Types Of Photovoltaic Panels
In the market there are several types of photovoltaic solar panels for domestic use. The most common types are monocrystalline photovoltaic panels, polycrystalline solar panels and thin-film solar panels.
Around 90% of the photovoltaic technology is based on the use of some silicon variation. In the case of solar panels intended for domestic use, this percentage is even higher.
The main difference between the different types of photovoltaic panels is the purity of the silicon used. The purer the silicon, the better aligned its molecules are, and the better it converts solar energy into electricity.
In this way, a direct relationship is established between the purity of the silicon and the efficiency of the solar panels. On the contrary, increasing the purity of silicon implies more expensive processes.
Crystalline silicon is the basis of monocrystalline and polycrystalline cells.
Silicon Cell Monocrystalline Solar Panels
In monocrystalline solar panels, monocrystalline silicon solar cells (mono-Si), are quite easy to recognize because of their coloration and uniform appearance, which indicates a high purity in silicon.
In this type of photovoltaic panels the monocrystalline cells are manufactured with blocks of silicon or ingots, which are cylindrical in shape.
Subsequently, with the aim of reducing the manufacturing costs of monocrystalline photovoltaic cells and optimizing their performance, the four sides of the cylindrical blocks are cut to make silicon sheets. This cut is what gives them this characteristic aspect.
One of the simplest ways to clearly distinguish a monocrystalline solar panel from a polycrystalline one is that in the polycrystalline the cells have no rounded corners and are perfectly rectangular.
The basic difference between a monocrystalline and a polycrystalline solar cell is the composition of the silicon crystal. The monocrystalline cells are formed by a single type of silicon crystal, that is, when the crystal has been manufactured, the growth of the silicon crystal itself has been controlled so that it only forms in one direction, achieving a fairly perfect alignment of all the components of the crystal. On the other hand, in the polycrystalline cells, the growth of the silicon crystal is not controlled, so the crystal grows in all directions creating a set of different crystals joined together.
Polycrystalline Silicon Photovoltaic Panels
Polycrystalline photovoltaic panels, unlike monocrystalline panels, the Czochralski method is not used in its manufacture. In this type of solar panel the raw silicon is melted and poured into a square mold. It is then cooled and cut into perfectly square sheets.
The first polycrystalline silicon solar panels appeared on the market in 1981.
Solar panels based on polycrystalline cells have a long history in the industry, since their manufacture started in the eighties. Its greater advantage compared to monocrystalline cells starts from a production process with lower cost, which pulls down the final price of these systems.
The photovoltaic cells of polycrystalline solar panels are more affordable. On the other hand, they have some disadvantages: The lower heat tolerance of these cells means that they have a lower efficiency than the monocrystalline alternative. In particular, it is estimated that in the panels that include these cells, the efficiency ratio is a maximum of 16%, mainly due to the lower amount of silicon they incorporate.
The negative effect that high temperatures cause on these cells, which makes them even less attractive than monocrystalline for users residing in warm areas, as well as their lower efficiency with respect to space, also appear as disadvantages of these systems.
Thin-film photovoltaic solar panels
The foundation of these panels is to deposit several layers of photovoltaic material in a base. Depending on the material used we can find thin-film panels of amorphous silicon (a-Si), cadmium telluride (CdTe), copper, indium, gallium and selenium (GIS / CIGS) or organic photovoltaic cells (OPC)
Depending on the type, a thin layer module has an efficiency of 7-13%. Because they have great potential for domestic use, they are increasingly in demand.
Hybrid solar panels
Another variant of photovoltaic solar panel are the hybrid solar panels.
In the solar hybrid panel, photovoltaic technology is integrated with that of solar thermal energy: photovoltaic solar energy absorbs solar radiation, while the part that is not able to accumulate thermal heat is recovered by means of an exchanger of heat that increases, in this way, the production of electricity, also disperses the energy of the photovoltaic panel itself.
Last review: March 6, 2018