Fuel Cell APU

Daggett, David L.; Eelman, Stephan; Kristiansson, Gustav

doi:10.2514/6.2003-2660

Cited by 40 publications

(13 citation statements)

References 1 publication

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“…UEL cells are continuing to gain credibility as alternative power sources in many applications, including stationary power, automotive propulsion, auxiliary power for large trucks, remote or backup power for telecommunications and other sensitive equipment, and even portable power for personal electronic devices. And although fuel cells have been used in space applications for decades, recently the aerospace industry has increased its attention on the possibility of using fuel cells in other applications, such as commercial aircraft auxiliary power units (APUs) [1,2], propulsive and/or auxiliary power for high-altitude long endurance (HALE) aircraft and orbiting platforms [3,4], and unmanned aerial vehicles (UAVs) [5,6].…”

mentioning

confidence: 99%

Performance of Proton Exchange Membrane Fuel Cell at High-Altitude Conditions

Pratt

Brouwer

Samuelsen

2007

Journal of Propulsion and Power

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The effects of oxygen concentration and ambient pressure on fuel cell performance are explored both in theory and in experiment. For fuel cells in general the effect due to a change in oxygen concentration is shown to be fundamentally different than the effect due to a change in cathode pressure, even if partial pressure is held constant. For a proton exchange membrane fuel cell, a significant reason for this difference comes from the nature of mass diffusion processes in the fuel cell structure, which infers that there is an optimum fuel cell design (macroscale and microscale) for a given operating pressure and oxygen concentration. In the experimental work a proton exchange membrane fuel cell was subjected to varying atmospheric conditions from sea level to 53,500 ft (16,307 m) with results analyzed up to 35,000 ft (10,668 m). The results showed that at low current density operation a decrease in either cathode pressure or concentration led to an increase in irreversible losses associated with reaction kinetics (activation polarization) and confirmed the differing effects of cathode pressure and oxygen concentration. Consideration of all these effects enables both fuel cell-and system-level optimization of aeronautical fuel cell-based power systems.

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confidence: 99%

Performance of Proton Exchange Membrane Fuel Cell at High-Altitude Conditions

Pratt

Brouwer

Samuelsen

2007

Journal of Propulsion and Power

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“…Daggett et al (2003) proposed development of an SOFC-turbine power system to replace the turbine APU, based on expected fuel savings, reduced noise and reduction of NO x emissions. They proposed using the SOFC-turbine APU both on the ground and during flight.…”

Section: Review and Discussion Of Literature On Sofc's For Aircraft Ementioning

confidence: 99%

Electrical Generation for More-Electric Aircraft Using Solid Oxide Fuel Cells

Whyatt¹,

Chick²

2012

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SummaryThis report examines the potential for Solid-Oxide Fuel Cells (SOFC) to provide electrical generation on-board commercial aircraft. Unlike a turbine-based auxiliary power unit (APU) a solid oxide fuel cell power unit (SOFCPU) would be more efficient than using the main engine generators to generate electricity and would operate continuously during flight. The focus of this study is on more-electric aircraft which minimize bleed air extraction from the engines and instead use electrical power obtained from generators driven by the main engines to satisfy all major loads. The increased electrical generation increases the potential fuel savings obtainable through more efficient electrical generation using a SOFCPU. However, the weight added to the aircraft by the SOFCPU impacts the main engine fuel consumption which reduces the potential fuel savings. To investigate these relationships the Boeing 787-8 was used as a case study.The potential performance of the SOFCPU was determined by coupling flowsheet modeling using ChemCAD software with a stack performance algorithm. For a given stack operating condition (cell voltage, anode utilization, stack pressure, target cell exit temperature), ChemCAD software was used to determine the cathode air rate to provide stack thermal balance, the heat exchanger duties, the gross power output for a given fuel rate, the parasitic power for the anode recycle blower and net power obtained from (or required by) the compressor/expander.The SOFC is based on the Gen4 Delphi planar SOFC with assumed modifications to tailor it to this application. The size of the stack needed to satisfy the specified condition was assessed using an empirically-based algorithm. The algorithm predicts stack power density based on the pressure, inlet temperature, cell voltage and anode and cathode inlet flows and compositions. The algorithm was developed by enhancing a model for a well-established material set operating at atmospheric pressure to reflect the effect of elevated pressure and to represent the expected enhancement obtained using a promising cell material set which has been tested in button cells but not yet used to produce full-scale stacks. The predictions for the effect of pressure on stack performance were based on literature. As part of this study, additional data were obtained on button cells at elevated pressure to confirm the validity of the predictions.An estimate of the electrical power required was developed based on an understanding of the Boeing 787 loads. The Boeing 787 engine generators produce 230 VAC power which is converted to ±270 VDC to drive the largest loads. In addition to generating a greater amount of electrical power than earlier aircraft, the 787 does so with dramatically improved efficiency. Compared to the 777, the 787 achieves twice the efficiency evaluated at the ±270 VDC loads. This is achieved using highly efficient direct drive variable frequency generators to replace less efficient generators with constant speed drives. In addition, advances in power elect...

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“…NASA is actively studying applications for commercial long-endurance UAVs and for power generation on commercial transports (Ref. 35). These results differ a bit from those of the previous chart and project that an all electric fuel cell powered commercial aircraft may not be reliably feasible for at least 25 years.…”

Section: The Potential For Compound Cycle Enginesmentioning

confidence: 94%

“…35,000 rpm and had to be significantly geared down to the rotor speed, also powered the French Alouette II helicopter, which flew in March of 1955.…”

mentioning

confidence: 99%

A Prospective: The Importance of Propulsion Technology to the Development of Helicopter Systems with a Vision for the Future The 27th Alexander A. Nikolsky Lecture

Rosen¹

2008

J. Am. Helicopter Society

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The intention of this paper is to link helicopter and propulsion history, summarize anticipated new turboshaft engine requirements for helicopters, and outline emerging opportunities for the future. The paper touches on some important contextual challenges facing both government and industry, specifically: specific fuel consumption and the "real cost" of fuel, the quest for speed, tip-jet propulsion, new engine concepts, as well as future design and integration challenges.

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Fuel Cell APU

Cited by 40 publications

References 1 publication

Performance of Proton Exchange Membrane Fuel Cell at High-Altitude Conditions

Performance of Proton Exchange Membrane Fuel Cell at High-Altitude Conditions

Electrical Generation for More-Electric Aircraft Using Solid Oxide Fuel Cells

A Prospective: The Importance of Propulsion Technology to the Development of Helicopter Systems with a Vision for the Future The 27th Alexander A. Nikolsky Lecture

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