Numerical Simulation And Expeperimental Study On The Ceiling Of Direct Evaporative Anti-condensation Radiation Air Conditioner

With the constant improvement of the level of national economy,as well as the global energy problem increasingly serious,radiation roof air conditioning systems due to its characteristics of high efficiency and energy saving and comfort has been applied gradually in People's Daily life,however,radiation roof system in the operation process,the phenomenon of the surface temperature distribution lead to local cold spots,make radiant panel surface condensation problem,greatly limits the radiation roof system in high temperature and high humidity areas of promotion and application.At the same time,most of the traditional radiant cooling roof adopts the form of indirect heat transfer of frozen water,which increases the energy loss to some extent and reduces the operation economy of the system.In view of these problems,a new type of direct evaporation anti-condensation radiant air conditioning system is proposed in this paper.To the new radiation air conditioning system cooling performance is more accurate at the end of the study,based on the experimental measurements and CFD(computational fluid dynamics)numerical simulation with the combination of research methods,put forward the concept of radiant panel surface temperature distribution uniformity,test and radiant panel to simulate the steady state conditions and cooling capacity and the surface temperature distribution,analyzes the different spacing,gas layer thickness and pipe diameter size and refrigerant flow characteristics affect the performance of radiant panel cooling,and the experiment test system are related to performance analysis.The main research work is mainly divided into the following aspects:(1)This paper to direct the working principle of the air conditioning system of evaporative condensation prevention,including air conditioning system and the terminal in detail in this paper,the structure,and the new type of air terminal for radiation heat transfer analysis,internal and radiation of radiant panel board and the theoretical research on the heat transfer process of indoor environment,and expounds the radiant panel surface temperature distribution of the significance of evaluation criterion is put forward,the uniformity of temperature distribution are introduced to evaluate the cold radiant panel in the steady state temperature distribution under the condition of surface.(2)Through the introduction to mathematical control equation,and the choice of calculation model,using CFD software to direct evaporative condensation radiation shield roof model for numerical simulation of thesteady state condition,analyzes the different structural parameters on the surface of the radiant panel cooling performance and the influence of the temperature distribution and radiant panel surface under different evaporation temperature and velocity variation law of cooling performance.According to the cooling capacity of radiant plate surface,indoor dew point temperature and temperature distribution uniformity,the structural parameters were selected.(3)Set up the experimental testing platform of the air conditioning system,briefly analyze the theoretical calculation formulas of the main experimental parameters,study and analyze the power consumption and energy efficiency ratio of the air conditioning system by using the measurement data and theoretical calculation,and verify the relevant accuracy of the numerical simulation results.The research results of this paper provide certain reference and exploration value for the research and innovation of the new radiant roof.To some extent,it can improve the operation economy of the radiant plate while reducing the risk of condensation.The study of better structural parameters is also conducive to the market to provide specific design scheme for practical application,which has certain reference value.