The sun delivers large amounts of energy to the surface of the earth. Figuring out how to measure solar intensity, even if it's just a general idea, is useful to help determine the best position to place solar panels in order to generate the most solar power.
High above the clouds, satellites have measured the solar intensity to be 1.366 kW per square meter. As the sunlight filters through the atmosphere, some of the energy is reflected back into space while some is absorbed by the air. The remaining amount of solar energy to strike the surface of the earth averages about 1 kW per square meter.
This immense amount of energy powers the wind, weather and water cycle that influence the entire world. Solar panels can tap into this energy but their efficiency is greatly affected by the solar intensity (the strength of the sunlight). Here are some factors that reduce the solar intensity:
You don't need complex equipment to measure solar intensity. Before installing a solar array and storage system, a small, inexpensive solar panel and data collector can be used to give you a general idea of how much solar energy is available in that location. It will record voltage, current and the time of day and will show how the electricity production changes from day to day and season to season. Place it in an open, unobstructed location, in the same area where you plan to install the larger solar panels.
Solar intensity is not the same as air temperature. Even on a cold winter day, if the solar panels face directly towards the sun, the solar cells will still produce electricity despite the cold air temperature. An automatic mechanical system & sensors can be used to align the panels in the best possible angle, but the extra components may be cost prohibitive for most household applications. A fixed-mount position for solar panels is the easiest and most affordable option for residential home use.