新型MnFe基复合磁热材料及其在回热制冷循环中的性能特性

A Novel MnFe-based Composite Magnetocaloric Material and its PerformanceCharacteristics in Regenerative Refrigeration Cycles

基于三种MnFe基磁热材料的热容及等温磁熵变随温度变化的实验数据,本文应用热力学理论设计一种新型MnFe基复合磁热材料,获得三种组分磁热材料与复合材料的优化摩尔质量比,进一步以该复合磁热材料为工质构建回热式Ericsson和Brayton制冷循环,基于热力学分析和数值计算,比较这两种制冷循环的非平衡回热量、净制冷量及性能系数等重要热力学参量,同时将复合材料的相关结果与单组分磁热材料的加以对比,结果表明:复合材料的大磁熵变温区要比任何一种组分材料的宽得多,而以复合材料为工质的制冷循环的净制冷量在近15 K温区内都较大,所得结果能为室温磁制冷机的参数优化设计提供有益的参考。

Based on the thermodynamic theory and the experimental data of heat capacity andisothermal magnetic entropy change versus temperature curves of three kinds of MnFe-based magnetocaloricmaterials, a novel MnFe-based composite magnetocaloric material is designed in this paper,and the optimal molar mass ratios of three kinds of component materials to composite material areobtained. A new model of regenerative Ericsson or Brayton refrigeration cycle using the compositeas the working substance is established. Through thermodynamic analysis and numerical calculation,the main thermodynamic performances, such as the cooling quantity, net cooling quantityand coefficient of performance (COP) of the regeneration Ericsson and Brayton refrigeration cyclesare calculated and compared. Simultaneously, we also compared the performance characteristics ofthe regeneration Ericsson refrigeration cycles using the component materials or the composite asthe working substance. The results show that the temperature range with large magnetic entropychange for the composite is much wider than those for any other component materials, and the bignet cooling quantity of the refrigeration cycle with the composite can keep in near 15 K temperaturerange. The results can provide significant reference for the parameter optimization design of roomtemperature magnetic refrigerator.