new concept of Stirling engine

Discussion on Stirling or "hot air" engines (all types)
normandajc
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new concept of Stirling engine

Post by normandajc »

Hello,

I designed a new type of Stirling engine. I respect the Stirling cycle, but the design is radically different than the alpha, beta, gamma types. I've made a website that introduces the engine. I removed the regenerator and replaced it with a heat exchanger. I've increased the heat transfer exchange times, etc.
An academic publication will be published very soon.
A patent has been filed
http://www.cyberquebec.ca/normandajc/
Tom Booth
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Re: new concept of Stirling engine

Post by Tom Booth »

normandajc wrote: Tue Aug 18, 2020 3:52 am Hello,

I designed a new type of Stirling engine. I respect the Stirling cycle, but the design is radically different than the alpha, beta, gamma types. I've made a website that introduces the engine. I removed the regenerator and replaced it with a heat exchanger. I've increased the heat transfer exchange times, etc.
An academic publication will be published very soon.
A patent has been filed
http://www.cyberquebec.ca/normandajc/
A Regenerator is a type of heat exchanger. Or so I've always thought. How is your heat exchanger different?
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

On my engine, all four phases run simultaneously. The gas is transferred from chamber to chamber. It takes two full engine revolutions to complete one cycle for the same volume of gas.A regenerator must immediately absorb the heat during the cooling operation and release the heat during the heating operation. This requires a low thermal inertia and a large heat exchange surface. The consequence is a dead volume which harms the performance of the engine.
With my engine, by using a heat exchanger , the heat transfer takes place immediately and this during half a revolution of the engine.
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

I tried to create a video to show an example.
In the video I didn't represent the system of changing the configuration of the pipes every half turn.
video on this link
https://secure.digiposte.fr/p/ee33fa03a ... dff3969b8b
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

On my website, I've added the video with a looping playback
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

the site address is http://www.cyberquebec.ca/normandajc/
The tab "Two-stroke Stirling engine" contains the video
Tom Booth
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Re: new concept of Stirling engine

Post by Tom Booth »

I think I've got the basic idea. Instead of a "Regenerator" which I'd call a reverse flow heat exchanger, your engine has multiple cylinders with counter current heat exchangers, so as one pair of pistons is in the cooling phase the other pair is in the heating phase?

So, rather than one stream reversing direction, there are two separate streams flowing in opposite directions?
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

Effectively, that's what it is.
Tom Booth
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Re: new concept of Stirling engine

Post by Tom Booth »

That is a very interesting concept, and I don't want to throw a wet blanket over it, but in trying to imagine a heat exchanger of that sort, I'm unable to imagine something that would be as effective as a Regenerator.

In a reverse current Regenerator the cold fluid streams over a hot metal mesh, absorbing heat, then the reverse, hot gas flows across cold metal. As heat flows from hot to cold, this is nearly 100% effective.

With heat flowing in both directions simultaneously, I can't picture an arrangement where the heat from the two flows is not tending to just get equalized with the cold, so the result would be warm gas flowing in both directions, after a cycle of two. Maybe I'm missing something, or have the wrong picture.
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

so far it's only on paper.
A regenerator is efficient but a counterpart is a dead volume which is detrimental to the performance and is detrimental to the different phases of the Stirling cycle.
Studies must be conducted to develop this engine. Studies will certainly make this engine evolve. The Stirling engine that we know about is more than two years old and its evolution did not happen in one day.
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

I forgot to specify. The countercurrent exchanger may be oscillating. You can choose to always have the cold on one side and the hot on the other side of the exchanger. But we can also alternate every half turn of the engine. This is what I represented on the video.
There are only studies that can evolve my new type of engine.
I'm looking for an industrialist, it's to develop my engine.
Tom Booth
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Re: new concept of Stirling engine

Post by Tom Booth »

The animation on this page: (2 stroke Stirling engine tab).

http://www.cyberquebec.ca/_layout/?uri= ... ormandajc/

Shows what looks like different size piston/cylinders, though I assume the apparent different sizes (small in the center) are just to fit the animation on the page?

Or do the different size cylinders have some actual functional purpose,, like compressing the air to a smaller space, or expanding to a larger space?

In other words, are the pistons actually different sizes, or all the same?
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

The pistons are of different sizes.
An isothermal compression is well realized.
An isothermal expansion is well realized.
The pistons have the same size for the cooling and heating phases, so that isochoric operations can be performed. In these last two phases the volumes of the exchanger are added.
Different piston diameters and strokes allow for the determination of the desired compression or expansion rates.
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

All Stirling engines have connections between cylinders. Calling this a large dead space seems to me to be an exaggeration.
The alternatif countercurrent exchanger will have to be optimized in order to reduce its dead volume.
At the end of the piston stroke a push rod can actuate a slide valve to direct the gas in one direction or another. This is very simple to do.
I'm not saying that my engine is perfect, but I think it deserves study. I think is a possible evolution of the Stirling engine. I'm looking for an industrialist who wants to develop my new type of Stirling engine.
normandajc
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Re: new concept of Stirling engine

Post by normandajc »

the patent has been filed
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