Research And Realization Of Central Air Conditioning Water Control System Based On STM32

In recent years,our country and some enterprise pay more attention to building energy consumption.Central air-conditioning energy consumption accounts for more than 60% of the whole building energy consumption.Water system is an important part of Central air-conditioning system.So reducing the energy consumption of Central air-conditioning system will reduce the whole building energy consumption.The cooling water system and chilled water system in the existing central air-conditioning water control system are often controlled separately.Each of them is often operating with maximum design load.The weather factor was without consideration.In the cooling water circulation process,the weather factor and some other factors were without consideration.The cooling tower fan was always running continuous.The floor branch control system mode is simple,resulting energy waste.In the course of chilled water cyclical process,the frequency control algorithm of chilled water pump is briefness and the control is not better.Aimed at the insufficient of the Central air-conditioning control system,The main works are as follows in this paper:(1)Design the distribution control system with remote monitoring function of central air-conditioning based on STM32 and complete the PCB drawing and debugging,which is the basic research platform for the central air-conditioning control system.Establish the remote server and design the central air-conditioning remote monitoring interface through the WINCC.The remote server is connected with the upper control system through the Ethernet.It can realize the remote monitoring function.The whole control system is divided into three layers;the upper layer is the core control system;the middle layer including the cooling water pump control circuit,chilled water pump control circuit,cooling tower control circuit and the branch control circuit.The bottom layer including water pumps,sensors and some other field apparatus.The core control system integrates the cooling water system and chilled water system through the RS-485 communication circuit.According to the Central air-conditioning load changing adjust the frequency conversion to change the pump speed can adjust the cooling water and the cooling water flow rate.According to the change of environment temperature the cooling tower control circuit decides the start and stop of cooling tower fan.According to the branch water temperature the branch control circuit changes the opening of the branch valve.It can reduce energy waste and improve the comfortable of the indoor.(2)Chilled water circulation is a nonlinear,time-varying,large delay,and complex process.The fuzzy PID control algorithm is simulated in Simulink.The result shows that the new algorithm can improve the real-time ability and control precision Compared with the traditional PID algorithm.(3)Conduct the relevant tests for the overall system.Debugging the whole system after testing each module of the overall hardware system.The result shows that the system is running well and has a good energy-saving effect.