The US Department of Energy announced $33 million in funding for 17 projects as part of the Advanced Research Projects Agency-Energy’s (ARPA-E) Aviation-class Synergistically Cooled Electric-motors with iNtegrated Drives (ASCEND) and Range Extenders for Electric Aviation with Low Carbon and High Efficiency (REEACH) programs.
ASCEND projects work to develop innovative, lightweight, and ultra-efficient all-electric powertrain with advanced thermal management systems that help enable efficient net-zero carbon emissions for single-aisle passenger commercial aircraft.
REEACH projects seek to create innovative, cost-effective, and high-performance energy storage and power generation sub-systems for electric aircraft, with a focus on fuel-to-electric power conversion technologies. Both programs work to decrease energy usage and associated carbon emissions for commercial aircraft propulsion systems.
Estimates comparing passenger-distance-specific CO2 emissions place commercial air travel on single-aisle aircraft at nearly double that of any other individual widely used transportation source, including by rail, bus, or car. REEACH and ASCEND teams seek to decrease these emissions as well as the economic burden associated with air travel for commercial airlines by developing elements of ultra-high efficient aircraft propulsion systems to use carbon neutral liquid fuels.
Of the $33 million being awarded through these programs, eight projects were selected under REEACH to split $18.5 million in funding, while ASCEND teams will receive $14.5 million for nine projects for Phase 1.
Project teams in the ASCEND Program that achieve technical success during Phase 1 may be eligible to receive additional funding under Phase 2 to further develop their technologies. Up to $18 million in total is currently allocated for Phase 2 of the Program.
REEACH (Range Extenders for Electric Aviation with Low Carbon and High Efficiency) project descriptions
Raytheon Technologies Research Center. Compact Propulsion Engine Optimized with Waste Heat Recovery (CO-POWER); $2,815,760
The CO-POWER project will enable a commercial narrow body electric aircraft by developing an ultra-efficient and lightweight fuel to electricity power generation system that includes the use of supercritical carbon dioxide (sCO2) as a working fluid. The proposed approach combines decades of knowledge in gas turbine engines with novel advances in additive manufacturing research and sCO2 power generation experience to increase the overall power system efficiency and its power density.
The work will result in the development of a first-of-its-kind aircraft gas turbo-electric engine with a sCO2 waste heat recovery cycle. This engine will deliver power more efficiently, with greater than 10% absolute increase in the fuel to electricity conversion efficiency and at comparable weight to current state-of-the-art gas turbines. These improvements will result in up to a 20% fuel burn savings. The system can operate with any carbon neutral liquid fuel to achieve net-zero GHG emissions.
Raytheon Technologies Research Center. Zero-carbon Ammonia-Powered Turboelectric (ZAPTurbo) Propulsion System; $2,652,778
The Zero-carbon Ammonia-Powered Turboelectric (ZAPTurbo) Propulsion System is a very high efficiency and light weight turboelectric system that uses green ammonia as both a fuel and a coolant via regenerative cooling. Coke-free heating of this carbon-free ammonia fuel enables a high level of waste-heat recovery that will be used for the endothermic cracking of ammonia prior to its combustion, significantly increasing the cycle efficiency. The proposed propulsion system includes an efficient AC electric powertrain for turboelectric cruise, with battery boost for takeoff and climb flight phases.
The ability to optimize the gas turbine at the center of the turboelectric system for cruise power drives maximum efficiency. The proposed system is projected to operate in cruising phase of flight with a 66% energy conversion efficiency.
General Electric Company, GE Research. FueL CelL Embedded ENgine (FLyCLEEN); $2,529,340
FLyCLEEN will leverage the robustness and efficiency of metal-supported solid oxide fuel cells that are integrated with the combustion chamber of a gas turbine engine-generator, yielding a hybrid system operating on synfuel with performance that maximizes the power density and energy efficiency of each component. Multiple advancement methods will be pursued to increase the power density of the fuel cell. The system is configured to benefit the balance of plant and to optimize thermodynamic synergies for electrified commercial aviation.
University of Maryland. Hybrid SOFC-Turbogenerator for Aircraft; $2,798,489
The University of Maryland is developing a highly efficient and cost-effective hybrid-electric turbogenerator suitable for powering narrow body aircraft such as the B737. A solid oxide fuel cell (SOFC) with integrated autothermal reformer is incorporated directly into the flow path of a gas turbine engine that also drives an electrical generator. The engine moves air through the system while boosting efficiency by recovering waste heat and unused fuel from the fuel cell. The system operates on carbon-neutral, liquefied bio-methane. Unique features include low temperature, redox-stable, high power density SOFC technology with internal reforming, an integrated autothermal reformer/SOFC/combustor that mitigates risks for thermomechanical failure, and a highly efficient turbo-generator.
