Tiny Generator?

Just smaller for given ratings, due to higher flux density. In given size and voltage they'd provide some combination of lower speed, higher torque more power and/or better efficiency.

Some electric trolling motors use rare-earth magnets. Very powerful efficient low-speed DCPM motors.

Reply to
Don Foreman
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I am going to, yes.

That would work, but the mechanical problems with containing a significant volume of air at 9000 PSI are substantial. You need to balance the heat flow through the neccesarily thick walls of such a heat exchanger with the increased power output brought on by the denser gas. Higher pressure doesn't really improve efficiency of the cycle (other than the mechanical losses remain mostly the same while the denser gas does more work.)

CO2 is a poor choice, as is argon. It has to do with the ability of the gas to exchange heat quickly, as well as the gas constants that are not related to mass vs. those that are. So, lighter gases automatically turn out superior.

If there is a phase change, then it is NOT a Stirling engine, but Carnot. Essentially a steam engine. The greater the heat of vaporization, the better. And, you really can't beat water (steam) in that regard.

Jon

Reply to
Jon Elson

Sunpower made some demo free-piston water pumps that looked like they were in this output class - about as much water as a garden hose. You could hold it in your hand, and they were so incredibly simple as to be "elegant". Ah, yes, it wasn't atmospheric. I don't recall, but I'm sure it was helium or hydrogen-filled, at some modest pressure.

Jon

Reply to
Jon Elson

Search for 4 cycle RC airplane engines and get your wallet out. Some beautiful stuff out there......

Heres one:

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Reply to
grumtac

I'd love to see your work when you get that far.

Reply to
Dave Lyon

Carnot? Don't you mean Rankine?

Joe Gwinn

Reply to
Joseph Gwinn

It does. It costs a great deal of money, and the amount of power is easy to reach using less efficient, but cheaper to produce gas engines.

Philips has built Stirling cycle engines that powered city busses, and were very efficient. DAGS "Philips Stirling" for more.

I can recall seeing online, a free piston stirling genset that was used in the US space program.

The developments of working Stirling engines pretty much died with the advent of safe easy to run, gasoline engines. Until they came along, engines like the Rider-Ericson were used as power sources that were safe and did not require any special skills to keep from blowing up, such as was the risk from a steam plant.

Most of the demo engines are built to simply run, so that is all most of them do.

There are competitions in the UK for Stirling cycle engines using limited heat sources (tea lights, little parrafin wax candles) where outputs are pretty substantial (5 watts or more) given the limited inputs. These engines do not look near as nice as the display models, and the average guy walking past one would not recognise it as an engine, so I can understand why they do not show up much in the press, where shiny rules supreme in the home shop stuff.

Probably as close to a "working" Stirling out there these days would likely be the assorted fans that are available DAGS "Moryia Stirling" for one.

Cheers Trevor Jones

Reply to
Trevor Jones

Grab one off of some of the import mini diesel tractors. They are SMALL. Although the older Delcos can be made into 120AC units easier. Or by installing an adjustable regulator you can play with the output.

I have a unit on my fire response rig that charges the spare battery and with a flip of the switch provides 120 volts to power the two light towers I have mounted on the back, they provide light for accidents and fire scenes without needing one of the rescue units.

Reply to
Steve W.

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a lot of neat "glowing" items.... Want some U238 blended marbles, or maybe some uranium glass....

Reply to
Steve W.

Well, it is going to be a while. But, I really do want to work on this. I got a TIG welder on eBay so I could weld up the tubing, etc. in the heat exchangers. I sawed up a bunch of HUGE 8" Seagate hard drives and have 75 Lbs or so of really nice aluminum to cast a crankcase.

Jon

Reply to
Jon Elson

Umm, yes, I suppose so.

Jon

Reply to
Jon Elson

Yup, that sounds like the Ametek motors from computer tape drives. The CDC keystone series used them, as well as a number of other makes/models.

Jon

Reply to
Jon Elson

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