Thermoacoustic generator

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Remundo
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by Remundo » 26/04/08, 00:22

Hi Nlc,
Public chat

http://www.savoirs.essonne.fr/dossiers/ ... sources=1#

There is a video that explains very well the principle of RTA (refrigerator ... thermoacoustic)

And as it can work in reverse ... it is also a GTA!

There are lots of interesting links on this page ...
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by nlc » 26/04/08, 00:57

Cold your link !!

Finally, I mean cool your link 8)

Especially this article: http://www.americanscientist.org/templa ... 006/page/1

7 pages to read, I just finished page 2
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by Remundo » 26/04/08, 11:24

Yes, that's not bad (extract from your link)
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Figure 4. Thermoacoustic engines are similar to optical lasers in that both types of apparatus amplify standing waves set up within resonant cavities. In a ruby ​​laser (top), for example, energy is added by means of a flash tube, which creates a "population inversion" of electron energy levels. In the thermoacoustic analog (bottom), energy is injected into the cavity using the heated stack, which creates a nonequilibrium temperature distribution.
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by Remundo » 26/04/08, 11:30

that too is very good ... The stack would play the role of regenerator ... it would be necessary to heat the tube on one side, and cool on the other ... :?:
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Figure 7. Stirling cycle contains four distinct steps — compression, heating, expansion and cooling — which produce a characteristic set of changes in pressure and volume (right). In a simple, two-piston Stirling engine (directly below), the compression step (1) keeps one piston fixed as the other moves inward, the heat of compression being rejected into the adjacent cold reservoir. The next step (2) produces constant-volume regenerative heating, as both pistons move simultaneously, forcing cool gas through the porous regenerator, which was heated during the final step of the last cycle. Next (step 3), heat from the hot reservoir causes thermal expansion of the gas, which forces the adjacent piston to move outward. Finally (step 4), both pistons move together to create a constant-volume regenerative cooling of the heated gas. The changes in pressure and gas velocity within the regenerator of such a Stirling engine mimic the relationship seen in a traveling acoustic wave, where pressure and gas velocity move up and down in phase (bottom pair of panels).
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by Remundo » 26/04/08, 11:32

I put that too!
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Figure 8. Traveling-wave heat engine that Peter H. Ceperley envisioned more than two decades ago amounts to a loop of gas-filled pipe with one or more porous regenerators inside. Heat exchangers attached to each regenerator supply heat or carry it away, setting up thermal gradients (solid arrows). In this configuration (adapted from Ceperley's 1979 patent), one regenerator is meant to amplify the traveling acoustic wave (dashed arrow), while the second provides useful cooling. Although Ceperley was never able to construct a working traveling-wave engine, T. Yazaki and three Japanese colleagues described in 1998 their success in building such a device to compare the properties of traveling- and standing-wave thermoacoustic engines.
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by Capt_Maloche » 26/04/08, 11:32

This is the principle of the laser

on the other hand on the output side, a traditional compressor refrigerator has a COP of 4, while with thermo-acoustics we will be below 1

will have to choose :D
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by Remundo » 26/04/08, 11:33

Hi Captain!

And yes, on the yield side, the shoe pinches apparently ... but there is technical simplicity, that's what Nlc is looking for : Idea:
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by Capt_Maloche » 26/04/08, 11:34

Remundo wrote:that too is very good ... The stack would play the role of regenerator ... it would be necessary to heat the tube on one side, and cool on the other ... :?:


excellent! this is the principle of the pseudo stirling on the photo on the previous page
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by Remundo » 26/04/08, 11:40

Finally on page 5, they say they found something, a kind of "non-return valve" ... which would bring performance to the level of current engines ... :?: : Idea:

http://www.americanscientist.org/templa ... ge/5#23077

American Scientist wrote:Once we realized what was happening, it was easy enough to correct the problem. One solution (which Ceperley had suggested years earlier for his circular design) would be to add a flexible membrane that passed acoustic waves yet blocked the continuous flow of gas. But prior experience with such membranes led us to believe that it would be hard to engineer something sufficiently robust to hold up over time. So instead we added a jet pump (asymmetric openings that allow flow to pass in one direction more easily than the other) to create a slight back-pressure in the loop, just enough to cancel the streaming. And we were pleased to find that the efficiency of the engine improved markedly. At best it ran at 42 percent of the maximum theoretical efficiency, which is about 40 percent better than earlier thermoacoustic devices had achieved and rivals what modern internal-combustion engines can offer.
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by Remundo » 02/06/08, 14:15

Perhaps something new in the field of thermoelectric energy

http://www.heat2power.net/en_benchmark.htm
http://www.auto-innovations.com/actualite/1118.html

Yield displayed by the English link 17% (to be confirmed + temperature Egypt ...)

BMW launches exhaust heat recovery projects : Idea:
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