New tech can make air-conditioning less harmful to the planet | Hacker News Reader

New tech can make air-conditioning less harmful to the planet

economist.com

40 pointslxm87 comments

AC is not harmful to the planet, carbon-based sources of energy are.

The ideological framing of the degrowth movement is all around us.

The energy source for AC is a big issue but the refrigerant gas in most AC units cause issues for the ozone and for global climate change.

Is this still true in 2024? AFIK, modern ( everything after 2010) ACs, pumps and refrigerator use ozone neutral gas like HFC.

It is still true, most common refrigerants still have quite high GWP [1]. Not as bad as in the 70's, but the transition to neutral gasses is not ready yet. And then there is also all the old installed systems still running.

1. https://en.wikipedia.org/wiki/Refrigerant#Common_refrigerant...

It says right in the table that propane only has 3.3 times the potential of CO₂. That's in fact quite low for the use.

HFCs are amongst the most damaging climate gases.

It's a very unfortunate outcome of phasing out CFCs that they have in many instances been replaced by powerful greenhouse gases. HFCs are slowly phased out as well, but there are still a lot of harmful gases out there.

The typically used R32 does not cause any ozone issues. It is a climate gas, but only if it escapes from the pipes which it doesn‘t if properly installed.

When we are actively warming the environment around us. Isn't that bad for our planet in some way?

Edit:// serious question. Maybe it doesn't matter, I don't know.

Not really. The Sun radiates about 1000W/m^2 of energy at Earth distances. AC won't hold a candle to that. That's why global warming conversations focus on greenhouses gases that trap the Sun's energy, not industrial processes that release heat.

Common refrigerants are also potent greenhouse gases.

The currently used R32 is equivalent to 675x the CO2, so a typical AC unit will have several tonne equivalents of it inside.

That's still an upgrade over its predecessor - R410a, for which the same figure was 2088x.

Heat pumps have the same problem, which is why the recently deployed 33MW district heating heat pump in Helsinki uses CO2 as a refrigerant:

https://www.man-es.com/company/press-releases/press-details/...

It‘s only a problem if the system is not properly installed.

In countries with proper regulation and professional certification this is not an issue.

This is incorrect. Every ounce of that stuff winds up outside eventually. Regulation can only put it off. It's a gas and it has to go somewhere. It's like trying to keep lithium out of landfills.

Please provide a source for this wild claim. Nothing winds up outside, unless it leaks. The gas can and does get reused indefinitely.

Additionally and just to put it in perspective, a typical AC Split-Setup contains around 1kg of R32 which would be equivalent to 677 kg of CO2 _if_ it would leak completely over the 20 years of usage (which it doesn‘t). That‘s equivalent of the CO2 contained in 285 liters of gasoline or about driving 3000 kilometers by car (for cars using 7-8 liters). The expected leakage is 1-3 percent. So that‘s around 30 kilometers by car per year.

In reality, modern ACs are widely used for heating in winter (I am doing this myself) and help to reduce CO2 emissions compared to heating with oil or gas.

edit: I had to edit this twice. Actually the first estimate was correct.

I think the claim that all working fluid put into an AC ends up in the atmosphere is correct for now. Most AC decommissions I heard about involved venting the gas to the atmosphere. Given the high cost of labour everywhere, the zero labour option is the one we must expect.

There's no country AFAIK that sanctions AC equipment owners or anyone else for not disposing properly of all their working fluid at the end of the equipment's lifetime.

In the USA the EPA will fine you for intentionally venting refrigerants to the atmosphere instead of using a refrigerant recovery system for recovery/reuse/disposal.

Pretty good reddit thread about the realities of enforcement: https://www.reddit.com/r/HVAC/comments/ugg89h/people_who_hav...

AC equipment is replaced at the end of its lifetime and picked up by professionals. That's a fact.

And as I pointed out, even if it wouldn't be picked up and leak _completely_, then it would still be 50x less than the average car owner emits in the same timeframe.

Even a single season of heating a house with natural gas already emits more than a complete leak. And who is loosing sleep about that? Maybe those who install an AC for a 20x emission reduction. Not those baselessly claiming that AC are environmentally problematic.

