Laws of Thermodynamics

0^th Law of Thermodynamics—if body A is in thermal equilibrium with body T, and so it body B, then A and B are in thermal equilibrium.

1^st Law of Thermodynamics—a measure of heat transferred into a system will result in an increase in temperature and in the system’s ability to do work. In other words, energy is conserved property that is neither created nor destroyed but, may change form and travel from place to place. Or, in terms of an internal combustion engine in an automobile, the first law describes the underlying principle of what occurs in the cylinder.

Other forms of the First Law…

2^nd Law of Thermodynamics—only in transferring heat from a warmer body to a cooler body can heat be converted into work, in a cyclical process. A cyclic process is a series of operations by which the state of the substance (working substance) changes but the substance is finally returned to its original state in all respects. In other words, heat is always transferred from regions of high temperature to regions of low temperature. Heat can be transferred by three processes…

1.    Conduction—the movement of heat through a substance without appreciable movement of the molecules.

2.    Convection—the transfer of heat by mixing of a fluid.

3.    Radiation—the transfer of energy by radiation that can occur through empty space.

Forms of the Second Law, considering the Carnot Cycle…

3^rd Law of Thermodynamics—there is no finite series of steps that can get you to absolute zero. In other words, since absolute zero cannot be reached an engine cannot be perfectly efficient.

Conclusion—heat can be converted into work, in a cyclic process, but can only be perfectly efficient at absolute zero, which is unattainable.