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The most famous carbon dioxide absorber

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41–50 of 79 posts

Re: The most famous carbon dioxide absorber

#41

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

Not sure what city you live in but in the big cities I’ve lived in it was always easy to get the level down to 500ppm by opening windows.

Re: The most famous carbon dioxide absorber

#42
post #30

Earlier quoted context omitted.

Be glad people still believe anyone ever went to the moon at all. That may not be the case in a few more years.

Pretty soon it will be possible for tourists to visit the moon and see the litter we left with their own eyes. In fact, job 1 needs to be building fences around the landing sites so people don't trample all over them.

The moon is further away than you think. The Apollo mission architecture was a lot more feasible than others that have been considered. The current plan to use a Starship returns about the same payload with a much larger and taller vehicle that is inclined to tip over. You really want a landing pad.

Refueling from lunar materials might be possible but volatiles seem precious. The mission with that vehicle that makes the most sense to me is to land it with a full payload and use it for habitat, workshop, storage tanks or scrap metal.

Space tourism to a micro O’Neill colony in LEO decked out as a flashy space hotel seems more believable to me. I designed one that needs 15 Starship loads of LN2 for the atmosphere but that is fewer launches than they plan to put one Starship on the moon.

Re: The most famous carbon dioxide absorber

#45

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

A HRV or ERV, depending on how humid it is where you live will help immensely. Unfortunately hard to retrofit into existing construction.

Re: The most famous carbon dioxide absorber

#46
post #30

Earlier quoted context omitted.

Be glad people still believe anyone ever went to the moon at all. That may not be the case in a few more years.

Pretty soon it will be possible for tourists to visit the moon and see the litter we left with their own eyes. In fact, job 1 needs to be building fences around the landing sites so people don't trample all over them.

Funny thing, I bet by then authentic Armstrong poop (which comprises some of that litter) will be more valuable than moonrocks.

Re: The most famous carbon dioxide absorber

#47

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

Not sure what city you live in but in the big cities I’ve lived in it was always easy to get the level down to 500ppm by opening windows.

Yeah I live in Chicago and it is not hard to keep it at 450ppm. Right now it’s 493ppm in here.

Re: The most famous carbon dioxide absorber

#48

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

The average human exhales about 1 kilogram of carbon dioxide on an average day. Carbon makes up 27.3% of that: ~300 grams. That's the weight of a smartphone.

The logistics would be complicated, average plants aren't going to be accumulating so much mass so quickly. You would need aquariums full of algae. Just isn't worth it.

Re: The most famous carbon dioxide absorber

#49

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

The average human exhales about 1 kilogram of carbon dioxide on an average day. Carbon makes up 27.3% of that: ~300 grams. That's the weight of a smartphone. The logistics would be complicated, average plants aren't going to be accumulating so much mass so quickly. You would need aquariums full of algae. Just isn't worth it.

[deleted]

Re: The most famous carbon dioxide absorber

#50

Anyone selling house-size CO2 absorbers to keep CO2 in my house to more like pre-industrial 200ppm rather than the 800ppm that's more common of house air in cities?

You'd only need a few hundred grams of triethanolamine if you regenerate it several times a day (with a vent to outdoors), but there are probably some spill risks and maybe mist. Soda-lime is cheaper but requires inconveniently high temperatures to regenerate, which probably result in unwanted emissions requiring mitigation as well as too much energy use. Regular lime (without the soda) avoids the emissions but takes a month to absorb the carbon dioxide. Alkali-metal oxides, hydroxides, and peroxides like those discussed in the article are extremely compact and fast-acting but even more difficult to regenerate. Bioreactors with spirulina or chlorella have been tested successfully but require hundreds of kilograms of algae per person and are finicky, being prone to infection. I think it's eminently possible at a technical level, but at a political level, basically you can only do this kind of experimentation if you live in China.

An actually physically feasible thing you can do is to whitewash some walls. You need to apply about 7kg of whitewash per person per week, so you are going to need a lot of walls, on the order of 400 square meters of wall per person, because the whitewash is regular lime, not soda lime. (If you're daring enough to dope your whitewash with lye, maybe you can get by with less wall area, but you still need to keep applying the whitewash at 7kg per person per week.) You can make them out of plywood, sheetrock, sheet metal, old sheets, whatever whitewash will stick to. After a few months you will need to start throwing out 14kg of fully cured whitewash per person per week, or calcining it to make fresh whitewash. Try to get whitewash with as little chalk in it as possible.

At this small scale, dozens of kilograms per week, you might be able to calcine the used whitewash in a pottery kiln on your patio. Beware that electric kilns generally do not handle reducing atmospheres well. I'm not sure if carbon dioxide would be too much for them. I think it should be fine, but don't blame me if you ruin your Kanthal.

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