磁制冷循环与磁工质的选择原则

磁循环和磁工质的选择对于磁制冷的成败与否是至关重要的。本文的主要目的是讨论磁工质所必要的磁学和热学特性以及探讨适合于不同温区的磁循环。文章首先给出了铁磁或顺磁材料的随温度和外场而变化的磁熵的计算结果,以及此类材料的晶格熵随德拜温度而变化的关系。在熵分析的基础上,就可得出磁工质和磁循环的遣择原则。本文还讨论了分别适用于低于20K,20～77 K,近300K三温区的磁工质的选用。最后,文章指出,高效制冷工质和蓄冷器是获得室温磁制冷的关键所在。     

热分离机内的非正常一维流动

分析了热分离机内的不定常流动过程 ,描绘了简化波图 ,指出了影响制冷过程的主要因素     

Experimental Study of Performance of Thermoelectric Refrigerator under Different Intensity of Heat Emission

Heat emission and the voltage are the main factors affecting the refrigerating capacity of semicon-ductor refrigerator.Some experiments were designed to obtain their influence on refrigerating capacity of semi-conductor and the interaction between heat emission and the voltage.The results shoW that fixing the heat dissi-pation,there is an optimal working voltage for the semiconductor module;and if improving the heat emission,the refrigerating capacity increases and the optimal voltage becomes larger.This can provide the basis for the op-fimal design of semiconductor refrigeration.     

Evaporative Condensers in Comfortable Air Conditioning System

The operating theory of an evaporative condenser was expatiated.The difference between an e-vaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative con-densers were analyzed.Some questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative con-densing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.