Enthalpy of vaporisation latent heat

The latent heats of vaporisation of the more commonly used materials can be found in the handbooks and in Appendix C. 

A very rough estimate can be obtained from Trouton s rule (Trouton, 1884), one of the oldest prediction methods. 

More accurate estimates, suitable for most engineering purposes, can be made from a knowledge of the vapour pressure-temperature relationship for the substance. Several correlations have been proposed see Reid et al. (1987). 

The equation presented here, due to Haggenmacher (1946), is derived from the Antoine vapour pressure equation (see Section 8.11). 

Az = Zgas - znqUid (where z is the compressibility constant), calculated 

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