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1、制冷与空调专业英语第1页，本讲稿共17页Lesson 13 Thermodynamic Principles of RefrigerationNew Words&ExpressionsTextNotes to the TextExercise第2页，本讲稿共17页New Words&ExpressionsLesson 13(使)循环,流通 principle of operation工作原理,操作原理refrigeration n.冷藏,致冷,冷却refrigerant n.制冷剂certain adj.;pron.确定的,必然的,/某些equivalent n.等(当)量heat equiv
2、alent of work热功当量gather vt.聚集,吸引substance n.物质,实质,主旨circulate vi.;vt.第3页，本讲稿共17页Lesson 13New Words&Expressions:蒸汽喷射式utilize vt.利用compression n.压缩compression-type压缩式vapor-compression蒸汽压缩subdivide vt.;vi.再(细)分subdivideinto把再分成absorption n.吸收jet n.射流,喷射喷射器vapor-jet type第4页，本讲稿共17页Lesson 13New Words&Exp
3、ressions:相反的,可逆的achieve vt.完成,达到extract vt.抽(取,排)出,萃(提)取repeated a.反复的perform vt.完成cycle n.循环,一个操作过程reverse a.第5页，本讲稿共17页Text The principle of operation of refrigeration machines is based on the second law of thermodynamics.A certain amount of work has to be done to transfer heat from a cold body to
4、 a hot body.制冷机的工作原理是根据热力学第二定律。要把热量从低温物体传向高温物体就必须消耗一定量的功。Lesson 13第6页，本讲稿共17页Text:The second law of thermodynamics is mathematically expressed as Qk=Q0+L,J;(Qk=Q0+AL,kcal),Where Qk is the quantity of heat transferred to the hot body;Q0is the quantity of heat given out by the cold body;L is the work
5、done to transfer the heat;A=1/427 is the heat equivalent of work.Lesson 13热力学第二定律的数学表达式为：Qk=Q0+L,J;(Qk=Q0+AL,kcal),式中 Qk是热量传向高温物体向高温物 体放出热量.Q0 是由低温物体放出热量。L 是所做的功转换成热。A=1/427 是热功当量.第7页，本讲稿共17页Text:Machines that gather heat from a cold body and give it to a hot body are called refrigeration machines.H
6、eat is transferred form a body at a lower temperature to a body at a higher temperature by a working substance(fluid)circulating in the refrigeration machine.1 Lesson 13 从低温物体吸取热量并把热量传递给高温物体的机器叫做制冷机。将热从温度较低的物体传递到温度较高的物体的工作是由在制冷机中循环的工质（流体）来完成的。第8页，本讲稿共17页Text:Refrigeration machinery in which mechanic
7、al energy is utilized is called compression-type refrigeration machine;refrigeration machines in which heat energy is utilized are subdivided into the absorption and vapor-jet type machines.Lesson 13 利用机械能的制冷机叫做压缩式制冷机。利用热能的制冷机可再分为吸收式和蒸气喷射式两种。第9页，本讲稿共17页Text:The working substance used in cooling may
8、be refrigerants or air.In the first case the cooling effect is achieved as a result of a change in the state of the working substance-boiling of a liquid are called vapor-compressing machines.In the second case cooling is achieved as a result of transfer of heat from the cooled product to cold air.R
9、efrigeration machines working on this principle are called air refrigerators.Lesson 13 用于制冷的工质可以是制冷剂或空气。第一种情况，由于低温下液体制冷剂的工质汽化状态的变化而达到制冷效果。这样的机器叫做蒸气压缩机。第二种情况，把热量从冷却物体转移到冷却空气进行制冷，依据这样原理工作的制冷机叫做空气制冷机。第10页，本讲稿共17页Text:Figure13-1 shows the working principle of a refrigeration machine.The working substanc
10、e extracts a quantity of heat Q0 from the cold body(surrounding medium)and gives it to the heated one,which is the surrounding air or water.According to the second law of thermodynamics,work equal to L has to be expended for such a transfer,so that the heat given to the heated body equals.2 Qk=Q0+L
11、after giving heat Qk to the heated body the working substance is once again ready to extract heat Q0 from the cold body and the process is repeated.3 Thus the working substance performs a cycle.To carry out this cycle work is expended so that heat from a cold body is given to a hot body,i.e.a revers
12、e cycle.Lesson 13 图13-1 说明了制冷机的工作原理。工质从低温物体（冷源）吸取热量Q0,并把热量传递给高温物体（热源）。这种高温热源通常是周围的空气和水（环境介质）。根据热力学第二定律，为完成这种传递必须消耗相当于L的功，致使传给高温物体的热等于 Qk=Q0+L.把热量Qk传递给高温物体后，工质重新对冷源吸热Q0，这种过程反复进行。于是工质完成了一个循环。要进行这样的循环，要利用工质膨胀到较低的温度，才能把热量从低温物体传向高温物体，也就是逆向循环。第11页，本讲稿共17页Notes to the TextLesson13第12页，本讲稿共17页Notes to the T
13、ext 1.Heat is transferred from a body at a lower temperature to a body at a higher temperature by a working substance(fluid)circulating in the refrigeration machine.Lesson 13 将热从温度较低的物体传递到温度较高的物体是在制冷机中循环的工质(流体)来完成的.circulating in the refrigeration machine，是现在分词短语,做substance的定语，意为“在制冷机中循环的”。第13页，本讲稿共
14、17页Notes to the Text 2.According to the second law of thermodynamics,work equal to L has to be expended for such a transfer,so that the heat given to the heated body equals Qk=Q0+L.Lesson 13 根据热力学第二定律,为完成这种传递必须耗费相当于L的功,致使传给热物体的热等于Qk=Q0+L.此句为带有一个结果状语从句的主从复合句.equal to L 相当于L的(形容词短语,做work的定语).according
15、 to 意为“按照;根据.所说;随.而”。例如：according to all accounts 照大家所说的act according to circumstances随机应变from each according to his ability,to each according to his work 各尽所能,按劳分配。第14页，本讲稿共17页Notes to the Text 3.After giving heat Qk to the heated body the working substance is once again ready to extract heat Q0 fr
16、om the cold body and the process is epeated.Lesson 13 工质把热Qk传给了受热的物体后,又立即从冷物体抽取热Q0,此过程便反复进行.连词and在本句中表示连贯关系.可译成“就,便,于是”等等。例如：The two men lay down and soon fell asleep.那两人躺下,很快就入睡了(或“不久便睡着了”)。第15页，本讲稿共17页ExerciseExerciseLesson 13Decide whether the following statements are true(T)or false(F)according
17、to the text.第16页，本讲稿共17页ExerciseExercise(T)(F)(T)(F)Lesson 13 1.Engineers use thermodynamics in the design of engines and propulsion systems.2.There are some processes which destroy entropy.3.It is possible to calculate the maximum amount of useful power that can be obtained from a given energy sour
18、ce on the basis of the idea of entropy.4.In a thermal power plant the steam is directly used to turn an electric generator 5.The efficiency of a thermal power plant can be increased through careful application of the basic principles of thermodynamics to the hundreds of components in the system.(T )第17页，本讲稿共17页