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The temperature coefficient is an essential parameter in photovoltaic (PV) systems, particularly solar cells.
- Definition: The temperature coefficient of a solar photovoltaic cell (or module) refers to the change in its electrical characteristics (such as voltage, current, and power output) in response to changes in temperature.
- Effect on Voltage and Current: Typically, as the temperature of a solar cell increases, its voltage decreases while its current increases. Conversely, when the temperature decreases, the voltage increases while the current decreases. This phenomenon is primarily due to changes in the semiconductor material properties as temperature changes.
- Calculation: The temperature coefficient is usually expressed in percentage per degree Celsius (°C). For example, a temperature coefficient of -0.5%/°C for voltage means that for every degree Celsius increase in temperature, the voltage decreases by 0.5% of its value at a reference temperature (often 25°C).
- Impact on Power Output: The temperature coefficient directly affects the overall power output of a solar PV system. Solar panels are typically rated at standard test conditions (STC), which include a specific temperature. However, in real-world conditions, solar panel temperatures can vary significantly. Therefore, understanding the temperature coefficient helps estimate how the panel’s output will change with temperature variations.
By considering the temperature coefficient, solar system designers and operators can better predict and optimize the performance of solar PV installations under different environmental conditions.
See
- Negative Temperature Coefficient
- Positive Temperature Coefficient