Today I have another great example where upgraded lighting is saving the hospital energy, time, and improving the patient experience. We’re talking about the parkade in the Peter Munk Building, now illuminated with LEDs. We are very pleased with the new lights and we hope you are too. Here’s a quick photo comparison, after which I’ll get into the project details and provide more photos at the end (all photos are taken with the same settings, as noted below the image).
The new lights, shown in the first photo are the Philips QLP Gen 3 LED fixtures. The original lights, in the second photo, were metal halide (MH) technology. The metal halides were lacking for a number of reasons:
- They were power hungry
- They needed constant replacement
- They didn’t provide good light
The LEDs improved on the old fixtures in every way and I’ll go through each point now.
How it works: Metal halide technology was developed in the 1950s; it introduces an arc of electricity through a contained gas/metal salt mixture, creating a superheated plasma. The plasma produces a lot of infrared, ultraviolet, and conducted heat, while emitting some visible light. LEDs produce light using a different method entirely; there is no burning, no ignition, no plasma. The light emitting diodes are made of semiconductor materials, which emit light through the process of electroluminescence. Significant heat is still generated, but not through the light itself.
As you know we use measure electricity in watts and light output in lumens. You may recall that we use the term “efficacy” to measure the ability for a lamp to produce light efficiently, the units are lumens per watt (see previous blog). Now both LEDs and metal halides have similar efficacies when new, so naturally you say “Why are there energy savings? Since they take the same amount of energy to produce the same amount of light, right?” Wrong, well mostly wrong.
- LEDs use the light they produce much more effectively. It’s directional, so that it’s put where you need it (on the ground). It doesn’t go out in all directions, bounce all around in a fixture, until the reflectors direct it where you really want it… down. There are losses in those bounces.
- LEDs maintain the amount of light output much better than metal halides. At around 5000 hours MHs will have lost ~40% of their lumen output. In the 24/7 garage that means we’re at almost half as much light in only 6 months. The LED’s by comparison lose only 20% after 100,000 hours. In the 24/7 garage, that’s over 11 years.
This allowed us to replace the old MH light fixtures, consuming 180W and 125W, with 79W and 53W LEDs, all while actually increasing the light quality. That’s 56% energy savings!
Freeing up resources!
The existing metal halides would last about a year, on average, before they needed to be replaced (I’m being generous). Some only lasted a few months. This meant UHN staff always had to monitor which ones had burnt out and be ready to replace them. Replacement was not a straightforward task; timing it so there wasn’t a car below the light, getting a lift jack, wrestling off the heavy class covering, and swapping out the failed bulb, whenever one failed, for all 68 fixtures each year. Less frequently they’d also have to replace the ballasts. With so many other items to attend do, having to spend all this time on garage lighting was an unwelcomed time sink. There was a materials expense as well. The bulbs cost $35 each and the ballasts were even more.
The new LEDs come with a ten year warranty and a L80 life of 100,000 hours. That means they should still be shining brightly 11 years from now, with virtually zero maintenance cost. It’s quite a difference.
This is maybe the most important benefit. When people first arrive at the hospital, we want it to be a comfortable and safe experience. In the parking garage this is assisted through proper lighting. The existing fixtures didn’t do that. Too many parking stalls were dark, lighting was uneven as lamps burnt out, poor light distribution resulted in bright spots under the lamps which quickly fell off to dark patches, displays and signs were difficult to read, side entrances were always in the shadows, and there were real concerns raised about tripping hazards. I paint a bleak picture, a bit sensationalized maybe, but it was the reality for people who have difficulty with their mobility or vision. Even as people age, their eyes need better light to navigate through spaces. Improving the light quality was a must.
We looked at the lux levels, the distribution, the colour rendering, the colour temperature, and the lumen depreciation. We had a computer simulation created (a photometric plot) which gave us the expected light levels and rationale to move forward. When all was said and done we met the lux requirements, but take a look next time you’re there. In the meantime, here’s a few more photos:
Near Building Entrance:
A special thanks to the people working on this project. You may have seen that Henry Gomolka retired from UHN recently (see Lisa’s blog), but we will see the efforts of his work for years to come. Henry and I reviewed many options together and he was great to work with. I’m sure Henry would agree that this project wouldn’t have been completed without the contributions of our colleagues Andy Lymberis and Gleb Doynikov, thank you both. Finally a big thanks to Dave Rycroft for his samples, insights, and tireless investigation on the hospitals behalf. And if you’re looking for more LED examples, please check out Mike’s article here.