A solar array is a loosely defined term referring to a group of photovoltaic solar panels or cells that convert sunlight to electricity, arranged and linked in such a way as to operate as a single unit. The term can also refer to a similar set of reflecting mirrors used for directing and focusing sunlight onto such a group of photovoltaic units. A solar array can be relatively small, such as a group of panels on the roof of a single family home, or very large, such as an array covering several acres, containing hundreds or even thousands of individual panels.
In the strictest sense of the term, even some individual solar panels are technically solar arrays. A typical solar panel is made up of several photovoltaic cells linked together and bound, or contained, within a single unit. The word array is not generally used in this manner, however, and a solar array is usually regarded as a group of solar panels, which can vary widely in size and shape. A typical solar array is composed of solar panels of one type, but this does not necessarily have to be the case.
Photovoltaic cells are the basis for most solar arrays. These devices convert sunlight into electric current, and can generate substantial amounts of electricity in large enough numbers. In the late 20th and early 21st century, it became more common for energy and environmentally conscious homeowners to install residential solar arrays in an effort to mitigate their energy costs. A typical residential array is mounted on the house, facing due south when possible, and usually on the roof.
While most solar arrays are stationary, some arrays are designed to use very efficient electric motors to turn the individual panels or groups of panels to follow the sun. This maximizes both the exposure of the panels to direct sunlight and the electricity they can generate. The small amount of electricity used by the motors is more than offset by the increase in the output. In some areas, where land has little value, such as deserts or other areas that receive a high percentage of sunlight, very large solar arrays can cover many acres.
Many spacecraft use solar arrays for generating electricity as well. They are easily oriented towards the sun and are capable of providing a significant amount of power. Both on earth and in space, groups of mirrors, sometimes called solar arrays, direct sunlight for conversion to electricity by solar cells or other purposes.