Thermal Device Beyond the Carnot Limit

Based on the Carnot cycle, we construct a theoretical heat engine working through the agency of the generalized polytropic gas. A heat engine described by using a thermodynamic equation-of-state defines a thermodynamical relation among state quantities such as internal energy U, volume V, entropy S, temperature T and heat capacity C. Investigating the thermal efficiency of the constructed heat engine shows that more efficient heat engine is obtained from the Carnot heat engine when the pressure of the working material takes certain values.