International Journal of Engineering and Technology

A two-axis scanning goniophotometer has been designed and developed at LIFT (Laboratorio Ingegneria Fisica Tecnica) at Engineering Department, University of Roma Tre (Rome) and the data compared with those obtained from the video-projection goniophotometer at an important national Institute of Metrology. By this instrument a correlation between the reflectance and the angle of incidence will be propoposed. This function is useful for all the programs that simulates the dynamics of the energy systems in buildings where, typically, the reflectance is approximated by a constant, overestimating the values of the solar gains.