>It has a 30-year lifetime, with an easy installation process
Normally, any kind of pressure vessel (steam, compressed gas cylinders, etc.) is subject to routine inspection and hydro-testing for re-certification.
What happens if/when it needs to be serviced? Do I need to draw down a crazy level of vacuum before charging it helium (or whatever working fluid)?
>Traditional fixed-output units cycle between on and off multiple times a day, switching between zero and maximum capacity to achieve the right temperature balance. But the new heat pump modulates its output to continuously provide the desired temperature.
New heat pumps / air conditioners already do this with variable speed compressors and fans.
IIRC turbomolecular pumps, which are used for deep vacuum applications, have a large intake area and work by basically spinning a huge array of blades at very high speed to bat the individual gas particles out of the working volume into progressively higher pressure areas, ultimately pumped out by a conventional pump.
The question is: does maintaining this require a very high vacuum to replace/maintain the working fluid. Its one of those scaling problems where you have to spend ten times as much to get to the next ten times less gas in a vessel (or thereabouts) and an absolute complete vacuum is more or less impossible.
Nature really abhors a vacuum.
[1] https://support.sodastream.com/hc/en-ca/articles/44038019714...
I would expect a more relaxed inspection schedule in this instance because there is no significant cyclical loading of the pressure vessel, and since there is no water ingress, internal corrosion should be fine. Vibrations taken as cyclical loading can be swallowed in the bathtub curve, since you get 30000 cycles in the first second, and very little variation of stress at each cycle.
edit:
- appendix 1 if the vessel has non-corosive gas and not been de-pressurized, internal inspection is not required. Internal visual inspection only if re-pressurizing it and last visual inspection is more than 4 years old.
- you seem to be able to replace the water pressure proofing test by an untrasound test under pressure with the nominal gas, but the document describing the procedure ("Guide des bonnes pratiques pour le contrôle par émission acoustique des équipements sous pression") seems to be behind a paywall, so I don't know if it's done at nominal pressure or if you need to open the vessel
Plain steel corrodes, so an inspection that it isn't corroded should be done once in a while. Plain aluminum doesn't corrode, so a visual inspection won't find anything, but the fatigue characteristics means that you need to count cycles and stop using it after some number of cycles. There are many other elements that can be used for pressure vessels (though iron and aluminum are most likely), and you can alloy them in different ways.
Of course there is more than visual inspection, sometimes ultrasound and x-ray inspections are done, each will show different things, and each requires different training to do.
For other pressurized tanks, I believe a line is drawn at 12 kg/cm2 (it depends also on size, those smaller than 25 lt are excluded), those up to that pressure have periodical visual and pressure tests (every 2, 3 or 4 years depending on a number of factors), those above that have additionally those (ultrasound) checks for the integrity every 10 years, but the norms are complex, no idea which specific ones may apply to this thing here.
To refill after maintenance you may also just purge with helium (or another cheaper gas that doesn't impede behavior of the device) then pressurize with helium .
So mostly a non issue. And there is really little safety issues with this kind of constant pressure containers containing non toxic gases just a routine inspection should be enough as they can be made of high quality materials and shielded.
Looks like it's creating a standing pressure wave and then tapping into the colder or hotter part as appropriate?
Based on the diagrams it seems like it would need a radiator or something for larger surface area?
Also curious as to how loud it is.
Source: https://www.pv-magazine.com/2023/01/02/residential-thermo-ac...
Which I just noticed was posted a few hours ago, here: https://news.ycombinator.com/item?id=34233719
It's a really cool application of the ideal gas law: PV = nRT where the sound is really playing with the pressure (P) using sound so various parts of the chamber have different temperatures (T).
“The sound our system produces stays confined inside the core, so you cannot hear it from outside,” said Loyer.
To be even quieter than that is remarkable, IMO.
Even your TNT figure has a distance indication. Pressure decreases with the square of the distance when it dissipates as a sphere. Doubling the distance = -6 dB
¹ 20*log(k)=180 => k=1e9, factor to reach between rest state and max pressure, I think.
