Lighting Lighting in Boucke Building is something of a buffet of different technologies. The most abundant lamps are fluorescent lights, but there is also a significant number of accent lights. The lighting in every hallway is dualbulb fluorescent fixtures. Per floor there are 22 fluorescent hallway fixtures. Each floor has an average of 17 individual classrooms, each with approximately ten dual bulb fixtures per room. This equates to 22*4 + 4*17*10 fluorescent fixtures. Bulbs = 2*fixtures Bulbs = 1536 bulbs An approximate energy usage for these bulbs is rated at 20 Watts. So energy usage for just these bulbs is: 1536 bulbs * 20 Watts * 1kWh / 1000 W * 16 hours = 491.52 kWh per day Cost per day (at .10 per kWh) 491.52 * .10 = 49.15 per day for lighting costs. Per year, this is $17,940.00.
If this would have been incandescent bulbs, at least a 60 Watt bulb (more likely 100 watts) would be needed to achieve the same light output. The cost suddenly becomes: 1536 * 1000 Watts * 1kWh / 1000 W * 16 hours/ 1day *365days/1 year * .1/kWh = $89,702.40!
The use of fluorescent bulbs saves the university over $70,000/year – in one building alone! Additionally, offices and other rooms have accent lights. For instance, the Residence Life office and Travel office each had approximately 20 accent lights per office. Let us assume that each accent light uses 25 watts *. Cost: 20 lights * 25 watts * 16 hours /1000 * 365 * .1 = $292 dollars per year per office or 292 * 2 offices with accent lights = $584 per year for accent lighting in the entire building
In our calculations so far, we have assumed that these lights are on for only 16 hours per day. Experience tells us that this is not the case. Hall lights are left on 24 hours per day. Interviews with the custodial staff have confirmed that there is no one who is responsible for turning off classroom lights. Investigations have shown that rarely are all classroom lights off, since the last person to use the room sometimes fails to turn off the lights. In our survey, all offices had their lights off, but some classrooms (approximately 10) had their lights still on through any given night. Taking these calculations into consideration, we can come up with new numbers for energy needed to light Boucke building. Energy used = Hallways + Classrooms that have lights on + classrooms with lights off + offices Energy used = (176 bulbs * 20 Watts * 24 hours / 1000) + ((68 – 10 rooms)(20 bulbs/room)* 20 Watts * 16 hours / 1000) + (10 rooms * 20 bulbs/room* 20 Watts * 24 hours / 1000) + (40 bulbs * 25 watts * 16 hours /1000) = 567.68 kWh / day Or $56.77 per day, which is $20,720.30 per year to light Boucke Building. Using incandescent bulbs, this cost would approach $100,000 per year.
With regard to lighting levels, our group found all the lighting levels to be acceptable. None were too high or too low. Our survey also found that some classes and rooms didn’t have lights on at all during the day. This fact leads us to conclude that some instructors do turn off lights after their classes, brining down the annual operating costs. Finally, the large number of windows appears to allow a great amount of natural light. Some classes were being held with only natural lights (all fluorescents lights off). While this may be dependent on the current time of year, it nevertheless reduces the costs of lighting Boucke building.
