Lesson13MarineRefrigeration剖析.docVIP

Lesson 13 Marine Refrigeration 第13课 船舶制冷 1. Refrigeration is a process in which the temperature of a space or its contents is reduced to below that of their surroundings. Marine refrigeration employs a system of components to remove heat from the space being cooled. This heat is transferred to another body at a lower temperature. The cooling of air for air conditioning entails a similar process. The usual system employed for marine refrigeration plants is the vapor compression cycle. 制冷就是将某个空间或其内物品的温度降至环境温度以下。船舶制冷利用一系列组件将热量从被冷却空间移出。这部分热量被传递给另一低温物体。空调对空气的冷却过程与此类似。船舶制冷装置通常采用的是蒸汽压缩循环系统。 2. The basic components of any refrigeration system working on the vapor compression cycle, are the compressor, condenser, expansion valve, and evaporator or cooling coils. The refrigeration fluid, also known as refrigerant, is alternately vaporized and liquefied during the refrigeration cycle. The temperature at which a fluid boils or condenses, is known as the saturation temperature and varies with pressure. The compressor in a refrigeration system in raising the pressure of the vaporized refrigerant, causes its saturation temperature to rise, so that it is higher than that of the sea water used for cooling the condenser. The compressor also promotes circulation of the refrigerant by pumping it around the system. 压缩制冷系统的主要部件是压缩机、冷凝器、膨胀阀及蒸发器或冷却盘管(见图13-1)制冷液，即制冷剂，在制冷循环过程中交替蒸发和液化。流体沸腾或冷凝的温度称为“饱和温度”，此温度随着压力的变化而变化。制冷系统的压缩机用来使汽化的制冷剂压力升高，使其饱和温度高于用来冷却冷凝器的海水的温度。压缩机的另一个作用是通过泵送制冷剂(从蒸发盘管中抽出，压送到冷凝器)，促进制冷剂在系统中的循环。 3. In the condenser, the refrigerant is liquefied by circulating sea water (or air for domestic refrigerators). Latent heat, originally from the evaporator, is thus transferred to the cooling medium. The liquid refrigerant, still at the pressure produced by the compressor, passes t o the receiver and then t o the expansion valve. 在冷凝器中，制冷剂被循环的海水液化(在家用冰箱中由空气液化)。最初在蒸发器中吸收的潜热被放出，传递给冷却介质。保持着压缩机出口压力的液态制冷剂流至储液器，进而流至膨胀阀。 4. The expansion valve is the regulator through which the refrigerant flows