Lighting- control systems - Intelligent Buildings and Building Automation - page 207

10 Lighting-control systems
Artificial lighting is essential for the visual environment in spaces for living,
working or other generic purposes where and when there is no sufficient
daylight available. In some special spaces, such as spaces for entertainment,
lighting is needed for creating a dramatic or dynamic environment. The
lighting system is one of the major energy consumers in buildings, typically
following the HVAC system in office and commercial buildings. The energy
efficiency of lighting systems and quality of the visual environment provided
are determined by the selection of lamps (including the associated compo-
nents), the architectural layout and the control. This chapter focuses on the
control systems of lighting for generic purposes.
10.1 Purpose of lighting-control systems
The external daylight condition, the occupancy and the use of a space are
changing. Control of the lighting system is required to meet the following
purposes typically, which may be achieved manually or automatically:
￿ functional need and flexibility of the space;
￿ energysaving;
￿ visual comfort of the occupants;
￿ the requirements of legislation;
￿ creating a dynamic or dramatic environment.
Different requirements of the visual environment are needed for different
activities or functions. For instance, a lecture theatre is often used for
PowerPoint presentations, so the luminance level in the space should be at
a lower level, allowing the audience to see the slides presented on the screen
clearly and comfortably. When the lecturer is speaking without a PowerPoint
presentation, a higher luminance level is preferred to allow pleasant and
effective communication. If an audience is entering a movie theatre and
people are finding their seats, the lights should be on, but they should be
off in order to allow the audience to see the film properly when the movie
starts. It is often important to provide different lighting in a space to allow