Building Controls Measures Can Reap Substantial Energy Rewards
Study concludes application of proper building controls, low-cost sensors and other methods will improve building operations and substantially reduce energy use
By taking basic steps to improve operational systems within offices, schools, and commercial structures, U.S. energy consumption could decrease so dramatically that it would equate to 12 to 15 million Americans stopping their energy use altogether.
This potential outcome is one finding from Pacific Northwest National Laboratory’s groundbreaking study, "Impacts of Commercial Building Controls on Energy Savings and Peak Load Reduction." The study, conducted for the U.S. Department of Energy (DOE) Building Technologies Office (BTO), represents the most comprehensive effort of its kind to date. It estimates the potential energy savings (for electricity and natural gas) from use of best practice efficiency improvements across many building types and climates.
Specifically, the study examines benefits to buildings from a process known as Re-tuning™—essentially detecting, diagnosing and correcting operational problems for functions such as heating and lighting. The process helps building owners make decisions on installation of enhanced sensing, better use of existing building controls and deployment of advanced controls.
Depending on how Re-tuning methods are implemented, the study concluded energy savings approaching 30 percent across all building types are possible in warm and cool climates. In addition, several building types—stand-alone retail stores, auto dealerships and secondary schools—could register savings of more than 40 percent. Extrapolated across the nation’s building inventory, such outcomes could profoundly reduce America’s overall energy consumption.
Study Approach: Simulation of Efficiency Measures
The study focused on application of “energy efficiency measures (EEMs)”—such as recalibrating faulty building sensors or improving thermostat management—which typically are inexpensive to implement. In addition to potential energy savings, the study also explored the measures’ “demand response” aspects—or the effectiveness to temporarily reduce a building’s electricity use to help address power grid supply or imbalance issues. Researchers at PNNL used data from nine types of buildings and 16 climate locations, and tapped DOE’s EnergyPlus whole-building energy modeling engine to simulate the effects of 43 EEMs on efficiency and demand response.
The building types, represented by comprehensive models developed by DOE, ranged from offices, schools and retail stores, to hotels and supermarkets. In addition to the nine varieties of buildings studied, results were extrapolated to five similar building types.
The study evaluated the simulated performance of individual EEMs, but also bundled the measures into packages for use in three types of buildings—efficient, typical, and inefficient. It’s believed that most building owners would choose to implement synergistic packages of measures, which likely would be more cost-effective and impactful than individual measures.
The study concludes that if the packages were extended to all building types across the U.S., the measures ultimately could deliver potential savings of 29 percent, or 4 to 5 quadrillion BTUs in energy yearly. That outcome translates to eliminating the per capita energy consumption of 12 to 15 million people in the U.S.
Individually, the EEMs also demonstrated energy-saving potential. The single EEM with the highest portion of savings (7.8 percent on average) involves adjustment of thermostat set points to alter the frequency of heating and cooling actions. Four other measures demonstrated potential savings of more than 5 percent each.
Regarding demand response, nine of the EEMs contributed energy reductions of three percent or more in at least one building type during periods of peak power demand. Four of the nine measures are capable of producing more than 10 percent in reductions during peak periods. The EEMs not only would reduce costs for building owners, but possibly help maintain grid stability and enable improved integration of renewable energy, such as wind and solar power.
Additionally, study findings strongly suggest it’s possible to implement EEMs and reduce electricity consumption without impacting building occupant comfort. Up to 20 percent of consumption can be reduced for short periods (less than four hours) with little impact on occupants and building service levels.
The report acknowledges there will be challenges for some buildings—particularly small- and medium-sized commercial structures that may not have building automation systems—to effectively implement efficiency measures. It’s likely these challenges can be overcome by technological advancements and improved training for installers and operators.
The study was funded by BTO, which is part of DOE’s Office of Energy Efficiency and Renewable Energy. For more information, read the PNNL press release.