Thermomechanical Dynamics (TMD) Applied to the Physical Concepts of the Zeroth Law and the Third Law of Thermodynamics

The zeroth law of thermodynamics, the Nernst-Simon and Planck statements of the third law of thermodynamics and the unattainability statement of the absolute temperature, T = 0, are discussed by thermomechanical dynamics (TMD) which is a classical theory of thermodynamics extended to study thermal transitions from thermodynamic equilibrium to nonequilibrium irreversible states (NISs). The method of TMD has been successfully applied to mechanisms of heat engines (a drinking bird, a low temperature Stirling engine and thermoelectric energy conversion technologies). The TMD is applied to the thermal phase transitions from thermodynamic equilibrium to NISs, and dissipative equations of motion for phase transition mechanism of heat engines in general are studied. The results are thermodynamically consistent and have produced new technical applications on a thermoelectric power-conversion method and devices for sustainable environmental goals. The method of TMD is applied to understand consistent thermodynamic concepts of the zeroth and the third law of thermodynamics and the unattainability statement, T = 0. The analyses help extend thermodynamics to NISs.