windmill composter

[RPM]

Re: windmill composter / Minto\'s Wonder Wheel

Yup, there are real challenges with this one.

I think the biggest one is probably the thermodynamics problem with regards to the fluid transfer between the tanks. The only way I can see this working reliably is to have it controlled by computer. The system would have to allow for some form of controlled pressure regulation between opposite tanks to keep the fluid at the right temperature-pressure point for it to exhibit the correct physical properties to make the system work.

The easiest way to do this would be to have a few thermo-couples on each tank and a pressure transducer somewhere in the system (could probably get away with one in the connecting pipe). You would also need a control valve to throttle down / open up the connecting pipe between tanks as ambient temperature varied. You'd also need an Analog to Digital convertor board and have to write the control software. All of this technology would allow the wheel to keep rotating - but you'd still be faced with a variable output in terms of rpm.

So, in a nutshell, you couldn't just set the wheel going and leave it for a few weeks. It would require lots of tinkering. Mr Minto may have been a tinkerer - but I think I would stick with the windmill - I could spend more time watching it and kicking back - and less time fiddling with valves and looking for propane leaks!!!

 

[StoneHeartFarm]

Re: windmill composter / Minto\'s Wonder Wheel

RPM,

That's basically where we're at. It's too bad, the idea has some merit, but the speed of the ungoverned wheel would vary too much to make it reliable for anything more than cutting some wood or grinding some grain, or occasional crop irrigation. This thing is going to be badly abused by the ambient temperature, which when cold, would cause the wheel to spin much faster than it would when warm. The websites I have visited talk alot about output and RPM, but none mention the ambient temperature at which these figures were attained. There may have been 3 feet of snow on the ground and someone rubbing snowballs on the tanks as they cooled.

Without all the electronics, I think the system would still work, but the output would be inconsistent. Therefore, the wheel would be limited to very simple labor, basically something to lift a load with.

Besides, visions of airfoils keep dancing in my head. What we need is a new, highly efficient airfoil design...

SHF

 

[JOR_EL]

Re: windmill composter / Minto\'s Wonder Wheel

Hi SHF, /w3tcompact/icons/smile.gif

[[[... visions of airfoils keep dancing in my head. What we need is a new, highly efficient airfoil design...]]]

There are plenty of efficient airfoil designs, used for human powered flight, radio-controlled sailplanes, remotely-piloted vehicles (military recon), etc.

Recent years have seen expanded research/publication of airfoils designed specifically for"low-reynolds-numbers" flight (relatively slow), whereas in the past, "faster" was generally considered "better", so most research went to that area.

A web search under "airfoils", "Dr. Selig" and "low Reynolds numbers" should give you a lot to look over. /w3tcompact/icons/wink.gif

Larry