My vision for the future is for each home to contribute as much of its own power as possible. In my simple brain, that makes me think solar power. And when I think solar, I think of concentrated light, such as from a parabola or fresnel lens.

But the real question as a DIY'er is, what would I best put at the focal point to generate that power?

1) Stirling engine? Probably the most efficient, but requires REALLY good milling and metalworking.
2) Silicon Solar Cells? Sure, but is that really DIY? I mean, I don't have the first clue about making one.
3) Steam engine? Sure, that would work, if it didn't explode killing a neighbor's kid, and if it didn't make my water bill go up.

I can build a really big, mirrored parabola, thanks to years of making pj crap. LOL It's that last piece of the puzzle that boggles me.

You could always uhh.. use thermocouples to convert the heat to electrical energy.

True, but at least from what I read, that is a pretty darned inefficient conversion, right? Plus providing a heat sink that will not mediate back to the hot side temperature after minimal usage. Of course, I do want to add a hot tub soon ... hmmm.

My guess is we would be talking about ~500 degrees at the focal point, and around 80ish ambient, which is a nice differential.

Sounds like the perfect application for a steam driven turbine. Even a simple steam engine with a genny coming off the end would do.

Hmm

Here is what I really want to build, but on a single-home DIY scale. Sure, easy huh?



Oh, and did I mention portable, heliostatic, and for under $1000?

So quit dreamin and start doing....

What you need is a big old 12 foot antenna dish, a crapload of mirror scraps, some liquid nails and a lot of patience. Make sure you put them on in a shady place and then erect the antenna with a boiler mechanism fed by a gravity feed to produce lovely amounts of steam. Insulate the pipe from the boiler or simply make a direct turbine and generate electricity. Feed the energy into a grid...Uhmmm.

A smart person would also figure out a way to use the servos on the dish to track the sun...

Im not tellin...Im just sayin..

More reading, more research!

http://www.popularmechanics.com/science/earth/4243793.html

A very interesting approach ... use a temperature differential to drive ions across a membrane generating an electric current.

The man patented the Super Soaker?

My money is on him...just look how he changed the basic squirtgun!

It seems to me that the JTEC technology might actually be accessible to a DIY builder!

But, the missing link is the proton conducting membrane. Even if it is not efficient, I wonder what an example of a readily available material that has PCM capability would look like?

For instance, if I wanted to make my own photovoltaic semiconductor, I could heat a square of copper on the kitchen burner. But what can be used or made as a PCM? Hmmm

DaveOxide ... got any clue?

Yeah I designed one of these a few years back.... he uses Unubtanium

That stuff is nigh impossible to get your hands on though...

Anyone able to put this in english?

http://www.freepatentsonline.com/7125621.html

Now,
imagine that the roof of the vehicles on road is covered with this kind of sheets. Then, whenever a vehicle enters a specific virtual zone marked by distinct radio waves, a reciever on this sheet sends a signal to the reflectors telling the to face the target. Sunlight falling on the roof of the vehicles gets concentrated on a point over the road.
A virtual zone marked by radio waves contains a single focus area.
Suppose that a 500 m long stretch of road comes under this virtual zone and in the middle of the stretch i.e. at 250 m there is a overhead post just like those traffic lights.
Now, if any vehicle enters this area, it's roof top sheet gets the signal to align the reflectors in such a way that sunlight is focussed on the overhead post in the middle of the stretch.

For some reason that reminds me of a suggestion by one of my favorite (mad) scientists:

From http://www.eskimo.com/~billb/hoax.html

"Kindergarten Solar-powered Death Squad
Take a large crowd of children out into the sunshine and give each one a 20cm square mirror. Show them how to aim all of their little spots of sunlight at the same distant object, then stand back and see what they do. Better yet, run away.

FAST!"

Saw this on MythBusters, they were trying to recreate Archemidies Death Ray, (I think it was him at least, and "Death Ray" may be poetic license ) They were trying to sink a wooden ship by concentrating sunlight with a whole bunch of mirrors.

I think it would be best to start small first

If you are looking to get your home off the power grid you have a few really easy things to start doing. One minimize the amount of power you are using in the first place. There is a product called "green switch" that will turn off all the stuff left on that still uses power. things like VCRs stereos TV's etc that still draw power in standby mode. Make sure your attic and crawl space are properly insulated. Replace regular bulbs with the mercury vapor ones. Insulate the water heater and turn the temp to around 120deg to save energy.

And yes, there are ways to create more power then you use, which you can feed back to the grid and the power company pays YOU. Solar power is a good Idea, but it is not THAT cost effective. If you are in a windy area, you can get some regular wind turbines for around as much as you would pay for a couple solar panels. Not so high winds? Then you could put up some vertical shaft turbines that don't need as much wind speed to run. Those are a perfect project for the DIYer

Idaho National Laboratory has figured out how to do Infrared Solar panels at around 80% efficiency. They will work in cloudy weather and even at night from background IR energy. Once they get the rectifier design figured out they will be very rich. What you are thinking about may actually be very plausible since the design is VERY cheaply produced and could be "painted" on almost any surface.
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With the parabolic stuff, it becomes rather difficult because you need allow of surface area, not only on the ground, but with the reflective media. It would be a good DIY project, but if you are looking to power your home... Probably not the best.

Thanks for the reply, Dead.

Yes, the dye-based solar cells do look very promising, particularly in the IR spectrum.

The nice thing about power is that it is scalar. ANY reduction in usage or increase in available current will reduce your bill, though maybe not replace it.

However, this is the place for mad skillz and DIY Powah baby! What would life be without some enormous handcrafted monstrosity annoying the wife and intimidating the men on the cul de sac?

My real hold up for moving forward is the piston sourcing and a decision on whether to go rotary or linear in piston arrangement.

With Rotary (not as in Wankel), I can focus my heat/light to a single point that all the Stirling pistons feed off of. With a linear arrangement (like a 6 cylinder car), I can use a parabolic trough rather than a dish for focus (like you would use for solar water heating). With linear, I could also perhaps forgo sun-tracking.

Still pondering, but got some GREAT drawings ready. Can anyone think of a cheap source of a piston arrangement akin to using a napkin holder for a reflector? Meaning retasking something cheap.