Abstract The general performance characteristics of an irreversible quantum refrigeration cycle using many non-interacting spin-1/2 systems as the working substance and consisting of two adiabatic and two isomagnetic field processes are investigated, based on the quantum master equation and semi-group approach. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to the finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of the temperatures of the working substance and the times spent on the two isomagnetic field processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is also analysed in detail. The results obtained here are further generalized, so that they may be directly used to describe the performance of the quantum refrigeration cycle using spin-J systems as the working substance.
Received: 22 July 2004
Revised: 20 September 2004
Accepted manuscript online:
PACS:
07.20.Mc
(Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment)
Fund: Project supported jointly by the Key Project Foundation of Science and Technology Research of Ministry of Education of China and by the Science and Technology Programme (Grant No JA03153) of Fujian's Education Department of China.
Cite this article:
Lin Bi-Hong (林比宏), Chen Jin-Can (陈金灿) Parametric optimum design of an irreversible spin quantum refrigeration cycle 2005 Chinese Physics 14 293
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