6 ms·
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
by condiment 9mo ago
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 one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.
The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.
- yodon 9mo agoDo you have a citation for that 20 years estimate?
- netcraft 9mo agoI was also a bit skeptical, but chatgpt gave a pretty good answer I think: https://chatgpt.com/share/69553e26-ea28-8011-bc17-8658fbea4e04 https://chatgpt.com/share/69553e26-ea28-8011-bc17-8658fbea4e... Buildings with higher people/sqft could already take advantage of indoor co2 scrubbers today.
- idiotsecant 9mo agohttps://en.wikipedia.org/wiki/Carbon_dioxide_in_the_atmosphere_of_Earth#/media/File:Mauna_Loa_CO2_monthly_mean_concentration.svg https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_atmosphe... Just extrapolate.
- marcosdumay 9mo agohttps://gml.noaa.gov/ccgg/trends/ https://gml.noaa.gov/ccgg/trends/ Extending the current exponential for 20 years, we get into the 500ppm region. I don't think that's enough to need scrubbers.
- Ringz 9mo agoIndoor 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.
- marcosdumay 9mo agoStill, 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.
- literalAardvark 9mo agoIt'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.
- deleted 9mo ago[deleted]
- mort96 9mo agoAccording to https://www.co2meter.com/blogs/news/carbon-dioxide-indoor-levels-chart https://www.co2meter.com/blogs/news/carbon-dioxide-indoor-le..., at 1000 ppm people start getting drowsy. Let's assume that a decent indoor environment has 300 ppm more CO2 This means that our threshold for when people start getting drowsy even in decent indoor environments is when atmospheric CO2 reaches 700 ppm. For reference, it is currently around 420 ppm, and pre-industrial levels were 280 ppm. From https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide https://www.climate.gov/news-features/understanding-climate/..., the pessimistic projections suggest that we may reach our 700 ppm threshold by roughly 2070; 45 years from now. (The graphs are hard to read precisely) The 300 ppm offset compared to the outside air is naturally just an arbitrary number, everything up to 1000 ppm (meaning everything up to 580 ppm more than atmospheric levels) is considered "acceptable". That means any increase in CO2 concentration will take an indoor environment which used to be considered "acceptable" and make it cross the threshold into "unacceptable". An indoor environment which would've been at 900 ppm around the industrial revolution (280 ppm) would've crossed the threshold when we surpassed 380 ppm (which was in 1965 according to https://www.statista.com/statistics/1091926/atmospheric-concentration-of-co2-historic/ https://www.statista.com/statistics/1091926/atmospheric-conc...). let's compare the past 20 years. In 2004, the concentration was ~377 ppm. That's 47 ppm lower than what was in 2024. An indoor environment which was "borderline but acceptable" at 955 ppm CO2 in 2004 would've crossed the arbitrary 1000 ppm threshold by now, and therefore would benefit from a CO2 scrubber. The next 20 years will likely have a higher increase than the past 20 years, so there will be a larger range of currently acceptable indoor environments which will cross the 1000 ppm threshold by 2045. TL;DR: It's complicated, 20 years is arbitrary, but as CO2 concentrations increase, indoor quality gets worse so indoor environments which were already bad will become worse. 45 years is a more realistic estimate for when your typical good indoor environment will become unacceptable, but it's a gradient.
- netcraft 9mo ago160F, non toxic, this already sounds like something that could feasibly be used in the home. I would already be interested in installing one. And would absolutely love to see what it would do to school performance. The hard part is capture and disposal.
- adrianN 9mo agoYou can heat definitely heat NaHCO3 to get CO2 and NaOH back. It just takes a lot of energy.
- 29athrowaway 9mo agoMaybe we just need to make cyanobacteria that multiplies faster.
- _yb2s 9mo agoI 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 heat exchanger, which can exchange air with the outdoors without compromising your homes heating and cooling like an open window will do. Noticeable cognitive impairment starts in the 700-1000ppm range, whereas it is very common for homes to reach 2000-3000ppm, especially when in a closed bedroom.
- lokar 9mo agoReally? Wow, I try to keep my place at 500-600, without that much effort.
