A novel methodology to spatially evaluate DGP classes by means of vertical illuminances. Preliminary results

A novel methodology to overcome the main limit of the Daylight Glare Probability DGP (i.e. the heavy computational time for an annual analysis of the DGP profile in one point) is presented. This uses a proxy based on the vertical illuminance (Ev) at the eye level. To do so, the most suitable value of Ev, to substitute DGP, is found by means of a comparison to the corresponding DGP value through a fault-detection diagnosis technique. The methodology was applied to a representative enclosed office with one South-facing window (Window-to-Wall Ratio of 50%) located in Turin. The glazing was assumed to have different transmission properties (specular and scattering) with different visible transmittances (in the range 3%-66%). The error in the estimation of the DGP classes calculated through the eye vertical illuminance was evaluated, for an analysis period of a whole year. The main advantages of the methodology proposed lie (i) in a significant reduction of the computational time required for its application and (ii) in the possibility of evaluating glare conditions not only for one or few points, but for a grid of points across a considered space. Its main limitation lies on its inability to quantify the exact DGP value, returning instead, at every time-step, the DGP class of performance