University of Louisiana at Lafayette. High Performance Metal-Supported SOFC System for Range Extension of Commercial Aviation; $2,263,000
The University of Louisiana at Lafayette will design and optimize an energy storage and power generation (ESPG) system for aircraft propulsion. The proposed system will consist of optimally sized fuel-to-electric power conversion devices; metal-supported solid oxide fuel cells (MS-SOFCs) and turbogenerators using carbon-neutral synfuel. The design concept will ensure adequate propulsive thrust and system power for a future airplane configuration by optimizing the ESPG and component performance, especially the synfuel- powered MS-SOFC. The team will use innovative fabrication techniques for high-performance, ultra-low weight, and low-cost MS-SOFC stacks. They will also develop reforming catalysts for synfuel and biojet fuel.
University of California, San Diego. High-Efficiency and Low-Carbon Energy Storage and Power Generation System for Electric Aviation; $2,131,246
The University of California, San Diego (UCSD) aims to develop a high-efficiency and low-carbon energy storage and power generation (ESPG) system operating on bio-LNG for electric aviation. The proposed system concept is a fuel cell, battery, and gas turbine hybrid system that incorporates a novel solid oxide fuel cell (SOFC) stack technology. The proposed SOFC is composed of (1) a lightweight and compact stack architecture based on an array of cell modules in electrical and gas flow parallel and series connections; and (2) exceptional high power density direct methane cells made by sputtering thin-film deposition process. The proposed system has been estimated to have the specific power and specific energy properties aligning to the competitive capital costs required for aircraft ESPG applications.
Fuceltech Inc. Extremely Lightweight Fuel Cell Based Power Supply System for Commercial Aircrafts; $1,656,438
Fuceltech proposes to develop an innovative low-cost, lightweight Energy Storage and Power Generation (ESPG) system for commercial aircraft. Fuceltech will develop a monopolar wound fuel cell potentially as high as 10kW rating and a novel stacking approach to deliver hundreds of kWs of power from a single small and lightweight stack. Fuceltech will use ethanol as a fuel and a reformer that delivers extremely low CO concentration in the reformate to the fuel cell.
Precision Combustion, Inc. SOFCs for FLIGHT; $1,750,590
Precision Combustion (PCI) is proposing an advanced energy storage and power generator design for meeting aggressive specific power and energy targets for all-electric propulsion of narrow-body commercial aircraft. Key enablers are an exceptionally power-dense solid oxide fuel cell operating with energy-dense carbon neutral liquid fuels and a hybridized system architecture that maximizes component efficiencies for ultra-high system efficiency. PCI will validate compliance via component demonstration and develop a verifiable model for scale-up. It will also address performance constraints to conform to takeoff/climb/cruise requirements and examine tradeoffs (weight vs. efficiency vs. complexity). Durability at aircraft operating conditions (e.g., start/stop cycles, peak power, transient operation, altitude) will be demonstrated.
ASCEND (Aviation-class Synergistically Cooled Electric- motors with iNtegrated Drives) project descriptions
Raytheon Technologies Research Center. Ultra-Light, inTegrated, Reliable, Aviation-class, Co-Optimized Motor & Power converter with Advanced Cooling Technology (ULTRA-COMPACT); $2,330,137
The Raytheon Technologies Research Center proposes ULTRA-COMPACT to improve the electric-to-shaft power electric drive train and demonstrate feasibility of a turbo-electric distributed propulsion-based electrified aircraft propulsion system. The ULTRA-COMPACT electric propulsion system leverages: (1) high-speed Permanent Magnet machines; (2) a series-parallel, multi-level silicon carbide (SiC) based motor drive topology; (3) an integrated and actively controlled thermal management system that provides coolant directly to the motor windings and power converter; and (4) a high-power density gearbox using lightweight composite.
Marquette University. High Power Density Motor Equipped with Additively Manufactured Windings Integrated with Advanced Cooling and Modular Integrated Power Electronics; $1,600,000
Marquette University and its partners are developing the next generation of electric drivetrains for aerospace propulsion. The proposed system consists of a high-power density motor enabled by (1) an additively manufactured winding and a novel thermal management scheme; (2) a modular power electronics topology; and (3) tight system integration and shared thermal management between the motor and power electronics to meet or exceed system-level targets. In the project’s first phase, the team will develop concepts and tradeoff studies and perform sub-component/component testing and risk retirement. Phase two will focus on component procurement, system integration, and verification testing of the technology.
