| In the past,the research on the control of fan coil system mainly focused on reducing the temperature fluctuation,overshoot and energy consumption of fan coil,but the research on the humidity control of fan coil was lack.According to the survey data,the existing buildings with fan coil system often have the phenomenon that the fresh air units is not put into use,and the design stage often adopts the method that the fresh air is treated to the indoor state point and does not bear the indoor load,so the fan coil needs to have the ability to bear and deal with the indoor wet load independently,so it is of great significance to study the dual control of temperature and humidity of fan coil.However,due to the analysis of a large number of different indoor and outdoor disturbance,fan type,geographical location and other influencing factors,it needs to invest a lot of cost to verify the temperature and humidity control effect of each control method through experimental means.Therefore,it is necessary to establish a simulation platform to calculate the temperature and humidity control effect of fan coil by means of simulation analysis.The key ideas of the approach includes: 1)the fan coil system model is established based on the classical model of surface air cooler.The model can obtain parameters through samples,and is suitable for the calculation of dry cooling and wet cooling,with high calculation accuracy,which is convenient for the subsequent analysis of temperature and humidity control effect of fan coil control strategy of different manufacturers,and can assist engineers in design and selection.2)The simulation platform can analyze the temperature and humidity control effect under different control strategies,and test the temperature and humidity control effect of different control strategies by changing the control logic.3)It can calculate buildings with different enclosure structure,internal disturbance,outdoor weather and other settings.Considering the room heat storage,it can achieve short step control and calculation.The reliability of the simulation platform is verified by comparing with dest load calculation results and the natural rising process of room temperature.Through the simulation platform,this paper makes a preliminary study on the temperature and humidity dual control of fan coil system,evaluates the temperature and humidity control effect of several commonly used control strategies,and analyzes the influence of different selection strategies,fan inlet parameters,room disturbance,ventilation strategy and outdoor weather on room temperature and humidity through constant air volume control.The preliminary results show that when the control strategy with temperature as a single control quantity can meet the room temperature control,it may not meet the humidity requirements.It is necessary to improve the control strategy to achieve the double control effect of temperature and humidity.Based on the above research,this paper attempts to put forward a temperature and humidity control strategy for fan coil system with three speed regulation and water valve onoff control.Through calculation,it is found that it can achieve better humidity control effect while controlling temperature.Based on the research of this paper,the temperature and humidity control strategy of fan coil will be further studied in the future to achieve better control effect. |
