| The fan coil is an important component at the end of the air conditioning system,and plays an important role in indoor temperature regulation.Generally,the fan coil adopts a combination of three-speed manual adjustment of the fan and opening and closing of the water valve to achieve room temperature adjustment.With the improvement of people's living standards,people have higher and higher requirements for indoor comfort,and traditional fan coil control methods are difficult to meet people's needs for comfort.In the terminal equipment,the power consumption will account for 30% of the air conditioning energy consumption.In the air conditioning control,insufficient attention is paid to the operation energy consumption of the terminal fans and water pumps.Based on the study of the working mechanism of the fan coil unit,this thesis proposes a dual-input and dual-output fuzzy control strategy for the fixed temperature difference of chilled water.This strategy controls the temperature difference between the inlet and outlet of the chilled water by adjusting the flow rate of the chilled water in the fan coil,and uses the deviation between the indoor temperature and the set value to select the fan speed to achieve simultaneous adjustment of chilled water flow and air supply,thereby improving The comfort of the indoor environment.This thesis mainly includes the following research contents:1)This topic discusses the modeling method of fan coil and indoor room through the analysis of the working mechanism of fan coil,and builds the simulation model of air-conditioning terminal system using MATLAB's Simulink toolbox.The model parameters were modified according to the parameters and experimental conditions of the established fan coil system experimental platform,and the simulation model was compared and verified through a large amount of experimental data.2)Based on a large number of experiments,a fuzzy control strategy of dual-input dual-output fan-coil constant temperature difference is proposed.Through experimental research under various working conditions,the module control rules of the fixed temperature difference of chilled water under three wind speeds are established respectively,and the fuzzy control strategy of the fixed temperature difference of chilled water under different wind speeds and the control strategy of the fan speed are proposed.Finally,the fuzzy controller is designed.3)This subject builds an experimental platform for the fan coil control system for the experimental verification of the control strategy.The experimental platform uses PLC's analog input port to realize the collection of water temperature,room temperature and other signals;uses PLC's analog output port to adjust the frequency of the pump inverter,and then realizes the adjustment of chilled water flow;uses PLC's digital output port to achieve fan three The adjustment of the wind speed and the on-off control of the chilled water.At the same time,the host computer monitoring software was developed on Labview,and the RS485 communication method was adopted between the host computer and the PLC to realize the real-time monitoring and storage of experimental data.The control effect was verified and analyzed by changing the room temperature setting value and setting the temperature difference between chilled water and returning water.Experimental results show that both room temperature and chilled water temperature difference can achieve fast tracking of the set value,and the control efficiency is good.The control strategy proposed in this thesis can effectively improve the comfort of the indoor environment when applied to the air conditioner terminal,and has a good application prospect. |
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