Study: Climate Change Friendly Air Conditioners Could Convert CO2 to Petroleum

Air Conditioners
Air Conditioners on apartment walls. Jason Kuffer from East Harlem, USA [CC BY-SA 2.0], via Wikimedia Commons

Guest essay by Eric Worrall

A new paper claims the vast artificial airflow created by the world’s air conditioners could be harnessed to suck CO2 out of the atmosphere, by adding or retrofitting a CO2 absorber and converter to air conditioners. But critics see a few problems with the concept.

Could Air-Conditioning Fix Climate Change?

Researchers propose a carbon-neutral “synthetic oil well” on every rooftop

By Richard Conniff on April 30, 2019

paper published Tuesday in the Nature Communications proposes a partial remedy:  Heating, ventilation and air conditioning (or HVAC) systems move a lot of air. They can replace the entire air volume in an office building five or 10 times an hour.  Machines that capture carbon dioxide from the atmosphere—a developing fix for climate change—also depend on moving large volumes of air.  So why not save energy by tacking the carbon capture machine onto the air conditioner?

This futuristic proposal, from a team led by chemical engineer Roland Dittmeyer at Germany’s Karlsruhe Institute of Technology, goes even further. The researchers imagine a system of modular components, powered by renewable energy, that would not just extract carbon dioxide and water from the air. It would also convert them into hydrogen, and then use a multistep chemical process to transform that hydrogen into liquid hydrocarbon fuels.  The result: “Personalized, localized and distributed, synthetic oil wells” in buildings or neighborhoods, the authors write. “The envisioned model of ‘crowd oil’ from solar refineries, akin to ‘crowd electricity’ from solar panels,” would enable people “to take control and collectively manage global warming and climate change, rather than depending on the fossil power industrial behemoths.”

This is a wonderful concept—it made my day,” says David Keith, a Harvard professor of applied physics and public policy, who was not involved in the new paper.  He suggests that the best use for the resulting fuels would be to “help solve two of our biggest energy challenges”: providing a carbon-neutral fuel to fill the gaps left by intermittent renewables such as wind and solar power, and providing fuel for “the hard-to-electrify parts of transportation and industry,” such as airplanes, large trucks and steel- or cement-making. Keith is already targeting some of these markets through Carbon Engineering, a company he founded focused on direct air capture of carbon dioxide for large-scale liquid fuel production. But he says he is “deeply skeptical” about doing it on a distributed building or neighborhood basis. “Economies of scale can’t be wished away. There’s a reason we have huge wind turbines,” he says—and a reason we do not have backyard all-in-one pulp-and-paper mills for disposing of our yard wastes. He believes it is simply “faster and cheaper” to take carbon dioxide from the air and turn it into fuel “by doing it an appropriate scale.”

Read more:

The abstract of the paper;

Crowd oil not crude oil
Roland DittmeyerMichael KlumppPaul Kant & Geoffrey Ozin 
Nature Communicationsvolume 10, Article number: 1818 (2019)

Climate change represents an existential, global threat to humanity, yet its delocalized nature complicates climate action. Here, the authors propose retrofitting air conditioning units as integrated, scalable, and renewable-powered devices capable of decentralized CO2 conversion and energy democratization.

Read more:

Turning every high-rise residential or office building air conditioner into a miniature flammable petroleum refinery which vents electrolysis oxygen. What could possibly go wrong?

Update (EW): Added more detail to the final paragraph

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April 30, 2019 5:08 pm

…….D’OH !

Carbon Bigfoot
Reply to  Marcus
May 1, 2019 4:29 am

There are too many intellectual morons with time on their hands that sit around in a circle and conjure up implausible thermodynamic wet dreams.

Reply to  Carbon Bigfoot
May 1, 2019 8:11 am

Those jerks in their circle!

Big T
Reply to  beng135
May 1, 2019 9:49 am

I suppose these would only cost a few dollars?

April 30, 2019 5:24 pm

“Turning every high-rise residential or office building air conditioner into a flammable petroleum refinery. What could possibly go wrong?”

You mean like a storing a fully charged 100 kwh lithium battery in your garage?

Reply to  co2isnotevil
May 1, 2019 1:16 am

Or 1000kWh of gasoline in your tank.

Kaiser Derden
Reply to  Magnus
May 1, 2019 3:21 am

ahhh … you mispelled it … its safely store 1000kWh of gasoline …

Curious George
April 30, 2019 5:34 pm

Down with the Second Law of Thermodynamics!

Reply to  Curious George
April 30, 2019 6:08 pm

… and the law of conservation of energy.

