Liquid vs. Compressed Hydrogen for Flying Wing Aircraft: Trade-offs in Range, Efficiency, and Design (pg 2)

Range Estimates for the B2N Boomerang with Gaseous Hydrogen vs Liquid Hydrogen (pg 3)

In a bold move towards sustainable aviation, Archon Aerospace is set to revolutionize the industry by offering self-manufactured hydrogen for self-service hydrogen refueling at its hangars on airports and beyond. This innovative initiative underscores the company's commitment to environmental sustainability and positions it as a pioneer in the adoption of hydrogen fuel cell technology in aviation.

The Durability of Gaseous Hydrogen Storage

A crucial aspect of this endeavor is the storage of gaseous hydrogen. When stored properly, hydrogen can last indefinitely without degradation, provided there are no leaks or deterioration of storage materials. Archon Aerospace is keenly aware of the importance of maintaining high-quality storage conditions, including the use of high-pressure tanks or underground caverns, to ensure the integrity of the hydrogen. Regular inspections and high-quality sealing are paramount to prevent leakage, which is the primary concern in hydrogen storage. Moreover, maintaining purity is essential, as impurities can contaminate the hydrogen over time, affecting its usability in fuel cell applications.

Steps Towards Establishing a Hydrogen Fueling Station

To achieve its vision, Archon Aerospace has outlined a comprehensive plan:

1. Feasibility Study: Conducting a thorough study to understand the demand for hydrogen fueling, considering both in-house fleet needs and potential third-party users.
2. Regulatory Compliance: Ensuring adherence to local, national, and international regulations regarding hydrogen storage and dispensing, including safety codes and standards.
3. Infrastructure Development: Selecting a safe and accessible site, deciding on storage systems (above-ground high-pressure tanks or underground storage), and installing hydrogen dispensers.
4. Supply Chain Establishment: Securing a reliable source of hydrogen production, possibly through electrolysis using renewable energy or partnerships with hydrogen suppliers.
5. Safety Measures: Implementing advanced safety systems, including hydrogen leak detection, emergency shutdown systems, and fire suppression systems, along with regular staff training on hydrogen safety.
6. Financial Planning: Calculating initial investments, operational costs, and potential revenue streams, exploring funding options like crowdfunding or grants.
7. Operational Strategy: Developing protocols for refueling operations, maintenance, and emergency procedures to ensure efficient, 24/7 self-service operations.
8. Marketing and Partnerships: Promoting the station to potential users, forming partnerships with vehicle manufacturers, and highlighting the environmental benefits to attract environmentally conscious clients.
9. Environmental and Sustainability Considerations: Emphasizing the green credentials of hydrogen fueling, aligning with sustainable aviation goals, and continuously monitoring performance to improve efficiency and user experience.

Electrolyzer Options for Hydrogen Production

Archon Aerospace is considering top-tier electrolyzer options for on-site hydrogen production, including:

1. Nel Hydrogen: Known for their comprehensive hydrogen solutions, Nel offers PEM and alkaline electrolyzers suitable for medium to large-scale production.
2. McPhy Energy: McPhy's McLyzer electrolyzers are recognized for their modular design and ability to produce low-carbon hydrogen on-site.
3. Proton OnSite (Cummins Accelera): Specializing in PEM electrolyzers, Proton OnSite is involved in notable green hydrogen production projects, offering efficient and safe systems.

Partnering with Vehicle Manufacturers

Archon Aerospace is exploring partnerships with leading vehicle manufacturers committed to hydrogen fuel cell technology, including:

1. Toyota: With their Mirai model, Toyota has been a pioneer in hydrogen fuel cell vehicles.
2. Hyundai: The Hyundai Nexo SUV is a prominent example of hydrogen fuel cell technology in the automotive industry.
3. Honda: Although focusing on battery electric vehicles, Honda has a history with hydrogen and continues to explore its potential.
4. BMW: BMW is testing the iX5 Hydrogen as part of a pilot project, indicating their interest in hydrogen as a complementary technology to their electric vehicle lineup.
5. Riversimple: A smaller player with a focus on sustainability, Riversimple aims to offer the Rasa through a subscription model, emphasizing zero-emission transport.

Other hydrogen manufacturers and concepts include:

• Hyperion Motors with the XP-1, showcasing high-performance hydrogen capabilities.
• NamX with the HUV concept, highlighting innovative hydrogen storage solutions.
• Volvo and Daimler have more focus on commercial vehicles but are mentioned in the context of hydrogen for transport.

