Use of solar energy can save expensive electricity supplied to homes energy companies, and even to make a supply of energy to the power grid if it is provided by local law.
The main component of a home solar power — solar panels or photovoltaic panels, as they are called. Their purpose — the direct conversion of solar energy into electricity.
Solar cell consists of individual photovoltaic cells, which are connected together, provide the necessary battery power. Currently on the market you can find five types of solar cells with different materials making up their items.
Solar panels of polycrystalline photovoltaic cells are most common because of the optimal price-performance among all panel types. Their efficiency is 12-14%. In elements that form the panel, typical blue and crystal structure.
Monocrystalline solar panels of photovoltaic cells more efficient, but also more expensive per watt of power. Their efficiency is usually in the range of 14-16%.
Usually take the form of single-crystal elements of polygons that are difficult to fill the entire area of the panel without a trace. As a result, solar power density is slightly lower than the specific power of its individual components.
Solar cells made of amorphous silicon have one of the lowest efficiency. Normally it is set in the range of 6-8%. However, among all the silicon photovoltaic technologies they produce the cheapest electricity.
Solar panels of cadmium telluride (CdTe) are based on membrane technology. The semiconductor layer is deposited a thin layer of a few hundred micrometers. Effective element of cadmium telluride is small, an efficiency of about 11%. However, in comparison with silicon panels watts of power these batteries cost a few tens of percent cheaper.
Solar panels based on CIGS. CIGS — a semiconductor composed of copper, indium, gallium and selenium. This type of solar cell is also performed on film technology, but in comparison with panels of CdTe has a high efficiency, its efficiency up to 15%.
Potential buyers of solar panels often ask themselves whether a particular type of photovoltaic cells to provide the necessary capacity of the entire system. It should be understood that the efficiency of solar cells is not directly affected by the number of generated power plant.
The same power the entire system can be achieved with any type of solar cells, but a more efficient photovoltaic cells will take up less space to house them will need less space. For example, if for one kilowatt of electricity will take about 8 sqm the surface of the solar cells based on monocrystalline silicon, the amorphous silicon panels will take about 20 sq.m.
These examples, of course, is not absolute. Electricity generation photovoltaic converters affects not only the total area of solar panels. Electrical parameters of any solar cell defined in so-called standard test conditions, namely, in the amount of solar radiation 1000 W / m. and operating temperature of 25 ° C. Panel
In Central and Eastern Europe, the amount of solar radiation is rarely reaches the normal value, so even on sunny days, photovoltaic panels work with underload. It may seem that the temperature is 25 ° C also does not occur very often. However, the question of temperature of the solar panel, and not the air temperature.
As a general downward trend in output power with increasing operating temperature, each type of solar cell behaves differently. So in silicon cells nominal capacity decreases with each degree beyond the nominal temperature of 0,43-0,47%. At the same time elements of cadmium telluride lose only 0.25%.