旋转式室温磁制冷系统的研制及实验研究

In this work, we have developed a new double ring concentric rotating magnet type room temperature magnetic refrigeration system with high efficiency and compact structure as the design focus. The whole machine space size is about 720 mm×440 mm×230 mm. The doublelayer concentric nested Halbach magnet group is adopted, and the magnetic field intensity at the magnet axis is between 0.18 T and 1.72 T. The filling length, filling weight, and diameter of the filling working medium Gd ball of the active magnetic regenerator are 120 mm, 440 g and 0.375∼0.5 mm respectively, and the heat exchange fluid is an alkaline solution with pH=8. Based on this system, we have conducted comparative experiments on the timing strategies of 100%, 80% and 60% of the flow time ratio, respectively. The maximum no-load temperature span of the system reaches 20.2 K, under the working conditions of 80%, 0.84 and 0.35 Hz in the proportion of flow time, utilization factor, and operating frequency, respectively. It is worth noting that when the utilization factor is selected as 1.26 and the operating frequency is 0.35 Hz, the system obtains a large cooling capacity of 60 W and 80 W under different temperature spans of 10.8 K and 5.2 K, respectively.