3 ms·

> For the kind of technology available to us, it could cost up to $100 a day to buy enough lime soda to filter out the CO2. Doing some napkin math based on qui

> For the kind of technology available to us, it could cost up to $100 a day to buy enough lime soda to filter out the CO2. Doing some napkin math based on quickly googled(maybe incorrect) numbers, 100g of lime soda can absorb 10-20L of CO2 depending on the setup. Random offer off a Google search is $30 for 1kg, and I can get it cheaper locally. To go from 1200 ppm to atmospheric 421, you need to remove ~0.8L/m³. For my 50m³ room, that's 200-400g of lime soda. CO2 takes several hours with closed windows to build up that high, though, and it'd need a control loop to avoid wasting the lime soda by scrubbing below atmospheric CO2 levels... I thought you were being hyperbolic but, damn, yeah, this doesn't sound very viable ):

OutOfHere 2y ago
Thanks for the math. The parent comment has been slightly edited. I'd ideally want the CO2 to be the preindustrial level of under 300 ppm. The reason is that I suspect it could lead to maximum alertness and a feeling of well-being. Note that some ventilation still is needed during the day to get O2 and remove VOCs, so the calculations are affected. In your calculation, remember to account for the presence of people who constantly breathe out CO2. This and the need for some ventilation add to the cost.
- Llamamoe 2y ago
  The amount of O2 removed from the air is negligible compared to the impact of elevated CO2 on human gas exchange tbh. I doubt you'd have much benefit going down to 300 instead of 400, and it introduces a whole other problem - aiming at sub-ambient CO2 targets makes ventilation increase the amount of scrubbing you need to do instead of decreasing it. I imagine the increase in cost would be massive. But yeah it'd probably be better to base the calculations on co2 breathed out by people. But like I said, that's just some quick, likely incorrect math to land in the right ballpark.
  - OutOfHere 2y ago
    Thinking ahead, as the atmospheric outdoor level keeps climbing, ventilation will become insufficient to achieve a desired target indoor level. Air conditioning suffers from the extreme version of the same problem. Yes, the cost is substantial if using Soda Lime. Amines are traditionally used instead in a closed loop system, but they are corrosive and unsafe for use at home, although refrigerators and ACs too make use of similar loops. GPT says that some non-corrosive common amino acid salts can be used instead, but I find it difficult to believe.

OutOfHere 2y ago

Thanks for the math. The parent comment has been slightly edited. I'd ideally want the CO2 to be the preindustrial level of under 300 ppm. The reason is that I suspect it could lead to maximum alertness and a feeling of well-being. Note that some ventilation still is needed during the day to get O2 and remove VOCs, so the calculations are affected. In your calculation, remember to account for the presence of people who constantly breathe out CO2. This and the need for some ventilation add to the cost.

Llamamoe 2y ago
The amount of O2 removed from the air is negligible compared to the impact of elevated CO2 on human gas exchange tbh. I doubt you'd have much benefit going down to 300 instead of 400, and it introduces a whole other problem - aiming at sub-ambient CO2 targets makes ventilation increase the amount of scrubbing you need to do instead of decreasing it. I imagine the increase in cost would be massive. But yeah it'd probably be better to base the calculations on co2 breathed out by people. But like I said, that's just some quick, likely incorrect math to land in the right ballpark.
- OutOfHere 2y ago
  Thinking ahead, as the atmospheric outdoor level keeps climbing, ventilation will become insufficient to achieve a desired target indoor level. Air conditioning suffers from the extreme version of the same problem. Yes, the cost is substantial if using Soda Lime. Amines are traditionally used instead in a closed loop system, but they are corrosive and unsafe for use at home, although refrigerators and ACs too make use of similar loops. GPT says that some non-corrosive common amino acid salts can be used instead, but I find it difficult to believe.