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liquifying hydrogen

liquifying hydrogen

liquifying hydrogen

I have used a table showing the ideal gas properties of hydrogen to find how much energy per KG of hydrogen needs to be done on hydrogen to liquify it. without considering heat of vapouration I get 3929 KJ/ Kg. heat of vapourisation is 445.7 KJ/Kg, Is this correct?

RE: liquifying hydrogen

It appears that your assumption is correct.

The larger of the two values is the enthalpy difference between the supercritical gas at ambient temperature and pressure, and the liquid at 20 K and at the same pressure.

The latent heat of vaporization at 20 K is, as you say, about 445 kJ/kg.

In short, cooling the gas from ambient conditions to 20 K would need 3484 kJ/kg. For condensing it, one would need additional 445 kJ/kg, totalling 3929 kJ/kg. Do you agree ?  

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