"Equium claims that the heat pump system is completely silent, despite the use of a speaker to generate the acoustic wave. The level of noise is reportedly lower than 30 dB – the equivalent of a whisper."
So, not too different from typical heat pumps. Ground-source heat pumps are especially effective.
> level of noise is reportedly lower than 30 dB
If it can provide water hot enough for residential use, and be silent, then it's a huge improvement over existing typical heat pumps. It would no longer need an additional boiler to get the water temperature up.
I think the reason that they haven't seen adoption isn't that they're a scam, but rather because they're more expensive than traditional approaches (not quite sure why, or by what margins). However, since our attempts to replace freon with ever-more-exotic refrigerants seems to inevitably fall face-first into environmental disaster, it's possible that a non-greenhouse-gas approach could be regulated/subsidized into existence, if it's not too much more expensive.
I find interesting that's very silent, and has a nice range of work temperatures. And the "no refrigerants" part too (although it needs some helium, though).
No info about the price.
This invention claims COP 4 for heating water to 80 degrees, that is a huge step up.
For instance it changes the game to replace oil and gas heated radiators, as you can only replace the heat source, not radiators that only work well with 80 deg C water (where COP is very bad for conventional heat pumps)
This may not be suitable for skyscrapers, but it works for 4-5 store apartment blocks.
This is setting off some massive BS alarms in my head. Why is this not violating conservation of energy?
https://en.m.wikipedia.org/wiki/Coefficient_of_performance
(I'm no authority here -- I only bought a heat pump and had the same reaction as you)
The thermo-acoustic ones are using sound waves instead of a compressor, but the same principle.
Producing heat can only be COP=1 if it’s 100% efficient, but you can use the same amount of energy to move three, four, even five times as much heat to or from the outside (moving heat the opposite direction is the way air conditioners work).
Technology connections did a good video on this.
[Of course, this is a heat pump used in the 'heating your house' use case - heat pumps are more general. Fridges and air conditioners are also heat pumps that use energy to move heat from a cold place (fridge/room) and release it in a warmer place (the outside)]
It just happens that physics allow you to move 3 or 4 kW (maybe even more in future) of heat energy from outside air inside with 1kW of energy and thus the COP. And if you run the loop in reverse you get what is traditionally called air conditioning.
How traditional heat pumps do this is with a refrigeration cycle just like your fridge or freezer does basically by compressing and decompressing a gas.
0 = change in energy inside + change in energy outside + added energy
Kind of like a post about a new kind of airplane getting a comment saying that the concept of flying makes their BS alarm go off. Yes, flying is a bit "magic" and seems to defy the laws of gravity....
Edit: 20-30%, up to 40%, according to wikipedia.
Or all the (very vague) specs could be marketing junk and it's vaporware. Neat either way.
Mitsubishi heat pumps with the "Hyper-heating inverter" technology are above 100% efficiency down to -15℉ (-26℃). They are 200% at 0℉ (-18℃), 300% at 32℉ (0℃).
Their capacity drops from 100% at 23℉ (-5℃) to 76% at -13℉ (-25℃).
Fujitsu has similar technology, as do a few others now.
100% efficiency on a heatpump is really, really, really bad. It's effectively like warming your house with electric baseboard heating which is very expensive, 4-5x the cost of natural gas in my area. Thus why I said they don't work great when its 10 below. Because they don't work great.
Typically this is a propane furnace, but may be a resistive heater. The heat pump saves on your bill except during cold snaps, and then cost spikes.
Incidentally we're in the process of installing a nat gas tankless combi heater to address this issue - you can get a forced air set up with those.
If you check the Blueheart "About" site here:
https://www.blueheartenergy.com/
they have nice pictures of the various prototypes and of the (supposedly final) product, you can appreciate at a glance how different they look, and it wouldn't be the first time that expected lifetime (estimated on prototypes) results vary for the industrialized product.
