Daylighting Reproduction in Interior Space with SIVRA System

摘要

The quality of the lighting environment is of fundamental importance for the psycho-physiological well-being of man, especially when it concerns rooms, where a person remains for a prolonged and compulsive amount of time (offices, hospitals, schools...) The effect of light goes beyond the mere perception capacity and it affects our general emotional well-being. The right integration between artificial and natural light is also very important to eliminate effects like glare or excessive illluminance in interior space and to counter these negative aspects the artificial lighting engineer must establish an accurate conversion from the daylight outside environment in the very first phase of project of light. The goal of our work shall understand how artificial light can be mixed with daylighting in indoor space to guarantee a good level of illumination uniformity for the visual tasks requested by different types of applications. To be able to do this we needs to take into consideration that daylight varies in its spectral composition from a rather reddish light in a clear day sunset to a white light from the sky dome on a dry clear day. The recently developed experimental SIVRA-system (this stands for: Variable Lighting System with Automatic Regulation) allows for the creation of a luminary capable of producing "natural" lighting and temporal rhythm in the given setting. In other words, a dynamic lighting system capable of varying the artificial light in terms of colour and intensity, according to scientifically predetermined programmes. The preliminary assessment of this work carried out the experimental and numerical results about the analysis of artificial light in interior space where SIVRA is applied. The experimental result are obtained in the laboratory where a room (6m x 8 m in plan and 2,80 m high) was realized, without windows, illuminated by SIVRA, to test the produced inside light's level and the distribution. During the day the colour temperatures inside the case- study changes to simulate different period of the day, of the year and different kinds of sky. A correlation between colour temperature and solar altitude has been defined. In a future step the work should show the SIVRA illuminance performances at different hour of the day (the illluminance levels varies according to correlated colour temperature). The theoretical analysis on numerical model is realized with Radiance program. The experimental and the numerical results obtained are compared to evaluate the luminance and illuminance distribution in the case- studv room.