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Is anybody successfully generating electricity from solar generated steam?

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Posted by Rick... (The other Rick) on September 4, 2008, 3:33 pm
Sometime in the near future I will me moving to Spain ( the East coast near

Now I got to thinking .... (Dangerous, I know)
I will have a bit of land to spare.
There is all that lovely sunshine available.

We will be running a business where I will have a lot of free time during the
day, and I will need
something to do to stop me going mad, or becoming an alcoholic.....

My idea is to build a smallish Compact Linear Fresnel Reflector array. About 20
square meters in
size (total size depends on power needed)
Using this to generate steam to power a small steam engine coupled to a
generator, any power that we
don't use will be sold back to the Grid generating extra income. Waste heat will
be used to heat the
house and pool in winter.

Building the array will be simple, however doing something useful with all the
heat generated is a
little more tricky (for me at least).

Here are my first thoughts...

Use oil in the primary collector loop, this will reduce the need for high
pressure pipes to be used.
As a guess the temperature of the oil will go up to between 400 to 600 C
depending on the mirror
area and the amount of insulation I use.

Maybe use a thermal store, ie a BIG block of insulated concrete.

Use a heat exchanger built into the boiler to generate the steam.
Use a steam engine, in particular one of these
http://www.greensteamengine.com/index.html  coupled to
an alternator to generate the electricity.

The above is just the bare bones idea. Obviously it will need filling out.

As a general plan what do you guys think?

Rick... (The other Rick)

Science and sound engineering will always prevail in the end
"for nature cannot be fooled" [Feynman]

Posted by gary on September 6, 2008, 1:36 am

One thing I would check on is the efficiency of steam engines.
My recollection is that they are so bad that even though the
collectors are fairly efficient, the efficiency of the whole system is
very poor and a lot of collector area is required.

It seems like kind of a catch 22 -- with solar electric, the PV panels
have poor efficiency, but the electric motors are good, but with a
steam system, the collectors are fairly efficient by the steam motors
are very low in effiency -- either way the total system efficiency is


Posted by Robert Scott on September 6, 2008, 1:55 am
 On Fri, 5 Sep 2008 18:36:16 -0700 (PDT), gary@builditsolar.com wrote:

The best-case efficiency of a steam engine is directly related to the delta
temperature as the steam goes through the system.  To get high efficiency you
need very very hot steam.

Robert Scott
Ypsilanti, Michigan

Posted by Mauried on September 6, 2008, 3:31 am
 On Fri, 5 Sep 2008 18:36:16 -0700 (PDT), gary@builditsolar.com wrote:

As a general rule, solar generated electricity is just about never
economically viable, if you have grid power avialable.
The cost of the hardware to generate the electricity will always be
far more than the value of the electricity so generated, unless your
local power company will subsidise your equipment and also buy the
electricity off you at some kind of premium rate.
You will do better with wind generators.

Posted by Rick... (The other Rick) on September 9, 2008, 10:11 am
 On Sat, 06 Sep 2008 03:31:53 GMT, mauried@tpg.com.au (Mauried) wrote:

I believe that the local utility company in Spain will buy back any power that
you generate.

However, if I can generate enough to run a couple of air conditioners I will be

I know that it seems crazy doing it that way, but I feel that becoming an
refrigeration engineer on
top of everything else is too much,

Basically, in the winter months, I want to be able to heat the house and some
outbuildings, and in
the summer months generate power for cooling and maybe selling back to the grid.

The following two documents give me hope,,,


Although I will have the space, I don't think I will build something quite that
large <Grin>

Rick... (The other Rick)

Science and sound engineering will always prevail in the end
"for nature cannot be fooled" [Feynman]

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