AC-APU – A hydrogen based A/C-unit for electric vehicles

In this paper a hydrogen-based air-conditioning unit, which can also function as range extender for electric vehicles, is studied. This hydrogen A/C-unit utilizes the endothermic reaction of hydrogen desorption from metal hydrides to generate a cooling effect. Within DLR’s Next Generation Car project a prototype system was developed and characterized on a test bench. This system represents a world’s first proof of concept, where two metal hydride reactors are coupled to a fuel cell to establish a process which provides cooling power without any electrical power input. The measured cooling power is directly coupled to the hydrogen mass flow taken from the reactors, thus being indirectly linked to the fuel cells electrical power output. A maximal heat flow of 0.72 kW was detected at 5 kW electric fuel cell power. The paper concludes with the discussion of an appropriate vehicle integration concept for this innovative technology.