Stirlingengineforum.com

I'm forever coming up with ideas for Stirling engine projects I may never actually get to in this lifetime, that might not actually work, or be feasible or practical, but are at least fun to think about. (Not to mention other schemes, unrelated to Stirling engines).

Here is the latest to pop into my mind, primarily, I think, due to recently reading about the P-19 Ultra LTD engine, proven to run for weeks (at least) on a little evaporative cooling.

Also, reading, a little less recently, about night sky cooling. I was thinking about a pool of water on a flat roof with a Stirling engine to power a building. That might be a little too ambitious.

So, instead, or in the short run, I thought, maybe a bird bath!
Notice the P-19 type LTD upside down. Some little underwater colored LED lights, as this will continue running (perhaps better?) at night.

Could it even power a small water pump for a fountain?

I won't be getting to work on this one right away. Today I have to work on cleaning out the basement and getting the old oil burner ready for winter.

Just so no one feels reluctant, this is not intended to be a thread exclusively for my own ideas. If an idea is shared here, though, It is, according to my own unenforceable made up rule, to be considered "public domain", unless otherwise indicated. That is, I'm not going to sue anybody if you "steal" my perpetual bird bath idea and start mass production tomorrow. Just let me know so I can buy one! It would be a nice addition to our rose garden.

I suppose this is something for this thread
https://youtu.be/mkIF01ieT_c

A good book:

Perpetual Motion the History of an Obsession by Arthur W.J.G. Ord-Hume

airpower wrote: ↑Wed Nov 24, 2021 3:01 am I suppose this is something for this thread

I tend towards being liberal, but this is a Stirling heat engine forum, so I would assume that posts, in general, should fall under that umbrella.

About scaling up this engine:
For the hot cap, I thought a spent fire extinguisher might do but that still leaves fabricating a close fitting displacer, which shouldn't be too hard, but could be a potential problem.
Then today I happened upon one of those tall stainless steel water bottles, double walled, vacuum insulated, by the kitchen sink and had the idea that this might be great for a midsize, but still, potentially power producing engine.

I ordered one of these online as a sample "blank" that can have a logo added, as it looked about the right size, comparatively inexpensive and most importantly is UNPAINTED.


I don't really know what the tolerance is for these things, but that's why I'm sending away for one to find out.

What I'm anticipating, is with the top cut off at the shoulder, this will provide both hot cap / displacer chamber, as well as the inner displacer itself, which should be a perfect fit.

Hopefully the inner and outer walls are not spot welded together or something.

These vacuum insulated bottles are available in all kinds of different brands, shapes and sizes, as well as price ranges. This sample 27oz. bottle was just under $6 (pluss tax and postage).

Tom Booth wrote: ↑Sat Jan 29, 2022 4:40 pm About scaling up this engine:

Screenshot_20220121-201126.jpg

For the hot cap, I thought a spent fire extinguisher might do but that still leaves fabricating a close fitting displacer, which shouldn't be too hard, but could be a potential problem.

Screenshot_20220128-121830_20220128123035353.jpg

Then today I happened upon one of those tall stainless steel water bottles, double walled, vacuum insulated, by the kitchen sink and had the idea that this might be great for a midsize, but still, potentially power producing engine.

I ordered one of these online as a sample "blank" that can have a logo added, as it looked about the right size, comparatively inexpensive and most importantly is UNPAINTED.


Screenshot_20220129-175608.jpg


I don't really know what the tolerance is for these things, but that's why I'm sending away for one to find out.

What I'm anticipating, is with the top cut off at the shoulder, this will provide both hot cap / displacer chamber, as well as the inner displacer itself, which should be a perfect fit.

Hopefully the inner and outer walls are not spot welded together or something.

These vacuum insulated bottles are available in all kinds of different brands, shapes and sizes, as well as price ranges. This sample 27oz. bottle was just under $6 (pluss tax and postage).

That red engine seems of the "You get what you pay for variety". It is more a heat radiator than a engine with the cooling fins on the hot side.
There is no structural integrity if the top is cut of that bottle, its paper thin and also some broken glass.


Crankshaft give me headaches, time is up for them, anyway

airpower wrote: ↑Sun Jan 30, 2022 7:45 am ...., its paper thin and also some broken glass.

The quality of stainless steel of different brands is likely variable. I tried cutting a stainless steel Yeti brand double walled vacuum insulated container with an angle grinder, it was very slow going. Very high grade stainless

These are not glass lined thermos bottles, but 100% stainless steel inside and out.

Good idea Tom ! I used a single wall stainless water bottle for a displacer cylinder and it works great. I think it has a soup can piston. Using the inner for a piston is even better. It gives me a "why didn't I think of that", moment.
Let us know how it works after you cut it open.

I'm also sending for some of these tall vacuum insulated stainless steel tumblers.

