Quick Answer
Temperature affects solar panel output in summer, reducing efficiency by around 0.5% for every degree Celsius above 25°C. This results in a significant decrease in energy production, especially in extremely hot climates. A 10°C temperature increase can lead to a 5% reduction in solar panel output.
Temperature Derating Factors
The temperature derating factor for solar panels is typically around 0.5% per degree Celsius (°C) above 25°C. This means that at 35°C, the efficiency of a solar panel can drop by 10% (5°C x 0.5% per °C). Some high-efficiency solar panels may have a lower derating factor, but the general rule of thumb is to assume a 0.5% decrease in efficiency for every degree above 25°C.
Measuring Temperature Derating
To accurately measure temperature derating, it’s essential to monitor the temperature at the surface of the solar panel, not just the ambient air temperature. This can be achieved using a thermocouple or a temperature sensor attached to the back of the panel. By comparing the measured temperature to the manufacturer’s specifications, you can estimate the actual derating factor and adjust your energy production expectations accordingly.
Mitigating Temperature Effects
While high temperatures can’t be completely eliminated, some techniques can help mitigate their impact on solar panel output. Shading, for example, can reduce the temperature of the panel, increasing efficiency. Using a reflective surface or a cooling system can also help keep the panel temperature in check. Additionally, selecting solar panels with a higher temperature coefficient can help minimize the effects of heat on energy production.
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