Air-conditioning system for vehicles with on-board hydrogen

Abstract

Electric vehicles with on-board hydrogen store not only the corresponding chemical energy of the H2, but also a significant amount of potential energy in the pressurized gas. This energy is provided by a compressor at the fueling station and so far, it is wasted by throttling the H2 to the fuel cell supply pressure. An ‘‘open” metal hydride cooling system can convert part of this potential energy into cooling power. In this publication, results for an experimental lab-scale setup of such a cooling system are presented and discussed in the vehicle context. The lab-scale system consists of two plate heat exchanger based reactors filled with 335 g and 353 g of Hydralloy C5 hydride material. At 10 °C an average cooling power of -532W or -586W could be determined for cycling times of 100 s or 75 s, respectively. Due to the small lab-scale reactors used in this study, this value is reduced to -76 W, when the efficient cooling power between 30 °C and 10 °C is determined. To conclude the results, scale-up effects and the relation of hydrogen flow and cooling power are discussed as well as a possible integration into a vehicle.