ABSTRACT
This chapter begins with a discussion of how to model the geometry of surfaces relative to the sky dome, and covers how to combine that information with solar radiation data to evaluate radiation gains on a surface. To understand how a surface is affected by solar radiation, one must first describe its position relative to the sun. Surface orientation can be described with either spherical or Cartesian vector coordinates in the same way that solar position is identified. Reflected solar radiation may come from a variety of sources, but the only one that is virtually always present is the ground. Surface global radiation is the total of all solar radiation components incident on a surface of arbitrary orientation. One of the primary lessons relative to building form and insolation is that the availability of surfaces to fenestration is the most important factor relative to building orientation.
