A solar panel is an essential element in solar power plants. Its function is to use solar energy to generate heat or electricity.
There are solar panels for photovoltaic energy and thermal energy. In this way, we distinguish solar collectors for thermal solar energy and photovoltaic (PV) panels to obtain electricity.
Both solar systems are considered renewable energy sources and can be used in huge power plants to supply electricity heat for space heating in home solar systems.
Photovoltaic Panels: DC and AC Solar Panels
The photovoltaic panel is designed for the production of electricity. The panels convert the Sun's radiation into electrical energy thanks to the photovoltaic effect.
A PV solar array usually generates electricity in direct current (DC). However, there are AC panels that have an inverter incorporated, and they supply AC power directly.
Usually, this type of solar panel is made of silicon. It uses the energy of the photons present in the light to blow up an electron from the outer layer of silicon atoms. The sum of several electrons causes an electric current.
Solar arrays made of DC panels are connected to a solar battery or string inverter to convert DC into AC power.
What Are the Materials Used in a PV Panel?
In general, solar cells are composed of crystalline silicon or gallium arsenide. Gallium arsenide crystals are created for these uses. Silicon crystals are also produced for consumption by the microelectronics industry.
According to the silicon configuration, PV panels can be one of these three types: polycrystalline, monocrystalline, or thin-film.
How Is a Solar Panel Made?
A 6 cm silicon cell exposed to direct 1 AU light can produce a current of 0.5 amps at 0.5 volts. Gallium arsenide is even more efficient than silicon.
Solar panel kits can produce electricity for isolated places with good lighting.
The glass is cut into small discs and polished to eliminate the danger of cutting. Dopants are inserted into the discs. Metal drivers are deposited on each surface: a small connector on the sun-facing surface and a connector on the other side.
Solar panels are built with these cells cut into appropriate shapes. They are protected against radiation and other damage by applying a layer of glass and cemented on a substrate (either a rigid or flexible panel).
Electric Connections
Electrical connections are made in series-parallel to determine the total output voltage.
The protective layer must be a thermal conductor. The cell enters when it absorbs infrared energy from the sun that is not converted into electrical energy. Since cell heat reduces operating efficiency, it is desirable to reduce this heat.
How Many Photovoltaic Cells Does a Solar Panel Have?
A solar panel is a set of photovoltaic cells. Although each photovoltaic cell provides little energy, a collection of solar cells can generate enough energy to be helpful.
Solar panels should aim directly at the sun to receive the most energy.
The most common solar cell configurations are as follows
36-cell solar panels: This type of panel is the most compact on the market. Connect 36 solar cells to obtain an output voltage of 12V. Recommended in small isolated installations.
60-cell solar panels: It uses 60 solar cells to obtain an output voltage greater than 24 V.
72-cell solar panels: This photovoltaic module connects 72 solar cells to obtain a voltage greater than 24V. They are mainly used in electrical grid connection installations.
What Are Solar Collectors?
Solar collectors are a crucial part of thermal solar energy installations.
The main applications are the production of hot domestic water (HDW), providing heat for a space heating system, and generating electricity in solar thermal power stations.
This type of solar panel works by circulating a working fluid inside it. The panel captures the heat energy from the sun. This fluid is heated as it circulates inside the collector.
Types of Solar Collectors
There are different types of solar collectors. Its use depends on the application where it is going to be used:
Low-temperature solar collectors are the most straightforward collectors. The most common types are flat solar collectors and vacuum tube collectors. Both collectors have an absorber plate to catch the heat from solar radiation and a transparent cover to prevent the heat from escaping and provoking a greenhouse effect.
High-temperature concentrating collectors are parabolic troughs collectors. Their objective is to concentrate sunlight into a focal point.
Very high-temperature collectors are used in big solar thermal power plants. They generally consist of several adjustable flat mirrors redirecting sunlight to a focal point.
What Is the Lifespan of Solar Panels?
The general rule indicates that the useful life of a solar panel is 25 years.
As a general rule, the power of a photovoltaic panel is reduced by less than 1% each year due to the degradation of its photovoltaic cells. Therefore, the power of a solar panel 25 years later will be over 75%.
With better technology and manufacturing techniques, today's solar modules have even better resistance.
For monocrystalline silicon, the degradation rate is less than 0.5%. For panels manufactured before 2000, and less than 0.4% for panels manufactured after 2000.
That means a panel manufactured today should produce 92% of its original power after 20 years.
However, with proper maintenance, these numbers can be improved.
