X(,224003):,,:;;:TB657.2:A:1008-5092(2001)03-0030-0311:1Fig.1TheprinciplefigureofcentralizedAirconditioningsystem,,,,,,,[1]22.1,(,),,,,,,,,,,,,:Q=SV,,,SQ,,,2.2,,,,,,,14320019JournalofYanchengInstituteofTechnologyVol.14No.3Sep.2001X:2001-04-11:(19632),,,,,,,,(),,3:n=60f(1-s)Pp,,,Tn2,Wn3,,,,,,,,50Hz40Hz,80%,n=0.8n.:W=Kn3,,40Hz:W=Kn3=K(0.8n)3=0.512Kn3=0.512W=(-)P=(W-W)PW=(W-0.512W)PW=48.8%,40Hz,,,,48.8%,,[2]4,,,,,,,,,,,,,,,,,,,,,PLC,,,PLC,,,255.1PLC,PLC,,,,,,,,,133.:1C11C2,2C12C2,,nC1nC22Fig.2Thecontrolledprincipleandmaincircuitfigureofwatercircularsystem5.2,,PLC,,,,PLC,PLC50Hz,,,,,,6318.5kW,318.5kW1118.5kWFREN2IC5000-P9S1NB0-P24R3-ACPLC;118.5kW1300NB0-P24R3-ACPLC42Hz,,,,11Table1Varyingoftheimprovedandunimprovedcurrentinwatercircularsystem(18.5kW33)1#2#3#(18.5kW33)1#2#3#27.5A27.1A27.0A27.3A27.5A26.9A16.5A15.9A16.7A16.1A16.6A15.8A1#,:W=1.732UIcos=1.73238027.30.9=16.17kW:W=1.732UIcos=1.73238016.10.9=9.54kW=(W-W)PW=(16.17-9.51)P16.17=41%,,,:[1].SPWM[M].:,1999.[2].[J].,1999,(1):46.(48)23143ADOTestFig.3TheinterfaceofADOTest:[1],.VisualC++6.0[M].:,1999.[2].VisualC++6.0[M].:,2000.ResearchofSeveralTechnologiesofDatabaseApplicationProgrammingwithVisualC++6.0andtheExamplesofADOmethodMARu2hong1,XIAOYong2jie2(1.DepartmentofMechanicalEngineeringofYanchengInstituteofTechnology,JiangsuYancheng224003,PRC;2.SoutheastUniversi2ty,NiangsuNanjing210096,PRC)Abstract:SeveralkindsofdatabaseprogrammingmethodsusingVisualC++6.0areintroduced,suchasODBC,DAO,OLEDBandADO,thefeaturesanddifferencesofthesemethodsarediscussedandcompared.TheemphasisisthemethodofADO,whichisthenewtechnologyhighlyrecommendedbyMicroSoft.TwobriefexamplesofADOapplicationprogramaregivenintheendofthispaper.Keywords:database;ODBCAPI;MFCODBC;DAO;OLEDB;ADO(32)TheApplicationofVVVFTechniqueinCentralizedAirConditioningSystemandEnergy-savingAnalysisCHENGKai2you(DepartmentofElectricEngineeringofYanchengInstituteofTechnology,JiangsuYancheng224003,PRC)Abstract:ThemaincausesofhighenergyconsumearepointedbytheanalysisoftheperformanceprocessofcentralizedairconditioningsystemTheapplicationofVVVFtechniqueinCentralizedairconditioningsystemisintroduced.Itsenergysavingeffectandeconomicaleffectareintroducedbycalculation.Keywords:centralizedairconditioningsystem;VVVFtechnique;energyconservation8414