By following this comprehensive plan and potential partnership opportunities with industry leaders, Archon Aerospace is poised to successfully establish a hydrogen fueling station, enhancing its operations with sustainable fuel options and potentially leading the way in the aviation industry towards greener technologies.

2.

Liquid vs. Compressed Hydrogen for Flying Wing Aircraft: Trade-offs in Range, Efficiency, and Design.

Compressed hydrogen gas and liquid hydrogen both serve as fuel options for hydrogen-powered aircraft, including a flying wing design. Here's a comparison of their compatibility, pros, cons, and implications for range when considering their use in such an aircraft:

Compressed Hydrogen Gas (CHG):

Pros:

Simpler Infrastructure: Unlike liquid hydrogen, CHG doesn't require cryogenic systems, which simplifies handling and reduces the complexity of the fueling infrastructure.

Lower Energy Input: It requires less energy to compress hydrogen gas compared to the energy needed to liquify it, although compression does consume energy.

Established Technology: There's more industry experience with CHG, which can make initial implementation easier.

Safety: In some aspects, CHG might be considered safer due to the absence of cryogenic risks like frostbite or embrittlement at very low temperatures.

Cons:

Lower Energy Density: CHG has a lower volumetric energy density, meaning larger tanks are needed for the same amount of energy, which can be a significant drawback for aircraft where space and weight are critical.

Tank Size and Weight: Higher pressure tanks required for CHG are heavier and take up more space compared to tanks for liquid hydrogen, potentially increasing drag and reducing payload capacity.

Range Limitation: Due to the lower energy density, the range of an aircraft using CHG might be limited unless very large tanks are used, which contradicts the goal of reducing aircraft weight for flight efficiency.

Range Considerations:

The range with CHG could be significantly less than with liquid hydrogen unless the aircraft design allows for very large tank volumes, which our flying wing design might facilitate. However, this would still be at the cost of added structural weight and potential aerodynamic inefficiencies due to larger fuselage or wing areas.

Liquid Hydrogen (LH2):

Pros:

Higher Energy Density: LH2 offers a much higher volumetric energy density, allowing for more energy to be stored in a smaller volume, which is critical for aircraft range and fuel efficiency.

Better for Long Haul: For longer flights, LH2 is more practical due to its energy density, potentially allowing for a range similar to or better than traditional jet fuel aircraft.

Aerodynamic Design: The design of the aircraft can be optimized with LH2 tanks, potentially reducing drag as tanks can be more integrated into the airframe or placed in less aerodynamically sensitive areas.
 

Cons:

Complex Infrastructure: LH2 requires cryogenic storage and handling systems, which are more complex and energy-intensive to maintain. The energy used to liquify hydrogen can account for up to 30% of the hydrogen's energy content.

Safety Concerns: Handling liquid hydrogen involves cryogenic risks, including the potential for thermal burns, material embrittlement, and the need for strict safety protocols.

Cost: The setup and operational costs for LH2 systems are higher due to the specialized equipment required for cryogenic handling.

Range Considerations:

LH2 can enable longer flight ranges due to its higher energy density, making it an attractive option for medium to long-haul flights. This would be particularly beneficial for a flying wing where space for tanks is more readily available, allowing for more fuel to be carried without compromising the aerodynamic profile as much as with CHG.

Trade-offs:

Weight vs. Volume: While CHG requires less weight in terms of the fuel itself, the tanks for high-pressure storage are heavier, and the volume needed for storage is larger, potentially negating some of these benefits. LH2 tanks, while dealing with cryogenic challenges, are lighter for the same amount of energy stored.

Operational Complexity: LH2 introduces operational complexities due to the need for maintaining very low temperatures, which might increase maintenance and operational costs but provides better energy efficiency per volume.

Aircraft Design: A flying wing's design might allow for innovative tank placement, potentially making CHG more feasible if the design can accommodate very large tanks without compromising aerodynamics. However, LH2 would generally be the choice for optimizing range and efficiency.

Environmental Impact: Both forms of hydrogen can be produced with zero carbon emissions if sourced from renewable energy, but the efficiency of the entire process from production to use might favor LH2 due to its energy density.

