One article in the last issue of Energy and Buildings is of particular relevance to the field of home automation, particularly where daylight control is involved:

Simplified correlations of global, direct and diffuse luminous efficacy on horizontal and vertical surfaces, by A. De Rosaa, V. Ferraroa, D. Kaliakatsosa and V. Marinelli.

A simple calculation method to calculate the mean hourly diffuse illuminance on vertical surfaces for all sky, clear sky, intermediate and overcast sky conditions, developed in Arcavacata di Rende (Italy), was compared with experimental data obtained at Osaka (Japan), Vaulx-en-Velin (France) and Geneva (Switzerland). In spite of its simplicity, the method furnishes reasonably good predictions, in comparison with a more complex reference calculation method and can be proposed as a simplified tool for design purposes.