A new air-conditioning system manages without nasty gases

https://www.economist.com/science-and-technology/2021/07/21/a-new-green-air-conditioning-system-manages-without-nasty-gases

by prostoalex • 5 years ago

78 63 5 years ago

economist.com

haspoken• 5 years ago

https://archive.is/y4OwA

KaiserPro3• 5 years ago

You can use propane for the refrigerant. The halflife in the atmosphere is pretty short. Its cheap, non toxic and fairly well understood.

In the EU/UK it also has the advantage of not needing a license to install yourself.

Obviously this new technology is important, but its not here now.

throwaway0a5e• 5 years ago

Rational people turn into tantrum throwing toddlers and absolutely go crazy if you suggest using a flammable hydrocarbon as a refrigerant (never-mind that many refrigerants are already flammable hydrocarbons or nasty in indoor spaces to the point where propane isn't worse).

Animats2• 5 years ago

Before freons, ammonia was used. Getting rid of ammonia refrigerants was considered a big step forward.

KaiserPro3• 5 years ago

to be fair I was a bit sceptical about it when I first put it in. Its pure, rather than having the tell-tale smell. So I was a bit worried about silent leaks.

However as you point out, some other refrigerants are pretty flammable, or otherwise generally a bit shit for your health.

Also, in my unit, there is something like 66grams, although I suspect 10 grams of that was bled off to purge the lines of air. So if there was a slow leak, its unlikely to persist for long, or cause an explosion.

userbinator10• 5 years ago

People remember things like this: https://en.wikipedia.org/wiki/Cocoanut_Grove_fire

edit: please READ the article before you think of downvoting.

s0rce2• 5 years ago

They sell them in appliance stores now, most people wouldn't even know, it's called R290. My fridge used it, sadly it died and was replaced with a conventional refrigerant model.

mannykannot• 5 years ago

Not to mention that gaseous hydrocarbons are widely used within homes, and not in hermetically-sealed devices either, as would be the case when used in a heat pump.

kube-system• 5 years ago

r1234yf is already in wide use. It a little bit expensive, but it does not pose the global warming concerns of HFCs, doesn't deplete ozone like CFCs, and isn't as flammable as hydrocarbons.

https://en.wikipedia.org/wiki/2%2C3%2C3%2C3-Tetrafluoroprope...

marcus0x62• 5 years ago

R1234YF is ridiculously expensive compared to R134A, like 10 times the price. (For reference - I can buy a 10 pound cylinder of R1234-YF on eBay for $500. A 30 lb cylinder of R134A is $150 - $200.)

It is also takes more expensive equipment and a significantly longer amount of time to charge a R1234-YF system. All around, it is a terrible refrigerant for an end-user.

tdeck• 5 years ago

Here's a guy who recharged an old fridge with propane:

http://www.sparkbangbuzz.com/els/refrig2-el.htm

s0rce2• 5 years ago

My old fridge used propane from the manufacturer, sadly it only lasted a few years and repair was more expensive than another one. The new one uses a more conventional refrigerant.

userbinator10• 5 years ago

Note the buildup of frost on the return tube all the way to the pump.

That's a clear sign that you've massively overcharged it! I agree with his position about environmentalists, but I think he should at least learn a bit more about the science first. YouTube can help: https://www.youtube.com/watch?v=lLauVofEDzY

(All the refrigerant should boil off in the evaporator, and the return out of the cabinet should contain only room-temperature vapor. Frosting all the way back to the compressor wastes power cooling what doesn't need to be cooled, and can damage the compressor with liquid refrigerant.)

throw0101a2• 5 years ago

You can use propane for the refrigerant.

Used in medical/scientific freezers that go down to -80C:

* https://www.thermofisher.com/ca/en/home/life-science/lab-equ...

A combination of R290 (propane) and R170 (ethane) + R290 mix.

throwawayboise• 5 years ago

A mix of propane and iso-butane can be used (perhaps illegally, depending on where you are) as a replacement for old R12 refrigerant.

jeroenhd• 5 years ago

Most portable air conditioners I've seen use "R290" (propane) as a coolant, both from expensive brands and budget brands. I'd say propane is very popular in that industry, it's not just an option.

Of course, there are some risks to using propane (which is why these devices come with warnings not to store them in small rooms) but I suspect many people will already be using propane cooling somewhere without even knowing.

matmatmatmat• 5 years ago

Wish they had mentioned the efficiency and how it compares to existing options. Anyone know?

Animats2• 5 years ago

No idea. Nitinol heat engines are available in toy-size.[1] There used to be interest in shape-memory alloys as robot actuators, but they're slow and need too much power. It takes too much heat to generate mechanical motion.

Does that mean it has high heat pumping capability, since refrigeration is the inverse of a heat engine? I don't know.

[1] https://www.imagesco.com/articles/nitinol/09.html

laurencerowe• 5 years ago

Tony Ennis, Exergyn’s chairman, reckons this method of cooling is not only more environmentally friendly than an HFC set-up, but will also be less expensive to buy and 30-40% cheaper to run.

Not absolutely clear, but the cheaper running cost implies it uses less electricity than existing options.

Waterluvian• 5 years ago

Say there’s a hypothetical AC that works very well and requires no environmentally problematic materials and lasts forever,

Does the simple act of moving heat from inside to outside do any measurable, meaningful harm to nature?

throw0101a2• 5 years ago

Does the simple act of moving heat from inside to outside do any measurable, meaningful harm to nature?

It would still take energy to run. How is/would that energy produced?

Cthulhu_• 5 years ago

Does the simple act of moving heat from inside to outside do any measurable, meaningful harm to nature?

No, the heat moved is trivial compared to the heat coming in from the sun. That said, urban design (concrete, asphalt, etc) that absorbs a lot of extra heat will have a noticeable effect, definitely on a local level. Cities with a lot of green are a few degrees cooler as well, in part because of shade (the heat is captured higher up), in part because of evaporation.

BayAreaEscapee• 5 years ago

No air conditioner is going to be 100% efficient. You're still going to consume a fraction of the heat energy being transferred from indoors to outdoors. Unless your home is powered by 100% green energy, you're still indirectly adding carbon to the atmosphere.

Scipio_Afri• 5 years ago

Even if its 100% green energy - which don't get me wrong is orders of magnitude better for warming of the planet - it still contributes to warming of the earth. You're taking some wavelengths of light that would normally be absorbed by say plant matter (thus using that energy to pull CO2 out of the atmosphere) over an area and/or some wavelengths simply reflected out to space without being absorbed by the solar panels (which definitely are designed to absorb as many wavelengths as possible). Then energy conversion from DC to AC and to transmissions lines to where its used all have losses which is energy dissipated in heat form. So the conversion process there can cause heating as well.

Certainly better than combustion which creates heat AND creates gasses which trap that and other radiation as heat.

stickfigure• 5 years ago

By doing work you're contributing, in a minute but measureable amount, to the heat death of the universe in about 10^100 years.

maxerickson• 5 years ago

That seems more like a philosophical opinion than a fact.

For instance, I challenge you to prevent the heat death of the universe.

MrStonedOne• 5 years ago

rubber band fridge: https://www.youtube.com/watch?v=lfmrvxB154w

same concept, less refined.

b0rsuk• 5 years ago

The Revenge of the Circulating Fan

https://www.lowtechmagazine.com/2014/09/circulating-fans-air...

mlwiese• 5 years ago

You can use CO2 as a refrigerant. Non flammable and enables heat pumps to be practical at lower temperatures. Lots of products on the market. See https://r744.com

tgsovlerkhgsel3• 5 years ago

I assume using it results in a less efficient system though, right?

namibj• 5 years ago

Runs at high pressure, can be quite efficient though, iirc.

GuB-42• 5 years ago

I don't know about efficiency but the pressure is much higher, making the system much more expensive.

kensai• 5 years ago

A similar amazing technology has been recently shown at a Fraunhofer Institute in Germany. And the magnetocaloric approach sounds even more promising!

https://www.ipm.fraunhofer.de/en/press-publications/press-re...

https://www.youtube.com/watch?v=6tKtc0cHrUg

TomatoDash• 5 years ago

Both the Economist's text and the Fraunhofer press release focus mostly on the benefit of not using certain refrigerants. But for in home AC use noise reduction might be a much stronger selling point. Especially in Europe where it is common with so called portable indoor AC units that put the noisy compressor inside the room you want to cool down.

nanomonkey• 5 years ago

Stirling engines can be run in reverse to act as a heat pump.

In fact, I have a two 25 liter coolers that utilize Stirling engines, they run silently and cycle between using 5 and 33 watts, averaging about 11 watts once the components the contents have settled on the 4 C set point.

Curious if anyone has looked into utilizing larger ones for cooling buildings.

tgsovlerkhgsel3• 5 years ago

Wikipedia: "At typical refrigeration temperatures, Stirling coolers are generally not economically competitive with the less expensive mainstream Rankine cooling systems, because they are less energy-efficient."

nippoo• 5 years ago

R32 (difluoromethane) or R290 (propane) both have ozone depletion potential (ODP) of 0 and are in common use with new refrigeration units.

This technology looks interesting due to its simplicity and could potentially be cheaper than existing phase-change systems which are prone to leaking and need maintenance. But refrigerants which don't directly harm the ozone layer are already here...

jjeaff2• 5 years ago

And propane has close enough properties to r21 that it can be used as a drop in replacement. Of course, HVAC guys flip their lid at the thought of it. Because they want to get that sweet markup on the extremely expensive, discontinued r21 or a pricey alternative.

A new air-conditioning system manages without nasty gases

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