When comparing the weight of hydrogen to jet fuel, hydrogen is significantly lighter per unit of energy; meaning, for the same amount of energy, hydrogen would weigh considerably less than jet fuel, with a weight factor roughly around 3 times lighter than jet fuel; however, due to its low density, storing enough hydrogen for an aircraft would require much larger tanks, impacting the overall weight of the aircraft.
Key points about the weight factor of hydrogen vs jet fuel:
- Higher energy density per mass:
Hydrogen has a much higher energy density per unit mass compared to jet fuel, meaning less hydrogen is needed to produce the same amount of energy.
- Lower volumetric density:
Despite its high energy density per mass, hydrogen has a much lower volumetric density, meaning it takes up significantly more space than jet fuel for the same amount of energy.
- Impact on aircraft design:
The need for larger hydrogen storage tanks due to its low density can significantly increase the weight of an aircraft, even though the fuel itself is
To store hydrogen gas in less space, “Type III” and “Type IV” hydrogen tanks are used, which are made with composite materials like carbon fiber and have a much higher storage density compared to traditional metal tanks, allowing for smaller and lighter cylinders to store the same amount of hydrogen at high pressure; essentially taking up less space in a vehicle or application.
Key points about space-efficient hydrogen tanks:
These tanks utilize carbon fiber wrapped around a metallic liner, providing high strength while maintaining a lightweight design.
While both are considered space-efficient, Type IV tanks typically have a slightly higher storage density due to using a polymer liner instead of a metal one, making them even more compact.
To maximize hydrogen density, these tanks operate at very high pressures, usually around 700 bar (10,000 psi)
To achieve the same energy content as one unit of jet fuel, you would need roughly three times the volume of hydrogen compressed at 700 bar due to hydrogen’s significantly lower energy density per unit volume compared to jet fuel; meaning, a 700 bar hydrogen tank would need to be about three times larger than a jet fuel tank to store the same amount of energy.
Key points to remember:
Hydrogen has a much lower energy density than jet fuel, even when compressed to high pressures like 700 bar.
To match the energy of a given volume of jet fuel, you would need a much larger volume of hydrogen at 700 bar.
- Liquefaction for higher density:
To further increase hydrogen’s energy density, it can be liquefied, but this requires additional energy and complex infrastructure.
Yes, when storing hydrogen at 700 bar pressure, commercial jets would likely need to be larger due to the significantly larger tank volume required to store the same amount of energy compared to traditional jet fuel, even though the high pressure increases hydrogen’s density considerably; this is because hydrogen still has a much lower energy density per unit volume than jet fuel, meaning more space is needed to store the equivalent energy.
Key points to consider:
Hydrogen has a much lower energy density than jet fuel, meaning a larger volume of hydrogen is needed to produce the same amount of energy.
Compressing hydrogen to 700 bar significantly increases its density, but it still requires a larger tank volume compared to jet fuel.
- Impact on aircraft design:
To store enough hydrogen for a long-range flight at 700 bar, aircraft designs would likely need to incorporate larger fuel tanks, potentially requiring a larger fuselage or modifications to the wing structure.
Alternative approaches:
Storing hydrogen as a liquid could potentially reduce the tank volume needed, but requires additional cryogenic systems to maintain the low temperature.
Developing new aircraft designs like blended-wing body configurations could potentially better integrate large hydrogen tanks while minimizing the overall aircraft size increase.
