Fuel cell vehicles (FCVs) equipped with CO2 air-conditioning systems

In most automotive air-conditioning systems, fluid, heated by the engine, is circulated through the heater to warm the passenger compartment. However, in FCVs and electric vehicles, a heat source is lacking, as they do not have an internal combustion engine. The first FCVs, powered by a hydrogen battery, have only been in circulation in the US since December 2003. In this new system, developed by Nissan for the X-Trail FCVs, using CO2 as the refrigerant, enables manufacturers to overcome the difficulty of heating the vehicle passenger compartment. The system is particularly effective in heating a vehicle, as the CO2 is compressed and supplied to the passenger compartment heat exchanger from which it radiates heat. Further developmental work is under way to enable the use of this CO2 air-conditioning system in vehicles powered by a gasoline engine.