Yes Trump could just withdraw the USA from the laws of physics and solve the whole problem in one squiggle of his fat tip marker pen.

Reply to  Greg
May 1, 2019 12:03 pm

Didn’t work for Obama. But who knows, we could keep trying the same thing over and over again and eventually get different results.

Reply to  Curious George
April 30, 2019 6:20 pm

It sounds like a perpetual motion machine. Anyway, it involves taking molecules in a low energy state and convert them to other molecules that have greater energy. ie. I can’t get energy by burning CO2 but, if I could convert it to CH4 (methane) I could burn it and get energy. In other words, CH4 contains more energy than CO2.

It takes energy to convert CO2 to fuel. The energy has to come from somewhere.

nw sage
Reply to  commieBob
April 30, 2019 6:54 pm

That has been my question about every CO2 conversion scheme. We burned carbon with oxygen to convert chemical energy into more immediately useful electrical energy. We then used that energy. It is gone! Grew marijuana with it or something else useful! If we want to take apart the CO2 and get carbon and oxygen again the energy to do that has to come from somewhere – a LOT of it!

Bruce Anderson
Reply to  nw sage
May 14, 2019 2:43 pm

The point that all of these studies miss is while it takes energy to take carbon (or anything else, e.g. hydrogen in water) from a fully oxidized state and put in in a partially or fully reduced state, the energy released by oxidizing the carbon again will never equal the energy required to reduce it. NEVER. It’s as close to ‘settled science’ as science ever gets. The second LAW of thermodynamics. You don’t call a hypothesis a law based on computer models.

You learn it in high school chemistry. Delta-S is greater than or equal to zero (and practically, cannot even equal zero). Delta-H is the same magnitude both ways, but Delta-S is always positive.

Reply to  commieBob
April 30, 2019 7:15 pm

When plants convert CO2 into biomass, the Hydrogen comes from water and the added energy comes from the Sun in the production of C6H12O6 + 6 O2 from 6 CO2 + 6 H2O which can then be anaerobically decomposed into 3 CH4 + 3 CO2 . Even biology can only convert half of the carbon atoms in CO2 into methane and this is the most energy efficient conversion possible.

Ian Magness
Reply to  co2isnotevil
April 30, 2019 10:41 pm

…. and then we burn the CH4 to make heat in buildings – a process that releases CO2 – which is what we are trying to reduce in the first place.
Run that past me again – surely I must be missing something? How does this make sense?

Reply to  Ian Magness
May 1, 2019 9:06 am

it creates more jobs for HVAC industry.

it ups the cost of air conditioning, thus discouraging AC and the use of electricity.

it creates more regulatory jobs (ensuring appropriate storage of flammable stuff in residential buildings)

it creates green energy jobs, in that we would need more windmills to produce the extra electricity that it would take to run the ac systems.

(If you want a real answer you need to rephrase to “With respect to efficiency, how does this make sense.”)

John Dilks
Reply to  Ian Magness
May 1, 2019 9:20 am

“We” aren’t trying to reduce CO2. CO2 is our friend, we need more friends.

Reply to  commieBob
May 1, 2019 8:29 am

“Because the system would rely on advanced forms of solar energy”
And those would be?….
I suspect that before any oil is generated by this process they will have to heat the conditioned air to very high temperatures.
…hmm, use large amounts of energy to remove heat from the air column and then even more to heat it back up again to extract even less energy than you used in the process. They obviously learned all the science they know from Wiley Coyote.

Who ties these moron’s shoes?

John Endicott
Reply to  Rocketscientist
May 1, 2019 12:41 pm

They obviously learned all the science they know from Wiley Coyote.

That’s very insulting. You owe Wiley E. Coyote (Super Genius) an apology for comparing him to those dopes.

mike macray
Reply to  Rocketscientist
May 2, 2019 3:46 am

Who ties these moron’s shoes?

Who pays their salaries?

Farmer Ch E retired
Reply to  commieBob
May 2, 2019 5:46 am

“It takes energy to convert CO2 to fuel. The energy has to come from somewhere.”

. . . and someone has to pay for that energy and the carbon capture machine. If costs were calculated for this scheme, I doubt we would have many volunteers installing them. It’s like asking for volunteers to stop buying cheap goods manufactured in coal-powered factories in China in order to reduce their personal carbon footprint. It ain’t going to happen.

Reply to  commieBob
May 2, 2019 7:43 am

If it was such a great and POSSIBLE idea then do it at the power plants where there is the greatest quantity and concentration of CO2.

