NBI Puts High Performance HVAC Units to the Test

The Daikin McQuay Rebel Rooftop Unit (RTU) now sits on the rooftop of NBI’s main office in Vancouver, WA. In May of this year, the U.S. Department of Energy announced that the Rebel was the first product to meet DOE's Rooftop Unit (RTU) Challenge.  Along with four other manufacturers, Daikin McQuay took up the challenge to commercialize highly efficient commercial air conditioners that satisfy a DOE-issued specification for energy savings and performance.  When all is said and done, these units are expected to reduce cooling energy by as much as 50% over current minimum federal efficiency standards.

NBI is testing the Rebel to help the Northwest Energy Efficiency Alliance (NEEA) and the Bonneville Power Administration (BPA) better understand and determine the energy performance of these units compared with basic RTUs. The testing, funded by the NEEA and BPA, will monitor three 5-ton rooftop units to determine their performance efficiency both in controlled conditions at NBI’s headquarters and then in commercial use in Idaho.  In addition to the Rebel, NBI is testing an energy code minimum efficiency Precedent unit from Trane and a high efficiency AAON RQ series unit.

NBI’s Senior Project Manager, Mark Cherniack notes “Efficiency features like direct drives on fans, variable speed motors and controls, and variable compressors [present on the AAON and Daikin McQuay units] should improve energy performance beyond the minimum energy code levels.”

Rooftop units with electric cooling and gas heating are found on approximately half of commercial buildings around the US. In the Northwest, they represent over 40% of the HVAC systems on nearly 50% of the commercial buildings.  Providing more efficient HVAC systems has the potential to save a lot of energy with positive widespread impact. According to the U.S. Department of Energy, if all 10 to 20 ton RTUs nationwide met the specification, businesses would save over $1 billion each year in energy costs. In turn, this would help American companies better compete on a global scale (USDOE). 

NBI expects to demonstrate the efficacy of the new units while demonstrating a method for analyzing RTU data that will save time when assessing RTU performance efficiency.  Results will be publicly available by the end of 2012 through the NEEA website and on the NBI website.