Transposition factor

The transposition factor is the ratio of incident irradiation (GlobInc) on the plane to horizontal irradiation (GlobHor). In other words, it indicates what you gain (or lose) by tilting the collector plane.

It can be defined in hourly, daily, monthly, or yearly values.

It is calculated by applying a transposition model (Hay or Perez) to horizontal hourly values. The result depends primarily on diffuse irradiance.

See the Orientation optimization tool.