Influence of the flow rate waveform and mass imbalance on the performance of active magnetic regenerators. Part II: Numerical simulation

In this part of the paper, an existing regenerator model was extended to predict the experimental data generated in Part I on the influence of the blow time fraction on the performance of a Gd packed bed AMR. The effect of mass imbalance between the hot and cold blows was evaluated numerically, and a significant improvement of the model predictions was obtained when the numerical and experimental mass imbalance set points were equal. A numerical assessment of the system performance beyond the conditions of Part I indicated optimal utilization factors and blow time fractions for temperature spans of 10 and 20 K, and operating frequencies of 0.25 and 0.5 Hz. For an operating point specified by fixed values of cooling capacity (20 W), temperature span (10 K) and frequency (0.5 Hz), the maximum COP was generated for a blow time fraction of 31% and a utilization factor of approximately 0.6.