Self-consumption is an excellent option to encourage the use of solar photovoltaic energy and increase the proportion of renewable energy in the home. However, a key question often arises: how to choose the best photovoltaic system? There are so many factors to consider, from the type of panel to the production capacity, that it can be an intimidating process.
In this article we will provide a detailed guide on how to choose the best photovoltaic system for the energy needs of your home, covering the different types of solar panels until important considerations for choosing the photovoltaic system that best suits your requirements. Here you will also find practical advice and recommendations based on technical details.
Types of photovoltaic panels
Before we begin to define the types of photovoltaic panels available, it is important to understand that the efficiency of a panel depends primarily on the quality of the silicon it contains. The purer the silicon, the better the panel's ability to convert solar energy into electricity. For this reason, around 90% of solar panels are composed of silicon in some form.
There are three main types of photovoltaic solar panels, each with different characteristics that can influence your choice. Below, we will explore each type in more detail.
Monocrystalline Silicon Photovoltaic Solar Panels
Monocrystalline silicon panels are known to be the most efficient on the market, as they are made from the purest silicon. These panels are produced using the Czochralski process, which generates cylindrical blocks of highly pure silicon. However, this manufacturing method results in a greater amount of wasted material, which also makes them the most expensive panels.
Monocrystalline panels have a distinctive, visible structure, as the cells are cut to create square-shaped silicon wafers with rounded corners. They have a very high conversion efficiency, around 22%-24%, and are guaranteed to last up to 25 years, making them an ideal choice when looking for quality and durability.
Polycrystalline silicon photovoltaic solar panels
This type of panel also contains silicon, but its manufacture is simpler than that of monocrystalline panels, making them less expensive but also less efficient. Instead of using the Czochralski process, the silicon is poured into square moulds, resulting in a panel with different crystals.
One of the biggest visible differences between the two types of panels is that the cells in polycrystalline panels are completely square and lighter in color compared to monocrystalline panels. Although they are less efficient (around 17%-18% efficiency), polycrystalline panels are a popular choice for those on a tighter budget. They require more space to generate the same amount of electricity as their monocrystalline counterparts.
Thin film photovoltaic panels
These panels are leaders in terms of production costs, due to their manufacture with thin layers of materials such as cadmium telluride or amorphous silicon, which makes them the least expensive in terms of installation. However, their efficiency is usually the lowest (between 10%-12%), and they require more space to produce a significant amount of energy.
For this reason, thin film panels are commonly used in specific applications such as irregular surfaces or mobile structures (e.g. caravans, boats). The installation of these panels is also more complex and expensive because they require additional support structures.
How to choose the best photovoltaic system
Once you understand the different types of solar panels available, it's crucial to consider other factors when choosing the right PV system. Below, we've provided an extensive guide to the key specifications you should consider when comparing options.
Number of cells and voltage
The number of cells in a solar panel directly influences its voltage and the amount of energy it can generate. For self-consumption installations, it is common to find panels with 36 cells (12V) or 72 cells (24V). If you want to install a higher capacity system, you will want to opt for panels with a higher voltage.
Output power
Power output refers to the amount of energy a panel can generate under optimal conditions. This value is measured in watts (W), and is often based on laboratory tests under ideal lighting conditions. However, since these conditions are rarely met in a real-world environment, it is important to compare the power output between different panels of the same dimensions to get a better idea of their performance.
Rated power at operating temperature
Many solar panels specify the power they can generate at common operating temperatures (Normal Operating Cell Temperature, NOCT). This parameter is crucial, as panel efficiency decreases with heat. A low temperature coefficient means the panel will be more efficient at high temperatures.
Tolerance
Tolerance is a measure that indicates the variability in a panel's power output. For example, if a panel is rated at 100W with a tolerance of +/- 5%, this means that the panel can output between 95W and 105W under real-world conditions. A tighter tolerance range generally reflects a higher quality panel.
Efficiency
The efficiency of a photovoltaic panel determines how much of the solar energy received is converted into electricity. This value is represented as a percentage and varies between different types of panels. If you have limited space, opting for a more efficient panel may be the best solution since you will need fewer panels to generate the same amount of energy.
Power temperature coefficient
The power temperature coefficient indicates how much power is lost as temperatures rise. The lower the value, the better the performance in hot conditions. Therefore, if you live in a warm region, this coefficient should be a key factor in your decision.
Nominal operating temperature of the cell
This is another important indicator that measures the temperature at which the panel will typically operate under normal conditions. The lower the rated temperature, the better the panel will perform in hot climates. Panels with a under NOCT They are preferable if your home is in an area where temperatures tend to be high for much of the year.
The best photovoltaic panels for home use
After considering all the necessary technical specifications, what are the best solar panels to install in a home? In general, polycrystalline panels are usually the most recommended for homes due to their cost-benefit ratio.
On the other hand, monocrystalline panels are preferable in situations where space is limited or when the installation is carried out in very hot areas. These panels have a higher efficiency than polycrystalline panels, which allows the maximum use of the available space. However, this advantage is reflected in a higher cost.
Thin-film panels can have useful applications in homes, but they take up considerably more space, so they are only recommended where space is not an issue or where budget is the main constraint.
The key to choosing the best solar panel for your home is to balance your energy needs, available space and budget with the technical features we have described.
In short, choosing the best photovoltaic system depends on both the technical specifications and the particular needs of your home. By reading this article, you now have the fundamental tools to make an informed decision, ensuring that your investment in solar energy is as efficient and long-lasting as possible.