanted 1300 ppm, it appears (to me) that the pressure from tank is so high that it over-saturates the room and valve is just banging on and off. Beginning to think they need a regulator for each grow room. Anyone familiar with CO2 control for pot farms or any indoor farms? Just looking for what CO2 pressure (appx.) should be introduced to supply duct, not really my problem but I am curious and only see more farms in my future.

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    LOL! Silly how these have become the rage of day. Local ASHRAE chapter meetings with long talks on them these days.

    Doubt there is a general rule as its going to be totally dependent on the sizing of the equipment, plant intake, infiltration, bla, bla, bla.

    If I were you, this is just PID tuning. Your current pressure sounds like way too much. Cut it 50%, review logs, tweak again. Guessing your going to be far better off with a lower injection rate since the levels are probably fairly stable and the loss/intake is slow. Far easier to hold open the valve 1-5min and bring it back after a door open vs 2sec and overshoot by miles.
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    Is there a hand valve on the CO2 tank that could be throttled closed, to reduce the flow from the tank?

    Throttle it closed a bit until you find the sweet spot, otherwise it sounds like their solenoid valve won't last very long.

    I'm envisioning a setup like an acetylene,oxygen or even propane bbq tank but that may not be your case.

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    Dungs makes 4-20 modulating valves for inert gases. Whether or not they will work with C02, I have no clue. If you can't modulate gas going into the room, what about modulating damper(s) and/or exhaust fan(s) on the way out using a C02 detector with modulating outputs?
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    I would definitely use a 4-20 actuator if it is a pot farm.

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    Quote Originally Posted by 2sac View Post
    Dungs makes 4-20 modulating valves for inert gases. Whether or not they will work with C02, I have no clue. If you can't modulate gas going into the room, what about modulating damper(s) and/or exhaust fan(s) on the way out using a C02 detector with modulating outputs?
    I did this at a facility in Nevada when it was still medical only. It was clear everyone was flying by the seat of their pants on how to set up the operation properly. In my case, there was a small fan that could pull from either the hallway or the grow room. A 0-10v signal modulated between the two. Not the most elegant thing in the world, but it worked.

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    Quote Originally Posted by mechmike2 View Post
    Now its CO2 control.
    No such thing as a modulating inert gas valve. They wanted 1300 ppm, it appears (to me) that the pressure from tank is so high that it over-saturates the room and valve is just banging on and off. Beginning to think they need a regulator for each grow room. Anyone familiar with CO2 control for pot farms or any indoor farms? Just looking for what CO2 pressure (appx.) should be introduced to supply duct, not really my problem but I am curious and only see more farms in my future.
    Why not put a PRV on the tank?
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    You need a regulator, a flow control, and an on/off solenoid valve. All very common items that can found at the local welding shops.

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    Regulate the pressure down to about 60 psi, then to the valve, then the flow control. Adjust that to whatever works. It’s just like a robotic wire feed welding setup.

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    Once you are down below 100psi just about any valve could modulate it, but the solenoid will do well with the right control. Just go to the welding shop and get a regulator so you are delivering low consistent pressure. Then a flow valve and meter so the flow is metered at a constant rate. Then adjust the flow so the solenoid valve cycles a few times an hour. If the space is currently in operation and they are using CO2 now, you may be able to get an idea of the flow rate required by inquiring how much CO2 they are buying a week or month. Divide the volume by time there is your ball park flow rate. Design your system so you can deliver 25% to 200% of their current use. (Size of flow valve and meter you buy). You may shift this value based on their complaints of the current system.

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    you could also use systems designed for tank blanketing.

    in chemical plants, there are LARGE storage tanks filled with all sorts of hazardous liquids. to make them "safe", they introduce an inert gas to the open space left in the top of the tank. they do this with various regulators, monitors, valves, etc. it would prolly be a good fit for that situation.

    here's a link to airgas systems:

    http://www.airproducts.com/Microsite...SAAEgIdAPD_BwE

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    Quote Originally Posted by 71CHOPS View Post
    you could also use systems designed for tank blanketing.
    Wouldn't think you would need anything too fancy. Regulator and needle valve with one of those floating ball flow meters like they use for flooding a weld with argon. Add a solenoid valve and dial in the flow to get a reasonable control. Could use two solenoid valves and get two stage control.

    Something like this. Pretty sure the tank connections are different between Co2 & Ar.

    https://www.grainger.com/product/5KJ...g!471329783024!
    https://sparcwelders.com/products/sp...iABEgIU8_D_BwE
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    Sized appropriately for the required flow of course.

    These spaces seem to be fair sized, have a good deal of air mixing. Once you have an idea on the required amount, would think solenoid valves with a metered flow would do the biz for their needs.

    You know what you have now is way to much. That's a starting point...
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