Air-conditioning systems require up to 40% of the overall energy demand in railway vehicles, which need to be reduced, especially in hydrogen trains, where fuel capacity is limited. One approach is the utilization of metal hydrides as a pressure-driven refrigeration unit. Simulation studies suggest an energy reduction of up to 13226 kWh per year and coach. A corresponding lab-scale system is already demonstrated. However, one research question arises: How can we integrate and operate a metal hydride refrigeration system in a real hydrogen train? In such a system, the hydrogen is directed through two metal hydride reactors alternately absorbing hydrogen exothermically and desorbing endothermically, which results in a quasi-continuous cooling effect without consuming hydrogen. In this study the development of a 5-kW metal hydride refrigeration system and the integration approach in the Talgo test train ‘TPH2’ is presented. The system will meet the requirements for the train environment, such as operating temperatures and mechanical stability. Before installing the system in the train, it is tested on a setup simulating the train environment. First measurements at two static cooling cases based on the railway standard EN50591 demonstrate a successful operation and show an average cooling power of 428–435 W.

Hydrogen-powered trains present a sustainable alternative to diesel-powered trains for railway transport of passengers and freight. Hydrogen as an energy carrier is cost-intensive, which is why energy demand should be reduced in all relevant operational scenarios. Since thermal losses are one of the main reasons for efficiency reductions, the presented work investigated the research question: Can hydrogen-powered trains combined with targeted energy management strategies be simulated and potential energy efficiency gains be quantified for European and North American scenarios? A digital railway vehicle simulation framework is developed, which models longitudinal dynamics and energy management. The framework is built with standardized functional mock-up interfaces (FMI) for component sub-models to enable a co-simulation with models from different entities. As input for the simulations, different passenger and freight transport scenarios from Europe and North America are used. Requirements for hydrogen-powered trains vary greatly for different use cases of passenger and freight transport, as well as the location with its surrounding climate. Recuperation of braking energy in freight transport is challenging and remains an opportunity for further enhancement. For passenger transport, metal hydride cooling systems can provide additional cooling capacity and reduce electrical energy demand for air conditioning.