Heating load and cop optimization of an irreversible quantum brayton heat pump working with spin-1/2 systems

Abstract

By considering quantum friction, heat resistance and heat leakage, this paper establishes a quantum Brayton heat pump model. The working substance is a two-level spin-1/2 system, and the cycle has four branches: two adiabatic branches and two isomagnetic branches. By using quantum thermodynamics and quantum master equation, this paper obtains heating load and COP of the pump. By using Euler-Lagrange method, this paper optimizes heating load and COP performance for two cases: the general case and the case at high temperature limit. Influences of quantum friction, duration of adiabatic process and heat leakage on the performance are further analyzed.