Co2 usage 2x 16kw 25x25 625 sqft rooms? 50lb bottles/tanks

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p0opstlnksal0t

Well-Known Member
Looking at having airgas come out and deliver/exchange for me using 50lb bottles. Any of you guys have similar size room? How much co2 do you use?

No not interested in a burner generator.
 
Keesje

Keesje

Well-Known Member
Renfro said:
Everyone and I mean everyone I know with medium to large sized rooms runs a CO2 generator.
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True.
I do know greenhouses that don't use generators, but they get their CO2 almost for free from some industry where it is a waste product.
 
Keesje

Keesje

Well-Known Member
p0opstlnksal0t said:
That's just not possible here believe I wish I could get a propane or Ng tank here and run a genny
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I can't do the math, but what would produce more CO2?
A 50lb of CO2 or a 50lb bottle of Propane?
My guess would be the bottle of CO2 because it is 100% pure, but I have no clue.
What would be cheaper?
 
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p0opstlnksal0t

Well-Known Member
CO2 cylinder pressure is about 860 psi at normal room temperature. Two pounds of liquid CO2 expands to about 20 cubic feet of pure CO2 at atmospheric pressure, or expands at a rate of 535:1 in volume. One gallon of co2 weighs 8.47lbs so a 50lb tank holds 5.9 gallons

50x10=500ft³

One gallon of propane contains 36 cubic feet of gas and over 100 cubic feet of CO2 (every cubic foot of propane gas produces 3 cubic feet of CO2). Propane weighs 4.24 pounds per gallon so a 20lb tank holds 4.7 gallons
4.7x100=470ft³

So a 20lb bottle of propane makes almost as much co2 as a 50lb co2 tank can store.
 
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newbplantgrower420

Well-Known Member
I lug out 20lb co2 tanks in my 20x20. I switched co2 about 8 times last run but its not a big deal for me. I have a backup one so i dont end up going to the hydro shop for just 1 tank. Hydro shop is down the street for me.

ive heard about 2 different instances where someones garage blew up because of a co2 burner so i just stick with tanks. Idk if it was human error on their part or what happened exactly....I just know the end result. So I just stick with tanks.

your room's slightly bigger so youre going to have to swap your 50lber out 4-5 times depending on lights...temps etc.
 
Keesje

Keesje

Well-Known Member
newbplantgrower420 said:
I lug out 20lb co2 tanks in my 20x20. I switched co2 about 8 times last run but its not a big deal for me.
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Interesting numbers!

How long was your run?
What is the ppm you are aiming at?
How do you build up the ppm during your grow?
Do you only run it with lights on?
Is your room totally sealed, or do you have some exhaust?
 
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TheOriginalKryptonite

Member
It’s a tough question to answer really, as each room design etc is different. For example, strength of extraction rates and say required ppm. Some controllers will slow extraction when co2 is dosing, etc. However, you shouldn’t use excessive amounts with your room dimensions. Set the solenoid controller to 1600ppm, like in Jurassic times and attach to the light cycle timer. I estimate you using a few 50lb cylinders, several at worst. But run the room more gentle, eliminating excessive heat from using too many lights. Hence the extraction rate can be slowed, as long as temp, humidity and air exchange are within limits. It’s all a balancing act, hope this helps.
 
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TheOriginalKryptonite

Member
It’s a tough question to answer really, as each room design etc is different. For example, strength of extraction rates and say required ppm. Some controllers will slow extraction when co2 is dosing, etc. However, you shouldn’t use excessive amounts with your room dimensions. Set the solenoid controller to 1600ppm, like in Jurassic times and attach to the light cycle timer. I estimate you using a few cylindersbut I could be
 
Keesje

Keesje

Well-Known Member
p0opstlnksal0t said:
CO2 cylinder pressure is about 860 psi at normal room temperature. Two pounds of liquid CO2 expands to about 20 cubic feet of pure CO2 at atmospheric pressure, or expands at a rate of 535:1 in volume. One gallon of co2 weighs 8.47lbs so a 50lb tank holds 5.9 gallons

