1. Diagram of wet mixtures (gas-water vapor mixtures)

A number of gases used in power engineering are mixtures whose composition may change as a result of condensation or vaporization of one of their components. In practice, the component that changes state is most often water, which is why particular attention is paid in this article to mixtures of gas and water vapor, hereinafter referred to as wet mixtures.

Dry air in particular is virtually unheard of: it almost always contains water, in gaseous or liquid form, or in the form of ice crystals. Controlling air humidity determines the comfort of a room, as well as the preservation of food and many other products. This is achieved by means of air-conditioning techniques such as the one described below, by way of example.

In this section, after the physical phenomena involved, the principles for calculating the thermodynamic properties of wet...