One of the competitions being run by the U.S. Dept. of Energy right now is that for a new generation of high-efficiency cost-effective air conditioners to go on commercial buildings. The rooftop a/c challenge just got its first entry: The Daikin McQuay Rebel rooftop unit.
McQuay says the new unit is expected to hit almost double the ASHRAE 90.1 minimum standard for energy efficiency. McQuay also claims it will be the industry’s most energy efficient unit available. Among the energy efficiency features: use of varible-speed fans so air volume can be metered down to three tons. The motors used on the fans are electronically commutated for variable speed, which also reduces noise. The Rebel unit offers a modulating hot gas reheat option, and operates efficiently in colder weather, unlike other rooftop heat pumps. The Rebel rooftop unit is said to work particularly well for low-rise commercial buildings such as schools or office buildings. As a dedicated outdoor air system, it provides energy efficient make-up air for 100% outdoor air applications.
The new performance criteria and challenge were developed through DOE's Commercial Building Energy Alliance. DOE brought together major U.S. companies representing a significant portion of the U.S. market to develop new performance criteria for 10-ton capacity commercial air conditioners, also known as rooftop units or RTUs. Entrants to the challenge will undergo testing by DoE in partnership with its Oak Ridge National Laboratory and Pacific Northwest National Lab.
Commercial buildings currently account for 18% of U.S. energy use. DoE says that if all the 10-ton commercial units currently sold annually were built using the Challenge criteria, businesses could save about $50 million a year in energy costs.
More information about the Rebel rooftop: http://www.mcquay.com/mcquay/Home/homepage