制冷与空调专业英语第2版 林慧珠 主编 4-4新.pptVIP

Unit Four Lesson 13 Thermodynamic Principles of Refrigeration Lesson 14 Mechanical Refrigeration Principles Lesson 15 Evaporation Lesson 16 Condensation Lesson 16 Condensation Text The refrigerant, upon leaving the compressor as a surperheated gas, enters a condenser through the discharge line. The purpose of the condenser is to provide a means by which the vapor may eject the heat absorbed during its passage through the evaporator, as well as the heat of compression, and reconvert it to a liquid. 1 Text: The condenser is an arrangement of pipes or tubes, possessing high heat conduction properties. These pipes of tubes are exposed to a continuous flow of cooling medium, usually water or air, which absorbs the heat from the refrigerant. Text: Connected to the outlet of the condenser, and in some systems forming an integral part of the condenser itself, is a tank or reservoir known as liquid receiver. The purpose of the latter is to receive the liquid refrigerant upon condensing and to hold it until such time as it is required by the evaporator. 2 The liquid receiver should be large enough to hold the entire refrigerant of the system in a liquid state. Text: The compressor, the condenser, and the liquid receiver combination is referred to as the condensing unit because it requires the services of all three of these pieces of equipment to complete the function of the high-pressure side of a vapor compression system. Text: The function of the condenser is to convert the superheated gas to its liquid form.It is a heat exchanger involving the principle of temperature differential. It extracts from the vapor the latent heat of vaporization and the sensible heat obsorbed by the refgerant in the evaporator, plus the superheat resulting from compression. 3 This results in transforming the vapor to a liquid at the boiling-point