Factors Affecting Performance Of Solar Panels- Problem And Their Solutions.
With advancement in technology Solar panels are quiet efficient and robust these days. They can withstand heat/cold cycles and heavy weather. But, like any other source of energy solar panels are not perfect and their performance is affected by variety of factors. However there are ways to mitigate the damage and improve efficiency. The following are most important problem causing factors and their solutions :
It can be a general notion of people that more environmental heat means more energy from solar panels. Actually, extremely high temperatures will have a significant impact on solar panel efficiency. Temperatures hotter than 77 degrees F will reduce performance by a fraction of a percentage point for each degree of temperature.
There are couple of ways to deal with this issue:
1. Install solar panels on a mounting system a few inches off the roof, this will help cool them by allowing air circulation.
2. Use photovoltaic panels that are designed to be more efficient in hotter climates.
3. Ensure that panels are constructed with light-colored materials, to reduce heat absorption.
4. Inverters and combiners can be moved into the shaded area behind the array.
The closer a location is to the equator, the more direct and consistent sunlight it receives. So a solar installation in Arizona will receive more consistent, direct sun exposure throughout the year than an array in Minnesota, where the sun’s changing angle affects system performance from summer to winter.
For maximum performance orientation of solar panel should be adjusted twice in a year. Because for highest output, solar panels must be perpendicular to the sun’s rays. In the summer months the sun is high overhead, catch more sunlight by tilting solar panel at a lower angle. During the winter, the sun moves across the sky at a lower angle. Set the solar panels at a higher angles during these months. Solar tracking is another great way of increasing the output power. It rotates the panel or array of panels so that they always directly face the sun.
This point is quite self explanatory, Shade is the enemy of solar because it blocks the sunlight required to produce electricity. Specially when solar cells are connected in a series. If a PV cell is shaded, it causes the energy that is generated by its neighbours to be drained. This is because it acts as a resistor and lowers the total current.
To overcome this problem simply do a shading analysis while deciding on the position and location of solar panel, make sure no shadows will fall on the solar panel array during peak sunlight hours. You may have to trim a few trees also.
Local Environmental Conditions and weather :
Conditions like rain, snow, hail can reduce the performance of solar cell. Heavy smog, industrial pollutants, or airborne particulates can cause dust and film clouded on solar panels which has adverse effect on their efficiency.
Panels should be cleaned periodically to allow maximum sun exposure and to keep energy production at rated levels. Making frequent physical inspections and spraying water on your modules can help reduce the weather effect.
Some other techniques to improve output of solar panel are:
Solar Cells Glazing:
For long life, solar cells must be protected from the elements (rain, snow, hail, bird dropping etc). Polycarbonate or low-iron glass is generally recommended due to high optical transmissivity — approximately 90%. Surface coating treatments reduce reflections for even higher transmissivity. Ordinary window glass reduces the output by about 40% — not recommended.
Solar panel output power may be increased via a light concentrator such as a Fresnel lens or mirror.
Solar Charge Controls:
Since the solar panel does not put out the correct voltage to charge a battery, it must be controlled via a solar charge controller to prevent battery overcharge.