The meaning of solar or solar energy varies over time. Presently most people equate solar with photovoltaics (PV). Thirty years ago, most people equated solar with active solar systems that heated water. It is best to think of the word “solar” as referring to any technique that uses solar energy to reduce our need for conventional energy. Thus solar refers to: photovoltaics, active hot water collectors, passive heating, daylight, and shading. Although most people do not see shading as a solar strategy, much conventional energy can be saved by rejecting the sun. Since most people of the world live in hot climates and because the sun is most plentiful in the summer, shading may be the most immediately available and valuable form of “solar energy.” Furthermore, shading design requires a good understanding of solar geometry.
