Composition of photovoltaic system
A photovoltaic system transforms directly solar energy in electric energy and is composed by:
1) modules or photovoltaic panels ;
2) inverter that transform electric energy from continuous to alternate;
3) electric panels and connection cables ;
4) organs of protection and manipulation.
The modules are composed by silicon mono crystal or poly crystal or unstructured silicon. All three types of silicon are suitable but from it depends the efficiency of modules.
The mono-crystal silicon has an efficiency of 13- 15 %, but the poly- crystal one has the efficiency of 11- 13% . The unstructured one has an efficiency of 6-8%.
As mentioned above it means that to have 1 kWp in mono- crystal silicon we need about 7,4 m² of panels, 8,4 m² for poly- crystal panels and 15 m for unstructured silicon for every kWp.
When the installation is on surfaces inclined well exposed ( for example on roofs inclined toward South, South- East, South- West) are necessary a quantity of meters of solar panels mentioned above, depending on the type of silicon used. For flat surfaces is needed an increase of at least 70% to avoid shading in various line of panels.
Optimal inclination is of 30°, when the exposition is on South and when the inclination is different, the productivity of energy is lower. For horizontal panels we have a 90% of optimal inclination production. For panels vertically exposed on South, the productivity is of 70% of optimal inclination.
It is necessary that there are not obstacles in the way that the sun goes in various periods of the year in order to maximize the productivity.
It is also necessary to study with attention every case in order to evaluate whole productivity of the system in order to avoid bad surprises and important delays in amortizations of system costs.
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