National Lab Creates ‘Autotune’ Building Modeling Software

September 30, 2014 By Linda Hardesty

Oak Ridge energyOak Ridge National Laboratory researchers are developing software that will automatically calibrate models for simulating building energy use.

Building Energy Modeling (BEM) uses computer simulations to estimate energy use and guide the design of new buildings and energy retrofits. Up to 3,000 parameters may be specified when modeling a building’s energy use.

Over the last 20 years, the Department of Energy has invested in EnergyPlus, its whole-building energy simulation tool, which estimates energy usage based on weather data and thousands of inputs related to heating, ventilation, and air conditioning (HVAC), water heating, lighting, and occupancy schedules.

But before using BEM to identify energy improvements to existing buildings, BEM parameters must first be collected, entered into the tool, and adjusted so outputs reasonably match past energy usage. This can be a time consuming chore, but it’s often required to receive tax rebates and utility incentives.

Now, the ORNL researchers have developed “Autotune” calibration software to optimize BEM parameters. The ORNL researchers used the lab’s 27-petaflop Titan supercomputer to perform millions of EnergyPlus simulations for a range of standard building types.

Additionally, they worked with building technology experts to identify about 150 of the most important parameters. The software uses machine learning algorithms to “learn” successful versus unsuccessful paths to optimization.

While programmatic guidelines for tax rebates and utility incentives often require an error rate below 30 percent when calibrating building models to monthly utility bills, Autotune’s fully-automated process has routinely calibrated models to an error below 1 percent on all building types tested.

The team is currently making Autotune capabilities available to a limited set of beta testers through a web service and anticipates making it publicly available in September 2015.

Photo: ORNL buildings researchers Jibonananda Sanyal, left, and Joshua New are developing software that will automatically calibrate models for simulating building energy use.

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