Dr. Li Song, assistant professor in the School of Aerospace and Mechanical Engineering at the University of Oklahoma, along with her fellow research colleagues created a method to overcome inefficiencies in heating and cooling systems to reduce building operation costs as well as reduce energy consumption significantly. Song’s research has the possibility of reducing energy consumption in a single structure by as much as 20 percent. Furthermore, Song estimates some buildings could save as much as 30 to 50 percent.
A mathematical formula was created by Song’s research team based on existing output data such as pump speed and power. This formula allows monitoring of energy use in heating, ventilation, and air conditioning units. From these results, the formula can detect unreliable systems and faulty equipment that affects energy consumption. The formula creates virtual sensors used to identify energy waste in an air-handling unit and in a whole building.
“Waiting until exorbitant utility bills appear may be a sign that the equipment hasn’t worked optimally for years,” said Song. “This method allows earlier detection of minor equipment faults, possibly preventing an overhaul of the entire system.”
In addition to saving money on utility bills, Song’s formula is a low-cost option for commercial monitors allowing more companies to track and reduce energy consumption. An organization would need to purchase several ultrasonic flow meters, which monitor water pump performance, in order for accuracy costing roughly $5,000 per meter. This virtual process is within ±2% uncertainty range compared to commercial meters.
Previously, Song applied the energy monitoring, fault detection, and diagnosis manually in over 100 buildings saving over $70 million. For instance, in one building Song’s method reduced annual electricity consumption by 53 percent, electricity demand by 21 percent, and gas consumption by 49 percent in only one year. Another building qualified as an Energy Star building just after five months.
Song’s research has grown from the corporate sector and will now focus on the government division starting at Tinker Air Force Base in Oklahoma City. The U.S. Department of Defense awarded her research team a three-year $1 million contract to increase building efficiencies at military installments.
“The U.S. Department of Defense spends $4 billion each year in facility operations,” said Song. “They have a federal mandate to reduce building energy consumption by 30 percent by 2015. My research team thinks we can double the reduction.”
Song is only one of a few researchers working on efficiency improvements in heating, ventilation, and conditioning units using virtual sensor measurements. In addition, Song is currently developing a smart-device that contains the mathematical formulas allowing building owners to easily monitor an existing system as an ongoing task.
“The virtual valve flow meter won’t replace conventional flow meters if they are needed for utility metering for billing,” said Song, “but it does offer companies an inexpensive and readily accessible solution to monitor energy consumption. Companies can use the information to create a more efficient system, saving them money while reducing energy consumption.”