Posted by Lord Gow333, Dirk Benedict's n on March 24, 2009, 4:35 pm
Not enough sunlight in Western New York to justify the expense, IMHO. I'd
probably be better off with a windmill. I was looking more for something
useful, or at least fun, to do with the pallet scraps in the summertime.
Failure is the opportunity to begin again more intelligently. - Henry Ford
Posted by Curbie on March 24, 2009, 5:29 pm
I suspect you're just goofing on me but on the off chance:
Looks like beta or gamma type Stirling engine with one or more liquid
pistons inspired by Home Power #76, April / May 2000 by Jay Wilson. It
probably competes "tooth and nail" with a hamster wheel in terms of
Stirling's where another one those AE cures I chased, the numbers
worked (simple gas law) until you got into design materials - pretty
The one that set the record for converting solar thermal into
electricity is somewhere on a sunny mountain top, has a round parabola
of 35' (roughly 1000 Ft.^2) that generates 275,000 BTU per hour and
they only run it on crystal clear days because the ring-less pistons
have such a short operational life.
The only commercial endeavor (a good indicator of viability) I've seen
is the Whisper-Gen, 800 watts per hour @ $5K+ with a something like a
20,000 hour operational life.
The hamsters don't look so bad.
Posted by Morris Dovey on March 24, 2009, 7:22 pm
I'm working on a pair of fluidynes (Stirling cycle with only a fluid and
a gas as moving parts): a low-temperature/low-efficiency version to be
used as a solar-powered pump; and a high-temperature/high-efficiency
version for other purposes.
The low-temperature version is what was shown in the videos at the link.
Those (student) builders have only been working on that engine since
the beginning of the month and the performance isn't exactly "gee-whiz"
yet, but I expect they'll end up with a 1.5 - 2 hp pump if they keep at
it. Even if it produces only 1 hp, it'll do hamsters proud. :)
Other than the blue dye (whatever it is), I don't think there's anything
So far, there isn't anything more expensive than a sheet of
polycarbonate mirror and finned copper tubing in the high-temperature
version - but that version isn't yet complete so I can't make any claims
for it. As you said, at this stage the numbers /do/ look pretty good,
with a 70+% thermal -> mechanical energy conversion efficiency.
You can see sketches of both types at
although the most recent plan calls for a reflector that's 4' long and
8' wide (instead of vice versa), to produce a hot head temperature in
the 1450F ballpark. It should provide some "interesting" problems. :)
Sounds terribly spendy! The beauty of fluidynes is that there isn't any
significant wear. I'm not much so much concerned with efficiency as with
ability to get a job done reliably with a reasonable price tag.
Thanks - you're making one of my points for me. When what's needed is
mechanical energy (rather than electric energy), sometimes there're
other ways to get and apply it. I'm perfectly happy to leave electrical
power generation to others...
...although if you /do/ figure out a really efficient way to produce
electrical energy from one of these things, I'd really like to hear
DeSoto, Iowa USA
Posted by vaughn on March 24, 2009, 7:54 pm
Potassium permanganate comes quickly to mind. Once after I backwashed my
iron filter and was a bit careless where I dumped the effluent, my well ran
blue for two weeks!
Posted by Morris Dovey on March 24, 2009, 9:01 pm
LOL - that would be disconcerting. :)
Dunno, if it'd been me it would have been the blue stuff my mother used
when she laundered white shirts - or the stuff my grandmother used to
make her hair blue (either of which may have been KMnO4-based)...
These youngsters strike me as being both bright and resourceful - and
it's good to know that in the midst of all Islamabad's problems, there's
a group of young folk trying to solve a water availability problem older
than history itself - and it appears they're succeeding.
DeSoto, Iowa USA