[HN Gopher] A new air-conditioning system manages without nasty ...
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A new air-conditioning system manages without nasty gases
Author : prostoalex
Score : 58 points
Date : 2021-07-23 20:18 UTC (2 days ago)
(HTM) web link (www.economist.com)
(TXT) w3m dump (www.economist.com)
| matmatmatmat wrote:
| Wish they had mentioned the efficiency and how it compares to
| existing options. Anyone know?
| Animats wrote:
| 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 wrote:
| > 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.
| mlwiese wrote:
| 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
| tgsovlerkhgsel wrote:
| I assume using it results in a less efficient system though,
| right?
| GuB-42 wrote:
| I don't know about efficiency but the pressure is much
| higher, making the system much more expensive.
| namibj wrote:
| Runs at high pressure, can be quite efficient though, iirc.
| kensai wrote:
| 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
| nanomonkey wrote:
| 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.
| tgsovlerkhgsel wrote:
| 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."
| haspoken wrote:
| https://archive.is/y4OwA
| Waterluvian wrote:
| 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?
| stickfigure wrote:
| By doing work you're contributing, in a minute but measureable
| amount, to the heat death of the universe in about 10^100
| years.
| throw0101a wrote:
| > _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_ wrote:
| > 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 wrote:
| 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 wrote:
| 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.
| KaiserPro wrote:
| 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.
| kube-system wrote:
| 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 wrote:
| 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.
| userbinator wrote:
| 152a is another cheap alternative, and can even be bought
| without any license, at least in the US - it's the gas in
| "gas dusters".
|
| While 134a operates at a higher pressure than 12, 152a is a
| close match and works well as a replacement for old R12
| systems.
| throwaway0a5e wrote:
| 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).
| KaiserPro wrote:
| 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.
| Gibbon1 wrote:
| Evaporated I think 66grams of propane is about 1cuft of
| gas. which doesn't seem to me to be that scary. A perfect
| air to fuel ratio would require mixing 16 cuft of air. And
| flammable range is narrow. Comparison, your kitchen is
| probably 1000 cuft.
|
| So I think you are right, slow leak isn't much of a hazard.
| tgsovlerkhgsel wrote:
| 66 grams of propane are 35.1 liters. The lower explosive
| limit is 2.1%. So if the content leaks out slowly enough to
| mix with at least 2 cubic meters of air, it's going to be
| fine. However, if it leaks a bit more quickly, I can
| totally see it creating an explosive mixture in the space
| behind your fridge (or inside), to be ignited when the
| compressor/light switch trigger next.
|
| I can see why people aren't super happy with the prospect.
| A stoichiometric mixture forming inside your fridge and
| blowing up when you open it would definitely ruin your day.
| ashtonkem wrote:
| A typical natural gas range probably releases more than 66g
| of unburnt hydrocarbons into your home.
| userbinator wrote:
| Natural gas is basically methane, which is around
| 16g/mol. 1mol of gas at STP is 22.4L, so 66g of methane
| is around 90L.
|
| A typical gas range has a flow rate of a few cubic meters
| per hour, or a few liters per minute. So just to get 66g
| of unburnt gas released, you'd need to leave a burner un-
| ignited for most of an hour, or considerably longer if it
| was burning.
| Animats wrote:
| Before freons, ammonia was used. Getting rid of ammonia
| refrigerants was considered a big step forward.
| cartoonworld wrote:
| In large commercial applications ammonia is still commonly
| used.
|
| Getting this crazy crap out of our homes and stuff is
| indeed a big step forward, though
| mannykannot wrote:
| 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.
| epistasis wrote:
| What, you mean this methane spewing stove that causes
| really bad air quality, and is no more responsive than an
| induction stove and far less powerful than an induction
| stove?
|
| "Cooking with gas" is great marketing, but not so great in
| reality unless it's an outdoor wok.
| userbinator wrote:
| People remember things like this:
| https://en.wikipedia.org/wiki/Cocoanut_Grove_fire
|
| edit: please READ the article before you think of downvoting.
| ashtonkem wrote:
| ... which had absolutely nothing to do with refrigerants.
| userbinator wrote:
| I know the article is lengthy, but did you even try to
| search for refrigerant or freon in it?
|
| _The air-conditioning also used flammable gas, because
| Freon was in short supply_
| [deleted]
| ashtonkem wrote:
| Which wasn't determined to be a source or contributor to
| the fire.
|
| > The Boston Fire Department investigated possible causes
| of ignition, the rapid spread of the fire and the
| catastrophic loss of life. Its report reached no
| conclusion as to the initial cause of ignition, but
| attributed the rapid, gaseous spread of the fire to a
| buildup of carbon monoxide gas due to oxygen-deprived
| combustion in the enclosed space above the false ceiling
| of the Melody Lounge. The gas exuded from enclosed spaces
| as its temperature rose and ignited rapidly as it mixed
| with oxygen above the entryway, up the stairway to the
| main floor and along ceilings. The fire accelerated as
| the stairway created a thermal draft, and the high-
| temperature gas fire ignited pyroxylin (leatherette) wall
| and ceiling covering in the foyer, which in turn exuded
| flammable gas.
|
| Yes, they used flammable gas in the AC, no that was not
| determined to be a source or contributing factor to the
| fire.
| nzgrover wrote:
| This one did:
| https://en.wikipedia.org/wiki/Tamahere_coolstore_fire
| [deleted]
| s0rce wrote:
| 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.
| blibble wrote:
| they seem concerned about labeling it as propane
|
| the one I bought had "R290 ECO-FRIENDLY REFRIGERANT" all
| over the box, with the chemical name nowhere to be found
|
| (of course I immediately wanted to know what R290 was and
| googled it...)
| tdeck wrote:
| Here's a guy who recharged an old fridge with propane:
|
| http://www.sparkbangbuzz.com/els/refrig2-el.htm
| s0rce wrote:
| 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.
| jeroenhd wrote:
| 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.
| throw0101a wrote:
| > _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 wrote:
| A mix of propane and iso-butane can be used (perhaps
| illegally, depending on where you are) as a replacement for
| old R12 refrigerant.
| frosted-flakes wrote:
| Confusingly labelled as R12a and sold under brands such as
| RedTek. This is the only type of refrigerant available to
| unlicensed consumers in Canada, and it is widely available
| in stores everywhere. R134a is not sold in stores here. The
| US is the opposite--R134a is available to DIYers
| everywhere, but R12a is banned because it is flammable.
| nippoo wrote:
| 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...
| MrStonedOne wrote:
| rubber band fridge: https://www.youtube.com/watch?v=lfmrvxB154w
|
| same concept, less refined.
| b0rsuk wrote:
| The Revenge of the Circulating Fan
|
| https://www.lowtechmagazine.com/2014/09/circulating-fans-air...
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