COMPONENTS OF A PHOTOVOLTAIC SYSTEM
Photovoltaic systems are increasingly chosen and installed to power their homes in an ecological way, but do you know what the components of a photovoltaic solar installation are ?
The photovoltaic solar panel is the element that captures solar radiation and is responsible for transforming solar energy into electricity through the photovoltaic effect.
But in addition to the photovoltaic panel, photovoltaic installations require a series of complementary elements that are necessary to guarantee the functionality of the control and durability of the solar installation.
COMPONENTS OF A PHOTOVOLTAIC SYSTEM
Photovoltaic technology instantly converts solar energy into electrical energy without the use of fuel thanks to the “photoelectric effect”, that is, the capacity of some semiconductors adequately treated to generate electricity when exposed to light.
Photovoltaic systems can be connected to the distribution (grid connected to the electricity grid), or users can be isolated (independent) in cases where it is necessary to provide electrical power in remote areas of the network.
Let’s see what are the main components of photovoltaic systems.
A photovoltaic system basically consists of:
- panels or photovoltaic modules;
- a photovoltaic charge controller;
- a system of control and conditioning of energy (inverter);
- an energy accumulator (that is, the battery).
How is a solar panel formed?
Several cells constitute a photovoltaic module ( rectangular shape with dimensions from 0.5 to 1.5 m2) and several modules connected in series form a photovoltaic panel.
The photovoltaic panels are made of cells in semiconductor material in crystalline silicon, in polycrystalline silicon or thin-film cells (“thin film”).
What type of solar panel is the most efficient?
The solar panels with greater efficiency are monocrystalline silicon cells, since they have a better performance at low temperatures (therefore, with less solar intensity) than polycrystalline silicon panels .
The most important component of photovoltaic systems is the solar panel. This element consists of the connection of photovoltaic modules and is capable of transforming the solar radiation into a continuous electric current.
Among the components of a photovoltaic system is also the inverter , which has the task of converting the direct current generated by the panels of the photovoltaic system, into alternating current at 230 volts and 50 Hz.
It is similar to an electrical panel, protected by a metal enclosure should be placed as close as possible to the panels and in a ventilated room. It is usually placed in the attic. Several investors are available in the market based on power.
The system connected to the public network also includes the presence of:
- counter;
- Two-way meter;
- frame of the series.
The bidirectional counter is a particular meter that is added to the pre-existing traditional meter during assembly. It is designed to receive electricity from the local distributor and sell it.
The chain frame of a photovoltaic system protects the system from dangerous rays and photovoltaic cells thanks to the fuse selector.
Main elements of a photovoltaic solar installation in depth
Photovoltaic cell
The photovoltaic cell is the part of the photovoltaic panel responsible for transforming solar radiation into electrical energy thanks to the photovoltaic effect. The result is an electrical current in direct current.
Generally, a module or photovoltaic solar panel consists of an association of photovoltaic cells, encapsulated in two layers of EVA between a glass front sheet and a back layer of a thermoplastic polymer or another glass sheet when it is desired to obtain modules with some degree of transparency
Usually this set of elements is framed in an anodized aluminum structure with the aim of increasing the mechanical strength of the assembly and facilitating the anchoring of the module to the support structures.
The photovoltaic cells most commonly used in photovoltaic panels are silicon, and can be divided into three subcategories:
- The monocrystalline silicon cells consist of a single crystal of silicon. This type of cells presents a uniform dark blue color.
- The cells of polycrystalline or multicrystalline silicon are constituted by a set of crystals of silicon, which explains that their performance is somewhat lower than that of the monocrystalline cells.
- The amorphous silicon cells. They are less efficient than crystalline silicon cells, but also less expensive. This type of cells is, for example, the one used in applications such as calculators or small devices that do not require a large amount of energy.
Current inverters
The inverter is an electronic device responsible for converting the generated direct current into alternating current.
The photovoltaic solar panel provides electricity in the form of direct current. This current can be converted into an alternating current current inverter and injected into the electrical network or into the internal network.
The process, simplified, would be as follows: Energy is generated at low voltages (380-800 V) and in direct current. It is transformed by an inverter into alternating current. In power plants under 100 kW power is injected directly into the distribution network in low voltage (400 V in three-phase or 230 V in single-phase). And for powers over 100 kW a transformer is used to raise the energy at medium voltage (up to 36 kV) and it is injected into the transport networks for its subsequent supply.
Read more about solar inverters
Solar trackers
The solar trackers are mechanisms that are orienting the position of the photovoltaic panels depending on the position of the Sun to increase its performance. Its use is quite common in the production of solar energy.
The solar trackers allow a considerable increase in solar production, around 30% for the former and an additional 6% for the latter, in places with high direct radiation.
There are solar trackers of various types:
- Solar trackers in two axes: the surface of the photovoltaic panel is always perpendicular to the Sun.
- Solar trackers on a polar axis: the surface of the solar panel rotates on an axis oriented to the south and inclined at an angle equal to the latitude. The turn is adjusted so that the normal to the surface coincides at all times with the terrestrial meridian that contains the Sun.
- Solar trackers on an azimuthal axis: the surface rotates on a vertical axis, the angle of the surface is constant and equal to the latitude. The turn is adjusted so that the normal to the surface coincides at all times with the local meridian that contains the Sun.
- Solar trackers on a horizontal axis: the surface rotates on a horizontal axis and oriented in a north-south direction. The turn is adjusted so that the normal to the surface coincides at all times with the terrestrial meridian that contains the Sun.
Cabling
The wiring is the element that transports the electrical energy from its generation, for its later distribution and transport. Its sizing is determined by the most restrictive criterion between the maximum potential difference and the maximum admissible intensity.
Autonomous photovoltaic solars installations and connected to the network
Taking into account these complementary elements, the types of basic photovoltaic installations are clearly differentiated:
- Autonomous photovoltaic installations isolated from the electricity grid, intended for electricity supply when the cost of maintenance and installation of power lines is not profitable.
- Photovoltaic installations connected to the grid, this typology of photovoltaic installation refers to small low voltage power plants connected to the electricity distribution network.
In the following sections we will explain and comment on the different elements that make up a photovoltaic solar installation depending on whether they are autonomous or are connected to the network.
