The Natural Resources Defense Council (NRDC) has a new report, Real Time Energy Management, which validates the substantial savings available by catching stray energy in buildings.
According to an NRDC blog posting, some examples of “stray” include: i) Thermostats that are set for specific events and not re-set afterwards; ii) Broken sensors for fans or pumps; iii) Problems with energy management software that goes undetected.
NRDC examined real-time energy management in three large office buildings owned by Tower Companies in Washington, DC. Tower’s initiative was designed to catch and correct operational stray, and to provide actionable recommendations to optimize energy use.
A case study found that Tower’s real-time energy management initiative achieved a 13.2 percent reduction in electricity use in the three buildings, showing that substantial gains are possible when building owners operate their buildings with attention devoted to reducing the amount of energy wasted.
The project was highly profitable, with savings from reduced electricity use in the first year alone exceeding total project expenses by more than 60 percent. Additional savings are expected from reduced maintenance expenses, and savings are expected to be persistent beyond year one.
The centerpiece of Tower’s initiative was engaging professional services company AtSite to deliver a range of services aimed at improving the energy performance of the subject buildings: AtSite assessed each building, delivered a plan for improvement, monitored the energy use in each building over the 12-month study period, delivered actionable recommendations on a regular basis, worked with the building engineers to implement the recommendations and best practices, and held regular meetings with Tower engineers and owners to address opportunities and review progress.
A key element of AtSite’s service is detecting and correcting operational stray, as illustrated by this example: AtSite reviewed the electricity usage in 1909 K Street and noticed an unusual pattern on July 7, 2012. The analysis suggested that both of the building’s chillers were cycling on for a few minutes at a time, then shutting off. AtSite alerted the building engineer, and working together the team found and corrected faulty variable-air-volume controls that were signaling the chiller to turn on even though the building management system (BMS) called for the chiller to remain off. While this problem might have been discovered eventually without AtSite’s service, it could have continued undetected for months. This delay would have resulted in wasted energy, wear and tear on the building equipment, and possible disruption to tenants when equipment failed.