Solar thermal is heating up.
Infinia, which makes a Stirling engine that can generate electricity or household heat by harvesting heat from the sun, has raised $9.5 million, the company said Thursday. Investors include Idealab and Khosla Ventures. As part of the deal, Infinia bought Stirling Cycles, one of Idealab's companies.
Stirling engines were invented in the 19th century as an alternative to steam engines. A Stirling motor has a closed cylinder that houses a gas, such as hydrogen, and a piston. Applied heat expands the gas to move the piston that, in turn, pumps other mechanisms, such as a crank, to create energy.
The Kennewick, Wash.-based company's main product will be a dish--which will look like a large satellite TV receiver--that will use the sun's heat to generate electricity. It can also generate heat.
The product is slated for final design later this year and commercial release in 2008.
Other solar thermal companies (also called concentrated solar power) use the sun's heat to warm oil in a closed tube. The oil is then used to create steam, which turns a turbine.
Some scientists and venture capitalists believe that electricity produced at solar thermal power plants can be as cheap as conventional electricity. Solar thermal plants, however, only work in dry, desert environments--like outside of Las Vegas or in the deserts of Algeria--and are quite large and expensive. Nevada Solar One, a recently inaugurated 64-megawatt plant, cost $250 million.