Conference Year



psychrometric properties, humid air, thermodynamics


Psychrometric properties of humid air are widely used in the analysis and modeling of thermal systems. In this work we present a method for obtaining these properties from the multi-fluid mixture formulation of the GERG mixture model. This mixture model was originally developed to model the thermodynamics of natural gas mixtures, and now has been extended to model thermodynamic properties relevant for carbon capture and storage. The primary advantage of this formulation is that the dry air composition is not fixed, and can be adjusted to suit the application, for instance in submarines, for Martian atmospheres, etc. We present an algorithm that can be used to calculate the saturated vapor water composition in vapor-liquid equilibrium, and other properties that arise out of this equilibrium calculation, such as relative humidity and dewpoints. Solid-vapor equilibrium is not considered, and neither is the calculation of wet-bulb temperatures.