Led Lighting how low can you go? What can I possibly mean by that? Well hopefully all will be explained. The appliance and control of LED lighting can be incredibly creative as there is so much to consider.
Fluorescent lighting which is the typical incumbent that is replaced by LED does have its limitations. When assessing a potential upgrade of fluorescent lighting, it is easy to just replace on a like for like basis and not address any underlying issues which mean you miss out on additional energy savings.
For example, I once had an office project that involved removing thirty seven 600x600 T8 80watt Fluorescent fittings (1 row of 13, 2 x rows of 12).
37fittings x 80w x 2000 hrs (50weeks @40hrs p/week) = 5,920 kWh per annum
The lighting array was controlled by a single switch. This is a fine example of poor controls as it meant that the lights along the glazed side of the office that didn’t need to be on during daylight hours were always illuminated.
If we were to replace these on a like for like basis the sum would be
37fittings x 40w x 2000 hrs = 2,960 kWh per annum
Thus, reducing the annual consumption by 50%, which is all fine and dandy. However, in the example I am referring to I had the experience of lessons learned from previous LED upgrades. Using this I decided to replace 37 fluorescent fittings with 31 LED panels which would be controlled as 3 individual banks. (1 row of 11, 2 x rows of 10).
I decided to incorporate a daylight sensor to control the row along the glazed side of the office. Which meant that for the large part of the year the 10 fittings along the glazed side of the office were hardly illuminated.
Therefore, through a reduction in, (a) the number of fittings, (b) the watts per fittings and (c) the burn hours of those fittings along the glazed side of the office I was able to create a snowballing of energy savings. This snowballing increased the annual energy savings to 71%.
The additional 21% gained was the result of both experience and intelligent controls
With all lighting upgrades it is important to communicate with the end users. I always enquire into the failings of the current lighting system. Are there areas that are too dark, too bright, would the area benefit from intelligent control. Someone once said to me………
“What are you trying to achieve?”
I think this is an important question. The answer isn’t as simple as we are trying to achieve energy savings. What is the point of undertaking an LED upgrade if you fail to address the shortcomings of the current system?
More recently I was involved in an LED upgrade of some science laboratories. The control system employed saved more energy than the upgrade from fluorescent to LED. This is how valuable a well thought out and designed controlled system can be.
The laboratory lighting was on almost 24/7. This was due to the long hours some of the scientists worked and that the lighting was controlled poorly in large banks by a single switch. This meant the lights were switched on by the first scientist and then stayed on until the security team made there late-night sweep of the building.
When the LED upgrade with intelligent controls was complete the savings were astounding. When the first scientist of the day walked into the lab a single LED fitting came on at 100%, fittings adjacent to this fitting came on at 50% and fittings adjacent to these came on at 25%.
If the scientist sited themselves at a work bench that area only would be illuminated at 100% with adjacent lights switched to 50%. If that scientist was the only person in the lab no other lights would come on until either the scientist moved, or another scientist entered the lab.
In terms of “What were we trying to achieve?” We were trying to eliminate waste energy and only light areas when there was a demand for lighting.
In terms of “LED, how low can you go?” We went as low as we possibly could without being detrimental. Which should be the target for all lighting upgrades as anything else is just wasteful.
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