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Flash steam | 39 comments (38 topical, 1 editorial)

experiments? (3.00 / 1) (#26)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Fri Jul 4th, 2003 at 05:33:30 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

In my opinion the problem
is to make it cheaply and simple.

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.

Did you see those homepages (User info) of mine?
Including pictures from Nepal?
It is possible to make good
parabolic mirrors even in rural conditions.

Re: experiments? (2.00 / 1) (#27)
by Andrew (andrew@lookingglass.com) on Fri Jul 4th, 2003 at 01:16:18 PM MST
(User Info)

Thats Ingenious!
I was thinking on just that on how to solve the problem of water just "skating" off.
I think a mesh of ceramic coated wire inside the flash chamber would be effective. (like steel wool) The problem now will be how to conduct heat rather quickly from the outside edges to the inside ceramic. (I have no idea on the thermal conductivity of ceramic)

-Andrew

[ Parent ]

Re: experiments? (3.00 / 1) (#28)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Sat Jul 5th, 2003 at 05:07:28 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

"I think a mesh of ceramic coated wire
inside the flash chamber would be effective.
(like steel wool)
The problem now will be
how to conduct heat rather quickly from
the outside edges to the inside ceramic."

You are probably right.
It is a problem.

Your design is something similar
I've got in my mind.
We might make holes in some
stones, but iron bars inside,
weld the bars on the container body?

My design idea is coming directly from sauna kiuas.
With electric kiuas the hot iron resistors are there
in between the stones. They are conducting heat
to various places in the stones.

With a fire wood kiuas the fire is under the stónes,
the water is poured on the top. Some of it boils directly
on the top. Some of the water goes further deep
in between the stones. Finally all the water
becomes steam anyway.

It might be better to design the chamber such a way
that the water is injected on the top of the stones,
and the steam could go out from the top only?

We can make in the water heat and pressure
enough already in the in coming water so that
it comes inside the chamber as flash steam?

Some water maybe could escape from
the bottom of the chamber
as well,
because we can maybe design the turbine such a way
that it can accept both steam and water?

I'm thinking that we should just somehow transmit the
all the heat to the water coming in so that the
heat energy is there in the water and the steam
coming out to the turbine.

Then we could use the heat still coming out from
the turbine to power a heat pump to get the water back
to the water tower?

- Hannu

[ Parent ]

Re: experiments? (2.00 / 1) (#29)
by Andrew (andrew@lookingglass.com) on Sat Jul 5th, 2003 at 06:22:54 PM MST
(User Info)

I would think that you would get more pressure if you went with a long and skinny chamber. It wouldvaporize the water in the front, and would be superheated along the way out by the rocks in front of it. As the pressure would increase, you would need the longer chamber because it would be too cool for steam because water boils hotter and higher pressures. Regarding the heats transmission. I was thinking that instead of drilling one hole in the rocks, just drill many smaller holes in the rocks (as much as you can) and weave a small iron or steel wire (6 guage?) through it. You would get more uniform heating as there would be more surface area covered. -Andrew

[ Parent ]

Re: experiments? (4.00 / 1) (#30)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Sun Jul 6th, 2003 at 02:12:17 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

I think that you are right.

a)
A long and skinny chamber is probably better.

b)
And we need enough surface to transmit the heat
from the chamber body to the stones.

It is a matter of experimenting concerning the
right dimensions.

And it might work quite well, if we just make
quite many bars inside the chamber, welded inside
the container, but not fixed on the stones?
Because electric sauna kiuas works this way.

--------------------------------
I'm trying to keep the pressure quite low and to
use as low level technology as possible so that
we could beat PV cells in price and power.

I'm trying to make this using 'village
technologies'. For example in India
and in Nepal I have seen that common blacksmiths
in rural villages and in small towns
are very very skillful (because
many of them represent a tradition of the same
'clan', 'caste' or 'extended family' hundreds of years old)
, but they are lacking modern materials and tools.

We people as well often are lacking the most
sophisticated tools and materials and in general
normal 'self-made people' or school-educated
engineers in the western world are far less
experienced using their hands than village
blacksmiths of the 'East' or of Africa'.
----------------------------------

Concerning the chamber body itself.
Maybe the easiest low level technology would be
to use cast iron?
But the problems include
a) welding on it is difficult.
b) it rusts quickly if heated red hot.

So maybe the best would be to use a steel pipe?

The next problem is how to get the bars inside and...

Maybe we need to cut it open with an angle grinder,
weld the bars, put stones in and weld it together?

Or we might just put in mixed steel bars and stones?

Concerning the water columns.
I think that it would be easiest to use normal
black painted pipes.

- Hannu

[ Parent ]

Re: experiments? (4.00 / 1) (#31)
by Andrew (andrew@lookingglass.com) on Sun Jul 6th, 2003 at 01:04:20 PM MST
(User Info)

Your idea of iron is not a problem. First simply make a "half cast" of the chamber, and then forge it twice. On the inside simply weld or braze small iron bars. As many as you can. Next have one of the villagers mix up some clay or ceramic type mix. Simply paint the iron bars and the inside of the chamber as much as you can cover. Do this with the other half as well. Welding shouldn't be a problem if the ceramic has time to harden. Weld the halves together. For your water towers, gravity will be fine. Do not paint them black as you could get too much pressure that it could force open the intake valve prematurely. As for the efficiency. I don't think you can beat pv cells. This machine at MOST will be about 20% efficient. Simply because of the thermal losses of the chamber, the turbine only being pulsed by steam, and not continuous flow. (Probably compansate for this by adding a large flywheel.) The longer the chamber the better. A coil type chamber would be ideal. This is how I made mine. About 2 or 3 turns.