I believe all of them also have a woodstove for backup heat and general coziness, but no separate fossil fuel backup.
They aim for fairly small heat pumps from the looks of it, so this might be something targeted at people renting flats. Something to replace the gas burner for most of the winter.
Reading up a bit, it seems like this has to be a traveling-wave device to get the efficiency advertised: standing wave devices seem limited to a Carnot cycle, where a traveling wave device can operate a Stirling cycle.
Since most of the worlds natural gas is in Qatar and Iran, the world will just have a helium resource crunch if this becomes widespread. Maybe a better working gas to use would be ammonia or desiccated propane.
Maybe the ultimate solution is to have neighbourhood heating/cooling units that serve multiple and pipe hot/cold water to them.
hydrogen is actually even better iirc
but air works too
but 2 ℓ of hydrogen (i don't know how much you'd use in a residential thermoacoustic cooler so that is a guess but probably the right order of magnitude) is only 0.02 megajoules, a thousand times smaller
otoh the kerosene doesn't form an easily detonated high explosive if it mixes with air, and the hydrogen does, and 20 kilojoules can still be plenty fatal in an explosion
And of course that we're leaking heat in various ways such as the output from sinks, showers or baths and in the form of stale air but a heatpump cannot scavenge from these.
It would seem logical to have some sort of "temperature management system" which could move heat around from the various points to make use of whatever natural sources and sinks were available at that time of year.
Also you'd end up needing hella fat wires; if you want to run 12v everywhere but say your cumulative prospective 12v consumption is like 2kW then you'd need wires for the trunk lines that are like 20mm diameter! (like 160A)
Unfortunately, it's just not that useful for my home. We don't have enough devices that charge concurrently to justify it
Relatedly, I found this fantastic video on to how to use the thermoacoustic effect for heating and cooling a few months back: https://www.youtube.com/watch?v=kkBBkQ8jFRY
Claims COP A7/W35 (I can't tell what A7/W35 means) of 4.8!
https://www.durocan.com/specificaties/
https://www.durocan.com/co2-heat-pump/
Curious if folks who know about heat pumps here have any opinions on this.
EDIT: It appears to be a Dutch company (I live in NL) that has licensed the CO2 heat pump tech from an American company - https://www.smallplanetsupply.com/sanc02
It was 7X the cost of just replacing the gas-fired heater. However, we turned the space the previous heater occupied into a much-needed pantry, significantly reduced pipe runs, and removed a source of combustion from inside the building envelope, which made up for the cost difference. Happy to answer questions.
how did you source the high cycles driver, what was it made of, and how much did it cost
I'm pondering how one would do accelerated reliability/life testing for the acoustic heat pump application. Maybe they have good-enough FEA/multiphysics on a suspension and cone, and strain/life curves they are prepared to trust. With a slope on log-log strain vs life they might project how much to overpower/overstrain for an e.g. 1000hr accelerated test.
[1] https://www.avforums.com/threads/speaker-life-expectancy.164...
I thought I read somewhere that we are running out of He.
Helium is the only element on the planet that is a completely nonrenewable resource.
On Earth, helium is generated deep underground through the natural radioactive decay of elements such as uranium and thorium. "It takes many, many millennia to make the helium that's here on the Earth," says Sophia Hayes, a chemist at Washington University in St. Louis. The helium seeps up through the Earth's crust and gets trapped in pockets of natural gas, where it can be extracted.
Like hydrogen, its immediate predecessor on the periodic table, helium is lightweight. But unlike hydrogen, it doesn't readily combine with other elements. So, once helium reaches the surface, it can easily escape the Earth's gravitational pull.
Other resources, such as oil and gas, may turn into pollution or be difficult to recycle. But only helium physically disappears from the planet. "It's the one element out of the entire periodic table that escapes the Earth and goes out into outer space," Hayes says.
[0] - https://www.npr.org/2019/11/01/775554343/the-world-is-consta...
Really cool to see a company getting this in the market. I'm surprised though to see a standing-wave device instead of a traveling-wave device.
