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Anybody know where to get a small steam turbine? - Page 2

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Posted by Curbie on March 24, 2009, 2:28 am
On Mon, 23 Mar 2009 18:36:11 -0800, "Ulysses"


I said in some other post (somewhere) that the numbers usually kick up
the problem(s) in an idea. The numbers for "Solar Steam" look
something like this:

33475 BTUs (1 Boiler Hp/Per hour)
250 BTU's for 1 Ft.^2 (of collector on a reasonably clear day)

Say you have a 12'x12' parabola = 144 Ft.^2
144 x 250 6,000 BTUs or roughly 1 boiler Hp

You would need 3 such collectors for just 3 Hp which is about 2250
watts per hour of sunlight(5-6 hours per day). To be used over a 24
hour period, including backup charging for clowdy days.

I pushed the numbers on this idea for a year or so (not the cheese
above, but serious numbers) inspired by
an engineering student who did a "Solar Steam" generator with limited
success. Solar tracking software, parabolic calculators, steam math,
heat exchange math, I did the whole 9 yards.

I may toy with it on a small scale for fun but if I read "between the
lines" correctly in a previous post, I like your setup better (if
you're growing your own fuel). Solar thermal is cost effective on a
large scale, on a small scale there don't see a CLEAR path.

If you have land (a couple acres) I'd focus on growing bio-fuels,
bio-diesel or ethanol (climate depending) and heat exchange to capture
and utilize waste I.C.E. heat.


Posted by daestrom on March 24, 2009, 11:19 pm



Problem with most steam turbine designs is they aren't very efficient until
you get up into the multi-stage units.  With just a single stage pressure
drop for one wheel, there are a lot of exit losses.  But to really get a
good multi-stage unit, you need a much higher steam pressure, out of range
for most home-brew boilers (who wants to qualify on a 600# superheated steam
plant, just to make home power?)

For external combustion such as biomass (or solar), I think the way to go is
piston.  I'd like the Stirling idea, but they need some hi-tech materials
/seals in order to amount to much.


Posted by Curbie on March 24, 2009, 11:41 pm


pressure, out of range

Laws vary state to state, some limiting by surface area size also, but
regardless, some real education is required before playing with steam.

I like the Stirling IDEA too, but they need I think a hi-tech break
through is needed in materials in terms of wear. Price/Preformance.

Posted by Curbie on March 24, 2009, 4:58 am
 On Mon, 23 Mar 2009 18:36:11 -0800, "Ulysses"

Like so many of the alternate energy ideas (stirling, solar thermal,
algae oil, ...) I bought into the hype and desperately wanted to get a
turbine to work, but after running the numbers I kept getting sucked
back to the piston engines.

I know I took a little grief for this opinion before (not to start a
spitting match) but it's just that (my opinion), if your plant is a
single stage, under 75hp, small turbines exhaust a greater percentage
of un-expanded steam than do equivalent piston engines. The larger
both engines get, the more efficient the turbine becomes relative to
the piston engine.

The Phoenix Turbine Builders Club
took a pretty serious wack at this idea posting monthly progress
reports until the progress reports abruptly stopped (dashed on the
jagged rocks of reality?), now they sell a 1 Hp Tesla turbine for
$000.00 (WTF)!

For small-scale electrical generation the piston engines are more
appealing to me now. To get a small-scale turbine to generate
electricity (as best as I can see), you'll either have to seriously
gear it down (more moving parts/cost) or deal with a custom built
generator and some pretty hairy frequencies.

A piston engine on the other hand could use less parts/cost, what you
need for electricity (in theory) is a conductor, a permanent magnet,
and motion. It doesn't have to be rotating motion it could be
reciprocating (a linear generator) dump the crosshead and flywheel? As
the load increases you can in the pressure to keep a stable RPM (or
frequency in this case).

Well, so much for this ramble.
Have fun.


Posted by Morris Dovey on March 24, 2009, 1:20 pm
 Curbie wrote:

For less than $00, you should be able to get that 1 hp out of something


and use Ulysses' solar furnace to make it go. :)

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

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