4.3热能专业英语

4.3Refrigeration 制冷

Refrigeration was used by ancient civilizations when it was naturally available. The Roman rulers had slaves transport ice and snow from the high mountains to be used to preserve foods and to provide cool beverages in hot weather. Such natural sources of refrigeration were, of course, extremely limited in terms of location, temperatures, and scope. Means of producing refrigeration with machinery, called mechanical refrigeration, began to be developed in the 1850s. Today the refrigeration industry is a vast and essential part of any technological society, with yearly sales of equipment amounting to billions of dollars in the United States alone. 当能自然地制冷时，曾为古代文明所利用。罗马统治者让奴隶们从高山上搬运冰、雪，用来保存食物，并在暑热时提供冷饮。当然，这种制冷的自然资源就地点、气温和范围而言是极其有限的。使用机械产生冷量的方式称作机械制冷，是19世纪20年代开始发展起来的。当今，制冷工业是任何技术社会的庞大而重要的一部分，仅在美国设备年销售额就达到数十亿美元。Uses of Refrigeration

It is convenient to classify the applications of refrigeration into the following categories: domestic, commercial, industrial, and air conditioning. Sometimes transportation is listed as a separate category. Domestic refrigeration is used for food preparation and preservation, ice making, and cooling beverages in the household. Commercial refrigeration is used in retail stores, restaurants, and institutions, for purposes the same as those in the household. Industrial refrigeration in the food industry is needed in processing, preparation, and largescale preservation. This includes use in food chilling and freezing plants, cold storage warehouses, breweries, and dairies, to name a few. Hundreds of other industries use refrigeration; among them are ice making plants, oil refineries, pharmaceuticals. Of course ice skating rinks need refrigeration.

Refrigeration is also widely used in both comfort air conditioning for people and in industrial air conditioning. Industrial air conditioning is used to create the air temperatures, humidity, and cleanliness required for manufacturing processes. Computers require a controlled environment. 1．制冷的用途

制冷的用途可以简便的分为下列几类：家用、商用、工业用和空气调节。有时，运输被单独列为一类。家用制冷用于家庭的食物制备和保存，制冰和冰镇饮料。商业制冷多用在零售店、餐厅和公共机关，与家用制冷目的一样。食品工业中的工业制冷用语食品加工与制备，以及大规模的保存。略举几项，它包括在食品冷藏冷冻厂、冷藏库、酿酒厂和乳制品厂中的应用。成百上千的其他工业也使用制冷，其中有制冰厂、炼油厂、制药厂。当然滑冰厂需要制冷。Methods of Refrigeration

Refrigeration, commonly spoken of as a cooling process is more correctly defined as the removal of heat from a substance to bring it to or keep it at a desirable low temperature, below the temperature of the surroundings. The most widespread method of producing mechanical refrigeration is called the vapor compression system. In this system a volatile liquid refrigerant is evaporated in an evaporator; this process results in a removal of heat (cooling) from the substance to be cooled. A compressor and condenser are required to maintain the evaporation process and to recover the refrigerant for reuse.

2. 制冷的方法

制冷，通常所说的冷却过程，可更加正确地定义为“从一物质中排除热量，使其达到或保持在一理想的低温状态，低于周围环境的温度。”传播最为广泛的机械制冷的方法称为蒸汽压缩系统。在此系统中，易发挥的液态制冷剂在一个蒸发器内蒸发，其结果是使用热量从被冷却物质排出（冷却）。为了维持蒸发过程和使制冷剂复员再用，需设置压缩机和冷凝器。