from the I-always-said-my-Fender-stack-was-cool dept.
Heat pumps cool buildings by removing heat from the inside and pushing it outside, like a refrigerator. But unlike a refrigerator, they can also heat an enclosed area by reversing the process. To top it off, heat pumps are typically more efficient than conventional heating and cooling devices.
[...] The team's thermoacoustic heat pump consists of a metal tube filled with nitrogen connected on one end to a loudspeaker that plays a sound roughly a hundred times more powerful than the noise from a chainsaw. The sound waves cause the nitrogen to compress and expand. When the gas is allowed to expand toward the loudspeaker end of the tube, it gets cool, much like how perfume sprayed from a mister cools as it dissipates.
"Inside of the tube it's as loud as rock and roll. Outside, it is dead silent," says Ramon.
Other thermostatic heat pumps work similarly, but the new one also uses water via a stack of wet paper strips placed at the other end of the tube. When the nitrogen condenses and expands, it evaporates some of this water and the turns it into vapour. This process releases energy and cools the gas further.
The whole process can also be run in reverse to generate heat rather than remove it.
[...] Simone Hochgreb at the University of Cambridge, who was not involved in the project, says that this kind of thermoacoustic device is promising because it may be efficient enough to run entirely off solar power. However, there is a trade-off. One benefit of thermoacoustic devices is that they are relatively simple to assemble because the only moving part is a loudspeaker. Adding the stack of wet strips makes the pump more efficient but also more complicated to manufacture, she says.
(Score: 3, Interesting) by istartedi on Tuesday December 13 2022, @11:31PM
3X some number, but how does it compare to current practical heat pump technology? Not having to use the other refrigerant chemicals would be an advantage that would make some loss of efficiency acceptable; but we can't judge any of this because they've left out that key number. I guess we're expected to know what X is based on our experience with thermoacoustic heat pumps... but we don't have it. A good journalist would have dug in and got that number for us.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by DBCubix on Tuesday December 13 2022, @11:35PM (1 child)
If a chainsaw is 120dB, this loudspeaker would be 140dB?
(Score: 2) by mhajicek on Wednesday December 14 2022, @08:41AM
I have a pretty quiet chainsaw. It runs on a rechargeable lithium ion battery pack, interchangeable with the lawn mower.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by SomeGuy on Wednesday December 14 2022, @12:41AM (3 children)
So in other words, about as loud as me snoring :P
(Score: 0) by Anonymous Coward on Wednesday December 14 2022, @12:53AM
Well, that's what SHE said...
(Score: 0) by Anonymous Coward on Wednesday December 14 2022, @01:45AM
"...and then he stops..." segment 1:50-2:00 in this skit [youtube.com].
Funniest SNL skit in years, but my boys are all "Big Boys", so it hits home.
(Score: 0) by Anonymous Coward on Wednesday December 14 2022, @01:52AM
Switch this thing on, put in reverse mode, take it to the DNC, wire it to the power grid, mention Trump, leave immediately.
Running in reverse mode, it now absorbs sound and generates electricity.
Our energy crisis averted!
I've already patented it. All of Bill Gates patents on mind control need energy to run.
I've got him by the balls.
(Score: 2) by darkfeline on Wednesday December 14 2022, @04:01AM (2 children)
This is a humidifier, not (strictly) a heat pump.
What's the difference? You'll need a dehumidifer too, which is just a heat pump in the reverse setup. If you want to break even on humidity, then you'll break even on net temperature delta (with extra energy wasted of course).
Conservation of energy is a bitch.
Join the SDF Public Access UNIX System today!
(Score: 2) by NateMich on Wednesday December 14 2022, @11:38AM
Yeah, any kind of swamp cooler isn't going to be a very good air conditioner. I suppose all the other parts of it are kind of novel, but that's not helping.
(Score: 1) by UncleBen on Wednesday December 14 2022, @11:18PM
Did you miss the part where the strips of wet paper are inside the sealed, nitrogen-filled tube? And before you try circularizing, they tune the the freq to make a hot end and a cold end, switchable for the desired room effect (heating or cooling.)
There’s always a hot and cool end. That’s happening because of the work done by the sound pressure. We just get to choose if it’s the end inside the room or outside the wall.
I’m sure it’s decades from commercialization. Wet paper being notoriously strong against repeated accelerations. (Vibration) But it looks like a cool project made a nifty prototype.