Numerical Simulation And Thermal Comfort Research Of Indoor Thermal And Humid Environment Of All Air Conditioning System

All-air air conditioning systems are one of the most common systems in HVAC(Heating,Ventilation and Air Conditioning,HVAC)systems,and its role is to regulate and improve the temperature,humidity,and air quality inside the building.In recent years,due to rapid social and economic growth and rising living standards,people’s requirements for their working and living environments have become higher and higher.Creating a comfortable and healthy indoor environment can not only improve the efficiency of indoor staff,but also improve people’s quality of life,so it is very important to study the indoor thermal and humid environment and thermal comfort of all-air airconditioning system.The purpose of this project is to study the effects of different thermal and humid conditions and air conditioning structures on the indoor thermal and humid environment of all-air air conditioning systems,and to compare and analyze the indoor environment of three air conditioning systems using the Predicted Mean Vote(PMV)and Predicted Percentage Dissatisfied(PPD)indexes Thermal comfort.First,the experimental measurement of the THPZKC-1 type all-air conditioning system was used for experimental measurement.The temperature and humidity values of each monitoring point in the air circulation system under three air conditioning structures(DC,primary return air and secondary return air)were measured by the temperature and humidity sensors in the experimental device.Using ANSYS CFX software,numerical calculation models were established for the air circulation systems of each of the three air conditioning structures,and the experimental measurement results were compared with the numerical calculation results to verify the feasibility of the numerical simulation method.Second,the influence of different heat and humidity conditions on indoor environment was studied by numerical simulation.ANSYS CFX software is used to establish a numerical calculation model for the all-air DC air conditioning system,and the indoor thermal and humid environment of the all-air DC air conditioning system is numerically simulated under three thermal and humid conditions of air supply speed,air supply temperature and air supply humidity,and the distribution of indoor temperature and humidity fields and airflow organization of the all-air DC air conditioning system under different thermal and humid conditions is obtained.The distribution of indoor temperature field,humidity field and airflow organization are compared and studied to obtain the distribution law of heat and humidity conditions on the indoor heat and humidity environment of all-air DC air conditioning system.Again,the influence of different air conditioning structures on indoor environment was studied by numerical simulation.ANSYS CFX software is used to establish numerical calculation models for all-air air conditioning systems with heat and moisture sources,and numerical simulations are conducted for the indoor heat and humidity environments of three air conditioning structures: DC,primary return air and secondary return air,respectively,to obtain the distribution clouds of the airflow organization of the indoor temperature and humidity occasions of the three air conditioning systems.The distribution of indoor temperature field,humidity field and airflow organization of the three air conditioning systems are studied in comparison,and the most obvious effect of heating and humidifying the indoor environment is obtained for the secondary return air type air conditioning system.Finally,the indoor thermal comfort of all-air air conditioning system is analyzed.The PMV-PPD index is used to compare and analyze the indoor thermal comfort of three kinds of air conditioning systems,namely,DC type,primary return air type and secondary return air type.For the three air conditioning structures,sections of different heights are set up in the room,and the numerical calculation results of the three air conditioning systems are used to calculate the PMV-PPD indexes of each section,to explore the influence of the air conditioning structures on the indoor thermal comfort,and to arrive at the air conditioning system with the best thermal comfort among the three air conditioning systems,so as to provide a feasible basis for the design and improvement of the experimental installation of the all-air air conditioning system.