With the help of the Energy office I’ve been investigating how much electricity is used in the Forum. Electricity powers everything in the Forum apart from cooling for the server rooms and heating, which are supplied from the Central Area Combined Heat and Power plant along with our electricity. To some (possibly quite large) extent the heating and cooling are “free” as they are by-products of the electricity generation, so I will concentrate on electricity here.
Total electricity use in the Forum is recorded automatically every half-hour and the results can be extracted manually by the Energy office from the Optima energy management system. (Before anyone asks, there is no direct database connection to the system, but the people at Transition Edinburgh University are working on scraping data from the email reports it can generate and making this data available.)
Below is a graph of the energy consumed in each hour of three representative weeks: a week close to midwinter, a week in the winter vacation, when the building is “closed”, and a midsummer week. Note that I’ve binned the half-hourly measurements into hourly bins, so the units are the somewhat ungainly kWh per hour, aka average power use in kW.
There are obvious daytime peaks, which are less pronounced at the weekends. It’s striking that the summer and winter working weeks are almost indistinguishable, as is also apparent in the table below which gives the average daily use in each of the three periods:
|Periods||Av. daily energy (kWh)||% winter|
|6-12 Dec 2010||6448||100.0|
|27 Dec – 2 Jan 2011||5159||80.0|
|20-26 Jun 2011||6571||101.9|
I would have expected the winter reading to be higher, due to extra lighting, but perhaps in the summer we need extra ventilation and fans. The vacation usage is about 20% lower than the working weeks. It hovers just over the 200kW mark, which also seems to be a baseline for the working week measurements.
There is probably more that could be drawn from this data; comments welcome! However, to end with I think it’s interesting to think about the per-person electricity use. The average electricity use per day in the Forum is around 6600kWh. There are around 600 of us (I believe), which means that each of us has an 11kWh per day share. Given that at home (3 people in a tenement flat) we consume around 2kWh per person per day, albeit with a gas hob, this seems quite high.
P.S. The raw data and an R script to generate the graph are at https://wiki.inf.ed.ac.uk/Vademecum/Energy