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Efficient method to capture carbon dioxide from the atmosphere

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Re: Efficient method to capture carbon dioxide from the atmosphere

#151

Post by lawrenceduk »

bluerooibos wrote: post #119
deadbabe wrote: post #108

Earlier quoted context omitted.

Ok this sounds like BS, what kind of sensor is being used to get such readings? What do you use?

I used an Awair Element after wondering if Co2 buildup was causing my groggieness in the morning and an ever so slight dull headache. My bedroom was quite small at the time, but I measured the same effect of buildup in a larger bedroom, just the Co2 level took a little longer to reach it's peak. In the small room it took about 45 mins to climb to about 1400 after I closed the door and went to sleep. I'm currently try…

We monitor air data quite closely at work.

CO2 rises really fast with people in even a large space.

I wouldn’t put too much effort into vents above a door as we’ve seen that CO2 will leak through doors and even floors/ceilings very quickly.

Re: Efficient method to capture carbon dioxide from the atmosphere

#152

Post by vscode-rest »

anotherpaulg wrote: post #115
saubeidl wrote: post #91

Earlier quoted context omitted.

What if one started emitting Nitrogen, Oxygen and Argon in the right proportions instead to get the mix right again?

I like the unconventional approach. A few minutes with GPT raises two issues: 1. We've raised CO2 from 280ppm to 420ppm, about a 50% increase. To dilute it back down would require 50% more total atmosphere. This would also raise the surface air pressure 1.5x. 2. How much heat is trapped is related to the absolute amount of CO2 in the atmosphere, not the fraction. So the diluted atmosphere would retain just as much he…

Would it increase the steady state surface air pressure by 50%, or would more molecules offgas into outer space to compensate?

If the latter, it might actually work. Assuming they offgas at-proportion. Which they probably wouldn’t…

Re: Efficient method to capture carbon dioxide from the atmosphere

#153

Post by kzrdude »

leobg wrote: post #116
PeterHolzwarth wrote: post #84

Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture: It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively. In order, air is, broadly, made up of the following: Nitrogen: %78.084 Oxygen: %20.946 Argon: %00.934 CO2: %00.042 The stuff is essentially beyond a rounding error - it rea…

So then, is it really the CO2 that produces the cognitive impairment, or is the CO2 here just the proxy value that we are measuring, and the real reason for the cognitive impairment is low oxygen?

You could climb a mountain to test your hypothesis, keeping an eye on partial pressure of O2

Re: Efficient method to capture carbon dioxide from the atmosphere

#154

Post by ifwinterco »

_yb2s wrote: post #67
condiment wrote: post #45

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes. Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s…

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…

This is a meme on hacker news that's usually stated as a fact, but I'm not sure there's any robust evidence of cognitive impairment at <1000ppm

Re: Efficient method to capture carbon dioxide from the atmosphere

#155

Post by sfn42 »

nilamo wrote: post #61
sfn42 wrote: post #30

Earlier quoted context omitted.

Well here's the thing - there's quite a lot of water out there too. How long and how many terawatts of power do you think it'll take to suck a significant fraction of the earth's seawater through a capture facility?

You're right, it's expensive and hard, so it's better to not do anything and... migrate all humanity onto space stations so we don't die with the earth, I guess is the alternative you're suggesting?

It's not expensive and hard, it's impossible. The largest carbon capture facility in the world is called mammoth, and in order to offset our current emissions we would need a million of them. We can not build a million of them.

This is why climate scientists have been saying for a hundred years that we need to stop producing all this CO2, because we can't take it back. We can't just fix it. We can't just get back all the ice that's melted and keeps melting, we can't unthaw the permafrost. We can't stop all the methane and other climate gases that have been trapped under ice for millions of years from being released and making it even worse. We just can not do it.

We were warned, we ignored the warnings and now we're seeing the consequences.

Re: Efficient method to capture carbon dioxide from the atmosphere

#156

Post by progbits »

ifwinterco wrote: post #154
_yb2s wrote: post #67

Earlier quoted context omitted.

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…

This is a meme on hacker news that's usually stated as a fact, but I'm not sure there's any robust evidence of cognitive impairment at <1000ppm

https://www.sciencedirect.com/science/article/pii/S036013232...

> In this study, a systematic review and meta-analysis of fifteen eligible studies was performed to quantify the effects of short-term CO2 exposure on cognitive task performance.

> The complex task performance declined significantly when exposed to additional CO2 concentrations of 1000–1500 ppm and 1500–3000 ppm

Re: Efficient method to capture carbon dioxide from the atmosphere

#157

Post by progbits »

wcoenen wrote: post #126
_yb2s wrote: post #67

Earlier quoted context omitted.

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…

> Noticeable cognitive impairment starts in the 700-1000ppm range The US navy failed to detect such effects in submarine crew, even at much higher levels like 10,000 ppm. Another reason to be skeptical is that exhaled breath is 4% CO2 (40,000 ppm!). Therefore a few thousand extra ppm in the inhaled air should not make much of a difference to the homeostasis mechanisms in our bodies.

See my sibling comment for meta-analysis that disagrees with you. Would love to see citation for those navy experiments.

Re: Efficient method to capture carbon dioxide from the atmosphere

#158

Post by literalAardvark »

marcosdumay wrote: post #107
Ringz wrote: post #82

Earlier quoted context omitted.

Indoor is always higher ppm (how much depends on many parameters) without proper ventilation. „Proper“ should include a „Heat exchanger“ thus you don’t need to reheat fresh air.

Still, it will add some 80ppm over the amount you have today. There's a huge amount of disagreement over how much CO2 is harmful, but it tends to happen over numbers way above 800ppm. If your room has 2 times the open air concentration, and you are concerned if it's 2.0 times or 2.2 times, you should already be dealing with the problem.

It's not way above, it's around 700+.

So at 500 external you'd pretty much need continuous ERV but not necessarily scrubbers just yet.

Re: Efficient method to capture carbon dioxide from the atmosphere

#159

Post by ProllyInfamous »

_yb2s wrote: post #67
condiment wrote: post #45

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes. Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s…

I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…

My quality of sleep/life have greatly increased since installing an Energy Recovery Vent (ERV) — it exchanges outside/inside air through a membrane, which is about 60-80% efficient for both humidity and temperature re-capture (depending on fan speed).

[•] https://en.wikipedia.org/wiki/Heat_recovery_ventilation#Ener...>

I use a Panasonic model — readily available from Big Box Retail (~$700 + $100 in vent/conduit) — which can do 20 - 60 cfm (in my 900 sqft home this can easiliy exchange the entire volume several times per day).

Re: Efficient method to capture carbon dioxide from the atmosphere

#160

Post by sfn42 »

umeshunni wrote: post #69
nilamo wrote: post #61

Earlier quoted context omitted.

You're right, it's expensive and hard, so it's better to not do anything and... migrate all humanity onto space stations so we don't die with the earth, I guess is the alternative you're suggesting?

The earth doesn't die because CO2 levels increase. There have been multiple epoch with higher CO2 concentrations than we have now.

Never in the history of the planet has the temperature increased anywhere near as quickly as it's doing now.

If you look at a chart of historic temperature levels, pretty much every significant change on that chart corresponds to a mass extinction.

So yes, the earth does die. The earth has died many times before and it's currently happening again. The rock itself will still be here but us and pretty much everything else that lives here will be wiped out by climate change. The only question is how long it will take, and as you can see it's going fast.

This is not controversial, except for ignorant people who refuse to face the facts. This is what climate scientists have been warning us about for our entire lives.

Doesn't matter whether you believe it, it's happening.

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