Saving Energy with High-Efficiency Bay Lights

Your lights are high up there. You could move them down. For movies we do some work with diffusion gels and sometimes build boxes out of foamcore and put the lights in them with a covering of diffusion to make a big source. In many places we find florescents. They are a green light. US manufacturers are Sylvania, and GE, and maybe some others for Industrial Lighting. Certainly I cannot tell you what to do with what you have, and without seeing the place. At the least I can say that it sounds like you don't have enough lights of one type, and you can either move them, or augment them, or do a complete do over.

All of the bay lights I have seen shine straight down. With the height that yours are mounted, I wonder if they were angled to cover, say, 20-30% more area, could you eliminate a few lights and avoid the costly changeover to a different system. The pattern would have to be worked out, but if one row were angled one direction and the next row angled the opposite direction, shadowing could be minimised like in television studios.

As I do not deal with metal halide lighting, I do not have an answer for you in terms of an alternative.

However, I only suggest that if the amount of light you need or the kind of light you need there is very important, and lowering a "lower powered" system cannot be done, try adapting your approach to one that can provide power cost saving solutions such as solar power.

Sometimes the only way to "conserve" is to provide alternative power solutions when parameters are hard to manipulate.

I look at it this way. Metal halide lighting is great for larger buildings, tall ceilings, and outdoor applications. More powerful halide lighting can be very bright, hung very high on a ceiling and usually utilizes a smaller array rather than a much larger low powered array.

In other words you may have to get many more fluorescent/LED etc. units that still draw considerable power so you must decide how important to your bay functionality are those Metal Halide fixtures.

Also, lowering fixtures and using different fixtures may be counterproductive, causing unwanted shadows or just not enough adequate light for workers to function properly.

Dear sir,

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best regards

stephen kelly

Most Standard HID high bay fixtures are mounted between 16ft and 22ft, yours are mounted around 31ft. Most T5 and T8 high bay fixtures are equivalent to 400W metal halides. What is the wattage of your fixtures? If it's 400W you could do a straight swap and receive the same lighting levels with more energy efficiency, less maintenance and a longer Lumen life.

If your using a larger wattage like 1000W, your best bet is to drop your fixtures to 16-20ft and retro-fit with T5 or T8 high bay fixtures.

First, I must say that since I work for a government agency, I am not recommending one company over another and am only providing this information to give you an idea of a type of lighting system that is more efficient than MH.

With that said, there are high bay flourescents available at a reasonable price. For example, this one is specifically designed for ice arenas. Ice arenas have some difficult lighting situations requiring different foot candle levels for different activities. http://www.sportlite.com/pdfs/pulseBlocBrochure.pdf - sorry, link no longer available

I have seen T8 30 W lamps in some facilities with 30 ft ceilings. T5s generally require more lamps than T8s for the same amount of lumens.

Be sure to install 5000 Kelvin lighting. It has been found through research that employees are more productive in 5000 Kelvin lighting in comparison to 3000 Kelvin and 4100 Kelvin lighting by reducing headaches and eyestrain. 5000 Kelvin is the color temperature of natural sunlight.

Remember to recycle the burnt lamps with flourescents. The mercury leaches out of landfills into our water supply.

There are lots of things you can do:

• You can lower the lights, but this may interfere with your process
• Swapping out your MH lamps with T5 is usually more energy efficient
• Paint your ceiling/walls to improve their reflectance
• Change your reflectors

In other words, there are a ton of things you can do, but depending on your specific situation, not all make sense for you.

I recommend having an energy consultant or a lighting expert look at your system.