Lighting is a major energy consumer in commercial buildings. Heat generated from electrical lighting also contributes significantly to the energy needed for cooling of buildings. ECBC prescribes the amount of power for lighting, specifies types of lighting controls, and defines situations where day lighting must be used.
In commercial buildings lighting typically accounts for 20-40% of total energy consumption. A typical commercial building has many lighting requirements and each normally has its own set of options for improving lighting efficiency.
- Specifying the amount of light for general usage without considering the needs of specific tasks (for example, supplying light for general office work but not addressing the effect of glare on computer screens);
- Designing a day lighting strategy but not enabling the lighting system to dim or turn off when there is sufficient daylight in the interior space
- Supplying inadequate control of lighting by not allowing lights to be adjusted to specific needs (i.e. turned on in groups or “banks”, or dimmed), and not providing easily accessible control switches;
- Adding a large window area to the façade for day lighting but ignoring the problems of solar heat gain and the need for shading;
- Designing/sizing the building’s HVAC system on rules of thumb and not ac-counting for the reduction in cooling loads created through efficient lighting system.
Lighting Controls Tips
Purpose of Lighting Controls: In many applications, the overall purpose of the lighting control system is to eliminate waste while providing a productive visual environment. This may entail:
- providing the right amount of light;
- providing light where it’s needed.
A few issues to keep in mind while de-signing controls are:
- Install a separate control circuit for each lighting element that operates on a distinct schedule;
- Where light fixtures are needed in a predictable variety of patterns, install programmable switches;
- Install lighting controls at visible, accessible locations;
- Where lighting is needed on a repetitive schedule, use time clock control;
- Install occupancy sensors in bathrooms, conference rooms, and other spaces not in constant use.
Many other prospective to control the lighting
Controls, switches, shades, timers, and other lighting strategies can get complicated. It is likely that adjustments will occur after occupancy. The easier the lighting system is to understand and adjust to accommodate the occupants and building function, the less likely it is that sensors will be disabled, disconnected, or bypassed. The following provides a strategy for selecting the right controlled buildings.