攀枝花学院本科毕业设计（论文）摘要摘要本文介绍了由变频器、PLC、数模转换模块、温度模块、温度传感器等组成的温差闭环控制在中央空调系统节能改造中的应用。通过温差闭环控制，使冷冻水泵和冷却水泵能随空调负荷的变化而自动变速运行，大大优化了系统的运行质量，达到了显著的节能效果。文中首先通过分析原中央空调系统及存在的问题，对系统进行节能改造的可行性分析。然后提出节能改造的具体方案，对节能改造需要的主要设备进行简单介绍。再次通过方案画出变频节能技术框图、PLC变频器节能改造原理分析、画出PLC控制梯形图。最后列举设备调试和遇到的问题并对中央空调改造前和改造后进行运行效果比较。而文中的重点和难点是：对原系统进行节能改造的可行性分析和节能改造的具体方案的确定；变频节能技术、PLC控制原理以及PLC控制梯形图。关键词PLC，变频器，中央空调，节能，温差闭环自动控制重庆科技学院高等教育自学考试本科毕业论文英文摘要攀枝花学院本科毕业设计（论文）ABSTRACTABSTRACTThisarticleintroducestheapplicationofthermoelectricclosed-loopcontrolintheenergysavingmodificationofCentralAir-conditioningSystem.Thethermoelectricclosed-loopcontroliscomposedoffrequency-changer,PLC,Digital-to-AnalogConversionmodule,temperaturemodule,temperaturetransducerandotherdevices.Chilledwaterpumpandcoolingwaterpumpcanbeinmotioninvariablespeedautomaticallywiththechangeofair-conditioningloadthroughthethermoelectricclosed-loopcontrol.Thatoptimizedtheoperationqualityofsystemgreatlyandnotableeffectofenergyconservationcanbeseen.First,thispaperwillanalyzethefeasibilityofenergysavingmodificationafteranalysisoftheoriginalCentralAir-conditioningsystemanditsexistingproblems.Thenitwillputforwardspecificschemeofenergysavingmodificationandbrieflyintroducethemainequipmentneededinenergysavingmodification.AgainthroughtheblueprintitwilldrawupconverterenergysavingtechniqueblockdiagramandPLCcontrolladderdiagramandcarryouttheanalysisofprincipleofPLCfrequency-changerenergysavingmodification.Atlast,equipmentdebuggingandproblemsmetwillbelistedandtherewillbeacomparisonofoperationeffectbeforeandafterthemodificationandreconstructionofcentralair-conditioning.Theemphasisanddifficultyofthisarticleis:analysisofthefeasibilityofenergysavingmodificationandconfirmationofspecificschemeofenergysavingmodification,aswellas,converterenergysavingtechnique,principleofPLCcontrol,PLCcontrolladderdiagram.KeywordsPLC,frequencyconverter,centralair-conditioning,energyconservation,thermoelectricclosed-loopautomaticcontrol攀枝花学院本科毕业设计（论文）目录PAGEIV攀枝花学院