Solar panel is a device that harnesses the sun’s energy to generate heat or electricity . According to these two purposes, we can distinguish between solar collectors, which produce hot water (generally for domestic use) using solar thermal energy, and photovoltaic panels , which generate electricity from the solar radiation that falls on the photovoltaic cells of the panel.
What is a solar panel?
In the collector or solar collector there is a liquid that absorbs solar radiation in the form of heat, this liquid then passes to a heat storage compartment. The panels consist of a receiving plate and ducts through which said liquid circulates. The hot liquid is passed through a heat exchanger, where it gives up its heat, heating the water for subsequent domestic use. When it leaves the heat exchanger the liquid is cold and is recirculated back to the solar collector.
The most widely used materials to manufacture these cells are gallium arsenide (GaAs), which is used in other complex electronic devices, and silicon (Si), which is cheaper and is also used in the microelectronics industry.
What cells exist?
Silicon cells are the most common and widely used. The performance of photovoltaic cells depends on the internal three-dimensional structure of these silicon sheets. According to this structure we can classify them as follows:
– Monocrystalline silicon cells: made up of a single large crystal that is cut into thin slices, generally uniform blue. They are the most advanced, the manufacturing cost is higher and they provide superior performance under certain conditions.
– Polycrystalline silicon cells: they are made up of several crystals, they have a non-uniform blue color although the latest manufacturing techniques already provide greater uniformity to the appearance of the cell.
– Amorphous silicon cells: it is not made up of crystals. It is the cheapest but also the ones that offer the lowest yields, they are used, for example, in devices such as calculators or watches and have the particularity that they can produce electricity (in a small amount) even if they are not directly exposed to solar radiation in a perpendicular manner. .