A star like the sun fuses hydrogen for about Ten billion years. With half of its hydrogen currently fused into robot joint helium the sun will continue to produce energy for about another five billion years. While not technically endless, it will go on producing energy for a very, very long time.
But how do we capture that practically limitless source of energy? With solar panels presumably. So lets take a look at how solar panels work.Certain elements and compounds exist in a state where the right frequency of light will add its energy to the electrons in its atoms. The now energized electrons can jump out of the influence of the nucleus and flow with other electrons through some conducting material. Silicon, cadmium telluride, gallium arsenide and copper indium diselenide, among others are all substances that have this property. Each substance however will be affected by different frequencies of light.These materials, affected by different frequencies are not able to use the full spectrum of sunlight.
Creative methods of construction have been devised to take advantage of the different frequencies in white light.One method is to stack different substances so that different layers absorb the relevant frequency for that material. In this way more of the sunlight is being used and converted into electricity. Another method is to break up the light with some sort of prism and then to direct the light to the relevant materials.
These methods greatly increase the efficiency of the photovoltaic array.The use of expensive materials may also create problems with efficiency. To overcome this difficulty, some designs use lenses to concentrate the light to a small area where only a small amount of the expensive material is needed to free enough electrons to produce usable electricity.When a wafer of one of these substances is attached with positive and negative electrodes, a photo voltaic cell is created. Several of these can be wired together to create a module.
Several modules wired together with copper, silver or some other conducting material create an array. If an array is large enough, a usable amount of electricity can be produced.But this is not enough to make a solar panel. The cells need to be protected from moisture and physical damage. They also need to be protected from overheating as excessive heat reduces the efficiency of the cells. Waterproof, protective cases are made to contain the arrays which are then mounted in a way to provide adequate airflow to prevent overheating.Power from the sun was first discovered in 1839 by Alexandre-Edmond Becquerel, the French physicist focused on the solar spectrum, electricity and optics. Since that time, the understanding of how to harness photovoltaic conversion has increased exponentially. Advances in this area were primarily driven by NASA who needed ways to power spacecraft and artificial satellites. With the problems facing this planet as the result of the fossil fuel consumption used to power our lives, the renewable and non-polluting alternative offered by solar power may eventually help us get away from petroleum dependence.
geardrives