50x10=500ft³

One gallon of propane contains 36 cubic feet of gas and over 100 cubic feet of CO2 (every cubic foot of propane gas produces 3 cubic feet of CO2). Propane weighs 4.24 pounds per gallon so a 20lb tank holds 4.7 gallons
4.7x100=470ft³

So a 20lb bottle of propane makes almost as much co2 as a 50lb co2 tank can store.
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As I said before: I have no clue.
However, on a different (non-english) forum I found a statement by a well known grower who is an expert on growing with CO2 and AC.
He wrote: "You forget that if you burn 30 kg of gas, for example, you get a larger amount of CO2 than if you get 30 kg of cold CO2."

Again, I have no idea and it is a really interesting subject for me as well.
But perhaps he is right. So I started googling and thinking.

First I thought about this: Propane for example is C3H8. There is still no O involved.
Only when you burn it, it uses O (which it gets from the air). Wikipedia: C3H8 + 5O2 > 3CO2 + 4H20 + heat.
So the Oxygen component is not in the bottle of Propane, but is only added to C during the burning.
This oxygen comes from the air in your grow room.
In the CO2 bottle, however, the oxygen component is already in the bottle. So in addition to the part C in the bottle, it also contains a lot of oxygen.
Could it therefore not be the case that you get less CO2 in gaseous state from 1lb of liquid CO2 than from 1lb of liquid Propane?

I also found some info on a site about how much CO2 a car produces that runs on Liquified Petroleum Gas (a mix of butane and propane)
1 liter of LPG weighs 550 grams. LPG consists of 82.5% carbon, or 454 grams of carbon per liter of LPG. To burn this carbon into CO2, 1211 grams of oxygen are needed. The sum is therefore 454 + 1211 = 1665 grams of CO2 / liter of LPG.
So that would mean that 550 grams LPG turns into 1665 grams of CO2. Or 1 gram LPG = 3 gram CO2.
20lbs = 9071 grams.
9071 grams of LPG turn into 27213 grams of CO2.
That are 60lbs of CO2.

So if this is all correct, then it looks to me that it is wiser to buy bottles of gas instead of bottles of CO2.
But again, this is just me using google. Hahaha.
 
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p0opstlnksal0t

Well-Known Member
Yes that part is already known I already know that a generator is the better option and I stated so in my original post. But it is out of the equation since I cannot run a generator which is why I'm specifically asking about bottled CO2 use in a large room
 
Keesje

Keesje

Well-Known Member
Ah, I thought that you could not have larger amounts of gas (in a truck for example) delivered to your spot.
I understood it wrong. Sorry about that.
Hope someone comes up with an answer.

But for us who can choose between a 20 lbs tank of Butane/Propane and a 20 lbs tank of CO2, the Butane/Propane would last us longer, right?
 
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Apalchen

Well-Known Member
I run 6 lights and it's looking like running a 20 lb tank is gonna be about a week. So since your room is let's say 2.5X bigger than mine you might run one 50lb tank a week per room.

For some reason here in MI a lot of large grows run C02 from a tank. They have large vertical tanks outside that get filled by a truck. I've heard through the rumor mill that it has something to do with the testing in MI, but not sure how true that is.

I know a guy down state doing the same thing on some large medical grows, his tank is smaller than the ones sitting outside the commercial grows but I'd say it's still 200 gal prob. When I get all my rooms done and ready for gas I'll prob look into a larger tank as well.
 
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newbplantgrower420

Well-Known Member
Keesje said:
Interesting numbers!

How long was your run?
What is the ppm you are aiming at?
How do you build up the ppm during your grow?
Do you only run it with lights on?
Is your room totally sealed, or do you have some exhaust?
Click to expand...
9 Weeks
1200ppm
Always the same throughout
Yes
Fully sealed.

