How Solar Panels Work

A Solar panel is a device used to convert solar energy into other forms of energy such as light energy and heat energy. 

Here are 3 kinds of solar panels -

1.  Panels used to generate electricity
2.  Panels used to generate heat
3.  Panels used to heat water in homes.

Panels used to Generate Electricity

Solar cells (also known as photovoltaic cells - PV) are common examples in this category of electricity generation. A combination of individual PV cells forms the Photovoltaic module.

A collection of connected photovoltaic modules, are known as photovoltaic panels or simply solar panels. The components include photovoltaic modules, an inverter, and a battery all connected to each other. Three main categories of solar modules are:

• crystalline silicon modules
• rigid thin-film modules 
• flexible thin-film modules.

Panels used to Generate Heat

The heat from the sun light is collected in this type of panel. They are called solar thermal collectors. They are specially made to absorb the sunlight in order to provide heat. It may appear that they are simple solar hot water panels but in reality they are more complex installations.

Though heat is generated from sunight in these models, the heat energy is ultimately converted into other types of energy, usually electrical energy as is the case in solar power plants. The heat produced in the solar power plants is then used to heat water, which in turn produce stream.

There are three types of thermal collectors primarily used in solar power plants:  solar parabolic, solar trough and solar towers. In domestic and light industry applications, flat plate and box type panels are used. Advantages of this type of solar panels are: getting high enough temperatures  to generate electricity,the  higher efficiency of these panels and a wide area coverage with the use of inexpensive mirrors.

Panels used to Heat Water in Homes

In solar hot water panels, sunlight is used to heat a fluid, which is then transferred to a heat storage vessel. Examples are the heating of drinking water and storing hot water in a tank. This type of solar panel is explained below:

Flat absorber plates are placed on the building roof tops. These absorbers are coated with a dark special surface which converts the sun’s radiation into heat. The heat produced is carried by the fluid in the tubes attached to the absorbers. The heat is taken away and either stored or used. In this process, the fluid heats up. To extract its heat and prepare it for reuse, the fluid is directed to a heat exchanger, where it gives off its heat. A mechanical pump or thermo siphon is often used to circulate the fluid.   The cooled fluid is then reused.

Solar panels  can be either active solar or passive solar or a combination of the two. In active solar technology, electrical or mechanical devices such as pumps are used.  In passive solar technology,  no other sources of energy are used.  A solar combisystem uses an auxiliary non-solar heat source.

As the sun’s rays are readily available and solar energy is inexpensive to use (as we don’t yet have to pay to use the sun), solar energy is rapidly becoming a substitute for our more traditional forms of energy derived primarily from fossil fuels, like coal and oil.  

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