Now on the design....
Put the intake poppet valve right near the water towers (ball valve could work too). Add heat sinks (as much as you could machine or weld, etc.). When the high pressure steam shoots out both directions, it will head toward the chamber. It will approach the valve, and then cool off. It will draw a vacuum when cooling off forcing more water in the chamber. (The neat part about this design is it needs no water towers for pressure, it can intake the water straight up, vertically, which means that instead one could simply put the intake hose in a small pond or lake, etc) If you put the valve right next to the chamber it will not work like this. You WILL need water towers. As for your turbine.... A simple pelton wheel type turbine will be excellent. You will probably need access to a lathe, as balancing this will be a pain. (you are spinning at many tens of thousands of rpm) I got my little pelton wheel to about 22,000 rpm. Everything else looks fine. (if there is anything else)

-Andrew

[ Parent ]

Re: experiments? (5.00 / 1) (#32)
by Anonymous Hero on Mon Jul 7th, 2003 at 04:50:20 AM MST

I think if he returns to the smaller flash box and stays with solar mirror, it will again be 80% efficiency or higher. Also pulsing a turbine, instead of steady stream, is not going to be a problem for what he intends. You don't need 100,000 rpm, or even 22,000, to generate 1000 watts. At $3.50 a Watt (Solar Panels) that is roughly $3,500. If you can make this cheaper by keeping it simple you'll be better off than panels. Any needed valves can be found at a Boiler supply web site. You need nothing in the (small) chamber, no rocks or pipe. The air inside the chamber will be over 600 degrees. The water will not skate anywhere, the air alone will flash steam it. Cheers

[ Parent ]

Re: experiments? (4.00 / 1) (#33)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Mon Jul 7th, 2003 at 05:54:36 AM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

--------------------------------
Andrew:
Your idea of iron is not a problem.
First simply make a "half cast" of the chamber,
and then forge it twice.
On the inside simply weld or braze small iron bars.
---------------------------------

- Hannu

You mean that after twice forged it will be easy
to weld? I will consult my friends, who work
for a very big foundry here.

-------------------------------
Andrew:

As many as you can.
Next have one of the villagers mix up
some clay or ceramic type mix.
Simply paint the iron bars and the inside
of the chamber as much as you can cover.
Do this with the other half as well.
Welding shouldn't be a problem
if the ceramic has time to harden.
Weld the halves together.
---------------------------------
- Hannu

Don't you think we should fire the whole thing
in a kiln
after welded together?
-----------------------------------

-----------------------------------
Andrew:

For your water towers, gravity will be fine.
Do not paint them black as you could get too
much pressure that it could force open the intake
valve prematurely.
------------------------------------
- Hannu

Yes. One of the main problem will be to control the
pressures.

I'm thinking that we might make the chamber that way
that the steam starts flowing out fast
and even creates a bit
suction. If we make the chamber to expand towards
the turbine and make it like a spiral inside?
------------------------------------
Andrew:

As for the efficiency. I don't think you can beat pv cells.
This machine at MOST will be about 20% efficient.
Simply because of the thermal losses of the chamber,
the turbine only being pulsed by steam,
and not continuous flow.
--------------------------------------
- Hannu

Yes I think that we have got two possibilities for the
design:

a pulsing steam system or
a continuous flow

system.

I'm trying to design this power system to be
as much as possible 'village technology',
'self-made'
so that the cost in money would be low.
PV cells you cannot make
in a village easily, so they cost money.
The cost will then depend heavily on the
salaries of the local hired people, like blacksmiths.
I'm thinking that some engineers in India, in Nepal,...
could try making something like these
in small villages there.

I agree that concerning how effectively we
are using solar radiation, good PV cells are
already hard to beat.
------------------------------------
Andrew:

(Probably compensate for this by adding
a large flywheel.) The longer the chamber the better.
A coil type chamber would be ideal.
This is how I made mine. About 2 or 3 turns.
------------------------------------

You already made one???
You seem to be very fast.
Please describe more!
-------------------------------------

Andrew:

Now on the design....
Put the intake poppet valve right near
the water towers (ball valve could work too).
Add heat sinks
(as much as you could machine or weld, etc.).
When the high pressure steam shoots out
both directions, it will head toward the chamber.
It will approach the valve, and then cool off.
It will draw a vacuum when cooling off
forcing more water in the chamber.
(The neat part about this design is it needs
no water towers for pressure,
it can intake the water straight up, vertically,
which means that instead one could simply
put the intake hose in a small pond or lake, etc)
If you put the valve right next to the chamber
it will not work like this.
You WILL need water towers.
-----------------------------------
- Hannu

I agree that making a pulsing steam flow would
be easier to make.

Could you, please
describe a bit more your
'heat sinks' concept?

---------------------
Andrew:

As for your turbine....
A simple pelton wheel type turbine will be excellent.
You will probably need access to a lathe,
as balancing this will be a pain.
(you are spinning at many tens of thousands of rpm)
I got my little pelton wheel to about 22,000 rpm.
----------------------------------
- Hannu

You think that a pelton wheel might work better than
a simple crossflow?

Are you running your pelton with this
steam system already???

------------------------------------
Andrew:
Everything else looks fine. (if there is anything else)
------------------------------------

Thank you a lot
for your very good contributions!

I've informed about this site some
of my friends in Nepal and in India , too.
Maybe some of them would start making
these things.

- Hannu
-Andrew

[ Parent ]

Flash steam | 39 comments (38 topical, 1 editorial)

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