Built in 1962, the original F.H. Collins Secondary School was a small building. Throughout the decades, as the population grew, an ad-hoc patchwork of several large additions were connected to the original building with hallway arteries. Until 2015, the school was the fifth largest Government of Yukon-owned building, covering 11,342 m2.
Covering a large surface area, the mostly ground-level structure became challenging to heat due to its sprawling design of short and long walls of varying insulation properties. With insulation ratings of R-12 to R-16 in its walls and of R-21 in its roof, the overall building was inefficient in its energy use.
As of 2016, secondary school students are attending classes in a new, modern building that replaced the original 53-year-old structure. The new F.H. Collins Secondary School has a smaller footprint and was designed for optimal energy efficiency.
By prioritizing energy efficiency in the building’s design, the Government of Yukon’s new school will reduce its energy demands and may become an example of successful demand side management applied in Yukon.
Figure 1: Energy Performance Study for old and new F.H. Collins school buildings. (From February 16, 2016.)
The map above illustrates how the new school’s rectangular-shaped footprint (yellow) contrasts sharply with the old school buildings’ footprint (blue).
Although the new school site is 18 per cent smaller, it is able to accommodate roughly the same number of students. The total conditioned floor area 7,400 m2 of the new school is about the same as the old school but spread out over two stories. Conditioned floor area means all finished space that is within the insulated envelope, including unfinished spaces, serviced by heating, ventilation and air conditioning.
The original school was heated with an oil heating system that was 80 per cent efficient and required far more fuel to adequately heat the space. From January 2011 to December 2014, 1,541,777 liters of oil were delivered to the school. This is an average of 385,444 liters per year. A conventional residential heating oil tank holds approximately 1,135 liters. To heat the old school over the four year period required 1,358 tanks’ worth of oil, or about 340 full tanks per year.
The charts below presents the old school’s overall energy use of oil, propane and electricity from January 2011 to December 2014. The pie chart comparing the sources of energy used illustrates that about 68 per cent of the old school’s overall energy use was dedicated heating, for a total of 36,502,756 mega joules (MJ) annually.
The new school’s design allows the building to function effectively as a whole system. Key energy efficient features include:
While the old school’s design was longer, narrower and equipped with less insulation, the boxier new school’s building shape and the superior R values in walls (R-28) and roof (R-37) address the “low-hanging fruit” energy-efficiency improvements. The new school is now equipped with a 95 per cent efficient propane condenser boiler as a heating system. Propane has a slightly cleaner on-site combustion than oil.
The new school’s heat recovery ventilation (HRV) system brings a steady supply of fresh air into a building and exhausts the same volume of outgoing stale air. HRVs act like lungs for building systems. The HRV retains a percentage of the heat contained in the outgoing air supply, and transfers it to the incoming air supply. Most HRVs retain 60 to 70 per cent of the heat, depending on the cold temperatures. The old school did not have an HRV.
Greenhouse gas emissions reductions are expected to be significant at the new school. The 2016 F.H. Collins School – Energy Performance Study predicts that the school will use 58 per cent less energy. If the new school performs as predicted, then the 1,062 tonne annual average of carbon dioxide equivalent (CO2e) at the old school will plummet to 287 tonnes of CO2e at the new one. This means an anticipated reduction in greenhouse gas emissions by 27 per cent.
The school is currently in its first year of use. The Energy branch is monitoring the energy use of the new building and will take note of any obstacles encountered or lessons learned during this period.
The Energy branch is monitoring energy use and is eager to compare the new school’s actual performance against predicted savings.
There is the potential for a number of energy saving benefits beyond the fuel savings emphasized in this case study. The Energy branch will conduct a full analysis once the energy use data from the new school is available.