Properties of Ideal Quantum Solids

Y. Nagaoka

doi:10.1143/ptp.69.335

Properties of Ideal Quantum Solids

Progress of Theoretical Physics Supplement ◽

10.1143/ptps.69.335 ◽

1980 ◽

Vol 69 ◽

pp. 335-341 ◽

Cited By ~ 1

Author(s):

Yosuke Nagaoka

Keyword(s):

Quantum Solids ◽

Ideal Quantum

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Performance Analysis and Optimization for Irreversible Combined Carnot Heat Engine Working with Ideal Quantum Gases

Entropy ◽

10.3390/e23050536 ◽

2021 ◽

Vol 23 (5) ◽

pp. 536

Author(s):

Lingen Chen ◽

Zewei Meng ◽

Yanlin Ge ◽

Feng Wu

Keyword(s):

Power Output ◽

Thermal Efficiency ◽

Combined Cycle ◽

Quantum Gases ◽

Carnot Cycle ◽

Leakage Loss ◽

Optimal Power ◽

Heat Leakage ◽

Working Medium ◽

Ideal Quantum

An irreversible combined Carnot cycle model using ideal quantum gases as a working medium was studied by using finite-time thermodynamics. The combined cycle consisted of two Carnot sub-cycles in a cascade mode. Considering thermal resistance, internal irreversibility, and heat leakage losses, the power output and thermal efficiency of the irreversible combined Carnot cycle were derived by utilizing the quantum gas state equation. The temperature effect of the working medium on power output and thermal efficiency is analyzed by numerical method, the optimal relationship between power output and thermal efficiency is solved by the Euler-Lagrange equation, and the effects of different working mediums on the optimal power and thermal efficiency performance are also focused. The results show that there is a set of working medium temperatures that makes the power output of the combined cycle be maximum. When there is no heat leakage loss in the combined cycle, all the characteristic curves of optimal power versus thermal efficiency are parabolic-like ones, and the internal irreversibility makes both power output and efficiency decrease. When there is heat leakage loss in the combined cycle, all the characteristic curves of optimal power versus thermal efficiency are loop-shaped ones, and the heat leakage loss only affects the thermal efficiency of the combined Carnot cycle. Comparing the power output of combined heat engines with four types of working mediums, the two-stage combined Carnot cycle using ideal Fermi-Bose gas as working medium obtains the highest power output.

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