Simple method of determining the influence of the overhang on window solar gains

This paper presents a simple tool (in the form of nomograms) for the preliminary design of solar gains of a window shaded with a horizontal overhang. The nomograms were based on the results obtained from the previously published, experimentally validated anisotropic model of shaded window solar gains and developed using the least squares method. The nomograms were verified using the Design Builder (ver. 1.2) simulation software. The numerical simulations corroborated the relationship between window and shading system dimensions and solar gain reduction in the room. As the vertical distance of the overhang from the window increases, agreement between the analytical model results and the numerical simulation results deteriorates. Nevertheless, considering the significant differences between the input climatic data for the analytical model and those for the simulation program, the agreement can be regarded as satisfactory.