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Version: 1.0 Approved

LDO-ID 2022PUB00102

Title Retrofit of hydrogen-powered helicopters: a sizing approach

Abstract

The quest for improved sustainability in aviation is promoting hydrogen as the next big thing about innovative aircraft propulsion in several ongoing projects and studies. Hydrogen has roughly three times the energy content of gasoline or aviation fuel in terms of mass: 120 MJ/kg for hydrogen vs 43 MJ/kg for kerosene. On the other hand, hydrogen is gaseous at ambient temperature and when liquefied, at 20 K, shows a density as low as 70 kg/m3 which implies a large amount of space and some difficulties in storing it efficiently. The storage technology is a crucial challenge that the industry is facing and has been one of the main limiting factor to a hydrogen economy transition, so far. On top of the technical opportunity, there is a strong political push behind hydrogen as it can offer the very first chance of true energetic independence, being possibly produced from domestic energy sources. From the sustainability standpoint, the use of green hydrogen (i.e., hydrogen produced from renewable electricity) is CO2-free and can be completely emission-free, depending on whether it is employed as fuel for direct combustion in a Thermal Engine (TE) or oxidized in a Fuel Cell (FC) system. FCs are similar to batteries, but the reactants are stored outside the cell. In fact, FCs are not energy storage, but electric power generation devices. The energy content is represented by the hydrogen stored in the tank, while the oxygen, which activates the reaction, is normally obtained from the ambient air. This differs from batteries, where the device operates at the same time as an energy storage system and a power generation device. Proton Exchange Membrane (PEM) FC and Solid-Oxide (SO) FC are two of the most appealing FC technologies. With a quick start-up, PEMFCs run at relatively low temperatures (70-80°C) and, commercially speaking, have proven to be the most successful, especially for mobility applications. On the other hand, SOFCs are usually preferred for stationary applicati

Authors Salucci, Francesco; Vicenzotti, Giorgio; Brunetti, Massimo; Nesci, Andrea

Type Paper for Seminar/Symposium/Conference

Media AIAA Aviation Forum (27 June - 01 July 2022, Chicago, IL, USA)

Web site

https://virtualaviation.aiaa.org/Title/f7d55679-4878-43fb-bbbc-7e0af896c7cd

Anno 2022

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