Daylight in buildings equipped with traditional or innovative sources: A critical analysis on the use of the scale model approach

tThe use of scale models is widely adopted as an efficacy method for determining the daylight assessmentof interior areas of buildings. Scale models can be tested under real sky or sky simulators. In both cases, itis commonly accepted among the researchers that the use of scale models leads to an overestimation ofexperimental data with respect to real scale test rooms. Starting from this assumption, the authors havecarried out an experimental analysis under real sky on a reduced scale model of a test room equippedwith a window and on two scale models of a room equipped with a double light pipe in order to definethe influence of the scale factor on experimental data both with traditional and innovative daylightsources. The analysis leads in particular to identify the influence of direct solar radiations on the results.Although the authors agree with the majority of researchers and confirm the common opinion thatdaylight performances are generally overestimated in scale model analysis, this study evidences that thepresence of intense direct radiations can produce exceptions and the opposite case can be experienced.