THE 2ND LAW OF THERMODYNAMICS REVISITED .1. THE ABSOLUTE-ZERO OF POTENTIAL AND THE GENERAL EXPRESSION FOR THE EFFICIENCY OF UNIVERSAL REVERSIBLE CYCLE

The fundamental equation of thermodynamics expresses the internal ener gy of a system as a function of all the extensive parameters of the sy stem. The differential form of this equation is referred to as the Gib bs equation. We have integrated this equation and have used it to deri ve an expression characterising the efficiency of a system for any kin d of cyclical process by which work is produced. This system has acces s to two reservoirs at low and high thermodynamic potential respective ly. It is claimed that all thermodynamic potentials (temperature, chem ical potential, hydrostatic pressure, electric potential, etc) can hav e an absolute value of zero which we defined as the value of the poten tial in the lower reservoir when the efficiency of the cycle is 1. It is also shown that the classical Carnot machine, in which heat is conv erted into mechanical work, is an example of the general expression.