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In 2024, Australian company Hysata announced a device capable of 95% efficiency relative to the higher heating value of hydrogen. Conventional systems consume 52.5 kWh to produce hydrogen that can store 39.4 kWh of energy (1 kg). Its technology requires only 41.5 kWh to produce 1 kg.
Liquid hydrogen also has a much higher specific energy than gasoline, natural gas, or diesel. [12] The density of liquid hydrogen is only 70.85 kg/m 3 (at 20 K), a relative density of just 0.07. Although the specific energy is more than twice that of other fuels, this gives it a remarkably low volumetric energy density, many fold lower.
The specific heat capacities of iron, granite, and hydrogen gas are about 449 J⋅kg −1 ⋅K −1, 790 J⋅kg −1 ⋅K −1, and 14300 J⋅kg −1 ⋅K −1, respectively. [4] While the substance is undergoing a phase transition , such as melting or boiling, its specific heat capacity is technically undefined, because the heat goes into ...
1.80 [16] 1.26: battery, Fluoride-ion [citation needed] 1.7: 2.8: battery, Hydrogen closed cycle H fuel cell [17] 1.62: Hydrazine decomposition (as monopropellant) 1.6: 1.6: Ammonium nitrate decomposition (as monopropellant) 1.4: 2.5: Thermal Energy Capacity of Molten Salt: 1 [citation needed] 98% [18] Molecular spring approximate [citation ...
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera). [13]
For hydrogen, the difference is much more significant as it includes the sensible heat of water vapor between 150 °C and 100 °C, the latent heat of condensation at 100 °C, and the sensible heat of the condensed water between 100 °C and 25 °C. In all, the higher heating value of hydrogen is 18.2% above its lower heating value (142 MJ/kg vs ...
Data from same reference as for liquid hydrogen. [21] High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of the total mass, [22] giving just 6.8 MJ per kg total mass for the LHV. See note above about use in fuel cells. Hydrogen, gas (1 atm or 101.3 kPa, 25 °C) 141.86 (HHV) 119.93 (LHV) 0.011 88 ...
On the other hand, the molecules in liquid water are held together by relatively strong hydrogen bonds, and its enthalpy of vaporization, 40.65 kJ/mol, is more than five times the energy required to heat the same quantity of water from 0 °C to 100 °C (c p = 75.3 J/K·mol).