- malfist 9mo agoI find it extremely unlikely that homes are routinely at 2000-3000 ppm. That is extremely high and would mean multiple people in a small area with no air exchange for a long while. I monitor my indoor co2, but don't take any action because it's extremely rare to be above 700 or 800. I can only remember a handful of times its reached 1k ppm. And my house should be prime candidate for co2, it was built during the era of "seal all air gaps" but before ERV or HRVs. I also use pressurized co2 to inject co2 into a planted aquarium. And my dogs are terrified of open windows so they are rarely open.
- jiehong 9mo agoCould something like this be used to make cement? Imagine capturing CO2 to turn it into cement, used for constructions. Pardon my ignorance, though.
- bobfromhuddle 9mo agoWe don't use CO2 to make cement, we use limestone, and CO2 is the byproduct of heating the limestone to make reactive calcium.
- henearkr 9mo agoDo you know ferrock? It is a kind of cement that uses CO2 to cure.
- henearkr 9mo agoYou can store CO2 and sell it to construction companies (to cure ferrock), to energy storage companies (who like to put the CO2 in huge bubbles nowadays, go figure), or to agricultural corporations (who enrich greenhouses air in CO2 to accelerate growth).
- marcosdumay 9mo ago> The ease of releasing CO2 is the key advantage of the new compound. I have no idea why the journalist that wrote this article choose to highlight the carbon density of the sub-header. It's almost completely irrelevant for carbon capture plants. Another clear benefit is that it's a liquid. Today people mostly use the substances that you called non-reversible in research plants (AFAIK, all plants are research right now). They are perfectly reversible, but that uses a lot of energy.
- nine_k 9mo ago> perfectly reversible, but that uses a lot of energy Looks like a perfect match to a solar plant, which provides basically free energy periodically. All you need is a large enough cistern to hold the liquid during night time.
- marcosdumay 9mo agoYes, it's a great match to solar plants. But you don't need to store the capture medium. You use a bit more energy to make they work faster while the Sun is shining, and stop everything when it's gone. The largest bottleneck is what you do to get rid of the CO2.
- nine_k 9mo agoI mean, you have to recycle the CO2-carrying liquid. You have to store some of it that has CO2 captured but not yet recycled because the Sun is down.
- eisfresser 9mo agoWe use the CO2 to synthesize methanol with the H2 we electrolyze using surplus solar energy. The methanol we burn in winter for heat. Yes, that releases the CO2 again. The goal here is not to save the planet. It is to bring solar energy to winter. My house produces many times the electricity that it needs per year, but most of it is wasted in summer. Efficient conversion is not a factor. If I can get 20% of the energy input back as heat in winter, it is worth it: that is oil or wood I don't have to burn for heat.
- omgJustTest 9mo agocitation for the co2 scrubbers in home need?
- witte 9mo ago[dead]
- DivingForGold 9mo ago"outperform" by only one metric too often fails usefulness. It's a one shot unless you heat the calcium carbonate to 900C, the compound in the article only requires 70C, and has quite a bit of ability to re-process CO2 absorption multiple times. Although solar ovens could reach over 900C, probably too dangerous for residential use.
- bilsbie 9mo agoJust to counter your extreme prediction, if co2 levels halve from here all life on earth goes extinct. https://www.researchgate.net/post/Minimum_necessary_concentration_of_CO2_in_the_atmosphere https://www.researchgate.net/post/Minimum_necessary_concentr...
- loeg 9mo agoThey aren't at risk of halving, though?
- gspr 9mo agoPlease stop trying to hurt every single human being with these derailments. There is no plausible mechanism by which carbondioxide levels would halve. That means you're just trying to derail the discussion by appealing to people's instincts about how fragile atmospheric composition is. Stop.
- bilsbie 9mo agoI can see how you’d think that. We’re all a product of the media we consume. It’s an interesting exercise to try to figure out what the ideal co2 level should be. Why are we fixated on preindustrial levels. I’m very open to thinking 600ppm might be more ideal than the current level. I feel that idea has some support from things like the optimal for many crops/greenhouse plants being 800–1,200 ppm. And that Earth's vegetation has greened since the 1980s due to increased CO2.
- belorn 9mo agoComparing it to sofnolime (the more common used scrubber material for rebreathers), the cost sits around $10 per kg. Cost will be the biggest question. A reusable scrubber need to be cheap enough that the reduce efficiency is worth it.