My Rube Goldberg idea for Steam power....

Okay, Why would anyone want steam power?

I'm still asking myself that same question.

But anyway, I was thinking of using a solar heater (or enclosed solar stove) to heat water with a solar powered pump to create steam.

Then have the steam power a generator.

Crazy? I haven't a clue. It's still in the "one of my bright ideas" phase.

Comments?

It's the basic principle behind solar thermal electricity, although from a more 19-century, DIY and (dare I say it) steampunk angle.

The tricky bit is going to be containing it in a pressure vessel to do some useful work (Otherwise you've just got a bucket of boiling water).

I made using the little piston and cylinder from a discarded toaster turning my bicycle generator. Hey it would light up a two cell flashlight bulb, kinda', sorta' for a moment.

One of my schoolfriends had a mini steam-engine - the size of 3 or 4 videos stacked up. You filled it with water, but a charcoal brick in the hopper, and it would spin like buggery for about 5 minutes. Looked a bit like this:



Very cool. :)

:thumbsup:

:)

I wish I had a link - sorry - but I read in Science or Discover of a solar concentrator that would store its energy by heating vats of salt to a molten state, and then these could be stored in super-insulated conditions, to have their heat "harvested" as needed. Turning heat energy to electricity is still (I think) most practical by heating water to steam and running it through a turbine generator.

First, realize that for steam to be able to do much useful work, it has to be like 300+ degrees. And that is if you have a very efficient steam engine. If not, it better be more like 400+ degrees.

Now what kind of temperatures can you get with a solar collector? Just a hotbox type arrangement will get you maybe 190-200F, but you can't boil the water due to the high heat of vaporization unless you use some focusing type collector. A parabolic trough with a pipe at the focus will get you the extra heat needed to make steam and you can calculate how much water you can boil on a sunny day to come up with engine power.

It's been tried, and it does work, but the problem is integrating it with how you are going to use the power. One advantage of photovoltaics connected to the grid is that you don't have the upkeep on a steam plant (turbines, corrosion, etc.), which can be all sorts of hassles.

Semiconductor PV technology is where the money's at.

Solar thermal is really the only kind of solar energy that's ready for broad-based, decentralized, cost-effective deployment. If you read some of the press releases that are posted here (by the hundreds), you will see most of them support funding campaigns with intellectual property backing them up. It's a lucrative business.

Very lucrative.

And heating water in a pipe isn't patentable.

--p!

http://www.solardev.com/SEIA-makingelec.php

http://www.solel.com/products/pgeneration/ls2/kramerjunction/

and there's 24,000 MW of concentrating solar thermal currenty under development in CA

http://www.energy.ca.gov/siting/solar/index.html

http://www.renewableenergyworld.com/rea/news/story?id=35263

and a new 64 MW CST plant in Nevada...

http://www.designnews.com/blog/460000246/post/850010085.html

and 200 MW of solar thermal under development in Spain...

http://www.ens-newswire.com/ens/jun2006/2006-06-30-02.asp

http://technology4life.wordpress.com/2007/05/16/solar-thermal-projects-mushroom-in-spain/

and another 100 MW planned in Israel...

http://www.businessweek.com/technology/content/feb2006/tc20060214_533101.htm

If your ultimate goal is to generate electricity why not just directly create the power from the sun using photovoltaic cells? You're going to have friction losses in the generator phase.

My guess is that solar thermal (Concentrating Solar Power, in particular) comes out ahead on both.
http://en.wikipedia.org/wiki/Solar_power

It might not be as efficient or direct, but I could build one in my backyard with odds and ends, and it could be scalable to a variety of functions depending on the sophistication of the design.

As far as PV energy, I wouldn't have a clue where to begin; you need a mature and dedicated infrastructure of technology in place first.

It's a small parabolic mirror about 5 inches across. A couple of years ago I saw an array of similar mirrors used to focus on a metal "cup" that contained fluid in a closed loop system hooked to a small 200w generator. The device tracked the sun using a printer motor and sensors. Total cost was about $1 per watt. US inventor, but I think he is selling them in India.

http://en.wikipedia.org/wiki/Stirling_engine

The Stirling engine concept has been around for almost 200 years, although modern material science is making them much more practical then they used to be. I heard recently about a project that used Stirling engines at the focal point of solar collectors.

http://www.renewableenergyworld.com/rea/news/story?id=43336


Called Nevada Solar One, the 64 MW commercial-scale solar energy plant will encompass 350 square acres, a nearly endless sea of mirrored troughs that will concentrate the strong desert sunlight and convert it into 750-degree F thermal energy, which can then be used to create steam for electrical power generation.
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The receivers (vessels placed in the foci of the parabolic mirrors) must be designed to withstand the daytime highs of 750 degrees F and the lower temperatures at night. This can be particularly challenging to the seal between the outside glass tubing and the vacuum-packed steel receiver inside that holds the heat transfer fluid, a special synthetic oil.

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a solar furnace which will track the sun and focus the rays on the "boiler" - a monotube design - maybe in a salt pack. Its been done in Australia. We are talking about a 14 - 14 foot dish for useful amounts of power however. Assuming you are in an area where you have the land - and the neighbors won't complain.... A 5hp marine steam engine will set you back about 1500.00 for the casting kit which you will either have to finish machining and assemble - or pay someone to do it. There are plans available online for heliostats and the circuitry to track the sun. By the time you are finished you are probably talking about 10,000 min. for material costs alone and that is doing much of the work yourself.
That said, NO - it's not a crazy idea - it will actually work if set up properly and maintained - if not, the boiler will explode taking your heliostat with it.

Have fun - and consider a wind turbine if you have the wind and the space.