That's illegal. Refrigerant from old A/C units must be collected and disposed of safely, typically through high temperature combustion.

This does release greenhouse gasses, but just normal CO2 not the extremely potent gases originally present.

If it's always reliably collected, why does every old vehicle need its AC unit recharged?

Say 32 oz of refrigerant per car, 675x CO2 equivalence, if your car AC vents all the refrigerant it's like releasing 0.675 tons of CO2.

EPA says an average passenger vehicle releases 5 tons of CO2 per year, so if your AC lasts 10 years it's about 1% of your car's greenhouse gas emissions.

Leaks in a larger building AC would be worse, but I bet all the vibration and getting banged around by potholes makes the car systems a lot more prone to leaks than a stationary unit.

AFAIK Vehicles use flexible rubber pipes because the rigid copper pipes of fixed split ACs would not withstand the vibrations of a car. The downside of these more flexible pipes is that they leak more.

Well I live in the USA and know PLENTY of people who either DiY to save a buck or hired some yahoo who just cuts the lines and did whatever because they were cheap to hire. Money will corrupt any regulatory illusion you have.

Problem is tradesmen want to charge too much.

The tradesmen charge what it costs to run a sustainable business. Unless all the tradesmen in your area are driving Lamborghinis and live in multimillion-dollar homes?

All those regulations make running a business a chore so something has to give.

How about this one? https://en.wikipedia.org/wiki/Einstein_refrigerator

Far as damaging the environment, I'm a contrarian. If people tell me "blah blah we're forcing you to help the environment because we think that's a good thing you should be doing" I'll do the opposite. At least for me they need to be saying "we're going to pass a law that forces you to pollute because our opinion is that is what you should be doing" and it is at that point that I would try to save the environment

This is irrelevant nitpicking.

For decades to come, we won't have 100% clean energy systems everywhere. Even if you power your AC 100% by solar energy, that solar energy won't be used to displace dirty energy elsewhere. Even if you make absolutely sure you have additional solar energy (I don't know how you'd do that), you still have production emissions for the solar panels.

For the forseeable future, if you can do X with less energy than before, that's an improvement.

During calm hot sunny days in the summer (so.. the ones when you need AC the most), we already have surplus of solar energy and serious problems (in some places) what to do with that energy (you have to dump it somewhere).

> you have to dump it somewhere

You don't. Solar panels are more than happy to sit idle. "Excess energy" is an economics problem, not a physics one.

Why sit idle, when they can cool your house by powering the AC?

No reason. It's obviously better to use power than waste it, but it's not a "serious problem" if we don't. It doesn't damage panels. It doesn't stress the grid. It doesn't cause additional emissions.

  > AC is not harmful to the planet

Scientists who studied and rank climate solutions beg to differ.

https://drawdown.org/solutions/refrigerant-management

https://www.youtube.com/watch?v=r6QCPN6KLB8

  > The ideological framing of the degrowth movement is all around us.

If growth (which itself is super vague; growth of what? benefiting whom?) was always a good thing without exception, this complaint would automatically be valid. However we're awash in ideological framing all around us supporting growth, even when growth is—yes Virginia—sometimes detrimental. An ideological counterbalance is desperately needed.

Wouldn't it be weird if growth of everything was always a good think in any scenario, forever? :-\ Maybe we should be just slightly more selective and data-driven than that...

I mean, AC will literally save lives during the increasingly frequent heat waves of the future. AC is not the problem, making sure the energy that powers it is renewable is the problem.

When I move to my next place, I will be installing a solar panel and battery setup sufficient keep the fridge, freezer, and at least one room of the house cool during a heat wave. I don't really care how much it costs.

Sure, in a world with an excess of carbon-free energy, air-conditioning is not harmful to the planet.

In the current reality, where global CO2 emissions continue to rise, yes it is harmful.

The ideological framing of ostriches is all around us.

Except of course they're related: AC uses energy and much of our current energy generation releases carbon.

