Analysis of a quantum irreversible Otto cycle with exergetic sustainable index

• An irreversible quantum Otto cycle with -1/2 spin system is considered.
• Exergetic sustainability index is derived for quantum Brayton cycle.
• Calculation are conducted for irreversible cycles.
• Numerical results are presented and discussed.

In this study, exergetic sustainability index is applied to quantum irreversible Otto cycle with -1/2 spin system. Exergetic sustainability index in a quantum engine is used first time. This index is the ratio of exergy output (work output for a thermal engine) to total exergetic losses. It gives an opportunity to evaluate for all thermodynamic losses in the system, that is why, it is an important index. In addition, some thermodynamic parameters (work output, exergy destruction, first and second law efficiencies) are considered and their relationships between the exergetic sustainability index are determined.