Simulation Research Of The Dynamic PMV-Controlled VAV System

In daily life,the comfort of human body is affected by many factors.However,the commonly used air conditioning system mainly uses fixed temperature as the control target.Therefore it often makes the human body feel uncomfortable.With the emergence of "air conditioning disease" and other problems,people began to pay attention to the research of the indoor environment dynamic thermal comfort.And the energy consumption of traditional constant air volume(CAV)air-conditioning system based on temperature control remains remarkably high.How to reduce the energy consumption of air-conditioning is also one of the key issues of energy conservation at this stage.At present,there are few research on VAV air conditioning system with the control target of dynamic thermal comfort index.Under the premise of meeting the needs of human body function and health,how to further reduce the energy consumption of the VAV air-conditioning system requires us to further explore.Contents and results are as follows:(1)In the article,the author uses a TRNSYS simulation software to establish a load model of an office building in Jinan.The outdoor meteorological parameters of this model are the typical year(TMY)meteorological parameters of Jinan,which are obtained by Meteonorm software.The indoor meteorological parameters are set according to the regulations of heating ventilation and air conditioning design.The indoor setting temperature is 26℃ in summer and 18℃ in winter.Ultimately,the dynamic change curve of hourly load of the standard layer over the year is obtained.(2)Through the combination of experiment and simulation,the regulation of air conditioning system based on dynamic PMV is obtained.In summer,the PMV value of the room with a fan coil for refrigeration can be obtained by SWEMA Thermal Comfort Test System.Moreover,the author calculates the thermal sensation of indoor personnel under different PMV values to determine the range of PMV index.Using TRNSYS simulation software,an office model using the CAV system is set up to determine the PMV value change period.Finally,the regulation rules of the air-conditioning system with the dynamic PMV index as the control target are obtained.(3)Most of existing VAV systems use Constant Duct Static Pressure Control,but frequency conversion fan module in TRNSYS Typel11 can not meet the needs of VAV system simulation of constant static pressure control.What’s more,there is no frequency conversion fan module suitable for variable static pressure control of VAV system.The paper refers to fan sample data provided by manufacturer,and then obtains the characteristic curve of the fan by MATLAB.After that,the mathematical model of frequency conversion fan with constant static pressure control is established.Based on TRNSYS software,a frequency conversion fan module Type 275 for VAV systems with constant static pressure control is developed.Based on module Type 275,a variable frequency fan module Type 278 for VAV systems with variable static pressure control is developed.This module can adjust the setting value of static pressure in the air pipe network according to the opening of the end air valve,so as to achieve the purpose of static pressure control.(4)The VAV system model with fixed static pressure control and the VAV system model with variable static pressure control are set up respectively based on Type275 and Type278.Simulation results show that the indoor environment of VAV system with two different control modes can basically meet the requirements.Meanwhile,by comparing the energy consumption of the two VAV systems,it is found that the VAV system with variable static pressure control is more energy-efficient.(5)The simulation model of fixed static pressure controlled VAV system with three different control targets has been established by using TRNSYS.The three control objectives are:constant temperature,static PMV,dynamic PMV.A statistical model for energy consumption of the temperature-controlled CAV system is also established.Through the comparative analysis of the energy consumption of four different air conditioning systems,it is found that in the same building,the energy consumption of the CAV system using traditional temperature control is the highest,and the energy consumption of the VAV system using dynamic PMV index as the control target is the lowest.The concept of a VAV system based on dynamic PMV control is proposed in this paper in order to make the indoor environment meet the needs of human health and comfort while reducing the energy consumption of air-conditioning systems in the building.Through the combination of experiment and simulation,the regulation of dynamic PMV index is obtained.The VAV system based on dynamic PMV control is established by using TRNSYS simulation software.And the simulation result shows that the comfort and energy saving of this system are more outstanding.This paper provides a theoretical basis for the practical application of the dynamic PMV-controlled VAV system.