|Does temperature affect the amount of energy a solar panel receives?
|Question Date: 2011-11-02|
On the next link you can read a complete answer with the math to explain the temperature-dependence on solar cells. It was prepared just for you from one of our scientists.
Thank you for asking.
Although the temperature doesn't affect the amount of solar energy a solar panel receives, it does affect how much power you will get out of it. To make a long and complicated story short, as the solar panels get hotter, they will produce less power from the same amount of sunlight. Normally, electrons at rest (low energy) are excited by the sun (high energy), and the difference between their excited and rest energies is the potential difference (voltage) that you could ideally get from your solar panel. However, heat also excites electrons (when we heat something we are giving it energy), which raises the energy of the electrons at rest. ("warmer" electrons have more energy at rest than their "cold" counterparts.)
Because we produce power from the difference in the states (at rest and excited by the sun), if the electrons have more energy at rest (your solar panels are hotter), the difference between the rest energy and excited energy (from the sun) is smaller, and our solar panels will produce less energy. A simple analogy would be to consider waterslide from the top of a building (let's say 5 stories high). If you built the waterslide from the top floor to the bottom, you'd go really fast. However, if you built it from the top floor to the 3rd floor, you wouldn't be able to get going as fast. (In this analogy, your difference in potential energy from gravity is converted into speed.)
There's a lot of science behind semiconductors and solar panels, but a lot of great resources to explore if you're excited to learn more!
Temperature does not affect the amount of energy a solar panel receives. The amount of energy depends on how much light is received rather than the air temperature. However, the position of the sun in the sky undergoes seasonal variations due to the tilt of the earth as it rotates around the sun. The illumination of a solar panel in a fixed position does indeed vary a bit seasonally due to this factor and the power generated is affected. click here
Some types of solar cells also have different power conversion efficiencies for the same illumination (light intensity) as a function of temperature. Thus, a change has more to do with the properties of the material in the solar panel than how much light is absorbed at a given temperature.
Yes it does. Light is composed of a huge number of "photons", particles which carry the energy associated with light. When they hit the solar cell they bump into an electron and give it the energy they were carrying. When this happens the electron goes from a low-energy state to a high-energy one. The solar cell is then designed to extract this electron in the high energy state and run it through an electrical circuit to use up this extra energy that the electron has. Sometimes though this high-energy electron will bump into other atoms in the solar cell before it manages to get out, and the electron loses this extra energy which turns into heat rather than electricity. On an atomic and molecular level heat is the vibration of atoms and molecules. If the solar cell is at a higher temperature that means that the atoms are vibrating faster, so it's harder for the electron to get out without bumping into these atoms. So when the solar cell heats up the output power will drop because more of the energy is lost before it manages to escape the solar cell.
I like your question. Yes, if the temperature is higher, there will be a little more energy reaching the solar panel. But the energy that's useful for the solar panel is light energy, not heat energy, so I don't think the temperature change would make any difference in how much useful energy hit the solar panel. Keep asking questions!
Yes, although how much and how it affects it would be complicated. Any piece of hardware, including a solar panel, has a range of temperatures in which it runs with optimal efficiency, and too warm or too cold and it won't work so well. However, because light and temperature are both energy, the temperature of the air is closely related to the amount of light available, and the more light, the more the solar panel gets.
This is a useful site with information on solar cells temperature dependence. There are tables that show it. I am not pretending to advertise this manufacturer of solar cells, but the information there might be useful for you.click here
It is useful to separate the function of a material into two crude categories: structural and electronic. That is, does the material work because of the way it responds to stress or the way it interacts with light? In solar cells, the behavior is entirely electronic - that is, something special about the chemicals in the films themselves are responding to light. Electronic properties are generally insensitive to modest changes in temperatures as long as the material doesn't change dramatically as a result (by freezing or melting, eg).
So the short answer is: not really!
There are some more subtle aspects to this, of course, that depend on the specifics of the solar panel in question, but as a first pass you don't expect temperature to play a large role. Hope this helps
The main effect of temperature on solar panels is that it reduces the efficiency of the solar cells at converting solar energy (sunlight) into electricity. In other words, the chemical reactions that occur within the solar panels are more efficient at cooler temperatures than at hot temperatures. This may seem counter intuitive, since you would normally think that the more sunshine you get, the more energy there is to be turned into electricity. In practical terms, a solar panel in the hot desert may produce a little less electricity per amount of sunshine than a solar panel in the Alaska, but this inefficiency is made up by the greater number of sunny days in the desert.
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