Every runs different too. Im in W5 and I think Ive swapped only 3 times so far this run. Could be me replacing my DE HPS with LEDs in one of my 4x8s
 
P

p0opstlnksal0t

Well-Known Member
Apalchen said:
I run 6 lights and it's looking like running a 20 lb tank is gonna be about a week. So since your room is let's say 2.5X bigger than mine you might run one 50lb tank a week per room.

For some reason here in MI a lot of large grows run C02 from a tank. They have large vertical tanks outside that get filled by a truck. I've heard through the rumor mill that it has something to do with the testing in MI, but not sure how true that is.

I know a guy down state doing the same thing on some large medical grows, his tank is smaller than the ones sitting outside the commercial grows but I'd say it's still 200 gal prob. When I get all my rooms done and ready for gas I'll prob look into a larger tank as well.
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That would be ideal I talked to airgas and they do swaps on 50s the largest. They don't fill tanks
 
2

2com

Well-Known Member
Keesje said:
As I said before: I have no clue.
However, on a different (non-english) forum I found a statement by a well known grower who is an expert on growing with CO2 and AC.
He wrote: "You forget that if you burn 30 kg of gas, for example, you get a larger amount of CO2 than if you get 30 kg of cold CO2."

Again, I have no idea and it is a really interesting subject for me as well.
But perhaps he is right. So I started googling and thinking.

First I thought about this: Propane for example is C3H8. There is still no O involved.
Only when you burn it, it uses O (which it gets from the air). Wikipedia: C3H8 + 5O2 > 3CO2 + 4H20 + heat.
So the Oxygen component is not in the bottle of Propane, but is only added to C during the burning.
This oxygen comes from the air in your grow room.
In the CO2 bottle, however, the oxygen component is already in the bottle. So in addition to the part C in the bottle, it also contains a lot of oxygen.
Could it therefore not be the case that you get less CO2 in gaseous state from 1lb of liquid CO2 than from 1lb of liquid Propane?

I also found some info on a site about how much CO2 a car produces that runs on Liquified Petroleum Gas (a mix of butane and propane)
1 liter of LPG weighs 550 grams. LPG consists of 82.5% carbon, or 454 grams of carbon per liter of LPG. To burn this carbon into CO2, 1211 grams of oxygen are needed. The sum is therefore 454 + 1211 = 1665 grams of CO2 / liter of LPG.
So that would mean that 550 grams LPG turns into 1665 grams of CO2. Or 1 gram LPG = 3 gram CO2.
20lbs = 9071 grams.
9071 grams of LPG turn into 27213 grams of CO2.
That are 60lbs of CO2.

So if this is all correct, then it looks to me that it is wiser to buy bottles of gas instead of bottles of CO2.
But again, this is just me using google. Hahaha.
Click to expand...
As you've worked out, it's not even close. Propane about 81% compared to Carbon Dioxide at 27%. If the option was there, it'd be silly to choose co2 over propane (or NG), unless the other considerations outweigh the carbon density (heat, moisture, fire hazard, whatever).

 
2

2com

Well-Known Member
Apalchen said:
I run 6 lights and it's looking like running a 20 lb tank is gonna be about a week. So since your room is let's say 2.5X bigger than mine you might run one 50lb tank a week per room.
Click to expand...
newbplantgrower420 said:
I lug out 20lb co2 tanks in my 20x20. I switched co2 about 8 times last run but its not a big deal for me. I have a backup one so i dont end up going to the hydro shop for just 1 tank. Hydro shop is down the street for me.
Click to expand...
Annnnd this^ saddens me.

My bad OP. I'm also trying to find (more) points of reference/experience as to how long I could expect for my scenario. 10x10, 2000watts max of LED, about 40sq/ft of canopy max. No venting - ac and dehu, obviously. Not a perfectly, hermetically, sealed room. But still, sealed to the best of our abilities.
 
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