A. ŞİŞMAN and H. SAYGIN, “*On The Power Cycles Working with The Ideal Quantum Gases: I The Ericson Cycle*”, **Journal of Physics** D: **Applied Physics**, Vol. 32, No. 6, pp. 664-670 (**1999**).

In classical thermodynamics, expressions for heat, work and thermal efﬁciency of gas power cycles are mostly derived by using the classical ideal gas equation of state [1–3]. On the other hand, under sufﬁciently low-temperature or high-density (or pressure) conditions, an ideal gas deviates from classical gas behaviour since quantum mechanical degeneracy becomes important [4–6]. Therefore, the ideal gas equation of state should be corrected to take into account this degeneracy of the gas. In order that the expressions for heat, work and efﬁciency of the gas power cycles can be valid even under conditions of degeneracy of the gas, these expressions should be derived using the corrected equation of state instead of the classical one.