Solar panels are basically of two types; monocrystalline (mono) and polycrystalline (poly). Here is a comparison between the two that will help you in deciding which type you should select for your rooftop solar energy unit.
Solar Panels work on the principle of photo-voltaic effect (PV effect). Basically, when light energy hits the solar panel surface, the solar cells start conducting electricity due to the photo-electric property of semiconductors like silicon that make up a solar cell. But here are some key differences in the technology regarding the type of silicon solar cell they use to manufacture the two types of panels.
In monocrystalline the cell is composed of a single crystal which is formed by first forming the silicon into bars and then cut into wafers. This is a complex manufacturing process and thus is expensive. However, as the cell is composed of a single crystal, the electrons that generate a flow of electricity have more room to move. As a result, monocrystalline panels are more efficient than their polycrystalline counterparts.
To recognize a #monocrystalline panel check out the edges and color of the panel. They have curved edges and are dark in color. The efficiency of a monocrystalline panel ranges between 16-22%.
Efficiency of different monocrystalline solar PV cell types
• Monocrystalline - 16.5 to 19%
• Monocrystalline PERC - 17.5 to 20%
• Monocrystalline N-type - 19.5 to 20.5%
• Monocrystalline N-type HJC - 19 to 21.7%
• Monocrystalline N-type IBC - 20 to 22.6%
Like the monocrystalline panel, #polycrystalline panels are also made from silicon. But here is where the similarity ends. Instead of using a single crystal of silicon, manufacturers melt many fragments of silicon together to form the wafers for the panel. These panels are also sometimes called “multi-crystalline,” or many-crystal silicon. As there are many crystals in each cell, there is less freedom for the electrons to move. As a result, polycrystalline solar panels have lower efficiency ratings than monocrystalline panels.
To recognize a polycrystalline panel check out the edges and color of the panel. They are square or rectangular and blue in color. The efficiency of a polycrystalline panel ranges between 15-19%.
Efficiency of different polycrystalline solar PV cell types
• Polycrystalline - 15 to 18%
• Polycrystalline PERC - 17 to 19.5%
While the efficiency of a panel is of prime importance, in real world situations the panels seldom perform at their rated output. This is because the efficiency is dependent on a number of factors.
The factor which can affect solar panel efficiency and performance:
• Shade on panel
• Panel orientation
• Temperature
• Location (latitude)
• Time of year
• Dust and dirt
Out of the above mentioned factors there are three which have the most impact on the efficiency of a solar panel. These are shading, panel orientation and temperature.
Shade on your panels can have a huge impact on the output. it is estimated that shade can reduce the power output by 50% or more. If your have your panels connected in series, shade on even one panel can have an impact on the overall power output by 20-30%. It is best to avoid shade but if you cannot avoid it there are devices (optimizer and micro-inverters) that reduce the effect of shade on your system.
Temperature is another factor that has an impact on the power output of the panels. The efficiency of the panels is measured under standard test conditions where the cell temperature is 25° C. This is known as ambient temperature. But as we all know in real world the temperature is almost every time above 25°C.
Generally the cell temperature is 20-30° C above the ambient temperature, which can reduce the efficiency of the panels by 8-12%. This drop in efficiency because of increase in cell temperature is know as power temperature coefficient and is measured in %/°C.
Power temperature coefficient of different types of panels are as below.
• Polycrystalline cells - 0.4 to 0.43 % /°C
• Monocrystalline cells - 0.37 to 0.40 % /°C
• Monocrystalline IBC cells - 0.29 to 0.31 % /°C
• Monocrystalline HJC cells - 0.26 to 0.27 % /°C
Here it is important to note that the Power Temperature Coefficient should be as low as possible to keep the efficiency of the panel high.
So now how to decide which is better for you?
Well here you need to consider the space available for your solar installation and your budget. If you have ample space then you can opt for polycrystalline panel as it is economical. If you have space crunch then you should opt for monocrystalline as it will give you more electricity per square feet of your installation.
Whether you choose mono or poly solar panels, you’ll be decreasing your electricity bills.
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#mono #poly #monopanel #polypanel #solarpanel #monocrystalline #PV #photovoltaic #polycrystalline, #carbonzerolife
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