| Using The Sun's Energy In A New Way |
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| Environment - Environment |
| Written by Michael Edwards |
| Thursday, 09 July 2009 07:43 |
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During the process of researching an article about green products on photovoltaic cell systems (solar panels), I came across another way to convert the sun's light into electricity. So let's take a look at another type of solar energy system.
During the process of researching an article about green products on photovoltaic cell systems (solar panels), I came across another way to convert the sun's light into electricity. So let's take a look at another type of solar energy system. This system is not new; it was originally conceived in 1816 as an industrial rival to the steam engine. It has been largely underutilized for the past century. With the need for renewable energy sources caused by the overuse of the fossil fuels interest has resurged in solar designs, and it is now being designed into many new solar collector systems. Sense its incarnation there have been many variations of the Stirling engine and many patents. The engine's simple design demands tinkering - everyone wants to add or change something to make it better. The engine has very few moving parts, requires only a single external heat source, is very efficient, and is quiet. With the new space age materials available, the problem of piston overheating is no longer a problem like it once was. The operation of the Stirling engine is not complex, it only requires an external heat source. Some heat sources have been fuel, while some solar designs use a Fernell lens, and the latest source is large parabolic mirrors. The Stirling cycle is pretty simple. When a heat source is applied to the large end, it causes the air to expand which moves a piston. A flywheel is used to maintain movement between cycles and add a convenient place to tap the power from the engine. What is so amazing about this design is that the design is very scalable. Engines have been produced that are as small as your hand to a large as a car but the concepts remain the same. The reason the Stirling engine works so well for a solar application is that heat from the sun can easily be concentrated to heat the hot chamber. A parabolic mirror much like that seen with the roof mounted satellite dishes is used to gather and focus the sunlight. With the sunlight focused onto the hot chamber of the engine, the temperature raises and the engine starts running. Connect the output shaft to a generator, and electricity is the product. The engine and support equipment is contained in a package small enough to be suspended from the end of a metal arm, much like the design of satellite TV systems but on a much larger scale. Some systems are producing 25K watts of power and have been installed and operational for a couple of years. In a future article about green products I will list the different solar technologies and how they compare to the competition. Michael |