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制冷原理培训教材Refrigerationprincipletrainingmaterial一：制冷原理简介Refrigerationprinciple本系统属于蒸汽压缩式制冷循环，主要包括压缩机、冷凝器、毛细管、干燥过滤器、蒸发器5个部件，经过压缩、冷凝、节流、蒸发四个过程不断循环，制冷剂周期性的发生从蒸汽变为液体，从液体变为蒸汽的状态变化，不端的把冰箱内的热量转移到冰箱外部，从而达到制冷目的。Theapplianceincorporatesavaporcompressorrefrigerationsystemthatconsistsofcompressor,condenser,capillary,filterdrierandevaporatorandaccomplishestherefrigerationthroughthecycleofcompression,condensation,throttling,andevaporation.Theprocessrepeatsandextractstheheatfromthefridgecompartmentbyhavingtherefrigerantevaporatedintheevaporatorandliquefiedinthecondenser.二：主关件简介：Maincomponents(一)：压缩机Compressor制冷系统的“心脏”，起压缩和输送制冷剂的作用，目前所用为往复活塞式压缩机。Servingastheheartoftherefrigerationsystem,thecompressorfunctionsthroughcompressingandpassingtherefrigerant.Areciprocalcompressorisadoptedinthesystem.主要性能指标Performance1:制冷量:压缩机工作时,每小时从被冷却物体带走的热量以(千焦/小时)活或瓦表示.制冷量大小随工况条件变化,工况条件不同制冷量大小不同.1.Coolingcapacity:refertotheheatinkilojoule/hourextractedfromthearticlestobecooleddowninanhour.Thecoolingcapacitychangesalongwiththeoperatingconditions.2.功率.是指压缩机每小时耗功的大小.Power:refertohourlypowerconsumptionofthecompressor.3.性能系数COP:性能系数就是制冷量与:压机输出功率大小之比,COP越大说明耗电量越小,冰箱越节能.COP:refertothecoolingcapacity–outputpowerratio.ThehighertheCOPvalue,thelowertheenergyconsumption.压缩机三个重要附件:Threeessentialaccessories:1.启动控制器Startcontrol电冰箱刚开始启动时,PTC元件温度较低,电阻小,启动绕组接通,由于启动电流大,PTC温度随之升高,当达到临界温度电阻猛增到数万欧姆,可视为断路.于是与之串联的起动绕组断电,运转绕组正常工作.PTC是一种无触电开关,但停机后由于PTC温度仍很高,所以无法马上启动.ThePTCelementhasalowtemperatureandsmallresistancewhentheappliancestarts.Thestartingwindingisenergized.ThePTCtemperaturerisesalongwiththeincreaseofthestartingcurrentandreachesthethresholdtemperaturewhentheresistancecomesuptothousandsofohms,whichisdeemedasanopencircuit.ThenthestartingwindinginserieswiththePTCopensandtherunningwindingworksnormally.PTCisano-touchswitch.Whentheapplianceisturnedoff,itcannotstartimmediatelybecausethePTCtemperatureisstillveryhigh.2.过载保护器Overloadprotector过载保护器是用来防止压缩机过载和过热而烧毁电动机而设置的,海尔压机一般采用碟形保护器.Theoverloadprotectorisusedtopreventoverheatingofthecompressorthatmaycauseburning-outofthemotor.Haiercompressorgenerallyusebutterflyprotector.3.启动电容器Startingcapacitor(二).冷凝器Condenser冷凝器将从蒸发器中吸收的热量连同压机耗工所转化的热量在冷凝器中释放到空气中,使压缩机排出的过热蒸汽冷却为过冷液体.Therefrigerantpartswithitsheatabsorbedfromtheevaporatorandthewasteheatproducedduringtheoperationofthecompressor.Theheatisreleasedintotheopenairandtheoverheatvaporfromthecompressoriscondensedintoovercoolliquid.1.内藏式冷凝器是由铜管制成的盘管贴附在U壳内侧而成.ThecondenserconsistsofcoilsmadeofcopperpipeaffixedtotheU-shapedshell.(三).干燥过滤器Filterdrier干燥过滤器是利用“分子筛”的吸附作用来去除制冷系统中的水分,酸质机杂质,以防止制冷系统冰堵或脏堵,一般采用钎焊焊接在冷凝器出口和毛细管之间.Theworkingprincipleoffilterdrieristomakeuseoftheabsorptionactionofmolecularsievetoremovethemoistureandimpuritiesfromtherefrigerationsystemagainstblockageduetoiceorimpurities.Thefilterdrierisusuallysolderedbetweenthecondenseroutletandthecapillarytube.(四).毛细管Capillarytube毛细管是制冷系统的节流装置,一般内径0.6-2.0MM,长度1.5-4.0M.毛细管因为细而长,所以对制冷剂有一定阻力，一方面可使制冷剂降压，一方面又可在一定范围内限制流量，有一定的自补偿能力，在冰箱停止运转后，可起均压作用，使高低压压力趋向平衡，便于下次启动。Capillarytubeisthemeteringdeviceoftherefrigerationsystem.Ithasaboreof0.6~2.0mmandalengthof1.5~4.0m.Thinandlong,thecapillarytubeaccomplishesthereductioninpressurefromthecondensertotheevaporatorbyusingthepressuredroporfrictionlossthroughalongsmallopening.Thepressuresthroughthesystemtendtoequalizeduringtheoffcycle.(五)．蒸发器Evaporator蒸发器是一个输出冷量的社设备，制冷剂在蒸发器中蒸发吸收冰箱内的热量，从而达到制取冷量的目的。Evaporatorisadeviceinwhichtherefrigerantevaporateswhileabsorbingheatfromtheinnercompartment.