Tuesday, September 01, 2009

Stirling and Sun

. .

Stirling and Sun

In this post I am outlining what, IMHO, is one of the most exciting developments of the Stirling engine; a solar concentrator and Stirling converter which can directly generate grid quality usable electricity.

The technology involved, with perhaps the exception of the control and automation systems, is very old indeed, how old is the mirror?, then the Reverend Robert Stirling's 1818 heat engine, and Ányos Jedlik's 1861 generator idea (yes he was the first to conceive the idea but like too many missed out on the kudos).

It has however taken quite a long time for to integrate and perfect all the systems into a practical and workable unit. Hopefully this is what has recently been achieved by Stirling Energy Systems.

Stirling Energy Systems have kindly given me permission to copy materials and have sent me some really interesting photographs of their "SunCatcher".

Try and Catch the Sun

The idea of using a mirror and Stirling to catch and convert sunlight into electricity is not a new one. There have been quite a few prototypes and development efforts. The Advanco and McDonald-Douglas Stirling units are pictured below.

Stirling based unit by McDonald Douglas

Stirling based Advanco Vanguard 63Kw

Stirling Energy Systems

SunCatcher is a 25Kw solar dish which uses a Stirling engine based converter. The convert utilises a closed-cycle, high-efficiency four-cylinder, reciprocating Stirling Engine. The engine uses a sealed cooling fluid that is recycled through the engine.

The suns heat is focused by mirrors onto the converter units receiver tubes which contain hydrogen gas. The heat pressurizes the gas in the heat exchanger tubing, the expanding gas powers the engine.

Waste heat from the Stirling engine is dissipated to the air by a radiator similar to one used in cars. The gas is cooled by a radiator system and is continually recycled within the engine during the power cycle. The conversion process does not consume water as it is a closed system.

The SunCatcher™ mirror system is an innovative radial design. The girasol (sun tracking device) is controlled by sophisticated software.

The SunCatcher's Stirling Engine based Power Conversion Unit has a peak efficiency of 31.25% one of the highest in the business.

Stirling Energy Systems should be shipping by next year so get your orders in soon. Ireland, because of our location and the greenness of the landscape (made so by all the rain and cloudy weather) need not rush out to invest in this technology. I think we will have to wait until someone comes up with "Rain Powered Technology"

Thanks to Stirling Energy Systems for permission to use photos etc.



No comments: