Product at a Glance

Product At A Glance

Detailed Frequency Analysis

A useful way to look at the interval data is to plot the demand change between any two points. The plot indicates what equipment started and stopped during each 15 minute interval of time. This slide shows the absolute values of these changes in demand. The start-up and shutdown of the building is clearly shown by the magnitude of the changes during these periods, while the changes during the fully occupied and unoccupied time periods are small.

In this case, between 6:30 and 10:00 am, the start-up period is identified by the 200kw changes in interval demand, while the occupied and unoccupied periods have demand changes of less than 25kw.

Detailed Frequency Analysis

Key Points of Interval Plot

The modeling program does not assume a demand curve shape, then move it up and down to fit the data, as many programs do. This program lets the data build the demand curve by hunting for the periods where the start-ups and shutdowns occur. These change points are mathematically identified, then different calculations are applied to each portion of data as shown in this slide.

Interval Plot

Three-Day Demand View

This slide depicts a store meter reading in KW plotted against temperature. The plot shows that for all temperatures, this store has two readings - the first in the morning as the temperature warms up and the second in the afternoon as the day cools off.

The key variables in the meter reading are the temperature independent internal demand (Lights and Equipment) and the temperature dependant HVAC demand. The program produces three day types: Weekdays, Saturdays, and Sundays. The stores in this study have very similar operating hours for each day type. The stores all open at 10:00AM and the shapes of the curves indicate that the store load is slightly higher on Saturday, which is to be expected.

3 Day View


Energy costs rose 31 percent from 2003 to 2005.




EIA Annual Energy Outlook for 2006


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