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Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

news.ycombinator.com

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Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#141

Post by jaakl »

danans wrote: post #107
abhv wrote: post #49

Quick math: Density of air at sea level: 1225 g/m^3 C02: 0.0383% by volume (383 ppmv) corresponds to 0.0582% by weight. Ergo, 1m^3 of air has 0.713 g of C02 in it. Ergo pulling 1 metric ton (10^6 grams) of C02 per day requires processing AT LEAST : 10^6/ .713 = 1.4m m^3 of air per day or 16 m^3 of air per second! (That would assume 100% capture) I was skeptical that 1 cooling tower generates this much flow, but the e…

> Ergo pulling 1 metric ton (10^6 grams) of C02 per day The CO2 footprint per capita in the United States is 15 metric tons [1], so at 300M population, that's 4.5e9 metric tons of CO2 per year. At 1 metric ton CO2 removed per day per tower, we would need 4.5e9/365 = 12.3M such cooling towers. Even if the efficiency increased 2 orders of magnitude it is still not enough, and I doubt there is a need for even 123,000 co…

Most of your yearly 15 tons is emitted via specific exhaust pipes, where capture part is quite easy problem, even without these cooling towers. The big problem is what to do with all of it: there is no commercial use/market, especially if you want that to be climate friendly, ie not dumped to atmosphere quite soon anyway. We'd need to think of it as toxic waste, similar to nuclear one, to be stored forever underground, but can we (as civilization) afford it?

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#144

Post by dojomouse »

jsantos511 wrote: post #119
elihu wrote: post #95

Earlier quoted context omitted.

> The use of CO2 that is sourced from the atmosphere is better from an environmental perspective than the use of CO2 sourced from offshoots of an ethanol plant. I thought that most ethanol is made from fermentation of corn, sugar, or whatever, and the carbon in that process came from the atmosphere originally. So, environmentally whether you make CO2 as a byproduct of ethanol production from CO2-absorbing crops or yo…

Great question - the carbon cycle definitely needs to be thought about in this scenario. The missing link here is in total embodied emissions that go into production of corn. There's data available to help piece together a comparison [1, 2], and I'd love to work through this and get back to you with what I find. At a high-level, CO2 production from corn isn't net-neutral because the production of a corn, and then eth…

I’d argue another consideration is the land occupied by the corn - it’s the real constrained resource, not the corn growing on it, and were the demand for corn displaced by something else (like direct air co2 capture) then that same land could sequester carbon far more effectively with e.g. trees.

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#145

Post by ficklepickle »

ip26 wrote: post #108
monopoledance wrote: post #99

Earlier quoted context omitted.

I don't think this is the complete picture. In an intact old forest, a lot of bio-matter doesn't decompose in time, but rather gets buried in the anaerobic zone. In a healthy forest the first few centimeter soil are so biologically active just about 30cm down there is very little oxygen left to house much life. That's also why murder victims don't decompose very fast, when the murderer buried them deep in forest soil…

I think it's pretty easy to see, though, that restoring the world's forests to their condition circa 1700 will not get us to 1700 CO2 levels, as we have added some 1.5T tons of fossil carbon to the mix since then.

And a few billion humans, the cause of this mess. It brings me peace to know the world will be fine without us.

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#146

Post by Fiahil »

colonelcanoe wrote: post #61
Fiahil wrote: post #25

How does this compare to the most ancient carbon capture tech: Trees ? I know this sounds boring, but a single $M would allow to plant as much trees and they will capture carbon from the atmosphere, without any maintenance, for decades.

While this does not answer your question, which I find interesting, it seems pretty sensible that you'd want to explore this option even if you are planting lots of trees. Doubly so if it's viable as a business venture, since that's a strong signal that it's cost effective. As jsantos511 said many times, we need more shots on goal!

We see a lot of companies "planting trees " or "offsetting their carbon footprint" in their marketing material. However, they're not -actually- doing anything. They're just giving money to someone else that will "plant trees".

If I want to go ahead, and plant trees, there's no way for me, as an individual, to claim a bit of that money.

I think that's an issue.

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#148

Post by hannob »

So if I understand this correctly you are adding this tech to existing cooling towers?

I don't see this answered on the page, but: what cooling towers do you have in mind? I don't have any statistics at hand, but my guess would be most cooling towers are coal power plants and other fossil fuel infrastructure. This seems problematic as you're creating an incentive to keep fossil fuel infrastructure.

Also industrial heat and heat in general is in itself something that needs to be decarbonized and one of the best options here is to re-use "waste heat". So ideally even if you have non-fossil processes with cooling towers you'll likely want to change that.

(Also from what I'm aware of carbon capture itself is something that needs a lot of heat and existing projects tend to want to use waste heat.)

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#149

Post by MayeulC »

How do cooling towers compare with clean rooms and datacenters, which both have huge ventilation mechanisms?

I guess it probably makes sense to focus on cooling towers first, as there are more of these ? That said, I think some datacenter providers (scaleway?) strive to reach carbon-neutrality.

Re: Launch HN: Noya (YC W21) – Direct air capture of CO2 using cooling towers

#150

Post by luplex »

tekstar wrote: post #65
Fiahil wrote: post #25

How does this compare to the most ancient carbon capture tech: Trees ? I know this sounds boring, but a single $M would allow to plant as much trees and they will capture carbon from the atmosphere, without any maintenance, for decades.

Trees capture co2 into the biosphere, and when they do so it is temporary (~100 years by the time they've decomposed and released it back in to the atmosphere). Still, planting trees helps hold more co2 from the atmosphere and needs to be part of the solution. Especially if we can re-green areas that are currently barren, like deserts. Proper sequestering, which I agree doesn't really exist yet, is to capture co2 bac…

Building and sustaining a forest on the other hand does bind carbon, because there are always new trees to take up the carbon from the dead ones.

It just takes land.

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