Stirling engines might be the best way to harvest the power provided by the sun
Nearly 200 years after their invention, and decades after first being proposed as a method of harnessing solar energy, 60 sun-powered Stirling engines are about to begin generating electricity outside Phoenix, Ariz., for the first time. Such engines, which harness heat to expand a gas and drive pistons, are not used widely today other than in pacemakers and long-distance robotic spacecraft.
The 1.5 megawatt (MW) demonstration site, known as Maricopa Solar, is set to begin operations early January 2010, with units provided by the Arizona-based Stirling Energy Systems (SES). While 1.5 MW is only a fraction of the power that may be generated at sites SES has contracted to develop in California and Texas, spokesperson Janette Coates says this is a necessary first step in the technology’s commercialization. “It’s important for our industry to see—and our partners and investors—that we can take a small-scale plant and get it operational before we break ground on larger ones,” she says.
That’s because Stirling heat engines have a reputation for being a bit impractical. First invented by Robert Stirling in 1816, the engines use a heat source to warm gas, which expands and is pushed into another chamber. When the gas cools and contracts, it flows back. The expansion and contraction pushes a piston, which in turn produces electricity.
In 1996, SES bought solar Stirling design and engineering patents from companies such as McDonnell-Douglas and Boeing. SES then partnered with Sandia National Laboratories, and over the next decade tweaked and refined the technology. In the SES SunCatcher, a circle of curved mirrors, resembling an upturned satellite dish, tracks the sun on two axes and reflects the sun’s heat onto a single focus point, the power conversion unit (PCU). The PCU contains four cylinders, in which hydrogen gas expands and contracts to move pistons.
Stirling engines are significantly more efficient at converting sunlight into energy than most photovoltaic panels or concentrating solar power plants, whether parabolic trough or tower designs. The test units have reached 31 percent efficiency, compared to 16 percent for parabolic troughs and about 14-18 percent for PV panels in use today (though newer designs not yet on the market range from 24 to as high as 41 percent). The high efficiency numbers alone, however, have not made Stirling an easy sell. The systems have been criticized as being too expensive, unreliable and requiring extensive maintenance thanks to many moving parts. Also, ground has not yet been broken on either California site for which SES signed purchase power agreements in 2005, adding to skepticism that these systems will ever become commercially viable.
The Latest on: Stirling engines
via Google News
The Latest on: Stirling engines
- Why Sir Stirling Moss was ‘Mr. Motor Racing’on April 12, 2021 at 10:49 am
In this clip from Racing Files (above), Sir Stirling Moss – who died on April 12 ... He could make magic happen, he flattered any car he was given to drive, he was Mr. Motor Racing. Two more Grand ...
- Rediscovered Stirling Moss photos offer unique glimpse of driver at his peakon April 12, 2021 at 3:49 am
In the scale of Stirling Moss’s sporting achievements, the 1958 International Trophy at Silverstone is barely worth a mention. During the disappointing May weekend, he retired from two races and saw ...
- Top 10 iconic F1 carson April 11, 2021 at 4:24 am
Powered by a Renault V10 engine mated to a semi-automatic gearbox ... Piloted by the duo of Juan Manuel Fangio and Stirling Moss, the Mercedes-Benz W196 was the world’s first fuel-injected F1 car.
- Auckland woman 'blown away' to be gifted piece of uncle's WWII plane wreckage from the Netherlandson April 9, 2021 at 10:00 am
Royal Air Force bomber plane Short Stirling BK716 was shot down by a German night fighter ... it was decided to gift their families with a fragment of the plane’s engine and a miniature version of ...
- Why Swedish Submarines are Taking the World’s Oceans By Stormon April 9, 2021 at 1:40 am
Back in the 1960s, Sweden had begun developing a modernized version of the Stirling engine, a closed-cycle heat conversion engine first developed in 1818. This was first used to power a car in the ...
- Prison fire drama as inmate treated by paramedics after Polmont cell blazeon April 8, 2021 at 12:52 am
At one point four fire engines and an ambulance were at the scene, but the blaze was extinguished by prison officers before they arrived. The youngster was given oxygen for smoke inhalation. Women ...
- This Custom Dynamometer Is A Stirling Example Of Homebrewingon April 7, 2021 at 10:42 am
Leo Fernekes] has fallen down the Stirling engine rabbit hole. We mustn’t judge — things like this happen in the best of families, after all. And when they do happen to someone like ...
- Air Independent Propulsion: Could This Technology Change Naval Warfare?on April 6, 2021 at 9:49 pm
The 60-meter long Gotlands are powered by a Stirling-cycle engine, a heat engine consuming a combination of liquid oxygen and diesel fuel. Since then, AIP powered-submarines have proliferated ...
- Power plants on other planets: How we’ll generate electricity on Marson April 6, 2021 at 9:00 am
The first Mars explorers will need electricity to survive -- but how do you generate power on a dusty planet where solar energy is in short supply?
via Bing News