Perpetual Ideas

[Tom Booth]

My understanding at the moment, (which could be wrong, as I've only just begun looking into these things and some of the informations is contradictory or confusing)

Is, what that chart indicates is when first starting up a Peltier device is at 0°∆T and it's power draw is low and it's COP is basically off the chart.

Then as it runs and the ∆T increases the efficiency drops and the current draw increases.

I would think then, if you had say a P-19 type LTD that can operate on a 0.5 ∆T and the peltier ultimately generates a 30°∆T at 12 volts the thing to do would be to incorporate some thermal mass of some kind and run the Peltier very intermittently letting the engine "cost" on the thermal mass until the ∆T is again minimal.

Stacking would also probably be helpful as the things are so thin the ∆T neutralizes almost instantly when the power is cut.

It might also be worthwhile to use some form of heat diodes

[Fool]

I think that chart is for steady state currents and temperatures and COP's.

At 0.1 times Amax, it will produce 10° of delta T, at a COP of 2.

At 0.2 times Amax, it will produce 20° of delta T, at a COP of .7

Very tiny amounts of power for small steady state COP's, and delta T's, max.

[Tom Booth]

I think that chart is for steady state currents and temperatures and COP's.

At 0.1 times Amax, it will produce 10° of delta T, at a COP of 2.

At 0.2 times Amax, it will produce 20° of delta T, at a COP of .7

Very tiny amounts of power for small steady state COP's, and delta T's, max.

Not sure how reliable the information is, but was reading a forum post on Quora or Reddit or someplace that for a high COP use a Peltier rated for a higher voltage but run it at a lower voltage.

As usual however, lots of disagreement and diverse opinions.

I've found experimentally, I can run an LTD Stirling engine easily on the hot side of a 12 volt peltier using a 9 volt battery but without a fan actively cooling the hot side the "cold" side of the Peltier chip gets warm instead of cold. The Stirling engine does not draw off heat enough to keep the Peltier cool enough on the hot side to provide refrigeration on the cold side.

Also, the 9v battery itself got very hot, over 100°F while discharging to run the Peltier. The hot side of the Peltier did not get as hot as the battery!

[Fool]

Yeah. Peltier's are temperature difference devices, not absolute temperature devices. Putting more energy into a Stirling Engine than it can use just rases the temperatures, and heat loss, mostly directly from the hot side. Definitely a good investigation.

[Tom Booth]

I think this is a replacement vacuum pump for the vacuum sealer used in the following video:

Compress_20240621_131358_8993.jpg (13.33 KiB) Viewed 1943 times

Video:

https://youtu.be/74wTirFTxvA

So my idea is to make a largely transparent closed loop refrigeration system using mason jars for the condenser and evaporator so everybody can see what's actually going on inside.

If such a tiny pump can create enough vacuum to boil water in a mason jar than it will almost certainly work for this application as well I would think.

[Fool]

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Perhaps the following web page might help people:

https://hackaday.com/2016/01/25/overuni ... f-youtube/

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[Tom Booth]

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Perhaps the following web page might help people:

https://hackaday.com/2016/01/25/overuni ... f-youtube/

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This is not intended as a "perpetual motion" thread or discussion. It is a Stirling engine forum.

The title is perpetual IDEAS not perpetual motion devices.

I am simply always (perpetually) having ideas for how Stirling engines might be built or used, not having anything to do, necessarily, with any perpetual motion machine or device.

Other creative and imaginative people are welcome to post ideas of their own here.

Of course, that would leave out people like you and Matt who's thoughts are perpetually banal and hackneyed at best.

Naturally that is not intended to exclude ideas bordering on literal "perpetual motion" such as an ambient heat powered heat engine, or "drinking Bird" type device.

[Fool]

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LOL

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