advance engineering techniques in the study

1. Energy Management for
Lighting Systems
Dr.K.Senthil Kumar
AP & HoD i/c
Department of EEE
UCE Arni

2. Basic Lighting Terminologies
• Ballast – A device used with an electric discharge lamp to provide the
necessary voltage and current for starting and operating the lamp.
• Candle power – Luminous intensity expressed in candelas.
• Coefficient of utilization – Luminous flux received per luminous flux
emitted.
• Colour rendering – Colour appearance of objects compared with colour
appearance under a reference light source.
• Luminous efficacy – Lamp efficiency in terms of lamp output per unit of
electrical input. (Lumens per Watt)
• Lumen – A unit of luminous flux.
• Task lighting – Lighting designed to provide illumination on visual tasks
usually at higher levels than the surrounding area.

8. Task and the working space
• Task lighting provides increased light for specific tasks in a room that may
already have some ambient light.
• Task lighting is especially useful for seeing small objects or objects of low
contrast.
• For example, a person who is sewing would need extra light to easily see
fine details.
• Task lighting can also provide increased light for tasks that require accuracy,
such as reading directions on a bottle of medicine or chopping vegetables
in the kitchen.
• Task lighting is also useful for workspaces, such as a workbench or
woodshop in the garage, or a space used for arts and crafts.

9. Task and the working space
• Task illumination
• Efficient lighting design
• Lighting design calculations
a) Zonal cavity method
b) Point by point method

10. Task illumination
• Vision requires sufficient light, size of the object, time to recognize an
image and contrast.
• Improved instrumentation and understanding of the visual
performance process are resulting in better methods of optimum task
lighting.
• Energy requirement for lighting spaces can be substantially reduced
without sacrificing task visibility.
• Luminance - The intensity of light emitted from a surface per unit
area in a given direction.
• Luminance contrast = background luminance – object luminance.

11. Task illumination
• Contrast improvement involves with matte objects and backgrounds.
• Veiling reflections – a condition where contrast is last because of the
reflection of the light source in portions of the task.
• Design and evaluation techniques like Equivalent sphere illumination
can be used for contrast enhancement.

12. Efficient lighting design
• Room acts as part of lighting system
• Need to focus how light is directed from the lighting equipment to the
task areas.