I’ve attached a project completed by my Sustainable Energy Class, which investigated energy use by computers in our newly constructed high school building. This project provided an authentic experience for my students, who made great strides in improving their math, science, technology, and team work skills. A key result of this project is that we were able to identify an opportunity to save the school a few thousand dollars per year. See the attachment for all the details.
While not included in the attached project, we were also able to use natural gas usage data to compare the energy densities of the new and old high schools (using 2014 data from the old school). Based on that data, the old building’s energy density was 13.1 BTU/Ft2-HDD, whereas the new building’s energy density was 11.5 BTU/Ft2-HDD. In short, the smaller number for the new building indicates greater energy efficiency.
To make a valid comparison, we divided total energy consumption for each building by its area in square-feet, which corrects for the different sizes of the two buildings. We also divided by the number of heating degree days (HDD), which corrects for differences in weather. Heating degree days are defined as the difference between the average temperature experienced on a given day, and a set point temperature where no heating is needed (the set point is usually set at 65°F). For example, if average temperature on a given day was 55°F, then 10 HDD’s accrued on that day.
The new high school experienced 1416.5 HDD in 2015 and the old building experienced 1277.5 HDD in 2014. The larger number here indicates a colder winter on average.