Design tool for offgrid hydrogen refuelling systems for aerospace applications

To validate the simulation tool a number of simulations were performed using experimental data from a prototype offgrid hydrogen refuelling station for UAVs developed by Boeing Research & Technology Europe. Solar irradiation data for a selected location and daily UAS hydrogen demands of between 2.8 and 15.8 Nm3 were employed as the primary inputs, in order to calculate a recommended system sizing solution and assess the expected operation of the refuelling system across a given year. The specific energy consumption of the refuelling system obtained from the simulations is between 5.6 and 8.9 kW he per kg of hydrogen delivered to the UAVs, being lower for larger daily hydrogen demands. Increasing the CPV area and electrolyser size in order to supply higher daily hydrogen demands (e.g., above 10 Nm3 H2 per day) improves the system operability. However this can imply excessive system size and costs, jeopardizing the techno-economic feasibility of a remotely deployable off-grid refuelling solution.