Solar Hydrogen Energy Corporation (SHEC) Labs claims to have developed the world’s most efficient solar thermal technology, developing a concentrator and complementary receiver technology that is able to concentrate sunlight to a very high level. In their prototype, they concentrated sunlight up to 5,000 times the intensity that normally would fall on a surface on earth. This immense solar concentration can create heat at the focal point that approach the surface temperature of the sun at 6,000 °C (11,000 °F). Metal placed at the focus is instantly melted. In commercial scale systems, SHEC expects that the concentrations could be as high as 11,000 to 16,000 times the intensity of the sun. In practice, the objective is to not let the receiver get that hot. This is accomplished by continuously pulling off the heat into whatever the system is designed to do.
One of the applications of technology will be power generation, such as via a stirling engine or by steam and turbine. SHEC has singed an agreement for the pursuit and capitalization for the generation of a total of 3 gigawatts divided among six solar farms of 500 MW output each, beginning overseas this year. Other applications include process heating, district heating, water distillation, synthesis gas (syn gas) production which can be used for the production of alternative fuels including hydrogen and other applications.
How it Works:
In the solar concentrator world, there are typically three different methods of focusing the sun’s rays. One is a troth that focuses the sun’s rays on a tube passing through the length of the focal point. Another is a heliostat in which mirrors on the ground focus the sun’s rays up to a tower. The third entails point focus, in which reflective surfaces focus the sun’s light to a point.
It is this latter method that SHEC uses. They employ one-foot-square, glass parabolic mirrors that they manufacture with their proprietary, highly efficient “rapid drooping process”, increasing throughput thirty-fold with a low rejection rate. Several of these squares are then fastened to a frame. The commercial array surface will be a 40 foot by 40 foot square with a parabolic surface.
To harness this intense sunlight, SHEC has developed a solar receiver to absorb this energy without destruction. The light enters the aperture of a long, cylindrical tube lined with a highly-reflective coating. That might seem counter-intuitive, but what happens is that as the light bounces back and forth down and then back up that tube, 95% of the heat energy is gradually — rather than suddenly — absorbed by the tube before the light bounces back out the aperture.
Cost:
While the capitalization costs of a SHEC array will be greater than for a fossil-fuel-based plant of comparable output, the operational costs are much lower, not requiring fuel, for example. So the payback time is in the region of five to fifteen years. Compare that to the 50 year amortization schedule common for a hydroelectric plant, for example. The primary bottleneck to bringing SHEC lab’s technology forward has been getting adequate funding, but that has begun to come into place for them, though they are not where they would like to be.
– from pesn.com