The idea of using flash steam in a turbine is a good idea since it would open up the possibility of using simpler valving and perhaps even utilize a batch process where you would heat a small reservoir of water (maybe a 50ml shot at a time); a temp senser could then pop a solenoid open to the turbine for a short burst and generate electricity. Then reload with condensate and start over. The vessel and tubing would have to handle serious pressures. Not something to taken lightly.

Here's an interesting aside: http://www.blastwavejet.com/rocketcar.htm

"Hot water rocket engine" that used a 2 foot metal ball filled with water, heated, then crack the valve...whoooosh!

I got from a friend a tiny tin toy turbine.

I connected that with a coffeemaker,
where I extended the
tube where the hot water and steam comes out,
with a plastic pipe,
which goes into the inlet tube of the turbine.

It works well.
There is very little power, of
course, because the turbine
is made with the vanes
of flat metal sheets.
About 5 cm in diameter.
But it goes fast.

I will later send pictures of this experiment
when I get my film from a lab.

Basically the coffee maker works exactly
with the principle as described earlier.

I think that Andrew's suggestions
are just right.
As the flash tube, a metal tube works
and we need no pressure to get water in.

There is a small very hot chamber and
a ball valve letting
the cool water to come in to the hot tube.
The other end of the hot tube is open.

That system of the coffee maker
of course works with electric heating
for the hot chamber.

-------------------------
But you can use any heat of course.
Solar heat, too.
-------------------------

If you will try to duplicate the experiment you
might have to modify the valve, which lets
the water in to the hot tube.
Mine was just suitable
broken so that it lets the water in as small droplets,
when the water is quite finishing.
Or maybe the extra pressure from the extended
tube made the valve leaking.

Next I have to ask somebody to make for me
a little bit bigger turbine,
which I could connect to a bicycle dynamo.

I will maybe visit a workshop
to ask them about the prices to make a small
crossflow turbine.
Or a Pelton wheel as suggested by Andrew.

I've got one solar concentrating mirror
of 80 cm in diameter,
made of a satellite antenna.
Glued a kind of chromium tape on it.

I've once tried to run a toy piston steam engine
(with a normal boiler) with that mirror.
It works well.

Of course this kind of solar turbine is quite
inefficient, however good technology
we will use for the turbine wheel,
but that is not necessarily
a problem. Solar energy is practically unlimited.

The main thing is to make the system cheap and
possible to be built with really low level
technology so that any blacksmith in developing
countries can make it.

The clockwork for moving solar mirror is maybe
the trickiest part of the project, but
Scheffler lens people have already shown how
to make a clockwork simple using mainly
bicycle parts.
(Please see the link provided above.)

You just opened up a whole new can of corn. Check out:

http://www.gov.on.ca/OMAFRA/english/crops/facts/93-023.htm

Sounds great for Winter heating.

Thinking outside the box...but half in the bag.

The above is my
very rough picture
of a solar flash steam turbine.
I simply got enough
of drawing with a computer
and wanted to put the main idea first here.
I will make better pictures later.

DESCRIPTION:

Part A.

1. There is water in the container.
In the bottom of the container there is pressure,
because of the gravitation forces.
A water tube starts from the bottom of the container.

2. Sun rays hit the parabolic mirror 3.
The available power from the Sun is about one kW per
one square meter.

3. The parabolic mirror of 2 square meters reflects all
the sun rays hitting the mirror to the chamber 4.
The water from the tube goes inside the chamber.

4. The flash steam chamber is finned inside
with spiral fins so that the water coming in
is effectively suddenly heated.
There is needle valve letting the water in the chamber
from a small hole.
The chamber is made of ceramic at least outside,
so that it can be heated by the parabolic mirror
more than 1000 C hot.
The chamber is expanding inside towards the outlet end.
Inside the chamber flash steam is generated.

5. The flash steam coming out from the chamber hits
a crossflow turbine made of ceramic.
The crossflow turbine runs a generator.

--

Part B.

The parabolic mirror is arranged to be turning round
on an axle, which is on the same angle
as the axle of the earth.
There is a clockwork to move the mirror
so that it all the time focuses in the chamber.

--

DISCUSSION:

1. The main power is coming from the Sun.
2. Water gravity is used to jet the water inside the flash steam chamber.
3. No big and complex boilers are needed for this kind of steam turbine.
4. This solar flash steam turbine is simple to build even in rural workshops,

--

5) The electric energy available
out of the process?

a) As told above, there is about
one kW heat energy available for
one square meter from the sun.
It is quite safe to assume that we can arrange
more than
50% of the sun rays' heat energy
to be absorbed as heat energy in the chamber body.

b) All that heat can be transferred into the flash steam
heat and kinetic energy, because the energy cannot escape other way?

c) A simple crossflow turbine generator can be made
maybe 20% effective.

