A comparison of ideal and real moist air models for calculating humidity ratio and relative humidity in the 213.15 to 473.15 K range and up to a pressure of 1 MPa

This study evaluates how the ideal mixture model of moist air approximates a real mixture model when determining both humidity ratio and relative humidity for the 0.1- to 1-MPa pressure range and the -60 to 200°C temperature range. The relevant thermodynamic properties are calculated using, among others, a specific algorithm based on the relationships proposed by Hyland and Wexler corrected for the new ITS-90 temperature scale.