In summary, if maximizing range and fuel efficiency is the goal, liquid hydrogen would likely be the better choice, despite its operational complexities. However, compressed gas could be considered for scenarios where infrastructure simplicity or safety concerns outweigh the range requirements. It could be reasonable to use gaseous hydrogen in our first variants of aircraft, the range is sufficient and industry standards have already achieved these milestones as seen in the hydrogen cars used today.  As the technology expands we can in the near future attain liquid hydrogen, and the range achieved will be quite astronomical.   We strongly feel the real world testing will literally blow peoples minds, with the potential for us to stay aloft for up to 2 weeks... 

cryogenic storage systems

hydrogen fuel cell technology

3.

Range Estimates for the B2N Boomerang with Gaseous Hydrogen vs Liquid Hydrogen

Estimating the range of a flying wing with a 69-foot wingspan using gaseous hydrogen, top-tier solar panels, a generator, and an advanced battery bank involves several speculative assumptions, as there aren't direct historical or operational precedents exactly matching these specifications. However, we can make an educated guess based on existing data and concepts:

Assumptions:

Wingspan: 69 feet (21 meters).

Solar Panels: Assuming the best efficiency solar panels available today (around 22-24% efficiency) covering the entire upper wing surface. This would provide significant daytime power but would be limited in direct solar-to-flight conversion due to energy storage inefficiencies.

Gaseous Hydrogen:

Energy Density: Hydrogen has an energy density of about 120 MJ/kg when burned with oxygen.

Tank Volume: With a larger wingspan allowing for more tank volume, let's assume you can fit tanks that can store around 100 kg of hydrogen (which is quite optimistic considering weight and space constraints).

Generator: An efficient generator to convert hydrogen energy into electricity for propulsion or to charge batteries, with losses considered.

Battery Bank: High-capacity lithium-ion or emerging technologies like solid-state batteries. Let's assume a battery bank capable of storing energy equivalent to what could power the aircraft for a few hours at night or during low solar conditions.

Aerodynamic Efficiency: Flying wings, especially those with solar panels, can have high lift-to-drag ratios, potentially around 20:1 or higher, which is better than conventional aircraft.

Power Consumption: Assuming propulsion requires around 50 kW during cruising (a rough estimate based on similar-sized experimental solar aircraft like Solar Impulse which had much larger spans but lower power requirements due to different design and weight considerations).

Calculations:

Solar Energy: With a wingspan of 69 feet and assuming a wing chord (from front to back) of about 10 feet (for simplicity), you get roughly 690 square feet (64 m²) of solar panel area. At peak solar irradiance (1000 W/m²), with 23% efficiency, this could generate up to 14.7 kW per hour at peak, but realistically, this would be much lower due to daytime/night cycles, panel orientation, and atmospheric conditions.

Hydrogen Energy: 100 kg of hydrogen at 120 MJ/kg gives 12,000 MJ (or 3,333 kWh, considering 1 MJ = 0.277778 kWh).

Battery Storage: Assuming a cutting-edge battery system can store 100 kWh (optimistic for current technology but feasible with future advancements).

Range Estimation:

Solar Alone: Solar energy would likely maintain flight during daylight but not extend range significantly without storage or hydrogen.

Hybrid System:

Daylight: Solar power drives the aircraft, with excess charging batteries or directly supplementing hydrogen use.

Night or Low Solar: Batteries provide power, then hydrogen through the generator.

If we assume 50 kW for propulsion, the 100 kg of hydrogen could theoretically power the aircraft for around 66 hours (3333 kWh / 50 kW), but this would be in ideal conditions, ignoring inefficiencies.

With solar assistance, you might extend this by utilizing solar power during the day, saving hydrogen for nights or low-light conditions.

Battery storage would add a few hours of flight time, depending on usage patterns.

Estimated Range:

Conservative: With inefficiencies, weather, and operational constraints, a range of 2,000 - 3,000 nautical miles might be feasible, assuming optimal conditions and careful management of all energy sources.

Optimistic: If everything is ideally managed, you might push this to 4,000 - 5,000 nautical miles, but this would require perfection in energy harvesting, conversion, and utilization. 

Liquid Hydrogen based on industry testing doubles the range.   If the solar is able to keep the craft aloft during the day, we could potentially achieve a range never even imagined before.  We will find out soon. 

***This estimation is highly speculative due to the unique combination of technologies and the experimental nature of such an aircraft design. Real-world testing would be necessary to get more accurate figures.