Hybrid Car – More Fun with Less Gas

Fluidyne (and solar powered!) Engines - Page 6

register ::  Login Password  :: Lost Password?
Posted by Curbie on April 15, 2009, 5:28 pm

I'm not even sure exactly what a fluidyne engine is, basically a
stirling motor to pump water is what I gather. If so, Jim's idea has
sound merit, the farmer doesn't have to pour water back into the upper
tank each morning, isn't the fluidyne a water pump? Seems like Jim's
idea could be totally automated to me?


Posted by Jim Wilkins on April 16, 2009, 12:33 am

If the fluidyne pump is reliably self-starting it could move water to
tilt the collector until a part of the collector shadows it. Something
would have to let the water flow back at night to re-aim the collector
towards the sunrise. A controlled leak will also rotate the collector
eastward (widdershins, opposite the sun's motion) when the sunlight
isn't strong enough to start the pump.

Posted by Morris Dovey on April 19, 2009, 1:43 am
 Jim Wilkins wrote:

They are self-starting, so that might help. The collector may be either
a flat panel (for low-temperature versions) or parabolic concentrator
(for high-temperature versions).

I like the idea of using the pump to power the tracker, but would like
to avoid weight-shifting strategies because I think they wouldn't be
stable in breezy conditions.

Totally automating the tracking mechanism would be ideal. Imagine an
unattended pump somewhere in the Kalahari keeping a pond filled for
wildlife in a species-preservation project...

If it can be made to work really well, the application possibilities go
considerably beyond agriculture.

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

Posted by Morris Dovey on April 19, 2009, 1:43 am
 Curbie wrote:

It's a Stirling cycle engine whose only moving parts are a gas (air) and
a liquid (water). They're fundamentally a plumbing construct. I have
conceptual drawings, a short video of a tiny fluidyne, and a photo of a
fuluidyne built largely of 4-inch Schedule-40 PVC drain pipe) at


Other folks have joined the engine development effort and you can see
photos and videos of their engines at


For a bit of the nitty-gritty stuff, there are pressure, volume, and
temperature formulas at


It seems like it /should/ be possible - I just don't (yet) have a good
handle on the "how".

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

Posted by Curbie on April 19, 2009, 4:26 am
Ok, if I'm getting this correctly now it's basically a gamma
Stirling engine (in your case) to drive a water pump with:

H = power
C = displacer
T = engine output

If it's not proprietary:
1)    What's the turn ball valve for, changing air flow for varying
2)    Shouldn't the regenerator be insulated to "beat the band"?
3)    Are you using copper scouring pads Chore Boy or the like in
the regenerator?
4)    Is the reason for your proposed regenerator design to transfer
greater heat without impeding air flow?
5)    Since the engine is for a water pump and since Striling cycles
depend on temperature differences, shouldn't the cold-side be water
cooled (route  pump water through it on its way to where ever it's
 If any or all of the questions are proprietary don't bother to answer

When I read Jim's idea I immediately thought "Water Clock".


This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread