Overview:

Product Description:

Most small PV arrays have fixed panels that do not track the sun’s daily path across the sky. Panels achieve their maximum efficiency when they are perpendicular to the sun at solar noon, which often does not equate to 12:00 PM. Solar noon is defined as the time at which the sun is at its daily zenith. In the southern hemisphere, out of the tropics, panels should be facing north to take advantage of the sun’s daily zenith. Conversely, in the northern hemisphere, also out of the tropics, panels should be facing south.

The tropics are defined as the area that lies between the Tropic of Cancer, at latitude +23.45° and the Tropic of Capricorn, at -23.45°, with the equator dividing the region in two. In this region, the sun’s daily path may pass to the north or south, depending on the time of year. This leads to complications in sun-tracking systems, but for fixed panels, using the panel angle guideline for sub-tropical locations is sufficient.

The angle at which panels are mounted varies according to the time of year when it is desirable for the PV array to be most efficient.  In order to determine this angle properly, the project location’s approximate latitude must be known. A list of Australian locations and their latitudes is available  here.

Panel angle guidelines:

• Year-round optimal power:         Angle = Latitude
• Maximum power in winter:         Angle = Latitude + 15°
• Maximum power in summer:      Angle = Latitude - 15°

For grid-tied applications, fixing the panel angle equal to a location’s latitude provides the best results on a year-round basis. For stand-alone systems, however, an angle setting that makes the most of the weak winter sun will ensure ample year-round electricity.

Next Step: Sizing the Array

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