General Electric Global Research. Electric Flightworthy Lightweight Integrated Thermally-Enhanced powertrain System (eFLITES) for Narrow-body Commercial Aircraft; $2,300,000
General Electric Global Research will develop a 2MW fully integrated all-electric aircraft powertrain and demonstrate a 350 kW lab-scale prototype to enable zero carbon emission narrow-body commercial aircraft with all-electric propulsion. The technology is supported by several key innovations such as a high-voltage, direct-drive, synchronous permanent-magnet motor with transformational embedded cooling of the windings using supercritical carbon dioxide and high-temperature, high-voltage electrical insulation; a modular inverter fully integrated into the motor to reduce component count with high-temperature, low-loss SiC inverter modules; and an ultracompact thermal management system that services the motor and inverter. The design and use of novel manufacturing techniques will lead to significant mass reduction and thus increase in specific power density while maintaining a very high electrical-to-mechanical energy conversion efficiency.
Honeywell. Advanced Electric Propulsion System (AEPS) - $1,800,000
Honeywell Aerospace proposes to develop a novel high-voltage 500 kW advanced electric propulsion system (AEPS) with a high efficiency and a high-power density. The cost-effective AEPS will include a highly effective and innovative thermal management system. This system will use high-speed air flow from the aircraft propulsor wash to cool the power electronics and the motor via an innovative heat sink integrated into the AEPS housing that minimizes the thermal resistance. Other key innovations enable overall machine weight reduction without compromising efficiency, such as the use of high-performance windings, which increases the copper fill factor for increased machine efficiency and thermal and electric conductivities. The AEPS also uses an integrated, direct drive permanent magnet electric motor and a motor drive (power and control electronics) with common chassis and cooling systems for enhanced performance.
University of California, Santa Cruz. Flux-Switching Machine Based All-Electric Power Train for Future Aircraft; $854,495
Power density and efficiency are crucial to electric propulsion for future aviation systems. The University of California, Santa Cruz proposes a novel all-electric power train. Each aspect of the proposed power train encompasses unique technology. The machinery relies on a flux-switching motor with superconducting field coils which has been shown to be smaller and lighter than conventional designs. The electronics are based on state-of-the-art multilevel inverter technology leading to improved efficiency and lower electromagnetic noise. The cooling technology is a hybrid system containing ultralight cryogenics as well as traditional air cooling methods. The development of the all-electric power train involves an aggressive design schedule and creation of a manufacturing plan that engages US suppliers.
Texas A&M Engineering Experiment Station. Multi-Physical Co-Design of Next Generation Axial Motors for Aerospace Applications; $1,300,000
Texas A&M will focus on the design, fabrication, and testing of a lightweight and ultra-efficient electric powertrain for aircraft propulsion to reduce the energy costs and emissions of aviation. The team’s technology will reach peak power density and efficiency via (1) an axial flux motor with lightweight carbon fiber reinforced structural material; (2) a GaN multilevel inverter; (3) a thermally conductive nanocomposite electrical insulation; and (4) a two-phase thermal management system with zeolite thermal energy storage to absorb the excess heat generated during takeoff. Each subsystem is designed for tight integration with the other subsystems to minimize weight.
Hyper Tech Research Inc. Cryo Thermal Management of High Power Density Motors and Drives; $2,910,479
Hyper Tech Research Inc., aims to design and demonstrate a multi-MW, high-efficiency, and high-power density integrated electric propulsion motor, drive, and thermal management system that meets the performance requirements of future hybrid electric, single-aisle passenger aircraft. The proposed technology incorporates an advanced and high-performance induction electric machine with a novel advanced thermal management techniques for synergistic cooling that safely uses cryogenic bio-LNG as the energy source for power generation and a large thermal-battery cooling system to provide a highly compact, light, and efficient thermal management system capability throughout all the different flight phases of a commercial narrow-body aircraft. If successful, the system will allow for a cost-effective motor capable of operating at a higher current density compared with existing conventional non-cryogenic motors without using superconductors.
Wright Electric. 2nd Generation Motor for Large Electric Aircraft Propulsion Systems; $647,039
Wright Electric will design engine systems that use cutting-edge innovations in integrated cooling, power electronics, and rotor design. The design will create a high-efficiency, high-performance motor without sacrificing safety or the use of existing manufacturing techniques. The team plans to use an aggressive cooling strategy coupled with a high frequency inverter. In phase one of the project, the team will create a detailed design and subcomponent testing of this system. In phase two, it will build and demonstrate this system. The unique innovations across the electric engine will continue the development of aircraft flying entirely on electric power.
Advanced Magnet Lab, Inc. High Power Density Dual Rotor Permanent Magnet Motor with Integrated Cooling and Drive for Aircraft Propulsion; $655,354
Advanced Magnet Lab (AML) seeks to develop high-power density permanent magnet motors. When coupled to an integrated SiC drive, these motors will enable an overall specific power beyond 12 kW/kg. The proposed concept relies on (1) the tight integration of a high-power density dual-rotor permanent magnet rotor based on "continuous flux directed" magnets (PM-360TM) currently under development at AML; (2) high-power density SiC power converters; and (3) a shared closed-loop cooling system rejecting the heat in the propulsion ducted fan air stream.