Automated control systems for indoor lighting: from design to actual performances' assessment

In recent years, but already around 1980, many buildings have been equipped with Building Automation and Control (BAC) systems. These systems were applied as a normal upgrade of traditional systems in different field of the industrial sector. In general, they can be applied to the building plants in order to carry out a series of functions. The main benefits of the installation of this kind of system are well known. First of all, it has been shown that BACs systems installation increases the energy savings and because using many typologies of sensors (e.g. presence detectors to control lighting system) and because, by monitoring the data it is possible to modify plant’s strategies and also to improve users response. As already cited, with these systems it is possible to monitor the plant and collect data. They can be analysed and results reported the on the system's computer. Lastly, the visual, acustic and thermoigrometric comfort can be increased using BACs. Unfortunately, even if these systems are no longer so recents, nowadays there is not sufficient attention to some steps of design, installation and commissioning of them. Being the actual performance of these systems affected by many factors, this causes the decrease of the performances in terms of energy and comforts. Most recent research literature shows that a great potential for energy savings in buildings is in the control and interaction of air-conditioning systems, appliances and, in general, electric devices, also thanks to specific algorithms able to coordinate all the energy facilities in the building. Commercial BACs, installed in residential or small offices, often include functions of lighting control, acting as Daylight-Linked Control Systems (DLCSs). Indeed, this kind of systems can play a key role to achieve a significant reduction of the electrical consumption for lighting and all the well-acknowledged benefits from the daylight (e.g. occupant comfort, health, well-being and productivity). Many authors proposed methods for optimizing BAC systems performance both in terms of energy savings and of comfort. Others investigated both visual and energy performance of lighting control strategies. In recent years, many standards and their updating included more or less simplified methods to preview energy consumption achievable with automated control systems application. Anyway, there is not a consolidated method to analyse how real figures of an existing BAC system differs from the expected ones. The aim of this thesis is to evaluate, with an original approach, the actual efficacy and achievable benefits of automated lighting control systems and to provide useful suggestions and new tools to design and manage this kind of systems in most effective way. Outcomes have been confirmed through the analysis of data measured in a laboratory set up where three commercial daylight-linked control systems were installed and evaluated for different end uses, operating schedules, control strategy (dimming and ON/OFF) and daylight conditions.