A parabolic solar collector focuses the sun's rays to heat a gas. When the gas is heated, it expands to push a piston, to drive a crankshaft, to drive a generator. When the gas cools, it contracts. The heat that drives the engine comes from mirrors that concentrate the sun's energy on one point. The whole mirror array is controlled by computers that track the sun throughout the day.
The concept was first developed almost 200 years ago by Scottish inventor Robert Stirling. Since then, a company called Stirling Energy Systems has developed a modern parabolic collector with Sandia National Laboratories.
Stirling Energy Systems already has two power plants operating in the southwestern U.S., displacing more than four million tons of global warming emissions, according to the company.
via Voice of America