At the centre of Princess Margaret Cancer Centre (PM) is 2-level atrium separated by a huge and beautiful skylight on 7th floor.  Every year, there are numerous events such as Music in the Atrium, fund raising, seminars, etc. on 7th floor around this skylight area.  More than 20 years ago when people constructed the building, they wanted to make this skylight as aesthetically pleasing as possible.  They picked tiny metal halide bulbs so that the light fixtures did not look bulky.  They also tried to hide all the wires and ballasts.  The job was done quite well as planned, and looked wonderful.

Unfortunately, they did not plan for how operators would maintain those lighting fixtures (like any other equipment in our hospital, they don’t last forever and require regular maintenance).  The wires and ballasts are hidden somewhere below and around the skylight, which is very hard to reach.

20180123_095321Figure 1: Nowhere to Find Wires and Ballasts for Existing Lighting Fixture

Without appropriate lighting, the skylight looks dark, especially from below.  But fixing them may create another issue.  The metal halide bulbs and ballasts use far too much energy.  Total electricity use is about 5.3 kW for those existing fixtures.  It may look low to some people. However if you consider that PM is class A customer and we pay global adjustment based on summer peak demand, 5.3kW is equivalent to about $2,700 extra of global adjustment on our hydro bills every year.

Metal halide bulbs also give off a lot of heat,  so in summer, we also need to run chillers, cooling towers, pumps and fans to remove the heat generated by those fixtures from the space. This drives operational costs even higher.  There are also other issues associated with metal halide including slow start time and fast loss of lighting output, which means they have to be replaced more frequently than what the manufacturers claim.

20180504_143728Figure 2: New LED Lighting Fixture for the Skylight – a 79% reduction in energy!

Thanks to Ontario Ministry of Health and Long-Term Care’s generous Hospital Energy Efficiency Program (HEEP), UHN received funding to replace those out-of-date lighting fixtures.  After vigorous testing of 8 different high efficient LED models, the project team selected one of them and installed them before HEEP deadline.  Amazingly they only use about 1.1 kW electricity in total, a 79% reduction from existing lighting fixtures.  We provided easy access to all the new wires, timer, dimmers and breaker so that they can be reached.  At the end of the day, we have a new, long-lasting lighting system that will save $2,150 on global adjustment, and that we can actually reach to maintain it properly.