制冷原理双语版第十一章

Chapter 11 Condensing Equipment

第11章冷凝设备

11-1 Function and Classification of Condensers 李增扬11-1 冷凝器的作用和分类

1. Function of Condensers

1. 冷凝器的功能

A condenser is a heat exchanger which condenses a refrigerant from its vapor to its liquid state. In so doing, the latent heat is given up by the refrigerant and will transfer to the condensing medium. The condenser is one of the principal components in a vapor compression refrigeration system.

冷凝器是将制冷剂从蒸气冷凝到液体状态的换热器。这样，制冷剂释放潜热，热量被冷凝媒介带走。在蒸气压缩制冷系统中冷凝器是一个主要的设备。

As shown in Fig.11-1, the purpose of the condenser is to remove heat from the refrigerant vapor leaving the compressor, so that the refrigerant will condense to its liquid state at the condensing pressure. Liquid refrigerant is often subcooled the condensing process.

如图11-1所示，冷凝器的目的是将离开压缩机的制冷剂蒸气热量移走，所以制冷剂在冷凝压力下将被冷凝到液体状态。在冷凝过程中，液体制冷剂被冷却到过冷。

The heat-transfer process in a condenser occurs in three stages as implicated in Fig.11-1.

在冷凝器中发生的传热过程发生在图11-1所包含的三部分。

1)Desuperheating of the hot vapor.

1)热蒸气的过热降低

2)Condensing of the vapor to liquid state and release of the latent heat.

2) 蒸气被冷凝为液体并放出潜热。

3)Subcooling of the liquid refrigerant.

3) 液体制冷剂过冷

Though the surface heat-transfer coefficient is lower on the hot vapor side during desuperheating of the vapor, it does not affect too much to the heat transfer as there is a greater temperature difference between the vapor and the cooling medium. The subcooling only takes place in a small portion of the condenser’s surface area. Therefore, for simplification, an average heat-transfer coefficient is used for the whole condenser’s surface area, and the condensation of refrigerant is assumed to occur at the condensing temperature.

虽然在热蒸气过热降低的过程中，蒸气侧的表面换热系数很低，但由于热制冷剂蒸气与冷凝媒介间的温差很大，所以它的影响并不大。在冷凝器表面，过冷值占了很少的一部分区域。因此，为了简化，整个冷凝器表面都用假定的平均换热系数，并且假定制冷剂在冷凝温度下液化。

2. Classification of Condensers

2. 冷凝器的分类

Based on the diverse applications, condensers are manufactured in a wide variety of types, shapes, and sizes. Condensers can be classified in a number of ways according to their structure, condensing medium and arrangement of air flow, etc. Fig.11-2 lists the ways of classification for condensers.

对于不同的应用，冷凝器加工为各种不同的形式，形状和大小。根据冷凝器的结构，冷凝方式和气流布置等许多方式可以将冷凝器分为许多不同类型。图11-12列出了冷凝器的分类。

Although brine or direct expansion refrigerants are sometimes used as condensing medium in low temperature applications, great majority of the cooling medium employed for condensers is either air or water, or a combination of them.

虽然在低温应用时，盐水或直接蒸发制冷有时也用做冷却介质，但大部分冷却介质还是用空气或水，或它们的混合。

Fig.11-2 Classification of condensers [1]

图11-2 冷凝器分类