How does the efficiency of solar panels change with temperature?

The efficiency of solar panels is an important factor when evaluating their performance and economic viability. One of the most significant factors affecting the efficiency of solar panels is temperature. In this article, we look at how temperature affects the efficiency of solar panels and what this means in practice.

The effect of temperature on the efficiency of solar panels

Solar panels convert the sun’s radiation into electricity, and their efficiency depends on many factors, such as light intensity, panel material and ambient temperature. In general, the efficiency of solar panels decreases as the temperature increases. This is because higher temperatures increase the internal resistance of the panels, reducing their ability to generate electricity.

How does temperature affect the performance of solar panels?

The performance of solar panels is often measured under standard conditions (Standard Test Conditions, STC), where the temperature is 25 °C. In actual operating conditions, however, the temperature may vary considerably. When the temperature rises above 25 °C, the efficiency of the solar panels starts to decrease. This phenomenon is known as the temperature coefficient concept.

The temperature coefficient can be used to estimate how much the efficiency of the solar panel changes when the temperature changes. For example, if a solar panel has a temperature coefficient of -0.5%/°C, the efficiency of the panel decreases by 0.5% for every temperature increase above 25°C. This means that if the temperature rises to 35 °C, the efficiency of the panel will decrease by 5%.

Practical examples

Let’s take an example where the nominal power of the solar panel is 300 W and its temperature coefficient is -0.5%/°C. If the ambient temperature rises from 25 °C to 35 °C, the efficiency of the panel decreases by 5%. This means that the power produced by the panel is 300W – (300W * 0.05) = 285W.

Means to reduce the effect of temperature

There are several ways to reduce the effect of temperature on the efficiency of solar panels:

• Good ventilation: Mount the solar panels in such a way that air can circulate around them to help cool the panels.
• Reflective materials: Use reflective materials around the panels to reduce heat radiation.
• Optimal placement: Avoid installing panels directly on hot surfaces, such as dark ceilings.

Conclusions

Temperature is a significant factor that affects the efficiency of solar panels. Higher temperatures can significantly reduce the ability of the panels to produce electricity. It is important to take this into account when designing and installing solar panels in order to maximize the energy they produce and the financial benefit.

You can read more about the efficiency of solar panels and the effect of temperature from the following sources:
Solar Power World
U.S. Department of Energy