Development of a methodology for quantifying insolation variables in windows and building openings

Energy audits of existing buildings require efficient devices and procedures to assess the solar potential through windows and building openings. The use of insolation is related to solar rights, solar gain, daylight potential and solar control. The methods described in the literature to assess insolation on windows require the geometric characterization of solar obstructions. In this paper we present a simple optical device which permits sky vaults that can be viewed from a central point of building openings to be characterized by means of photographs and image analysis. When these images are processed, it is possible to determine hours of solar insolation and characterize the obstruction angles, the sky opening indicator and the view factor indicator. The results of the proposed model are shown graphically in the form of stereographic, orthogonal, gnomonic, isoaire [9] and cylindrical sun path projection diagrams.

► Energy audits of buildings require quantifying the solar access potential of windows and building openings.
► The authors have developed a method to generate hemispherical projections based on photographs and image analysis.
► The LRTV device developed for us is presented in this paper.