Bjorn’s Corner: Sustainable Air Transport. Part 25. High Temperature Fuel Cell-based 70-seat airliner

By Bjorn Fehrm

June 24, 2022, ©. Leeham News: Last week, we discussed how a High Temperature Fuel Cell (HTFC) could improve the installation of a propulsion system in our 70-seat airliner. We now add this variant to the systems we examined for installation effects and efficiencies.

The deeper discussion is in the sister article, Part 25P. High Temperature Fuel Cell-based 70-seat airliner.

Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.

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Bjorn’s Corner: Sustainable Air Transport. Part 24. High Temperature Fuel Cells

By Bjorn Fehrm

June 17, 2022, ©. Leeham News: Last week, we looked at the installation effects and efficiencies of the fuel cell systems we discussed in earlier parts of the series.

We could see the variants were significantly heavier than the propulsion system they would replace for an ATR72 size aircraft. The discussion assumed classical PEM fuel cells, also called Low Temperature PEM Fuel Cells. Now we look at if High Temperature PEM Fuel Cells can improve the installation situation.

Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.

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Bjorn’s Corner: Sustainable Air Transport. Part 23. Fuel Cell-based 70 seat airliner

June 10, 2022, ©. Leeham News: Last week, we looked at the different fuel cell systems that can go into a 70-seat airliner like the ATR 72. In this week’s Corners, we implement these in the aircraft and look at installation effects and efficiencies.

The deeper discussion is in the sister article, Part 23P. Fuel Cell-based 70-seat airliner.

Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.

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Bjorn’s Corner: Sustainable Air Transport. Part 22P. Fuel Cell system efficiency and mass. The deeper discussion.

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June 3, 2022, ©. Leeham News: This is a complementary article to Part 22, Fuel Cell system efficiency and mass. It analyses the power, loss, mass, and efficiency consequences of the different fuel cell architectures described in the main article.

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Bjorn’s Corner: Sustainable Air Transport. Part 20. Dimensioning the Fuel Cell system

By Bjorn Fehrm

May 20, 2022, ©. Leeham News: Last week, we looked at the principal parts of a Fuel Cell-based propulsion system. We need a fuel cell that converts hydrogen to electric power and then an inverter and electric motor that drives the fan, Figure 1.

The fuel cell system is the complicated and heavy part of this setup. Let’s look at how we size such a system.

Figure 1. The principal parts of a fuel cell propulsion system compared with other electric motor-based systems. Source: Leeham Co.

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Bjorn’s Corner: Sustainable Air Transport. Part 17. Gas Turbine Propulsion

By Bjorn Fehrm

April 29, 2022, ©. Leeham News: Last week, we looked at the thrust generating device that aircraft propulsion systems use. We could conclude that independent of how we create the shaft power, we can choose different thrust technologies with desired characteristics. A propeller, open fan, or fan in nacelle covers different speed ranges and efficiency profiles.

Now we look at how we generate the shaft power for these devices. We start with the hydrogen-burning gas turbine alternative.

Figure 1. Airbus ZEROe hydrogen gas turbine turboprop concept. Source: Airbus.

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Bjorn’s Corner: Sustainable Air Transport. Part 15. Hydrogen propulsion system choices.

By Bjorn Fehrm

April 15, 2022, ©. Leeham News: Last week, we examined different airliner types’ power requirements and the importance of their size classes in the market.

Now we look at what propulsion system alternatives are available when using hydrogen as the energy source and their principal advantages and disadvantages.

 

Figure 1. CO2 emission by airliner segments. Source: EU Hydrogen-powered aviation report.

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Bjorn’s Corner: Sustainable Air Transport. Part 14. Propulsion system requirements.

By Bjorn Fehrm

April 8, 2022, ©. Leeham News: Last week, we discussed the architecture of a liquid hydrogen fuel system. We now start looking at the propulsion system of a hydrogen aircraft.

Before discussing how a propulsion system is done, we must understand what power requirements different airliner types have and the importance of these types in the market.

Figure 1. The World Jet market forecast for the next 20 years. Source: JADC.

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Bjorn’s Corner: Sustainable Air Transport. Part 13. Hydrogen fuel system and APU.

By Bjorn Fehrm

April 1, 2022, ©. Leeham News: Last week, we looked at how to store hydrogen in an aircraft. We could see the gaseous storage of hydrogen is too heavy other than for demo systems and extreme short-haul. For practical airliners, liquid hydrogen is the solution.

Now we look at what this means for the aircraft fuel system and how to configure a suitable Auxiliary Power Unit, APU.

 

Figure 1. Typical placement of hydrogen tanks. Source: Leeham Co.

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Bjorn’s Corner: Sustainable Air Transport. Part 11. Hydrogen and SAF.

By Bjorn Fehrm

March 18, 2022, ©. Leeham News: In our series, we have now seen the major limitations batteries as an energy source impose on an airliner and that hybrids work but don’t bring any advantages for an airliner.

The alternatives are to use an energy source with a higher energy density and combine it with an efficient propulsion system. Sustainable Aviation Fuel, SAF, has the same high energy density as today’s Jet fuel and hydrogen’s density is three times higher than Jet fuel.

Figure 1. The Volume and Mass densities of fuels. Source: Boeing.

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