WHICH SOLAR PANELS TO CHOOSE : Poly or monocrystalline

WHICH SOLAR PANELS TO CHOOSE : Poly or monocrystalline

20 abril, 2019 Off By admin

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Solar panels monocrystalline or polycrystalline, is our first question when wanting to make a photovoltaic installation, here I will explain the basic differences so that you can choose the photovoltaic solar panels that best suits your needs and budget.




The basic difference is in the manufacture of the solar cells that make up the solar panel

The monocrystalline cells are formed by a single type of silicon crystal, that is, when the crystal has been manufactured, the growth of the silicon crystal itself has been controlled.

This allows it to only form in one direction, achieving a fairly perfect alignment of all the components of the glass and therefore greater energy efficiency in the same space if we compare it with another type of plates.

On the other hand, in polycrystalline solar cells, the growth of the silicon crystal is not controlled, so the crystal grows in all directions creating a set of different crystals joined together.




Initially the monocrystalline crystal manufacturing system was a bit more expensive than the polycrystalline crystal, but little by little these differences in both economic cost and performance have been decreasing.

You should also know that the performance specified in the technical sheets of the photovoltaic solar panels is a value obtained in a laboratory at 25ºC and with an insolation of 1,000W / m², and it can be said that it is like a theoretical value to which under normal conditions we will never get there, and that means that a performance of 15% means that a photovoltaic solar panel with a square meter of surface is capable of generating 150W of power in the conditions previously exposed.

How to know the performance of photovoltaic solar panels?

To know which solar panel has better performance, just look at the percentage of performance that puts the technical sheet, but we must bear in mind that currently similar performances are achieved with both monocrystalline and polycrystalline technologies, and as I said, these values ​​are always in the technical sheets of each of the plates.

What is the thermal coefficient?

On the other hand in photovoltaic solar panels there is a value called thermal coefficient which must be taken into account when deciding which plate to buy. The thermal coefficient quantifies what affects the temperature to the performance of the solar cells.

With this value it is also true that the yield of the monocrystalline cells, at first, was seen a little more affected by the increase in the temperature in the plate, although at present there are monocrystalline cells that behave better than the polycrystalline ones against increases in temperature.

But yes, an obvious difference is that monocrystalline cells tend to be darker and therefore absorb more heat from the sun, so in normal operation, the temperature of the cell increases a little more in monocrystalline cells, which can affect to its performance against polycrystalline.

Although in cases where it is not too hot, as it may be in the northern part of Spain, these differences are still reduced, and may even be negligible.

On occasions when monocrystalline photovoltaic solar panels respond better to the increase in temperature (they have smaller thermal coefficients), so even though monocrystalline ones increase a little more temperature than polycrystalline ones, it does not always mean that in the same atmospheric conditions, monocrystallines more affected than monocrystalline ones in yield.

In summary, today the differences, are so insignificant and despicable, that I advise you to make the decision of what photovoltaic solar panel to buy.

You have above all the price € / W obtained by the plate that any other thing, as long as it does not prioritize above all to reduce to the maximum the space to use for the plates, since if that were the case you should get the best relation W / m² of panel that could. And for that, yes I advise review above all the value of the percentage of performance of each of the photovoltaic solar panels.

Solar panel technology

A photovoltaic system (or photovoltaic system) is formed by a series of solar panels and an inverter. The inverter converts the direct voltage generated in solar panels into normal alternating voltage.

Alternating voltage can be used immediately in your home or business. If an excess of energy is generated, it is supplied to the electrical network.

green electricity meter records the amount of energy your solar energy system produces. An uninterrupted power supply is guaranteed through the connection of the solar panel to the electrical network.

Solar panels are usually placed on the roof, but can also be installed separately, for example, in a garden. All types of roofs are eligible: tiles, slates, corrugated sheets, flat sheets, sandwich panels, etc.

The roof should not be in the shade and should be able to absorb enough sun. Ideally, it should be oriented between the southeast and the southwest, at an angle of 20-60 ° degrees. There are adequate fixing materials for each type of roof.

How does a solar panel work?

A solar panel or photovoltaic panel  (from the English photo voltaic) is a panel that converts solar energy into electricity. A solar panel consists of solar cells or photovoltaic cells that capture sunlight. Solar cells are usually made of silicon. That silicon is made up of several layers. Under the influence of light, an electric current (direct) flows between the layers.
Depending on the type of silicon, the cell converts a larger or smaller part of sunlight into electricity. The solar cells are interconnected and placed in a solar panel.

Different types of solar cells.

  • Monocrystalline silicon.
    Color: black (dark blue).
    Efficiency module: 15-20%
    Manufacture: the silicon melts and forms in a cylindrical crystal, in which the crystals are in the same direction. This cylindrical silicon bar is cut into slices (wafers) to make solar cells from it.
  • Polycrystalline Silicon
    Color: Blue marble cellulose
    Efficient efficiency: + 15%
    Manufacturing: liquid silicon is poured into square molds and cooled. During the cooling process, the crystals are placed in random directions.
  • Thin film color  : black cells (dark blue) Efficiency of the
    module: + 10%
    Manufacturing: the thin film technology is based on amorphous silicon. It has no glass structure, but it has an irregular shape.

What type to choose?

Crystalline silicon is the most used technology at this time. The efficiency of this type of solar cells is significantly greater than that of thin-film panels. In this way you can generate more energy in less surface. Crystalline silicon is the best choice, especially for private homes where space is limited.

The choice between monocrystalline and polycrystalline silicon depends on several parameters. These are some of the benefits of both technologies:

Monocrystalline silicon

  • It gives a greater capacity per m2. In this way you can generate more power on the same surface with monocrystalline silicon.
  • It generates more energy in direct sunlight.
  • Aesthetic appearance: completely black panel.

Polycrystalline silicon

  • It has a cheaper production price.
  • It generates more electricity with diffuse light, that is, with cloudy weather and side radiation.

Our recommendations:

The performance per watt installed (Wp) differs little with monocrystalline or polycrystalline.

  • If the panels are oriented towards the east or the west, we recommend the polycrystalline panels. These render better with side radiation.
  • If the surface area available for solar panels is limited, monocrystalline panels provide more power.

In terms of quality and guarantee, mono and polycrystalline panels have an equally good score. The panels of our manufacturers still deliver at least 90% of the yield after 10 years and at least 80% after 25 years. When choosing quality brands  , that number continues to rise.