Yes, these terms can be used interchangeably. A module or panel is a set of interconnected photovoltaic cells that produce electricity in the form of direct current.

The term “panel” appeared in Poland as an English loanword and has been in use on our market for several years.

It is also useful to know what a photovoltaic cell is. It is a single junction of P-type and N-type semiconductors that converts solar energy into electricity. The cells, often called wafers, generate a low DC voltage when exposed to light. For the most common silicon cell, it is about 0.6 V. To obtain a useable voltage (around a few dozen volts), the wafers are connected in rows by solder or glue. The standardised number of 60 silicon cells can achieve around 40 V. The voltage of a single cell will vary depending on the material of the semiconductor. Therefore, string lengths vary, which directly affects the electrical performance of the entire photovoltaic module.

Strings of cells are often connected in parallel to obtain more power for the entire module.

A module is a collection of individual cells, so the wrongly derided name, “photovoltaic cell battery,” is the correct one.

In contrast, the term “solar collector” should not be used as it means a device used to convert solar energy into thermal energy.

Sunlight is a stream of photons. When it falls on a photovoltaic cell, i.e., a P-N junction, it causes the electron-hole pairs to break apart. The released negatively charged electrons and positively charged holes accumulate at opposite poles of the cell, generating a constant flow of voltage. When the electrical circuit is closed, electrons travel from cells connected in rows toward positive holes through metallised contacts to equalise the potential. The electrical current created in this manner can be processed by a photovoltaic inverter or used, for example, to power DC loads.

It can be said without any doubt that PV installations are an investment for years. Photovoltaic modules are long-lasting devices, made to ensure their reliable operation for several decades – even in extreme weather conditions. Manufacturers provide up to a 30-year warranty on the module’s power output and failure-free performance. Over time, however, each module slightly loses its efficiency. Depending on the manufacturer, materials used, and the manufacturing technology, the guaranteed efficiency loss is between 0.2 and 0.7% per year.

The long lifetime of PV modules can be demonstrated by an example from Germany. In the 1990s, our western neighbours launched the “1,000 roofs” programme to encourage Germans to switch to alternative sources of energy. 20 years later, scientists at the Chemnitz University of Technology tested the modules that were installed at that time. The performance of all installations significantly exceeded 80% of the initial capacity.

Yes, there are mounting structures dedicated to different roof coverings and roof angles. Thanks to their easy adjustability, they can provide a solid foundation for photovoltaic modules while maintaining the durability and airtightness of the roof.

The slope and azimuth angle of the roof surface largely determine the performance of the installation. In Poland, the highest efficiency is obtained with PV modules facing south with an angle of about 35°. Flat roof owners can take advantage of special designs that optimise the angle of the panels to increase the installation’s safety and annual energy yield.

The only constrains of installing PV modules are the building’s poor structural condition and shaded areas of the roof.

This is something that the installer or an advisor should assist the customer with. They will be able to calculate the required capacity of an installation based on electricity bills from recent years and an analysis of the technical parameters of the roof to help their customer choose the appropriate type and number of modules.

The home’s power requirements are an important consideration. The installer, along with the investor, must also consider whether major investments are planned in the coming years. Installing air conditioning, a heated driveway, or an electric car charger will all significantly increase power requirements. It is worth it to include these plans in the design.

Yes, it does. For silicon photovoltaic cells, low temperature has a beneficial effect on the operation of the photovoltaic system. This is because the cell voltage increases as the temperature decreases. The design of the modules allows them to work in very low temperatures, which is why we can use them even in Antarctica.

However, keep in mind that winter days are relatively short, and the intensity of sunlight is smaller than in the summer. As a result,, energy production will be lower than in sunny seasons.

If you are not a licensed installer – we strongly advise against installing a PV system yourself. Attempting to set up a photovoltaic system on your own without proper training is putting your health and life at unnecessary risk. An untrained “installer” can be electrocuted or fall from a great height. What is more, poorly installed systems will also operate less efficiently and may be more prone to faults and fires and also void manufacturer’s warranty.

Please contact experienced companies that specialise in PV installations.

A polycrystalline module is made from polycrystalline semiconductor cells, while a monocrystalline module uses monocrystalline cells.

Producing monocrystalline silicon requires more energy than producing polycrystalline silicon, which means that the former is more expensive. However, monocrystalline cells have higher solar conversion efficiency compared to polycrystalline cells, while amorphous cells rank last. This translates into the size of the area occupied by the modules. Respectively, monocrystalline cells occupy the smallest area of those listed, so they require less money for the mounting structure and installation itself.

Polycrystalline cells are cut from blocks of polycrystalline silicon, so they are square in shape. Monocrystalline silicon is made with the Czochralski method to form a cylinder, which is then cut into wafers after milling the side edges. The substrate of a mono cell has a characteristic shape like a square with rounded off corners.

Monocrystalline cells are very dark blue, almost black – much darker than blue or navy polycrystalline cells.

From a performance standpoint, it does not make a significant difference. A photovoltaic generator of a certain capacity, regardless of the type of modules used – polycrystalline or monocrystalline – will produce almost the same amount of power per unit time. When choosing cell technology, programs that simulate the yield of PV installations usually do not distinguish between poly and monocrystalline modules, only between crystalline and amorphous. However, in recent years, more emphasis has been placed on the development of monocrystallisation technology, so these cells feature, among other things, improved temperature coefficients that contribute to the increased efficiency of monocrystalline PV modules.

In most manufacturers’ modules, PV cells are connected using a metal strip designed to conduct electricity. Busbars are places prepared for soldering this tape, located on the back and front of the cell.

A traditional PV module is typically made up of 60 square cells. In half-cut modules, the cells are cut in half, thanks to which the panel is made up of not 60 but 120 rectangular cells. These are 2 strings of 60 half-cells connected parallel to each other. By changing the structure of how the cells are joined together in the module, resistance to the flow of current is reduced, resulting in an increase in the device’s efficiency of between 1.5 and 3%. In addition, the panel handles partial shade better.