Fundamental performance optimization of an irreversible quantum spin 1/2 Brayton refrigerator

This paper takes a quantum spin-1/2 Brayton refrigerator as research object. At high temperature limit, optimal fundamental relation (cooling load versus COP characteristics) is obtained by using numerical calculations, and influences of quantum friction, external magnetic field, heat leakage and time of adiabatic process on the fundamental performance are also analyzed. The results display that both cooling load and COP have maxima. The quantum friction changes the optimal fundamental relation quantitatively and qualitatively as well as the heat leakage. As the time of adiabatic process decreases, the quantum friction increases and that makes both cooling load and COP decrease.