Snake Oil

David S
Reply to  Curious George
April 30, 2019 6:41 pm

Yes let’s ask congress to repeal the 1st and 2nd laws of thermodynamics. AOC could write the bill.
That should be entertaining.

Reply to  David S
April 30, 2019 7:05 pm

“Well, thermodynamics is like … thermal. Whatever. “

Rich Davis
Reply to  David S
April 30, 2019 7:14 pm

yeah, why not? We’re getting rid of the 1st and 2nd Amendments to the Constitution, why not the 1st and 2nd laws of thermodynamics?

Paul S
Reply to  Rich Davis
May 1, 2019 7:11 am

After all, Thermodynamics is a living document

E J Zuiderwijk
Reply to  Curious George
April 30, 2019 10:43 pm

Absolutely! It appears that contemporary education in physics and chemistry is not what it used to be.

What a howler.

mike macray
Reply to  Curious George
May 2, 2019 3:42 am

Curious George:
..”Down with the Second Law of Thermodynamics!”

Repeal and replace!
Problem solved

David Dibbell
April 30, 2019 5:37 pm

If one thinks there is a way to convert CO2 to fuel economically, why go looking for your source material at such low concentrations? Why not get it from a coal power plant stack? It’s sad to see this loony stuff get any exposure at all.

Reply to  David Dibbell
April 30, 2019 6:32 pm

Reminds me a few years back when we were all going to produce diamonds with special catalytic converter attached to our “hopefully” electric cars.

Reply to  David Dibbell
May 1, 2019 6:49 am

Bolt one to the mouths of our politicians!

April 30, 2019 5:37 pm

“The researchers imagine a system of modular components, powered by renewable energy, that would not just extract carbon dioxide and water from the air. It would also convert them into hydrogen, and then use a multistep chemical process to transform that hydrogen into liquid hydrocarbon fuels.”

Low density energy to make high density energy by using people’s air conditioners. Can anything go right? Not likely.

Paving the world’s surface with low density inefficient solar/wind energy producing machines what find it near impossible to barely supply base load electricity with rolling brownouts when energy demand is high; and these characters want to increase the demand?

“The result: “Personalized, localized and distributed, synthetic oil wells” in buildings or neighborhoods”

This claim smacks of a return to serfdom where citizens raised sustenance and built structure for the upper classes, but were left with scraps and hovels for themselves.

Michael S. Kelly LS BSA, Ret
Reply to  ATheoK
April 30, 2019 8:07 pm

It also hearkens back to the Great Leap Forward in China, when Chairman Mao declared that China would increase steel production via “mass fervor.” Every farm was to have a small steel production furnace in the backyard, and this would catapult China to a steel output greater than the United States by 1967. Farmers threw everything into it – plows, shovels, machinery, anything made of metal, and it was all melted down into unusable mixes of “steel” while the farmers left their crops to rot. The steel was unusable, and the drop in farm output caused widespread famine. So this sounds pretty familiar.

Mr Real
Reply to  ATheoK
April 30, 2019 11:42 pm

Sounds strangely familiar

Tombstone Gabby
Reply to  ATheoK
May 1, 2019 5:29 pm

Remember – from the article – The researchers imagine a system…..


“Imagine” – is even less forceful than “projected” – (man made global warming increases). I can ‘imagine’ these folk ‘winning’ the lottery – by buying every single ticket…..

steve case
April 30, 2019 5:40 pm

And maybe we could harness squirrel cages.

April 30, 2019 5:45 pm

Perhaps these people at Karlsruhe Institute of Technology would be interested in reviving research into the philosopher’s stone too. Research into the philosopher’s stone has lapsed for a while since the 17th. century. Turning CO2 and water into hydrogen and petroleum is a very similar idea to the philosopher’s stone’s alchemical process of turning base metals such as mercury into gold or silver. The philosopher’s stone was called the ‘elixir of life’ and was also useful for rejuvenation and for achieving immortality. This would be a good fit for Gaian philosophy and equally practical.

4 Eyes
Reply to  nicholas tesdorf
April 30, 2019 8:09 pm

These people are looking for grants from ignorant people who control grants.

Steven Mosher
April 30, 2019 5:48 pm

comment image?quality=75&strip=all&w=1900&h=1068

Reply to  Steven Mosher
May 1, 2019 3:17 am


Reply to  Steven Mosher
May 1, 2019 7:09 am

Is that a server farm? Why did you put a picture of a server farm here? Server farms are the only way you get your name on the Internet.

Reply to  Steven Mosher
May 1, 2019 7:19 am

It looks like a bitcoin miner setup one of Mosher pet dribbles. I think he is against them but you can never tell with our English Lit grad who like above often makes no sense.

