An infrared camera helps determine the area and U-value of the window frame

The Challenge: Verifying Energy Models

The Rapid Building Energy Modeler (RAPMOD) easily and automatically maps a building and interacts with energy modeling tools, saving time and money while boosting accuracy. Deployed on all commercial buildings with a floor area greater than 50,000 sq ft, RAPMOD could save ~$3B by reducing energy modeling costs for major retrofits, retro-commissioning and performance monitoring. But how could researchers prove that it can quickly and accurately determine how building components perform – in this case windows? 

The Solution: FLEXLAB®

Testing RAPMOD in FLEXLAB’s life-size, controlled environment while precisely measuring conditions across a range of interior temperatures allowed researchers to verify RAPMOD’s window-measuring capabilities. The experiment showed RAPMOD can quickly and accurately evaluate a window’s performance in terms of energy and visual quality, revealing new possibilities for energy efficiency and occupant comfort.

FLEXLAB rotating test bed

The Bottom Line

The FLEXLAB® experiment verified RAPMOD’s performance while helping fine-tune the measurement method for windows, contributing to RAPMOD’s ability to cut building energy model creation time by 30 percent. The FLEXLAB tests helped to speed the development of RAPMOD and increase the accuracy of its window-measuring capabilities. FLEXLAB provided a unique controlled environment to test a wide variety of window conditions, solar orientations and interior temperature conditions, all at a realistic scale. FLEXLAB testing also suggested ways to improve the RAPMOD system.

Download the full case study here: RAPMOD

"LBNL’s FLEXLAB® facility provided a perfect platform...
to experimentally verify our method of measuring the U-values of windows, which are key to predicting the energy use of real buildings."