Winter and summer analysis of daylight characteristics in offices

This paper reports a comparison of the results of daylight measurements carried out in summer and winter in three offices, with different exposures and characteristics, located in Naples (Italy). The aim was to extend and enrich the findings of a previous study which reported the results of summer measurements about desk illuminances and circadian impact. The research project includes measurements carried out in other seasons and a comparison between measured and software simulated values with the final goal of developing design guidelines. This research confirmed that the spectral distributions and CCTs of the light reaching the eye of a person seated at the desk in these offices are similar, irrespective of the different sky's conditions and season and of the rooms' different characteristics (dimensions, surfaces' spectral reflectances, external obstructions, etc.). It was also confirmed that eye level irradiances and thence their circadian impact are similar to those of D50 and D55 CIE standard illuminants. (C) 2014 Elsevier Ltd. All rights reserved.