Chapter 7: Properties of Gas Mixtures: Moist Air

Air is a very common fluid in engineering thermodynamics. Its composition can be assumed invariable for most processes. Therefore, for practical reasons, air is usually treated as a single substance. However, for air-conditioning processes, atmospheric air has to be considered as a gas–water–vapor mixture. As long as no condensation occurs, both these constituents can be considered ideal gases. It is, therefore necessary to have some way of deducing the properties of the mixture from those of its constituents.