Abstract
Solar radiation can significant affect air-conditioning loads in buildings. Moreover, it has an impact on occupants’ performance and well-being from a psychological and physiological point of view, influencing thermal and visual comfort conditions. However, large windows on building façades, facilitating daylight entry, may increase the risks of overheating or visual discomfort, requiring proper control of shading devices in order to prevent glare and direct solar radiation on the occupants. The hard task becomes defining a balance between those contrasting requisites, considering the specific application context and using different metrics in order to analyze both comfort and energy aspects. In this paper, the effects of external and internal roller shades, both on thermal and visual comfort and on overall building energy demand, have been considered for the climatic condition of Rome (South Italy) in order to assess the long-term comfort conditions and energy performance of an open space office. Some office characteristics, such as windows extension, glazing type and shading characteristics has been changed in order to assess the performance under different conditions. The indoor thermal comfort levels are controlled by fixing adequate operative temperature set points while visual comfort is ensured through control of shading and lighting systems. Evaluation of building performance has been assessed through (i) total primary energy demand regarding energy aspects (ii) the Predicted Mean Vote and the Discomfort Time weighted by the Predicted Percent of Dissatisfied, including the effect of the diffuse and beam solar radiation, for analysis of thermal comfort and (iii) the Daylight Autonomy and the Daylight Glare Index for visual comfort.