Thanks, I'll read those tonight when I have more time. I've seen pics of the collection of parabolic mirrors focused on Stirling engines before but I haven't heard about that lately.
And you're right, 500Mw is the real deal.
I read a piece a couple of years back about
Bill Gross and his Idealab biz. This link covers part of the idea I liked which I can't find the link for anymore. I've got the article saved...it's
lonnnngg.
Here's a bit of it:
So on this glorious sunshiny day at Idealab, engineer Denes Zsolnay and industrial designer Gregg Luconi are outdoors fussing over a six-foot solar dish. Wearing welder's masks to protect their eyes, they focus a beam of sunlight on a black stainless steel cup, known as a hot cup. They watch as a digital thermometer measures the air temperature in the cup. It begins to soar, passing the melting point of tin (450 degrees Fahrenheit) in a matter of seconds, then lead (621°F), then aluminum (1,220°F). As if to drive home the point, Luconi grabs a scrap of lumber, a two-by-four, and jabs one end at the cup. In a heartbeat, the board erupts in flame.
Six months ago, Gross unveiled a prototype, dubbed Sunflower. It had an array of 12 small parabolic mirrors arranged like daisy petals around a central core. It was compact, and the lightweight mirrors of aluminized plastic could be moved by the sort of inexpensive but durable stepper motors commonly found in disk drives and ink-jet printers. Off-the-shelf heat sensors guided the motors that turned the mirrors. The mirror array followed the sun, no matter how high or low in the sky it happened to be, and then pumped heat into a small Stirling engine that turned a generator.
The link above covers the same "Sunflower" thingy but I believe that was the earlier idea -- to use photo-voltaic cells. The Stirling application could be more efficient and cost effective, I'm not sure though.