Performance of quantum Otto refrigerators with squeezing

Rui Long and Wei Liu
Phys. Rev. E 91, 062137 – Published 25 June 2015

Abstract

The performance of a quantum Otto refrigerator coupled to a squeezed cold reservoir has been evaluated using the χ figure of merit. We have shown that squeezing can enhance the coefficient of performance (COP) dramatically, surpassing the Carnot COP defined by the initial temperatures of the heat baths. Furthermore, when the squeezing parameter approaches its maximum value, the work input vanishes while the cooling rate remains finite, in apparent contravention of the second law of thermodynamics. To explain this phenomenon, we have shown that squeezing renders the thermal bath into a nonequilibrium state and the temperature of the bath becomes frequency dependent. Thereby, a correlation to the Carnot COP has been deduced. The results reveal that the COP under the maximum χ figure of merit is of the Curzon-Ahlborn style that cannot surpass the actual Carnot COP, and is thus consistent with the second law of thermodynamics.

  • Figure
  • Figure
  • Received 11 December 2014
  • Revised 8 May 2015

DOI:https://doi.org/10.1103/PhysRevE.91.062137

©2015 American Physical Society

Authors & Affiliations

Rui Long and Wei Liu*

  • School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China

  • *Corresponding author: w_liu@hust.edu.cn

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Issue

Vol. 91, Iss. 6 — June 2015

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