How do solar panels work and how are they installed?
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Solar photovoltaic panels contain arrays of solar cells that convert light into electricity. Solar cells, or PV cells, rely on the photovoltaic effect, which describes how certain materials can convert sunlight into electricity to absorb the energy of the sun and cause current to flow between two oppositely charged layers. Individual solar cells provide a relatively small amount of power, but electrical output is significant when connected together as an array making up a panel.
On a bright day, the sun delivers about 1 kW/m² to the Earth's surface. Typical solar panels have an average efficiency of 12%, with the best commercially available panels at 20%, and recent prototype panels at around 30%. This would result in 200 W/m². However, not all days have bright sunlight, and therefore not enough solar energy can be captured.
A solar water heater uses the sun's energy to heat a fluid, which is used to transfer the heat to a heat storage vessel. In the home, for example, sanitary hot water would be heated and stored in a hot water cylinder. Panels on the roof have an absorber plate to which fluid circulation tubes are attached. The absorber, usually coated with a dark selective coating, assures the conversion of the sun's radiation into heat, while fluid circulating through the tubes carries the heat away where it can be used or stored. The heated fluid is pumped to a heat exchanger, which is a coil in the storage vessel or an external heat exchanger where it gives off its heat and is then circulated back to the panel to be reheated. This provides an effective way of harnessing the sun's energy.
There are two types of solar panels, active and passive. Passive work by running water in thin tubes behind light-absorbing panels. The water gets hot. It can be used to run a turbine in a large scale operation, and can generate electricity. In a small operation, the water can replace hot water in other household applications.
Active solar panels create electricity directly in specially designed chips.
It's not difficult to install a solar panel. You basically mount in on a roof or other place where it will get direct sunlight and either hook it into the electrical or water system. If you decide to purchase a system, there will be instructions.
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