Thecentralairconditioningsystemiscomposedofoneormorecoldandheatsourcesystemsandmultipleairconditioningsystems.Thissystemisdifferentfromtraditionalrefrigerantairconditioners(suchasasingleunit,VRV)tocentrallyprocessairtomeetcomfortrequirements.Theprincipleofliquidvaporizationandrefrigerationisusedtoprovidetherequiredcoolingcapacityfortheairconditioningsystemtooffsettheheatloadoftheindoorenvironment;theheatingsystemprovidestherequiredheatfortheairconditioningsystemtooffsetthecoolingandheatingloadoftheindoorenvironment.　　Therefrigerationsystemisavitalpartofthecentralair-conditioningsystem.Itstype,operationmodeandstructuredirectlyaffecttheeconomy,efficiencyandrationalityofthecentralair-conditioningsysteminoperation.