Outdoor Temperature and the Efficiency of Home Solar Panels

The weather outside is hot: really hot. You sit inside, pleased because all of this sunshine must be good for your solar panels. You expect great returns on your energy investment, so you’re surprised when the efficiency of the panels seems to be dropping. Surprise! In extremely hot temperatures, photovoltaic solar panels actually become less efficient.

Around the home, you may use thermal solar panels for heat energy. These common solar panels are used to collect heat and warm up hot water. Place them on a hot roof and they work wonderfully. However, photovoltaic solar panels do not use heat to make energy. These solar panels use the light that falls on your home and turn it into energy to power appliances. When you are researching, installing, and using solar panels around the home, it is important to understand that these different solar systems work in very different ways. Heat is what is required for solar hot water systems. These systems work well on warm days. Light is required for photovoltaic solar systems. These solar systems work well when it is sunny, but it does not need to be warm. In fact, a cold, clear day is ideal for solar energy.

Why is this the case? Temperature changes the efficiency of photovoltaic solar panels. The efficiency of a solar cell is expressed as a wattpeak (WP). On the package for your solar equipment, you will generally find the efficiency in wattpeaks. This number gives the efficiency of the cell under laboratory conditions. The laboratory temperature used for peak efficiency is 77 degrees Fahrenheit.

A photovoltaic solar panel is designed to collect visible light. However, it is also very dark. Dark colors absorb heat. When the air temperature is a nice, stable 77 degrees, all is well with the solar panels. However, as temperatures climb to 100 degrees and beyond, the energy output of the solar panels decreases. To reduce the effects of heat on solar panels, avoid placing solar panels on a metal roof. Allow for some air flow around a solar panel to provide ventilation. Also, consider what use the solar energy will go to. If you live in a desert climate and plan to use solar panels to power an air conditioner in the heat of summer, this is possible, but the panels will certainly not be at their most efficient.

Oddly enough, photovoltaic solar panels work extremely well in light, cold environments. Actually, all electronics work best in the cold, because cold materials are good conductors of electricity. Cold locations such as Colorado and Scandinavia have been very successful using solar power on a large scale. If it’s hot where you live, you can certainly use solar panels to generate energy. However, be gentle with the solar panels and give them good ventilation to improve their efficiency. In the peak of the summer heat, reduce your use of household appliances and lights since the panels will not be operating at peak efficiency.

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