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New Nissan FCV Vehicle Has CO2 AC

Tokyo – Nissan Motor Co., Ltd. announced today that the X-TRAIL FCV fuel cell vehicles (FCVs) it started leasing Monday under its FCV limited leasing program come equipped with an air-conditioning system jointly developed by Nissan and Calsonic Kansei Corp. that uses carbon dioxide as the refrigerant.

Since the thermal property of CO2  is different from current refrigerant, CO2 is especially effective in heating a vehicle compared with the HFC-134 alternative refrigerant used in other automotive air-conditioning systems. In the CO2 system, heating is accomplished by switching to the refrigerant channel so that the refrigerant can be compressed and supplied to the passenger compartment heat exchanger from which it radiates heat. In other automotive air-conditioning systems, a hot engine coolant that has been heated by the engine heat is circulated through the heater core to warm the passenger compartment. Until now, fuel cell vehicles and electric vehicles (EVs) have had the drawback of not providing very effective cabin heating because they lack a heat source as they do not have an internal combustion engine.

The CO2 air-conditioning system uses the same process as ordinary automotive air-conditioners to cool a vehicle. The refrigerant – in this case CO2 -- is evaporated by a passenger car compartment heat exchanger to absorb heat and cool the vehicle’s cabin.

CO2 is a naturally occurring, non-flammable refrigerant and is more environmentally friendly than the HFC-134a alternative refrigerant. The new CO2 system can help to reduce the amount of CO2 discharged from factories because CO2 waste from factories can be reused for use in the system.

The implementation of the new air-conditioning system has been made possible in part by the successful development of a compact, lightweight compressor capable of withstanding the high temperature and high pressure needed to compress CO2. Another contributing factor is the successful development of a heat exchanger capable of withstanding the high pressure and temperature of the highly compressed CO2 gas supplied from the compressor.

Moreover, the power loss that ordinarily occurs in a small car when the air conditioner is operated while driving can be reduced with this air-conditioning system through suitable control of the compressor torque. Further development work is now under way with the aim of using this CO2 air-conditioning system on vehicles powered by a gasoline engine.

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