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Here is the problem Ian. WhisperGen is $20K. Their justification is that 1kW ELECTRICAL output. Most of the fuel is used to produce heat/HW and I can get an 30 gallon oil fire HW burner for less than $600, and on demand ones are much less. To me, it is a scam.

Fuel is much more expensive in Europe where the target market for the Whisper Gen is, so is main grid power. When it was first marketed it was cheaper to run a home in Germany or UK on the Whisper Gen, and sell the surplus to the state generator. I'm not in contact with Whisper Tech now as it is no longer in New Zealand, the earth quake of 7 years ago demolished their HQ here.
Ian S C

That does not make sense Ian. If the real situation is what you described, should WhisperGen be more efficient in the production of electricity? As I say, its electricity generation efficiency is less than 10%. The rest is heat and you can't sell heat back to the grid.

So I have finally discovered the inner working of the Sunpulse Stirling Engine.

https://www.youtube.com/watch?v=mpBa0nt ... ture=share

I have one new problem I discovered which is that I cannot run the "cold" pipe through my pond without it freezing in winter. So I have decided to dig a 10 foot deep trench to bury it in. How long do I need to run this pipe for so that the water cools from ~120F to ~60F by the time i am pumping it back into the Stirling Engine cooling tubes?

Could I just bury it in a large 10 foot x 20 foot rectangle and run the pipe zigzag throughout? Or would the ground get too warm over time from it running 24/7?

If you bury it too deep you will if you just pump it round will find that the temperature rises, pumped buried water pipes are used for house heating systems. Could you use anti freeze in the cooling system and circulate that in you pool, depending on the size of the pool, and the motor you might even get the pool temperature to rise a degree or so.
Ian S C

actually that should work quite well. dont know why i didnt think of it. i think i just had my brain too focused on pumping water. thanks.

Hutch687 wrote:So I have finally discovered the inner working of the Sunpulse Stirling Engine.

https://www.youtube.com/watch?v=mpBa0nt ... ture=share

No magic there. The trick to LTD stirling is to have very very large exchange area, lots of working fluid, and minimum amount of non-working fluid.

P.S. In my book. Working fluid is the amount of fluid that can actually go through the heat exchangers.

How long do I need to run this pipe for so that the water cools from ~120F to ~60F by the time i am pumping it back into the Stirling Engine cooling tubes?

You should be able to figure that out
[youtube]https://www.youtube.com/watch?v=QMg3vr7KgDA&t=385s[/youtube]

Hi Hutch687,
Indeed I was thinking for the same idea of using solar evacuated tubes in combination with Stirling engine so I am very interested of your progress.
Up to now what I have in mind is to have such a setup for the solar evacuated tubes
https://www.youtube.com/watch?v=6Eh4a2nYWpg and then use the hot plate to put one large LTD Stirling engine like “Sunpulse”
Another possibility for me is to use many small LTD Stirling engines in series. What I mean is to use the following setup https://www.youtube.com/watch?v=Z5L2KK1JBCc (or this one https://www.youtube.com/watch?v=vT1VaSL_Z5M&t=0s ) but instead of one vacuum tube to use 10 ~100 and the same amount of Stirling engines in series.
Let me know the progress of your project.

A much higher temperature can be had by using a suitable reflector/mirror directly on the hot cap of the Stirling Engine, a large Freznel Lens will generate enough heat to etch stainless steel, only problem (in this part of the world)is to get the sun to shine at the right time.
Ian S C

I want to build same engine. Have you made any progress on it. Will you share it with me ?

Have you seen this video of internals of sunpulse?

https://www.pinterest.com.au/pin/337207090842559684/

I have built a ltd solar engine with a 4 1/2 cu. inch displacer and a 2" dia. power piston. The best power I have attained so far is 1.7 volts pulling an old car fan motor. this is at 440 degrees f. hot and 180 degrees cold.

How'd you go with it? any updates??
Regards Gebsy

I'm looking at a thermos flask, and a hot air motor, do you think it's worth combining the two to see how they go. Maybe I'll wait a while until the temperature goes up a bit, and we get out of mid winter.

tew, try putting a lighter motor on the LTD, or find a brushless permanent magnet motor and run it as an alternator(less friction), it will need a diode to get DC current (that drops .5 Volt).

Ian S C

Hello,
the same group of people made a 1kW Stirling engine at 2.5 bar. It is much more compact than the first.
here is a photo and the link to the original publication (instagram) : https://www.instagram.com/p/B4ApxFUFhLC/
I also work on a stirling engine which operates at low temperature. I'm on my sixth prototype and it's starting to work well.
Are there people who are still working on the same subject?
Rafik