---

So if our mirror is
2 square meters,
we might expect
200 watts from the turbine?

There would be a ball valve
to stop water going back, if it starts boiling in that area.
So there would be already some real steam power for the
flash chamber.

Then there would be the real flash chamber, heated with
a point focusing parabolic mirror. The water would
come in trough a small hole, with a needle valve.

The focusing mirror can be going around
with the same clockwork and axle as the trough mirror.

-------
To Troy:

If a point focusing parabolic mirror is moving the same
way as a trough mirror we have no need to
track it with altitude and azimuth?

-------
How to make parabolic mirrors cheaply even in rural
areas, there are many drawings, if you
look at my pages with my 'user info'.

More drawings are available for example here:
http://www.solarcooking.org/

------
How to pump water high up?

Maybe the best way is to use solar.
I've given some ideas how to build simple
solar pumps earlier.
Please look at my earlier comments.

I'm not intending to make now any 500 kW power, but
about 50 W - 500 W power.
Because sunshine is
(still, it might happen that big American companies
will try to patent sunshine? <grin>)
free, the machinery doesn't need to be so
efficient,
built cheaper than PV cells and possible to make
in rural conditions.
-------

In my idea the water would come injected
inside of a really hot
chamber (about 1000 degree),
where it instantly becomes steam, which
goes into the turbine.

I got the idea to use ceramic (or stone) inside Sauna.

You ever go to any Finnish Sauna?
In a sauna there is a container ('Kiuas')
with stones, which are made
hot by a fire or by electricity.
You pour water on the stones, and
steam is coming out.
(The air temperature inside sauna is normally
about 80 degrees Celsius.)
The stones are generally about as hot
as red hot iron.

Yes, I know about a problem with most metals
and 'red hot'.

Normally a barrier of hot steam between water
and metal stops steam formation if the metal is too hot.

This is the reason I suggested using
ceramic or stone chamber and
injecting the water inside.
Injecting the water with reasonable
pressure might solve that problem with metals. too.

Even if stones in a 'kiuas' are as hot as you
can ever get them,
it produces steam very effectively.
In an electric sauna kiuas
there are red hot electric resistors,
in between the stones.
It produces steam very effectively, you have no need
to inject the water in.
You just pour it on the stones.
The water makes many many movements
in between stone pieces, before it is all steam.

Many people probably got
all the necessary machinery to try it.

You might try with a quite big chamber
made of reasonable good steel,
put in stones or ceramic pieces
(for example broken wares from your
kitchen will do).
Lead a pressurized water pipe in with a small pipe
hole. Heat first the chamber outside red hot
for half an hour.

Make the chamber body shaped such a way
that the steam has a way
to escape from the other end
so that it produces a good flow
of steam.

You certainly can produce steam this way.
If it is cost effective, I don't know yet.

Here is a very rough picture of the concept

To refine the concept I think that the first thing to do is
to make an adjustable needle valve for the water injection.

Hannu Virtanen
hvirtane@cc.jyu.fi

P.S.

I was fooling around with a different kind of drive system so the flywheel could spin freely and faster having nothing to do with returning the piston.  Only where you see the "spring piston return" I would try to use an air pocket that the piston compressed when fired, thus the air pressure in the air pocket would return the piston when the steam eacape through exhaust port.

The thing is, when the air pocket gets hot it may have an expanding mind of it's own, this could be countered by desiging it to accomidate a set known running temperature.  In anycase, a number of things can be used for piston return but I feel some sort of air pocket could last longer than replaceable springs.
Bugs can be refined out of any system.

My general idea is as follows:
I will later try making a picture of it.
(At present it is past midnight here.
Just came back from seeing my friend, who
is very good at building small steam engines....)

(JCP's picture is really cool.)

1) The water pressure is generated
by gravity (and maybe air pressure)
in a water container on the top
of the valve.
(Pumped up by solar pumps... or by this machine itself)

2) Water is coming out of the container
through a small needle valve,
which can be adjusted and
can as well close itself from the hot side, by
a big pressure.

3) Water goes into a tube,
inside of it there is a spiral structure,
the tube is expanding towards the turbine,
the tube is made of ceramic.

4. In the ceramic tube flash steam is generated.
5. The flash steam goes into a steam turbine wheel.

6) The ceramic steam tube is heated
by a solar parabolic trough mirror.
About 1000 C degrees.
Something quite similar as my drawing here:
http://www.cc.jyu.fi/~hvirtane/through.jpg

----------------------------------------------

So my concept is actually quite near to
the concept of JCP.
But instead of a piston engine, a steam turbine.

I think that it is possible to keep the needle
jet for water flow open all the time.
No valve closing mechanisms.
What do you think?

Who would try to build one?