Solar panels collect energy from the sun and use it to provide electricity, or to heat water. There are various types of solar panels, which work in different ways, for example, photovoltaic (PV) panels produce electricity, and flat plate collector and evacuated tube panels heat water and other liquids, such as oil.
Photovoltaic (PV) panels are made from silicon, which is a semi-conductor, and are used to generate solar electricity. They can either be Amorphous, Monocrystalline, Polycrystalline, or a combination of the two.
Amorphous solar panels are the cheapest type of PV panels, and are manufactured by applying a thin film of silicon onto a sheet of metal. The silicon is in one piece, whereas with monocrystalline and polycrystalline panels, the silicon is in cells, which are connected together then encased in a glass covered, metal frame. The monocrystalline and polycrystalline types are blue or black in colour and are more efficient than amorphous panels.
Some panels, called hybrids, are produced using a combination of amorphous and monocrystalline technology, in order to utilise the benefits of both types.
Flat plate collector panels
With these panels solar power is utilised to heat water. The panels contain liquid which is heated by the sun. This liquid then travels through a coil in the water tank, heating the water in the tank. They are manufactured in varying sizes to service buildings of any proportions, but are mainly used domestically.
They can be used alongside a conventional water heating system to reduce bills and are effective at reducing carbon emissions. Flat plate collector panels also have the advantages of easy installation and maintenance.
The styles of flat plate collector panels vary, with surface mounted models available for flat roofs or pitched roofs, as well as A-frames, in-roof models, complete roof, canopy or facade construction. They need to be connected to a twin coil cylinder so that one coil receives heat from the solar collector panel whilst the other coil receives heat from the conventional heat source. These twin coil cylinders are usually larger than a standard hot water cylinder.
Evacuated tube panels
These are used in solar thermal systems, but work in a different way to flat plate collector panels.
Instead of a flat plate, evacuated tube panels consist of a number of parallel cylindrical collectors, which can capture the sun from many directions and therefore produce more energy. These collectors have selective absorbers to collect solar energy in vacuum-sealed tubes.
They are fully effective even when the sun is low, and have minimal thermal losses even in cold weather. Although they are more efficient than flat plate collector panels, they are also more expensive.
Models are available for both commercial and domestic use, and they are usually fixed to a wall, flat roof or pitched roof that receives sunlight for most of the day. Installation options also include A-frames, in-roof, complete roof, canopy or facade construction. They need to be connected to a twin coil cylinder so that one coil receives heat from the solar collector panel whilst the other coil receives heat from the other heat source.
As with flat plate collector panels, they can be used in conjunction with an existing central heating system to reduce bills, are easy to install and maintain, and are effective at reducing carbon emissions.
During the summer months thermal panels can heat 100% of necessary water, and can save 30% on hot water heating costs throughout the year.