Variable load control strategy for room-temperature magnetocaloric cooling applications

Room temperature magnetocaloric cooling is more environmental friendly but not yet more energy efficient than the state-of-the-art vapor compression technology. In this paper, we provide one more argument to support magnetic cooling technology, which is the superior energy saving potential under part load conditions. Therefore, magnetic cooling system may not compete with vapor compression under full load nominal condition, but its seasonal or annual overall efficiency could be better when part load characteristics are taken into account. To show the operation feasibility under part load condition, a feedback control strategy is proposed and incorporated into a magnetic cooling system model in Simulink first. The robust control quality is then revealed by numerical simulation studies for five different variable part load profiles. Furthermore, the transient accumulated energy performances are compared with those estimated based on the quasi-steady state condition to simplify the calculation on the overall energy efficiency benefit. Finally, a case study is carried out for unitary air-conditioning application, revealing that the overall energy efficiency is almost twice of the energy efficiency evaluated under full load condition.