Разработан тепловой насос, основным источником питания которого является природный газ

http://www.rdmag.com/Awards/Rd-100-Awards/2011/08/Heat-Pump-Saves-With-Gas/

Engineers 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 outdoors heat exchangers, as we 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 the home, 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.