2011 R&D 100 Winner
Oak Ridge NextAireEngineers at Oak Ridge National Laboratory, Oak Ridge, Tenn., have developed a heat pump that does not rely on the electric grid for its power. The NextAire Packaged Gas Heat Pump (PGHP), recently commercialized with co-developers Southwest Gas, Las Vegas, and IntelliChoice Energy, Phoenix, Ariz., uses natural gas as its primary fuel, allowing users to avoid high kilowatt demands and time-of-use rates.

The PGHP uses both an internal combustion engine to drive a vapor compression heat pump and the waste heat rejected by the engine for heating indoor air. The engine-compressor section features engine exhaust and waste heat recovery components and two belt-driven, scroll-type refrigeration compressors. Engine coolant is pumped through waste heat recovery components and the engine to remove and recover waste heat. Indoor and outdoor heat exchangers, as well as high-efficiency fans, comprise the rest of the system.

Because only 3% of the fuel energy is lost when transporting natural gas from a wellhead to a user, the PGHP represents a major efficiency improvement over traditional electricity, which sees losses of up 68%, as well as high levels of emissions and water use. Approximately the same size as traditional electric units, the PGHP runs at 74 decibels, about 12% quieter than a traditional electric air conditioning unit, and uses a small amount of electricity to run various subsystems.

Natural gas heat pump

Oak Ridge National Laboratory
Southwest Gas
IntelliChoice Energy

Development Team

Oak Ridge NextAire Development Team
(l-r, back row): Isaac Mahderekal, Randall Linkous, Randall Wetherington, and Patrick Geoghegan
(l-r, front row): Abdolreza Zaltash and Ed Vineyard



The NextAire Packaged Gas Heat Pump Development Team
Tommis Young, Principal Developer, IntelliChoice Energy
Robert Gaylord, IntelliChoice Energy
Patrick Geoghegan, Oak Ridge National Laboratory
Anthony W. Hills, Southwest Gas
Randall Linkous, Oak Ridge National Laboratory
Isaac Mahderekal, IntelliChoice Energy
Dudley Sondeno, Southwest Gas
Edward Vineyard, Oak Ridge National Laboratory
Randall Wetherington, Oak Ridge National Laboratory
Abdolreza Zaltash, Oak Ridge National Laboratory