I don't agree with the degrowth framing at all. The article's intro actually suggests growth is expected and desirable:

> By one estimate, the number of room-cooling ACs could nearly triple between now and 2050.

> These additional units will save lives, make cities liveable and stave off losses in economic productivity.

Your framing is interesting too! Is there a name for discussing technology only in the abstract, ignoring it's connection to the real world? Ideological pedantry?

Is it really a problem? A/C is the dumb easiest thing to solve with renewable energy. We need most A/C when it's day and the sun is shining - much less need when it's dark or cloudy - so consumption almost matches supply of solar power. With some shift at the evening... yeah between some 6pm and 9pm there's still a lot of A/C demand but little to no solar... but this is the lowest hanging fruit for the most minimal amounts of deployed battery storage.

Proper insulation and blasting the AC during solar excess could also be a way to shift the evening demand.

It's only a problem if you're into virtue signalling your green cred by "swearing off air conditioning." There is a ton of low hanging fruit to make cooling more efficient, but people just don't consider it worth the cost (esp considering the opportunity cost vs thinking about almost anything else).

You must live in a deeply hostile world if you think that's how people function.

in the PNW, where a lot of people live in condos, it is not unheard of for HOAs (which basically all condos have) to be against the more efficient air conditioners and to force everyone to use the lowest efficiency inside-house, single or dual hose ones.

Why? Do they make a commission on electricity bills?

I'm not defending the practice, but a lot of HOAs prioritize aesthetics, and retrofitting AC into an existing unit is always going to end up with some kind of visible external machinery that may not harmonize with the existing design.

They don't like how the in-window unit ones look, and don't like how the heat pump external units look and/or don't want to pay to retrofit anything

It's pure aesthetics

This was sadly seen at the Paris Olympics. The village didn't have A/C for so-called environmental reasons, and teams from rich countries dragged portable units in because they (reasonably) did not accept the facilities provided.

It's one of those things that chips away at one's beliefs about the human spirit.

I have heard enough discussions about the Paris Olympics budget that I would consider that A/C was not provided for purely cost reasons.

I do agree myself that A/C is a luxury in most cases (at least in Paris) and many other things that would help the environment should be done before installing that.

This is a common belief but is actually not true. Heating is a necessity, and resistive heating is a very inefficient use of electricity. Heat pumps (using energy to pump heat up a temperature gradient) yields far greater coefficients of performance. Once you have a heat pump, you might as well use it to also cool things down in the summer.

All of France takes a break in August because it's too hot to work. This is only going to get worse with climate change.

Not sure what is "no true" from my comment as you were not specific, but at least to the suggestion of installing heat-pumps in Paris, this will be a much bigger investment than putting "some A/C". I don't think such an investment is more beneficial than (for example) transforming more of the side street parking to bike lanes (which seems to be what is happening).

What is too hot for you? For me an average a mean high temperature of 25 deg Celsius in August is reasonable (source: https://en.wikipedia.org/wiki/Climate_of_Paris).

My point is just that viewing A/C as a luxury leads to more energy use. Yes, I think Europe needs to have a large scale deployment of heat pumps — not only for the climate benefits but also to lower dependency on Russian oil and gas. A/C just comes along for the ride as a thing that makes lives better. New developments like the Olympic village should all have heat pumps.

I would aim for maybe 95-97% of expected weather to be covered.

Apparently the officials relented and put portable units in the bedrooms but not in other areas. Certainly better than only rich countries getting them, but portable units are very inefficient.

(Also, air conditioning can be fully solar powered and in fact has synergistic effects with solar power. And also, making a permanent venue for the Olympics will probably save a lot more resources in the long run, but no one's willing to talk about that.)

Production and consumption might match, but the grid throughput might not.

Passive cooling is coming along too - https://www.youtube.com/watch?v=5zW9_ztTiw8

I really like the idea of passive cooling. Got waste heat? Beam it into space! For free!

Worth noting that "passive cooling" includes things like solar architecture, planting trees, and painting stuff white. You can do surprising amount for free!

I’ve always wondered why heat pumps don’t also have a water line attached. We water cool servers because water is a much better conductor than air, and cold tap is usually colder than outside air. We should be misting tap onto the condenser to make it significantly more efficient and effective at cooling unless I’m missing something.

