Here are some of our top recommendations: 

• Aeration. Use dissolved oxygen sensor aeration controls and fine bubble aeration to reduce energy consumption.
• Blower. Consider upgrading to a high-efficiency, variable capacity blower.
• Electric motor control. Use variable frequency drives on aeration blower motors and pump motors.
• Flow controls. Adjust flow rates during low and peak times for more consistent, optimized operations.
• Wastewater system piping. Inspect piping for leaks and repair as needed to reduce pumping energy requirements.
• Lighting. Choose efficient lighting sources, such as LEDs, and occupancy controls.
• Heating and cooling. Tune up existing equipment. Use high efficiency condensing boilers and furnaces of 92% efficiency or better. Use high efficiency air conditioning equipment with an outdoor air economizer.
• Temperature setbacks. Use automatic or manual controls to adjust temperature settings and system operation according to time of day and building loads. 

In the last SEDAC newsletter, the importance of benchmarking was recommended as a first step in energy efficiency planning. Benchmarking not only provides a snapshot of how a particular facility is performing at a certain point in time, but it also allows it to be compared to similar type facilities. This comparison, although rather approximate, still provides an estimate of how a facility is performing.

Benchmarking usually involves taking a year's worth of electrical and natural gas consumption, converting it to thousands of BTU's (kBtu), and then dividing by the gross square footage of the facility. The resulting value, called the Energy Use Intensity (EUI), measured in thousands of Btu per square foot (kBtu/sf), is a common metric so that buildings can be compared to one another. It's how a 200,000 sf school can be compared to a 50,000 sf school. Naturally, common ranges for EUI's vary from one building type to another, e.g. the EUI for a non-cooled warehouse will be very different from a hospital.

The square footage used in the derivation of the EUI is the gross square footage. That is the footprint of the facility. The dimensions are taken from the exterior of the facility. If the architectural drawings of the facility are available, they usually contain the square footage. If not available, taking actual dimensions is best, or if not too complicated, Google Earth can be used to derive an approximate square footage.

If you would like to benchmark your facility and have questions, please call SEDAC at 800-214-7954 or email us at info@sedac.org. We can help.