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Lighting for Warehouse Energy Efficiency!


September 2nd, 2011
Bhaskar Ale- MSME, E.I.T

Lighting options in a warehouse differ with the type of goods stored. Efficient lighting is always an issue that needs to be dealt with. Back in the day it might have been fine to have introduced or installed HPS lighting into a new building or a warehouse. But with the newer energy efficient lights such as T5s and advancement in LED technology, it is possible to get even more energy savings on lighting. The US department of Energy estimated that Light Emitting Diode lights can potentially help save 1,488 terra watts of electricity, valued at $ 120 billion between 2010 – 2030. At the same time, the green house gas emissions will come down by a colossal 246 million tons.” source DOE.

You don’t necessarily need to go overboard when lighting warehouses. There are some areas where low glare lights are required such as near office spaces and some parts where overhead lighting is required, such as near loading docks. You also need to consider the sharp sightedness of the workers and the activity level when considering lighting options. So with these considerations lets look at our lighting options for warehouses.

Some Lighting options for warehouses:

  • Mercury vapor lights – The internal surface of the outer elliptical bulb is coated with a phosphor, which converts ultra-violet radiation from the discharge into light. It has poor color rendering index and low light output per watt. It requires ballast to prevent it from taking in excessive current.
  • High Pressure Sodium lamps – High Pressure Sodium Lamps have very high efficacy (up to 140 lm/W).They have good lumen maintenance and long average lamp life , almost 12,000 hrs. They also have poor color rendering index. One of the most common uses for these lights was in open parking areas where color discrimination is not important. Metal halide lamps – have a lifetime of 12,000 – 15000 hours and good color rendering properties. They are expensive compared to other HPS light sources. Metal Halide Lamps have a lamp efficacy range of approximately 75-125 lm/W.
  • Fluorescent tubes and CFLs– These are the most common type of lighting retrofits done in warehouses. Fluorescent lamps range from about 30 lm/W to 100 lm/W. and are generally used for lighting indoor spaces. These are not suitable for low temperature operation (cold climates) and in cold storage locations. But newer designs in T5 lamps are much better and more energy efficient than its predecessors T10, T12 and even T8s. The compact florescent lamps (CFLs) are a new class which can compete with incandescent and mercury vapour in the market of lighting fixtures having smaller round or square shapes. But the problem of mercury contamination and short life span  (compared to LEDs) is a problem for these lights.
  • LED  lights – the last word in lighting efficiency. They produce high Color rendering indexed directional light. LED is a semiconductor chip supported by a reflector and encapsulated with an epoxy lens for controlling light distribution. The LED lamp has no filament or breakable glass bulb. Colour of light output depends on the semiconductor materials used in the chip, which require different voltages to enable electron flow. LED have a service live of almost 50,000 hours. They are available in various colors red, red-orange, amber, green, cyan, blue, and white. These lights are also not affected by on-off cycling and readily comply with intelligent systems, which allows for even greater energy savings. The only thing hindering LED light right now is the cost. It will, however, be the future of lighting and maybe even wireless data transfer (http://blog.ted.com/2011/08/02/wireless-data-from-every-light-bulb-harald-haas-on-ted-com/)

One should also take into account the occupancy sensors that can be placed with lighting for greater energy savings. Occupancy sensors are located where they will detect occupants or occupant activity. There are two types of occupancy sensors: ultrasonic and infrared. Ultrasonic sensors detect sound, while infrared sensors detect heat and motion.

With these suggestions, you should be able to begin the process of selecting the right type of lighting for your warehouse.