The Solar Highbeams Project: draft front page for Github

THE SOLAR HIGHBEAMS PROJECT

is an open hardware/software project to improve awareness and modeling of solar furnace power, and develop under creative commons license the required new hardware components. Since developing the hardware components, like those needed for a moonshot, makes no sense without an understanding of how they all will work together, a high priority is developing 3d models and ray-traced images and animations of systems and components that convey the motivation for the work. Needs of the Solar Highbeams Project range from mechanical and optical design, to system optimization, environmental impacts and promotional media.

WHY SOLAR FURNACES?

Renewable energy is often criticized for requiring expensive energy storage, but in a gigawatt-scale solar furnace, storing energy as high-temperature heat is easy, comparatively safe, and, in fact, almost unavoidable. Unique among all sources of power, a solar furnace is primarily a means of making things. In particular, if a solar furnace is itself made mostly of glass, it can make most of the parts for the next solar furnace from inexpensive local raw materials. In so far as solar energy for making glass will be the limiting factor, it appears the doubling time to make parts for the next solar furnace will be only a matter of months. An advantage solar furnaces enjoy over other sorts of solar power is that the solar energy collected travels the last couple of kilometers to the power network, not through expensive copper wires or steel pipes, but as an optical beam, just as freely as it travelled the first 150 million km from the sun to the earth.

WHY TWO-MIRROR HELIOSTATS?

Solar furnaces built to date use many flat mirrors, called heliostats, to redirect sunlight toward a common focus. A consequence of using a single mirror reflection to accomplish the entire redirection of sunlight toward the focus is that the heliostats tend to block each others' view of the focus. That results in both an expansive use of land (the deployed mirror area might be as little as 18% of the land area), and a focus that is uneccessarily high above ground level (typically about 1/7 the radius of the field.) A rough way to put it is that designing a conventional heliostat field is as difficult as designing a theater for Sponge Bob Squarepants  with eyes at the level of his torso. Using two mirrors per heliostat—a large primary mirror near the ground (think of it as the body,) and small secondary mirror mounted high above it (think of it as the head)—permits a heliostat field that uses ground as efficiently as a Broadway theater. Also, the mechanical motions in a field of one-mirror heliostats are all different; with two-mirror heiostats the motions are all the same.