Thermodynamics is the science and technology that deals with certain laws those govern the transformation of energy from one form to another. The name thermodynamics is derived from Greek words thermo and dynam-ics meaning heat and mechanical power respectively.

The conceptions of thermodynamics are more or less idealistic. As an engineer we are always interested for bulk phenomena. Hence macro level conceptions are usual for an engineer.

Classification of Thermodynamics

Thermodynamics is applied to every wake of life. There is hardly any stream in science and technology which does not follow the laws of thermodynamics. A broad classification of the subject is shown in Table 1.1

Table 1.1 Classification of thermodynamics

Classical thermodynamics is an experimental science which deals with macroscopic or large scale properties of matter. General relations of parameters or quantities such as coeficients of expansion, compressibility, specific heat capacities, heats of transformation, magnetic and dielectric cofficients, etc can be established with the help of classical thermodynamics. Unfortunately, acutal magnitude of such quatities can not be estimated with the help of classical thermodynamics.

Kinetic theory of matter helps in estimating numerical value of the individual quantites. This class of thermodynamics deals with molecular model in which individual molecules follow the laws of mechanics.

Statistical thermodynamics ignores the detailed consideration of molecules as individuals and applies statistical considerations to find the distribution of the very large number of molecules that make up a macroscopic piece of matter over the energy states of matter.

It is worth mentioning that these theories are applicable under equilibrium conditions.

Irreversible thermodynamics is another branch of thermodynamics dealing with non-equilibrium, irreversible processes.