Basics, Zeroth and First Law

simply an expression of the conservation of energy. It states that energy is a thermodynamic property. But, the second law of thermodynamics shows that the actual processes occur in the direction of decreasing quality of energy. Therefore, it states that the energy has both quantity as well as quality. For example, a cup of hot water left on a table eventually cools but a cup of cold water in the same room never gets hot by itself. The high-temperature energy of the hot water is degraded once it is transferred to the surrounding air.

Thermodynamics is a field of science which deals the:

(a) energies possessed by gases and vapours

(b) interaction of a system and its surroundings

(c) conversion of energies in terms of heat and mechanical work and

(d) relationship between properties of the system.

But, thermal engineering deals the applications of thermodynamics and its laws relative to the work absorbing and producing devices and also improvement in their performance.