I like this site as they have a variety of large tall plain stainless steel, double wall, vacuum insulated bottles and tumblers, are willing to sell single units, (many sites require a minimum order), and this site also has a reasonable flat rate for shipping.

https://atgtumblers.com/collections/ss-tumblers?page=2


They also appear to be of seamless construction, though sometimes I've seen seams on the bottoms, so, not sure.

I don't really know yet how suitable any of these things may be for the intended purpose, but seem worth a try.

For the type of engine, I think thin stainless is a good thing. If they can hold up under the pressure of a vacuum, I would think they should be fine.

The displacer chamber in this type engine is both hot and cold, why it is so long and made of thin stainless, that does not conduct heat readily along it's length.

An idea sprouted up in my mind early this morning/last night, about 2:00 AM maybe.

It is for a kind of rotary displacer, with, theoretically, near zero "dead air space".

Of course, SOME air is necessary, but what I mean is, all the air in the displacer chamber should be exposed to heat.

I bought some cheap air tools from Harbor Freight a few weeks ago, intending to tear them apart and get out the air motor or turbine or whatever was in there, but as it turned out, the guts were actually vane type motors.

Hmm. Not exactly useful for what I had in mind at the time.

However, this morning, more or less out of nowhere, I got an idea for a kind of vane type rotary displacer, sort of, anyway, at least it would use a similar mechanism as used in a rotary vane compressor or motor but kind of in reverse.

Instead of the vanes popping out from the inside of the rotor, heated vanes drop down, or up, or sideways or whatever into the displacer chamber from the perimeter. The rotary "displacer" acting more like a cam. Instead of at right angles to the rotor, though the vanes are in line with the displacer "cam" and shaped so as to fill up the void as the cam rotates.

In some ways, kind of like a Tesla turbine, utilizing the boundary layer between the plates to heat up the air.

The vane tension could be adjustable in order to avoid friction as much as possible. Probably less friction that way than with a typical rotary vane motor.

If all that isn't clear, I'll try sketching it out or make an animation.

I've been puzzling over the "problem" of the rotary displacer for years now. Too much dead air space, not enough surface to air contact, too much mixing of hot and cold, but otherwise, ideal in some ways.

Possibly the vanes could even be on an axil so that they roll on the displacer/cam, further reducing friction and potentially increasing heat distribution.

The point is, the heat source for the engine is heated plates or vanes that are encapsulated in a very close tolerance heated enclosure with slots the vanes or plates fit into.

A cam controls when the vanes or hot metal plates will drop or slide out or down, out of their slots in the heating unit, into the air filled space, quickly and effectively heating ALL the air at once.

airpower wrote: ↑Wed Nov 24, 2021 3:01 am I suppose this is something for this thread
https://youtu.be/mkIF01ieT_c

Hi airpower,

do you know how it works?
I have see many videos they created, but no explanation about the mechanism.
So I think it is fake, or so many dams around the world are all joke.
Thanks!

ccspring3021 wrote: ↑Mon Feb 14, 2022 9:31 am

airpower wrote: ↑Wed Nov 24, 2021 3:01 am I suppose this is something for this thread
https://youtu.be/mkIF01ieT_c

Hi airpower,

do you know how it works?
I have see many videos they created, but no explanation about the mechanism.
So I think it is fake, or so many dams around the world are all joke.
Thanks!

I'm not airpower, and also await, or would like some explaination.

I can see, or imagine how this could work, for a while. If the barrel is, say, filled 3/4 full of water and the water is allowed to run out a long tube, the vacuum created in the barrel will, conceivably, draw in water through a shorter length of pipe.

The pumping force is not gravity or a normal siphoning action but due to the vacuum created. Atmospheric pressure pushes the water up into the barrel.

So as long as a vacuum is maintained, water will continue being pushed into the barrel by atmospheric pressure. It seems unlikely, if such is possible at all that it could continue indefinitely.

Though, the energy used to lift the water up in buckets starts the process and creates a vacuum. Atmospheric pressure does the rest. So, who knows?

Maybe it could be demonstrated with a small table top version using a clear bottle and clear tubing and a pot of water. But that suggests the water could be siphoned out of the pot and drained right back into the same pot.

It has me thinking of a live steam injector, which seem absolutely impossible, but nevertheless works.

But I suspect this is a variation on Heron's fountain and would stop working and have to be recharged periodically, assuming it works at all.

https://youtu.be/K49QOM_B8dA

So maybe it isn't exactly fake, but might only work long enough to make a short video.

Hi Tom,

We know there are one input(in the river) and one output(in the field) of the water.
So if the vacuum can cause the water in the river to fill in the tank, why it will not cause the water stop going out in the output port?
Maybe they use some one direction valve, but it will stop water go back from output port, but the vacuum will not increase to pump the water in the river.

They seem to be implying that the output in the field is lower than the river, lake, or pond level, hence the reason for the long output pipe. It's the only way I see it would work as described.