Category Archives: Sun

How the Sun Moves Through the Sky

For people working on solar power it is important to understand the movement of sun across the sky. It has a direct bearing on the proper orientation of the solar energy collectors and photovoltaic modules. A simple explanation of shadow plot to find exact geographic north-south is also given. Continue reading

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Sun and Its Sunshine

The radiant energy from the sun covers the entire electromagnetic spectrum; however, the atmospheric interference restricts this solar radiation spectrum to 290 nm to 3000 nm. The maximum spectral radiant energy, irradiance, is at around 500 nm. The amount of solar energy at any place varies with latitude and season, scattering and absorption by atmospheric gases, local climatic factors like cloud cover, humidity and pollution etc. Solar irradiance of the order of 1000 W/m2 is about the best sunshine obtained under clear skies. It is also the standard test condition for wattage rating of solar panels and is thus connected “sun hours” of insolation received at any location. Continue reading

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