HIGH PERFORMING BUILDINGS SERIES: ELECTRIC DEMAND ANALYTICS
The Demand heat map is one of the many tools property managers and building engineers can utilize through InSite to gain actionable intelligence by investigating their facility’s energy usage and refining their operational schedule. The heat map brings the added benefit of being very easy to visually understand and manipulate. Moreover, the calendar like layout allows for users to quickly filter through different dates, and simplifies analysis on long time periods by displaying results in a compact format. Each point on the x-axis represents an hour of the day, while the rows on the y-axis represent a specific day. The legend at the bottom uses a color range to indicate the magnitude of the demand, dark red shows the largest peak demands. The greatest asset of the demand heat map lies in its simplicity, giving any user the ability to quickly and visually investigate their operational schedule.
SCHEDULING & PEAK DEMAND
Two of the most common and effective uses of the demand heat map are to find scheduling related energy savings and analyze a facility’s peak demand issues. In terms of property’s operational schedule, the demand heat map can be used to identify scheduling errors such as earlier start ups, the effects of an unplanned overtime, or constant operation. In addition, it can be used to verify effective scheduling on days that a facility should be operating at reduced loads such as unoccupied days like holidays and weekends. With demand charges representing almost half of a property’s monthly electric bill, understanding the peak demand and when it occurs can be used to avoid additional charges. This analysis is especially helpful in service areas where the utility company bills on ratcheted demand charges, for example the highest demand set by the property in the last 12 months. Knowing the timing pattern for a property’s peak daily demand allows for an assessment of the activities in the building that are contributing the most to the peak. An example of an energy conservation measurement implemented from a peak demand analysis could be the use of a staggered start up schedule for a property’s air handlers in order to reduce the morning load.
The Demand Heat Map shown below represents an office building’s demand analysis from 8/12/2018 – 11/17/2018. Going from the bottom of the chart to the top, the first red box highlights the impact from the building’s 24/7 operation during the first week of Sept after Labor Day. At the time, high humidity and outside air temperatures made it necessary to run HVAC around the clock. The next red box shows that after the week of high loads, the property moved its morning start up time back an hr saving about 200 kWh per day. The final red box at the top of the chart highlights when the outside air temperature dropped in the area enabling the property management team to run in free cooling mode until noon each day, reducing the hourly demand by 100 kW and leading to energy savings. Successful energy management depends accurate and actionable intelligence, the demand heat map provides a user friendly and visually pleasing way to better understand a facility’s electric demand.