People do sometimes do this when the circumstances make it feasible. I think the most common version of this is to couple a heat pump to a swimming pool.

Water is the problem. For maximum efficiency you want water to change phase. So a thin layer of water that can evaporate and then extract maximum heat. But in places like CA, South AZ, etc water is scarce and very hard. And since you want it to evaporate it'll leave lime scale behind.

Doesn't mean it isn't done. Hospitals do it in Phoenix. But it's cheaper to just turn up the nearby nuclear plant.

A household uses a non- negligible amount of hot water . Why not to use AC waste heat to pre-heat water and store it in a tank? It probably won’t be hot enough but it would take less energy to heat this warm water to an exact temperature.

Yep, since heat pump water cylinders already exist, this is most obvious next step.

I don't know about US, but it is not a novelty in Europe to use heat pump to prepare hot water and cool the air in a house at the same time. It is just that such designs are much more expensive than simple AC units or air-to-air heat pumps.

At least from my perspective in the US South, this is non-existent. Hot water is heated with resistive heating elements and stored in an (under-) insulated cylinder until needed, accounting for as much as 30% of monthly household energy use.

On-demand systems (gas and electric) are available, but I've not personally been in a house where they were used for other than quality of life (i.e., providing hot water sooner than and until the water can get from the hot water heater).

I have a hydronic heating system in one of my houses, but the electrical service can't provide enough amperage to heat the water up, so it's running on propane. Unless you're willing to spring for an upgrade to a 300A service, usually you'll have some combination of gas for heat or for water heating or for clothes drying. There are electric versions of all of these but you don't normally have enough budget on a 200A service to run them all at the same time because you also have to have budget for a lot of 120VAC kitchen and garage appliances. Houses built 20 years ago also had weird circuit configurations to accommodate separate lighting and power circuits because incandescent bulbs were so inefficient. So you'll have a bunch of lighting circuits that are only pulling an amp or two and then a bunch of appliance circuits that are pulling 10's of amps, but your panel gets filled up because of the unnecessary lighting circuits.

At least, in my experience this is how it goes as a homeowner.

So to get to an on-demand water heater you'll probably have a lot of electrical work that needs to be done(potentially thousands of dollars).

I actually have one of these on-demand hot water systems at home, on gas, as it is much more powerful than an electric one.

What really bothers me is that you always read that they are instant.

The fact that they are instant is not because they don't have storage, it is because they are smaller and thus could be placed much closer to where you need the heat. The problem is that everybody who replaces their hot-water tank puts that 'instant' (I prefer the term on-demand) water heater in that place.

The following is anecdotal, I promise you, I'm not lying, but again, N=1.

We have one that we unlocked to go up to 140F (default 120F for protection).

I live in North Phoenix, bordering the desert, so it gets to around 32F (8 hard freezes last winter).

The capacity of our hot water heater, which is already high, as they really work hard, isn't enough to heat up city water fast enough to get water that is the temperature I like, in winter. Remember that thing needs to heat up water from say 40F to 140F. And while it can do that, it cannot do it at the same pressure as the previous one with a tank. It'll literally reduce pressure if it cannot reach the right temperature, which is really annoying, as that makes the overall temperature go down.

The previous one with the tank was 140F, got refilled with 40F, but could deliver me a much more continuous pressure for much longer.

That exists already, see for example https://coolnsave.com/products/the-original-patented-cool-n-...

Not sure about heat pumps, but in the UK at least there are a couple of companies that specialise in residential water cooled AC, e.g [0]. They use the cold water intake to cool down the compressor which sits inside the property

From a marketing perspective it’s not (as far as I’ve seen) driven by eco credentials, but by not needing planning permission - external AC compressors are not automatically permitted in the UK.

[0] https://www.urbancooling.com/water-cooled-air-conditioning

My clothes washer water use is about 5x in terms of cost compare to electricity.

Water is actually expensive.

