Liquid hydrogen storage design trades for a short-range aircraft concept

Abstract

Preliminary design trades for the liquid hydrogen storage system of a short-range aircraft are presented. Two promising insulation methods, namely rigid foam and multilayer insulation, are identified as main design drivers. In addition, the maximal pressure and the shape of the hydrogen storage tank influence the aircraft performance and the insulation efficiency. In this study, the hydrogen storage tanks are integrated in wing pods. The main effects driven by the design parameters are addressed using conceptual and preliminary methods: models are carried out for the storage mass, additional drag, propeller efficiency loss and the dynamical thermodynamic behavior of the liquid hydrogen storage. These effects are coupled making an integrated design method necessary. For the sizing of the liquid hydrogen storage, a multidisciplinary workflow is set up including the aircraft sensitivities on the design mission block fuel. The trade-off study reveals the opposing trend between insulation efficiency and aircraft performance. For the insulation architecture based on rigid foam, the penalties implied by the storage tank on aircraft level and the penalties due to vented hydrogen can be balanced and result in minimal block fuel for the design mission. The application of multilayer insulation avoids venting during the design mission, but has an increased penalty on the aircraft performance compared to rigid foam insulation. Besides the criterion of minimal block fuel, the dormancy time is compared, indicating the thermal efficiency. Applying multilayer insulation, the dormancy time can be increased significantly calling for a discussion of operational requirements for hydrogen-powered aircraft.

Switching Logic for a Direct Hybrid Electric Powertrain

“…If hydrogen is converted in fuel cells, the only emission is water vapor [6,7]. In this context, the tradeoff between the low volumetric energy density of hydrogen of 600 kWh/m 3 at 200 bar [9] and the high gravimetric energy density of 33 kWh/kg [10] is well known and subject to developments in the field of hydrogen storage systems [11,12].…”

Optimal Sizing of Fuel Cell and Battery in a Direct-Hybrid for Electric Aircraft

“…The storage of hydrogen on board an aircraft comes with its own challenges due to hydrogen's low volumetric energy density of 600 kWh/m 3 at 200 bar [14], and its high gravimetric energy density of 33 kWh/kg [15]. The development of suitable tanks as well as the integration into the aircraft is currently an important research topic [16,17]. The usual approach is to connect the fuel cell and the battery into a hybrid system with the help of one or even two DC/DC converters that adapt the voltage levels of both energy sources to that of the load [18].…”