Solar energy has ceased to be a promise of the future and has become a present and very real energy solution. Thanks to the drive for sustainability and technological improvements, more and more homes and businesses are choosing to install solar photovoltaic systems to reduce their electric bills and ecological footprint.
But to make the most of this clean energy source, it's essential to understand the components of a solar system and how each one works. From the solar panels visible on the roofs to the investors, batteries, mounting systems and more, each one plays a strategic role within an efficient facility.
What is a photovoltaic solar system?
A photovoltaic solar system is a set of components designed to convert sunlight into usable electricity., whether for domestic, industrial, or commercial use. Its core is formed by the solar panels, although the complete system includes other equally important parts for its operation, such as regulators, investors, structures and in some cases, batteries.
There are two main types of solar systems: Grid-connected (self-consumption) and off-grid systems. Both seek to harness the sun's energy, but they do so differently depending on whether or not they are connected to the grid. conventional power grid.
Fundamental components of a solar system
A photovoltaic solar installation is composed of a series of elements that work together to capture, store, and distribute solar energy transformed into electricity. Below, we analyze each one in depth.
1. Solar panels
Solar panels are responsible for capturing solar radiation and transforming it into electricity. They are formed by a matrix of Photo-voltaic cells that work thanks to the photovoltaic effect, a physical phenomenon that allows certain semiconductor materials to generate electric current when exposed to light.
The most common materials used to make these cells are monocrystalline silicon, polycrystalline silicon, and amorphous siliconThere are also advanced technologies such as gallium arsenide (GaAs) and the cadmium telluride (CdTe).
The cells are arranged in encapsulated modules and protected by several layers (as we will see later), which makes them the most exposed but also the most visible component of the system.
2. Charge regulator
The charge controller acts as an intermediary between the solar panels and the batteries. Its main function is to prevent batteries from being overcharged or over-discharged, allowing you to maximize your useful life and secure a reliable operation of the system. For optimal performance, you can refer to the technical guide for installing solar panels.
There are two types of regulators:
- PWM (Pulse Width Modulation): more economical, ideal for small systems, although less efficient in energy management.
- MPPT (Maximum Power Point Tracking): they allow you to make the most of the energy generated by the panels, adapting their operation to achieve the maximum power point.
Usual recommendation: Use MPPT regulators for installations of more than 500W and thus guarantee a optimal performance.
3. Investor
The solar inverter converts the direct current (DC) generated by the panels and stored in batteries into alternating current (AC), which is what we use at home in common outlets. In grid-connected systems, the inverter also synchronizes the generated current with the electrical grid, and in isolated systems it can include additional functions such as managing the use of backup generators or control the entire system.
Some modern inverters even allow monitor consumption and mobile energy generation, thus optimizing the use of the energy produced. In addition, it is advisable to review the advantages of the rotating solar panels that can improve the efficiency of your facility.
4. Solar batteries
Batteries are necessary in isolated installations, as they allow the electricity generated to be stored for use when there is no sunlight (at night or on cloudy days). In grid-connected systems, the use of storage is optional, but increasingly common in installations seeking energy independence.
Most commonly used battery types:
- Lead acid (AGM or gel): economical, although with a shorter lifespan and efficiency.
- Lithium: more expensive but also more durable, efficient, lighter and with greater discharge capacity.
Lithium batteries have gained prominence in recent years for its performance, ease of monitoring, and reduced maintenance requirements. For more information on its use, you can consult the maintenance aspects of solar panels.
5. Support structure
For solar panels to do their job properly, they need to be installed on a structure that keeps them stable and at the proper angle. These structures can be installed in:
- Roofs: with coplanar systems, with angle or weighted structure.
- Land: ideal for solar farms or large installations.
Correct orientation (towards the south in Spain) and an adequate angle maximizes the solar collection and the system performance. To learn more about proper installation, see the solar panel installation guide.
6. Wiring and electrical protections
Although they may go unnoticed, cables and protection systems are vital for the proper functioning and safety of a photovoltaic installation. They are elements that must withstand extreme environmental conditions, so It is important that they are specifically certified for solar use, thus ensuring long-lasting durability and low electrical resistance. For more details on safety, we recommend reviewing the costs and performance of solar panel systems.
Additionally, included protections such as fuses, circuit breakers and grounding systems to avoid overloads, short circuits and electric shocks.
7. Junction box
The junction box is the point where all the cables from the photovoltaic modules converge and from where the connection to the rest of the system begins. It is located on the back of each panel and is usually designed to withstand harsh environmental conditions. Some even include blocking or bypass diodes to prevent energy losses when part of the panel is shaded.
8. Auxiliary generator (optional)
In isolated installations, a backup generator can be added, especially in locations where unfavorable conditions occur for several consecutive days. This generator can be activated automatically when the batteries are low and the system does not receive enough solar radiation to power it. In these cases, it may be useful to consider portable solar panels for emergency situations.
Detailed parts of a solar panel
Solar panels are designed to withstand all types of weather conditions and perform their function for decades. To achieve this, they are composed of multiple layers, each with a specific function:
- Tempered glass: first layer, protects against impacts and allows the passage of solar radiation with hardly any loss.
- EVA (ethyl vinyl acetate) encapsulant: absorbs thermal stresses and protects cells from moisture and other elements.
- Solar cells: They are those that transform light into electricity.
- Another layer of EVA encapsulant: similar to the previous one, on the reverse of the cells.
- Backsheet: It is usually made of polymers such as PET or TPT. It insulates and protects against the elements.
- Aluminum frame: It gives structural rigidity to the panel, facilitates assembly and protects the edges of the glass.
- Connections Box: connects the cells to the rest of the system and may include additional protections.
This layered design improves the performance, durability and safety of photovoltaic modules.
Manufacture of solar panels
The solar panel manufacturing process is highly technical and requires a series of steps to ensure the final product's quality and efficiency.
1. Silicon production
It all begins with the purification of silicon, which undergoes smelting processes to become ingots. These ingots are then cut into thin sheets called wafers.
2. Doping of wafers
Chemical impurities such as phosphorus and boron are added to the wafers to alter their conductivity and allow the creation of an electric field (pn junction).
3. Creation of solar cells
The doped wafers are coated with anti-reflective materials and etched with patterns to improve the light collectionFor more information on the evolution of these technologies, you can consult the historical evolution of solar panels.
4. Assembly
The cells are connected in series by means of conductive tape, forming strings. These strings are encapsulated between layers of EVA, glass and back sheet.
5. Framing and junction box
The module is mounted on an aluminum frame and a junction box is added to facilitate wiring.
6. Quality controls
Each panel is tested for performance, resistance, exposure to extreme conditions and visual scans that ensure the absence of cracks or defects.
Thanks to this, current panels can maintain their efficiency for 25 to 30 years or more.
Differences between isolated and grid-connected systems
When choosing a solar installation, one of the biggest dilemmas is whether to opt for an isolated (off-grid) system or one connected to the grid (self-consumption). Let's look at their main differences:
- Self-consumption: It produces energy for the home and uses the grid as a backup. It can sell surplus energy and doesn't necessarily require batteries.
- Isolated: It doesn't rely on the power grid; it requires batteries and (optionally) a generator. Ideal for areas without grid access.
Both systems have their advantages, but self-consumption is more common in urban areas, while off-grid systems are often used in remote areas.
Clearly Solar energy allows users and companies to save, be more autonomous, and reduce their environmental impact. By thoroughly understanding each part of the system, you can make better decisions when installing or maintaining an efficient and long-lasting photovoltaic system.