> I’ve always wondered why heat pumps don’t also have a water line attached

Some have, some don't. Heat pump is just a vapor compression cycle with a reversing valve. Having water/dry air/moist air/air with water mist/ground/sewage as a heat source or sink is a matter of design and application.

You would need distilled water I assume. Seems like it would introduce complexity for not much gain.

The article didn’t mention them but I’ve been following Montana Technologies and their AirJoule product which also uses MOFs- pretty interesting stuff.

I don't like CO2 emissions being framed as harming the planet. They harm the human economy in the long run.

Is the human economy happening on some other planet I'm not aware of?

CO2 is highly soluble in water - on the order of one unit volume per one unit volume at standard pressure. This has been having devastating effects on ocean life.

CO2 emissions in excess compared to recent time (what seems to be happening) "harm" the natural equilibrium with the result that some (many) things on the planet (humans but not only) can't adapt fast enough.

If you consider the planet just as a big rock orbiting the star, doubt that anything we can do at this point will make a difference.

The framing should be that CO2 emissions destroy the very foundations of our life.

That's exactly what they said about oxygen emissions.

https://en.wikipedia.org/wiki/Great_Oxidation_Event

Ah yes, the majestic human goal of paving the way for whatever comes next.

I suppose Singularitarians have that goal, but I don't think they see pushing the environment away from human beneficial conditions as meaningful progress.

Did you miss the context of this subthread? My point was to agree with one of the (grand)*parent posts that it's still a human-specific matter.

I would rephrase this article as "Dehumidification Is All You Need".

We should also Paint Everything White, Glaze and Cover the Windows, Roman House, and Plant Shade Trees.

If it's too hot, people should really also move to higher latitudes and elevations. No, seriously.

At higher lattitudes and elevations, it often gets too cold; and remediating that takes more energy than A/C.

Perhaps we could simply build double the housing and infrastructure we currently have, and move whole populations north/up and south/down seasonally, to save energy?

Energy is dirt-cheap in the long run (at least at midday), it's energy storage that will be hard. And it just so happens that storing heat is easier than storing cold.

Cold requires an air conditioner instead of just resistive heating, and you can't go down more than 300ish degrees, and realistically you're not using liquid nitrogen let alone liquid helium. Meanwhile, generating heat with resistive heating is literally just the cost of wires.

High latitudes are ideal here, as you lose temperature without losing sunlight. Wind speeds are generally higher too.

If energy production--including its externalities--is too cheap to meter, all this is moot. However, if you're worried about time-shifting renewables, please note that it tends to get hot when the sun is shining. You can observe this in Florida (I kept my house at 73 cheaply with my solar panels), and California, where the duck curve has gone negative.

I think it's also worth noting that people can survive in a colder temperature range with warm clothes and insulation much more easily than hot temperature ranges

Hot environments start becoming potentially lethal at around 40 degrees Celsius

Cold environments are easily survived with decent clothes and coverings down to -40C, and can go much colder with specialized layers and personal warming

Heat is just plain more dangerous for humans

Meanwhile, generating heat with resistive heating is literally just the cost of wires.

And the electric current you need to run through them. Resistive heating has a COP of 1.0 by definition. A modern, cold climate, air source heat pump can achieve a COP of 4.0 or higher at temperatures down to -15C (5F). This means 1/4 the winter heating bill for heat pumps over resistive electric.

Where I live (Canada) the winter heating bills are far higher than the summer cooling bills, despite our humid summers with heat waves reaching 30C+ (86F) for weeks at a time.

An air conditioner (air-air heat pump) has an efficiency of ~450%, resistive heating has ~100%

To be fair I live in the Alps basically and it's not colder on average than the city areas below. In fact we do have a lot more sun hours.

I live were the warm winds from the south hit the Alps. It's arguable warmer and nicer here on average than in most of central Europe. But it never gets as hot as in city areas or even worse areas where people run many ACs

You're making me wish I could move up from the Rhine valley; that sounds pretty nice.

Sure, but who would buy their houses from them?

Oh, great, we'll just move 5 billion people to an elevation nowhere near them, no problem

The most energy efficient solution is what animals have been doing in the desert for millions of years: burrow.

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