I'm planning to build a Stirling generator to work off heat from our kitchen stove.

[Jack]

What would the "regenerator" consist of?

It appears (upper right) to reduce to zero volume.

It does. The remaining hot/warm air in it will be used in the cold cylinder.
It is another rotor of the same size as the other two. I don't think it's a regenerator as we know in other engines, but it separates fluid and moves it around to be reused while keeping the temperature in it.

[Jack]

Jack, are you striving for a first ever pseudo-Carnot cycle?That's what it looks like. Excellent.

It didn't start like that, but along the way I realized it comes very close to one. I'm hoping it works as planned haha.

[Jack]

I'm starting to think I shouldn't open the green port to all cylinders, but limit it between hot and cold. That way I get a higher delta t in the hot side and the fluid in the regenerator doesn't mix with cold fluid so it puts out work more efficiently when it gets to the cold cylinder.

[Clarkey]

Any inspiration to be drawn from this paper, which describes a dual vaned rotor Stirling engine and has a downloadable full pdf that includes some potentially useful design details, such as block shapes, ports, etc.
https://www.researchgate.net/publicatio ... hitecture

[Jack]

Yeah I found that one. Great info!

[Jack]

I'm stuck. I imagine it's a common problem with these engines. I'm thinking myself in circles. Every time I get to grip with a new concept I think I find a "weakness", try to solve that and end up with a previous concept.

My search has turned from trying to find a way to make power from our stove, to trying to find the most efficient engine.

So I've started asking myself a different question. What do I need for this to be the most it can be?
I don't know how much heat input I can get from the fire. I can guess, but I could be way off.

Because I don't know that, I can't really tell how much displacement I should aim for.
So is the solution to that an engine with adjustable displacement? And how can I achieve that?

Another day, another problem. Does this ever end? Haha

[Jack]

The universe provides.. down another rabbit hole we go..

[Tom Booth]

A reverse image search turned up this article:

https://www.tomorrowstechnician.com/var ... oil-pumps/

[stephenz]

I'm stuck. I imagine it's a common problem with these engines. I'm thinking myself in circles. Every time I get to grip with a new concept I think I find a "weakness", try to solve that and end up with a previous concept.

My search has turned from trying to find a way to make power from our stove, to trying to find the most efficient engine.

So I've started asking myself a different question. What do I need for this to be the most it can be?
I don't know how much heat input I can get from the fire. I can guess, but I could be way off.

Because I don't know that, I can't really tell how much displacement I should aim for.
So is the solution to that an engine with adjustable displacement? And how can I achieve that?

Another day, another problem. Does this ever end? Haha

Why don't you measure it? You mentioned stove and fire, while I don't know what your stove looks like, maybe you could measure how much time it takes it to bring up the temperature of a known mass of water. All you would need is a good way to measure the mass of water, its temperature and of course a stopwatch.

[Jack]

That's an idea, yeah. Hadn't thought of that. Thanks.

[Jack]

After getting myself in a mental loop of efficiency and solutions I had to take a little step back and try to see what was really important.
I've got one rotor here that I'll turn into a single rotor prototype. So I'll heat up one side of the cylinder and cool the other. Just to see if this concept could work.

Another thing I want to try is a brayton or Ericsson engine. With two rotors, one compressor and one turbine. Usually this needs valves to work. But I want to try to make the hot reservoir out of tesla valves. No idea if it can work, but worth a try.
I found this video and I'm guessing it will work kind of similar with a hot air engine.
Tesla valve with flammable gas

I'll try to make the gearing between the compressor and turbine adjustable on the fly, so I can adjust it according to the heat available by just turning a knob.
If it works on atmospheric pressure I'll turn it into a closed loop system that I can pressurize.

[Jack]

Wow, was it really december since I last visited here? Time really flies. Had some other things to take care of, so I couldn't work on this. But the thinking never stopped.

I recently got back into it because a friend gave me a nudge I wasn't expecting. In stead of Stirling engine I'm now looking at a brayton cycle with Tesla turbines.
It fills the needs for less moving parts, combining functions and ease of construction.

I would only have one shaft, with a turbine, a pump and a generator. The moving discs are basically the flywheel and work is mostly done on the outer edge of that. The generator, or load, is on a much smaller arm compared to the shaft.
The pump would pump air, and maybe added water through a venturi, into the Tesla valve heat exchanger. The valves hopefully allow most pressure to be built up on the downstream side to power the turbine. The water/steam will condensate and be drained for pickup later. This way the pump will pump dry air into the heat exchanger again.

As usual, I don't know if I'm explaining this in a way others can understand. Jeremiah on YouTube has some good info.

[VincentG]

I get the premise. I and many others have been hoping someone would make a heated tesla valve. Seems to have lots of potential.

[Jack]

I think so too. I'll first try to get my hands on a Tesla valve to run some tests. I can't readily find a metal one, so I might have to get one made.