John Endicott
Reply to  LdB
May 1, 2019 12:43 pm

It’s funny, for an English major he sure does have trouble communicating in English (or any other language).

April 30, 2019 5:49 pm

After 100 years of trying, they’ve finally perfected perpetual motion.

Reply to  MarkW
May 1, 2019 7:20 am

Look on bright side we can get politicians, climate scientists and climate activists to talk into them all day to generate unending supply of hot air.

April 30, 2019 5:51 pm

“They can replace the entire air volume in an office building five or 10 times an hour.”

Wrong by at least an order of magnitude.

mike the morlock
Reply to  MarkW
April 30, 2019 8:15 pm

MarkW April 30, 2019 at 5:51 pm

Not sure if my swamp cooler can move that much air. But it can blast any paper, magazine or empty paper cups off the table in front of it.
Its even funnier if someone is down wind when its turned on. Well thats what the kids say,
considering I tend to be that person!


Reply to  mike the morlock
May 1, 2019 10:35 am

I worked for a summer in a woodshop in Tampa. We used those 24 inch hurricane fans to keep cool.
You could always tell which end of the bench the fan was placed on by which way everyone’s hair was pointing by the end of the day.

April 30, 2019 5:55 pm

So we waste huge amounts of money and energy converting oxidised CO2 into a non oxidised fuel. This will be useful and can burned to make … oh wait, I’m confused. Let’s try again.

April 30, 2019 6:22 pm

What ever is bent with the help of Oxygen, will of course produce CO2.
Hardly a Green solution for a World which is crying out to be “”Saved””.


April 30, 2019 6:39 pm

LEAVE THE CO2 IN THE ATMOSPHERE for the PLANTS, you IDIOTS!!!!! You know, those organisms that consume carbon dioxide in the process of photosynthesis!!! Or are you so self-loathing that you have no regard for humanity?? AARGH!!

Not Chicken Little
April 30, 2019 6:41 pm

Proposing “solutions” to imaginary problems, and forcing the taxpayers to pay you for them – what a great racket!

P.T. Barnum was right – he just under estimated the frequency by at least an order of magnitude…

(There’s a sucker born every minute)

April 30, 2019 6:43 pm

I think the trees that shade my house accomplish the same thing.

April 30, 2019 7:02 pm

On the hour, every hour.

[MODS] could we have more timely treatment of comments. Once an hour means it is virtually impossible to have any kind of exchange/dialogue on WUWT any more.

Reply to  Greg
April 30, 2019 7:18 pm

Mine are showing up immediately.

Reply to  MarkW
May 1, 2019 10:36 am

They were yesterday. Not so much today.

April 30, 2019 7:03 pm

I don’t know if any of you remember the air conditioning system from the move Brazil but I think that it would look exactly like the system they are proposing. BTW the ac system was as large as the apartment.

Tom Johnson
April 30, 2019 7:14 pm

A new paper claims the vast artificial airflow created by the world’s air conditioners could be harnessed to suck CO2 out of the atmosphere, by adding or retrofitting a CO2 absorber and converter to air conditioners.

Yes, and all of the motion created by the worlds automobiles could be harnessed to create a time machine, by adding or retrofitting a time converter to the automobiles.

April 30, 2019 7:25 pm

So crap like this gets media attention and legitimate CC skepticism is either ignored or vilified.

alastair gray
April 30, 2019 7:37 pm

It’s not the eejits who wrote he paper that get me although -see comments on 1st and second law of thermodynamics, and comment on why not use power station exhaust gas. They seem to be a few publications short of a CV but are trying to improve that state affairs by writing twaddle. Its the moron from Harvard who lends his, and his university’s , support and endorses the daft sceeme with the imprimatur of ” Harvard professor of applied physics and public policy”.
“Isn’t Harvard supposed to be a centre of excellence? Mind you with Al Gore and Naomi Orexkes associated with it one weeps for a fine institution reduced to appalling mediocrity.
Maybe also Kahrsruhe should ask why it took 4 of their brightest to write this awful claptrap.
Am I trolling greenies? Shame on me!

April 30, 2019 7:43 pm

Everyone in the office or home should walk around with a facemask with a slaked lime filter cartridge. They can then do Darth Vader impersonations.

Moderately Cross of East Anglia
Reply to  Alex
May 1, 2019 4:26 am

What’s wrong with having buildings with windows that open?

Reply to  Moderately Cross of East Anglia
May 1, 2019 10:37 am

Windows that can open are a lot more expensive. Such windows also leak more air.

