Performance Simulation of the Active Magnetic Regenerator under a Pulsed Magnetic Field

Abstract

Magnetic refrigeration is acknowledged as a potential substitute for the conventional vapor-compression refrigeration technology, owing to its high efficiency and environmental friendliness. Existing magnetic refrigeration systems are mostly based on permanent magnets, owing to the characteristics of lower magnetic field intensity, non-uniform magnetic field distribution, and lower operating frequency due to the moving parts, which results in a low cooling capacity and small temperature difference. Thus, this study proposes the application of a pulsed magnetic field, with a high intensity and frequency, to a magnetic refrigeration system to achieve a high performance. A verified numerical model is established to investigate the thermodynamic cycle and cooling performance of an active magnetic regenerator (AMR). The transient and steady-state performances of AMR under pulsed and permanent magnetic fields are compared. The results suggest that an AMR can establish a stable temperature difference under a pulsed magnetic field that is 40 times faster than that under a permanent magnetic field. The maximum steady-state cooling capacity under a pulsed magnetic field is 2.5 times that under a permanent magnetic field when the temperature difference is 20 K. Additionally, the effects of pulsed magnetic field waveforms, frequency, and intensity on the performance of AMR are investigated under various utilization factors. These results can guide the improvement of room-temperature magnetic refrigerators.