Based On The Central Air Conditioning Energy Saving Control System

The central air-conditioning provides comfortable environment for the people while a large amount of energy being consumed. In the social circumstance of the energy crisis and the country's national policy to implement energy saving, the energy saving of the central air-conditioning system has become one of the most valuable and significant issues.The central air-conditioning system is the object of study in this paper. The relationgship between the controlled variables and the variables of the energy consumption equipments, and the coupling relationship between the variables which belong to the different devices were analyzed on the basis of full understanding its working principle, and then a mathematical model of energy consumption was created. According to these mathematical models, a simulation module of the energy consumption of the central air-conditioning system was built by using MATLAB/SIMULINK toolbox. The experimental result demonstrated the accuracy of the simulation model, which means that this module can simulate the output of the energy of the actual system and provide a good simulation platform.Siemens S7-300 PLC is selected as the core controller, the computer which running the monitoring software WinCC is used as the upper computer, Siemens MM 430 is selected as the inverter device, HMI devices can be used for as the local monitoring and management equipments, Using PROFIBUS-DP field bus, PROFINET, AS-Interface bus, the electrical and mechanical equipments in this system are connected between each other, and then the control network structure is constructed. This control network system provides a good hardware platform which can realize the central control in system level.Fuzzy-PID control strategy was used in the central air-conditioning energy saving control system. Not only this paper provide the steps that how to implement fuzzy-PID control in hardware, but also design fuzzy-PID controller and role in the energy consumption model in the simulation software. Through the analysis of the operation results, and the comparision with the results that in the routine control mode, the feasibility of the application of fuzzy-PID control algorithm in the central air-conditioning energy saving control system is proved, which provide experimental support and a theoretical foundation for the practical application.