N₂ boils at −195.8 °C, but that will be higher at 30 bar.
Next question: why do they need gas at lower temperatures to achieve higher temperatures? Do temperatures inside that acoustic wave vary that much?
I'll speculate that since it's compression and decompression (as opposed to phase change) that's being exploited, you need a small gas whose behavior is as close to the ideal gas law as possible. Smaller gasses are also more volatile and leaky though, so there is probably some tradeoff.
FTA: Because helium remains a gas until -200 C, we can achieve higher temperatures inside our heat pump core
N₂ boils at −195.8 °C, but that will be higher at 30 bar.
Would be interesting to see how much.
(Please correct me if I’m wrong. I read it on slashdot decades ago)
There's no shortage of helium, at least for several hundred years. There just aren't many gas wells capturing it because it didn't make any economic sense to do that until recently.
Banning the sale of helium is foolish. The market is already responding to less supply, as it always does. We don't need people running around stopping innovation because they don't understand how price signals work.
This tech does this too, you can see here: https://youtu.be/wg96lDw7sNw
A cartoon of them actually screaming, is in ny head.
For example, I would like a water-sourced aircon which cooled a radiant or chiller circulating system on the cold side, while heating incoming water for hot water on the hot side (plus an 'overflow' cooling ground loop if necessary). Maybe this isn't beyond the ability of current systems, but I think having a fairly large gap of 60C hot/5-15C cold is inefficient currently, and maybe a reason you don't see this obvious setup too often.
So, no advantage from an energy efficiency point of view. The ability to modulate is certainly good, but they don't provide figures. My inverter air-source heat pump can modulate in the 1-8 kW range. How much better are they? Maybe they are more efficient in the whole modulation range. I'd love to see figures.
> Loyer said the heat pump can generate domestic water at up to 80 C.
That could certainly be an advantage. Traditional R410, R32 based heat pump are happy up to 45 C and then they really start to feel the heat (pun intended :) )
> helium at a pressure of 30 bars
I doubt that will last the stated 30 years. Gases such as hydrogen and helium are very hard to contain. Even the smallest crack or gasket problem will let it go.
> Given that its core is filled with water, it works best as a water-source and geothermal heat pump
Huge disadvantage IMO. Air source heat pumps are way easier and cheaper to install and service and work even in residential buildings. Most of the pumps I see installed around are air-source. They say that they can convert to air-source using a fan, but don't state what the disadvantages will be (e.g. wrt efficiency)
>Equium claims that the heat pump system is completely silent, despite the use of a speaker to generate the acoustic wave. The level of noise is reportedly lower than 30 dB – the equivalent of a whisper. This could be a big advantage in residential areas. Big air source heat pumps emit a lot of noise from the compressor.
> Equium is now conducting field tests for its thermos-acoustic heat pump. It expects to launch it at the end of 2023
Wold love to see some MSRP figures. Interested in early adoption in Bulgaria, Greece and the region (EU). My overall opinion is that factory made air-source heat pumps are overpriced compared to an AC unit with the same output power. That is why lots of people over here do a conversion by replacing the refrigerant-air heat exchanger with commercially available plate refrigerant-water exchangers. This however voids the warranty of the AC unit and you have to do some custom electronics to convince the AC unit that it is still and AC unit, while still providing the desired water temperature (mine works best in the 33-38C range, but my whole heating system is sized accordingly).
Might be slightly easier than usual in this case because it's self-contained. It's not a reservoir that needs connection to the outside.
Cost difference is going to vary by an order of magnitude (and more) depending on the local conditions :
as per u/alexose in this thread.
The first time I read about acoustic heat pumps was when the Dutch governments' research arm spun off their start-up: Blue Heart: https://www.blueheartenergy.com/
I had no idea multiple companies were pursuing this. That's great! If we can replace every gas boiler with a acoustic heat pump that can produce 70 degree water that will enormously speed up the electrification of domestic heating in Europe.
A much larger COP at 20C delta would be more effective for heating in moderate climates.
