5th March 2008
Join Date: Jan 2008
Thanked 15 Times in 7 Posts
Please Check My Calculations
Well I donít want to spend a bunch of money for a CO2 detector, generator, etc. So I have looked at the mechanics/cost of making CO2 chemically.
Lets take a room that measures 6 foot X 6 foot X 8 foot:
Volumn of room= L X W X H= 6X6X8=288 cubic feet
Now lets convert cubic feet to liters: (1 cubic foot=22.8 liters):
228 cubic feet X 22.8L/1 cubic foot=6566.4 liters=6566400 milliliters (ml or cc).
Now the current atmosphere has an average CO2 concentration of 383 ppmv (parts per million by volumn).
Therefore in a 6X6X8 foot room:
Total Co2 (by volumn)=383/1,000,000 X 6566400=2514.9312ml (rounded=2.5 liters).
Now lets assume that we want to increase the CO2 content of the room to 1500ppm:
Total Co2 (by volumn)=1500/1,000,000 X 6566400=9849.6ml (rounded=9.85 liters).
Therefore we would add 9.85-2.50=7.35 liters of CO2
Now lets convert the gas conditions to STP (standard temperature and pressure) using the ideal gas law:
PV=nRT(or better yet lets just use an ideal gas law calculator on the internet to do it (here I used 7.35 liters CO2 at 24 degrees C=74 degrees fareheit (converted to 297 degrees kelvin) and 1 atm (760 torr):
So we will need 0.30178moles CO2 for the increase.
Now lets look at some baking soda (NaHCO3) and acid combinations:
First lets look at the best combination, baking soda and hydrochloric acid:
NaHCO3 + HCl ŗ NaCL + H2CO3 ŗ NaCl + CO2 + H2O
Note for every mole of CO2 produced, 1 mole of baking soda is needed.
Now how much does one mole of baking soda weigh?
Using the periodic table of the elements:
Na=22.98g/mole, O=15.99g/mole, C=12.01g/mole, H=1.01g/mole, therefore
1 mole of NaHCO3=83.97grams
Now in my room I would only need approximately 0.3 of a mole or approximately 25 grams to increase the CO2 to 1500ppmv.
Baking soda weighs roughly 18g per tablespoon, therefore I would need aproxamately 1 Ĺ tablespoons to raise my CO2 near 1500ppmv in my room above.
Of course, this would have to be done, every time I exhaust my room, which is about once a day. So I could just turn on the fan of my room for about 30 minutes to get rid of that nasty oxygen buildup, and at the end dump a tablespoon and a half of baking soda into my jar containing acid, to bring up the CO2.
As the garden grows, my babies would use up CO2 faster during the time of illumination, so as the garden becomes follage infested, another baking soda dump during illumination may be benificial
At Costco I can buy like 3 lbs of baking soda for like $2.00. Cheep!
I guess if I am going to look at my plants one or two times a day, well, I might as well dump baking soda into the glass CO2 vat to help them grow.
Just another cheaper way of providing CO2!
Hopefully my next thread will be about generating Co2 biologically. Yeast? Compost formulations?