We shall treat the types of solar panels available in the market and how to specify them in this section.
TYPES OF SOLAR PANELS
There are different types of solar panels depending on how they are manufactured and the purpose for which they would be applied. We shall review only 4 types mostly/commonly used worldwide. It is trite to mention that about 95% of SP used worldwide are based on silicon crystal of varying purity. The ability of any photovoltaic material to convert electron to electricity is directly proportional to the purity of the silicon crystal used in its manufacturing.
A single layer of crystalline material or ingot in cylindrical shape is used to form a cell, by cutting 4 of its edges. The rounded shaped materials so produced, are then coupled together to form the silicon wafers. This arrangement leads to a lot of savings in space and so more efficiency.
In this manufacturing method, the most purified silicon is used and so the conversion rate is the best. The conversion efficiency of mono-crystalline SP is around 18 to 20%, but some specially produced models can achieve 25% efficiency. Also, this type of SP last longer than others, with some manufacturers offering 25 years warranty on the product.
However, Mono-crystalline manufacturing process leads to a lot of wastages, which makes it the most expensive solar panels in the market. When the relative efficiency is analyzed against space and cost, it is still better in many applications to use mono-crystalline solar panels.
In this manufacturing process, moulds are made in square shapes where melted silicon crystals are poured to form PV cells. These cells are then coupled and wired together to form solar panels.
You will notice that this process which was first demonstrated in 1981 in producing the first ever commercially available solar panels is very easy and low cost. Invariably, the cost of the polycrystalline or multi-silicon solar panel is usually lower than polycrystalline.
Its conversion of solar to electricity or efficiency is between 13 and 18%, so to achieve the same electricity or wattage as mono-crystalline, more spaces are required.
Typical warranty for this type of solar panel is 18 to 22 years.
The polycrystalline panels are about 2-5% less efficient than the mono, but are quite reliable and preferable for some environments where the sun intensity is suspect
Note that in poly, the silicon wafers and/or ingot used are not necessary of the highest purity. Also, note the clearly different shapes and formats of the two types already discussed in case your installer is trying to exchange one for the other.
The Mono and Poly crystalline SP are the most common you will ever need for domestic installations.
NEXT: Amorphous/Thin film SP and SP Sizing
©Tunde Y. Salihu, 2017
234-803 324 6068