Renewable Energy Applications include Solar, Wind, Biomass, Geothermal, and Hydropower. They can include residential, commercial, government, and utility-scale operations.
Solar Applications - Concentrating Solar
Solar PV concentrators are designed to focus sunlight onto a small space and generate power with greater efficiency. They must use tracking devices to keep the light aimed at a central area. The lenses, reflectors and more sophisticated tracking systems make these more complicated and expensive. However, they can be cost-effective in larger applications such as industrial and utility-scale electric generation.
This is a concentrating solar system where receiver tubes are positioned along the focal line of each parabolic mirror. A curved trough forces sunlight on an ‘absorber tube.’ The trough is rotated throughout the day to maximize the received solar energy. The absorber tube is filled with a fluid, typically oil, which becomes very hot. The oil is then passed through a “heat exchanger” that transfers heat to water, which boils and produces steam. The steam is used to drive steam “turbines” that produce electricity. (NREL)
A system of large field of mirrors reflects sunlight onto a ‘receiver’ in the top of a tower. This heats a special material (“solar fluid) to extremely high temperatures. The high temperature boils water, produces steam, turns a turbine and generator to produce “AC” electricity.
These systems use a mirrored dish similar to a very large satellite dish. The most common type of heat engine used today in dish/engine systems is the ‘Stirling Engine.’
This system uses the fluid heated by the receiver to move pistons and create mechanical power (“mechanical energy”). The mechanical power is then used to run a generator or “alternator” to produce electricity. (NREL)
The SunCatcher solar thermal system, developed by Tessera Solar and built by Stirling Energy Systems at the Sandia National Laboratories’ National Solar Thermal Test Facility, captures solar energy at 31.25 percent efficiency, the highest ever achieved by this technology. Each of SunCatcher’s 38-foot-wide dishes collects enough heat energy to run a Stirling engine that can then generate 25 kilowatts of electric power. The system will fulfill two of the world’s largest solar contracts, providing a planned 1,600 megawatts to Southern California by 2014. It improved on its predecessor with a new design that makes each dish substantially lighter and cheaper to manufacture. (Discover Magazine, Energy Forum, Alternative Energy, 10/8/09, discovermagazine.com)
A device for orienting a solar photovoltaic panel towards the sun. The sun's position in the sky varies both with the seasons and time of day as the sun moves across the sky. Solar powered equipment works best when pointed at or near the sun, so a solar tracker can increase the effectiveness of such equipment over any fixed position, at the cost of additional system complexity.