Joel O'Bryan
April 30, 2019 8:10 pm

Nature and the biological evolution of 4 billion years of photosynthetic tinkering have already figured out the most efficient method of converting CO2 into simple sugars which can make methane.

So why would we want to use additional electricity to remove the plant food from the air that is the feedstock of the most efficient photon gathering and conversion process probably in the entire universe?

Craig from Oz
April 30, 2019 8:21 pm

Okay, so their core argument centres around the fact that HVAC already shifts large volumes of ‘air’, hence they can take advantage of it by passing the air through a secondary process, because, hey, free air flow.

Grud. Are these people even allowed access to sharp knifes?

Restrict the air flow in any way and you either accept the result or you return the air flow to the original value by increasing the fans. More fans = higher running costs.

This is before the costs of the magical Lead into Gold add ons. Simply by restricting air flow they are increasing operating costs. This is basic level stuff. Anyone who cannot grasp this concept probably needs constant adult supervision.

Dave O.
April 30, 2019 8:21 pm

Develop a working prototype so all of us can evaluate it.

High Treason
April 30, 2019 10:14 pm

Look in the sky!
There is a pie!
I suspect some people out there are the equivalent of dung beetles-they will swallow every scrap of BS served up to them. This is total BS. Where will the energy come from?

April 30, 2019 10:56 pm

Perhaps with a Unicorn repeating some mantra near each CO2 absorber-Air-conditioner the process could be more effective … with some diamond as a by-product ?

Mr Real
Reply to  Petit_Barde
April 30, 2019 11:40 pm

Publish or perish, I guess.
Feels like logorrhea on the train tracks, right before the train hits. When the thawing permafrost starts the methane loop/chain reaction, we’re going to need more than air conditioners.
Too bad, the human animal was an interesting development.

Rod Evans
May 1, 2019 12:02 am

Did the Karlsruhe institute, also work with VW on how to reduce tail pipe emissions from their cars…..?

Phil Rae
May 1, 2019 12:11 am

This cr*p is everywhere in the media these days. Just yesterday the BBC were ranting on about a “revolutionary new process” (/Sarc on) for making carbon neutral liquid aviation fuel out of wood chips by heating them up to 600C to produce synthesis gas and then presumably doing some kind of Fischer-Tropsch process to produce hydrocarbons. They report all this drivel without realising how stupid it is and, of course, the public is fed this daily diet of fantastical nonsense with no idea about thermodynamics. They are left with the idea that all this is possible and makes good sense if the government just provides funding to help this “research” – sad and increasingly unbelievable!

Sent from my iPhone

May 1, 2019 2:07 am

I take it that this paper was produced under a hidden (sarc tag to test the stupidity of editors and Harvard Professors.

May 1, 2019 2:33 am

We already have a device that uses solar energy to remove co2 from the atmosphere to produce a source of organic climate friendly energy. They are called plants.

Reply to  Chaamjamal
May 1, 2019 10:09 am

There is simply not enough VC startup potential and government grant program admin potential for political insiders with plants, unless you mean marijuana.

mike macray
Reply to  Chaamjamal
May 2, 2019 3:48 am


Robert of Ottawa
May 1, 2019 3:31 am

It is criminal to suck life-giving CO2 from the atmosphere, just like it is criminal to burn food in cars.

Michael Ozanne
May 1, 2019 3:38 am

comment image

Bruce Cobb
May 1, 2019 3:50 am

My idea is better: Use car-mounted wind turbines using the already-existing airflow past the car to charge an electric car’s batteries, allowing it an infinite range. Free energy. Genius. Now, where’s my grant?

May 1, 2019 3:58 am

After this is accomplished can we start on changing rust back to iron.

May 1, 2019 6:02 am

I’m still hurting financially from the last green new deal and lobbyist ploy that said changing the coolant type in AC units would cost pennies when in fact the chemical pressure differences had huge impacts from the design, mfg, service maintenance, and end user customer cost. As a saver, I will not soon forget that green smack down.

May 1, 2019 9:02 am

Suggestions like this are why we must get beyond temperatures and economics and focus on Carbon Dioxide as the Basis of All Life (on Land–some sea life comes from abiotic oil at the sea bottom).

This idea and so many others are monstrous because people would go hungry and endangered species have nothing to eat.

May 1, 2019 10:49 am

Another solution built around Unicorn farts.

May 1, 2019 12:01 pm

On the other hand, if it works, I could become a member of OPEC.

May 1, 2019 4:01 pm

‘a developing fix for climate change’

What is it? How can you ‘fix’ it when we don’t even know what it is?

Let’s just declare it fixed and move on.

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