Establishing a Demand Curve for Plug-Load Electricity Consumption in an MIT Dormitory
Austin Oehlerking
5/20/08
2.671 Measurement and Instrumentation
Prof. Leonard
Abstract
Plug-load electricity consumption was measured for eighteen undergraduate dorm rooms in German House, an MIT living group, over the span of four weeks. Each room was monitored for 24 hours using a plug-load meter named the Watt's Up Pro. The devices being used in each room were recorded, and specific usage patterns were identified for particular devices and rooms. The eighteen rooms consumed a total of 28.10 kilowatt-hours, or 1.56 kilowatt-hours per student per 24 hours. The average demand per student was 65.08 watts, and over the course of 24 hours each room was responsible for approximately 0.20 pounds of carbon dioxide emissions. Based upon an analysis of power usage during periods of room inactivity, it was estimated as a lower bound that 14% of the energy that the eighteen rooms used was wasted due to idling computers and speakers.
The individual room demand curves were aggregated to create an overall German House electricity demand curve. Data was also taken for the communal German House lounge over a 24 hour period. Sinusoidal and parabolic curves were fit to the data for the aggregate lounge and no lounge cases. It was determined that the optimal fits occurred in the no lounge case, since the lounge data did little more than add noise to the system. The parabolic fit was slightly better than the sinusoidal fit for the no lounge case in terms of error, but the sinusoidal fit curve made more sense because electricity consumption must be a periodic function that repeats each day. The sinusoidal demand function of German House peaks just after midnight and dips to a minimum during the day when students are gone to class.
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