The Control System Of The Central Air Conditioning System Based On DCS

Central air conditioning is necessary equipment of intelligent building, and the totalamount of building energy consumption in China increased year by year, the central airconditioning as an important part of the control system design requirements not only tofull-featured,but also energy-efficient. Central air conditioning is the most energy-intensiveequipment of the intelligent building, and its consumed about50%to60%of the electricityin the chiller load, therefore the control quality of the chiller control effect the wholebuilding energy consumption, is one of the most critical factors in energy conservation.In this thesis, through the working principle and domestic central air conditioner ofexternal control system present situation analysis, in view of the existing intelligentbuilding central air-conditioning water chiller refrigeration system and building automationsystem adopts the control method of the respective independence, proposed the central airconditioning chiller system based on DCS.Firstly, analyses the composition of central air-conditioning refrigeration system, thestructure and working principle of refrigeration system of central air conditioner areintroduced; Secondly, this thesis introduces the structure and function of distributed controlsystem characteristic, analyzes the difference between DCS and PLC, briefly introducestheABB Industrial IT DCS distributed control system.Secondly, according to the central air conditioning refrigeration system needs analysis,based on the distributed control system characteristics and control requirements of chillers,Proposed ABB AC700F Industrial IT distributed control system based on the design of thecontrol system, carries on the central air conditioning chiller. First, the hardware systemdesign of central air-conditioning chillers:including the selection of controller, I/O modulesand other equipment.Second, the central air-conditioning chillers software configuration:including the engineering station,operator station,gateway station; For each station featuresare described in detail; In the engineer station design4control task: chilled waterloop,cooling water loop,refrigeration loop, cooling water fan control, and a trend displaytask in operator station. In the operator station, design graphics display to observe centralair conditioning chiller and refrigerating machine work, design group display to adjust PIDparameters, and design trend display to observe historical data.Application of DCS control system to hardware configuration and software configuration,adopted self-tuning moduleand PID module to control the refrigeration machine, adopted PID module control of thechilled water loop and cooling water loop, and adopted the operator station onlinemonitoring of the chilled water loop and cooling water loop.Finally, used the laboratory’s DCS control system to realize. The running results showthat: used DCS to control the central air-conditioning chillers can achieve the effect ofreal-time control, accurate, fast, stably, improve the control stability.