Study On Characteristics Of Evaporative Cooling Fresh Air System Based On Solution Dehumidification

Solution dehumidification evaporative cooling fresh air system is a new type of environmentally friendly,energy-efficient air conditioning system.This system does not use conventional refrigerants,which effectively avoids the damage to the environment by CFCs refrigerants.Moreover,the system can also use solar energy,industrial waste heat and other low-grade energy as a driving force,which effectively reduces the energy consumption of air conditioning in buildings.In view of the economic benefits and social benefits of the solution dehumidification evaporative cooling fresh air system,the system is expected to replace the traditional air conditioning system.The study on the working characteristics of the dehumidification evaporative cooling fresh air system helps to improve the understanding of the system and optimize the system control parameters,which have great significance to the actual operation of the system.This paper has carried out the following main research contents:Firstly,the research background of solution dehumidification evaporative cooling fresh air system was introduced.The basic principle of solution dehumidification technology and evaporative cooling technology and the selection of common dehumidifier were described.On this basis,the mathematical model are established: Air,LiCl solution,water and other working fluid thermal parameters of the mathematical model,as well as dehumidifiers/regenerators,heat exchangers,direct evaporative cooler and other major functional components of the mathematical model.Secondly,six different types of solution dehumidification evaporative cooling fresh air systems in hot-summer and cold-winter zone were introduced.The regenerator solution outlet concentration,air supply parameters and the thermal coefficient of the system were analyzed.The system is validated under the conditions of the outdoor design parameters of different cities.The type of dehumidification evaporative cooling fresh air system suitable for hot-summer and cold-winter zone is proposed,which provides a reference for the actual system type selection.Then,the MATLAB/Simulink simulation platform was introduced.Based on MATLAB/Simulink simulation platform,the simulation model of solution dehumidification evaporative cooling fresh air system was established,and the system has been experimentally verified.The model was simulated and the simulation results were analyzed.The influence of components NTUm on the performance of the system was analyzed.The optimal range of the components NTUm are determined and the optimal ranges of various influence parameters in the system are determined.The results of the study can guide the operation of the system.Finally,based on the second law of thermodynamics,the exergy analysis of the dehumidification evaporative cooling fresh air system was carried out.The influence of each factor on the exergy of the system and the influence of the exergy loss of each component were analyzed.The results show that the parameters with great influence on the efficiency of the system are hot water temperature,gas-liquid ratio,atmospheric relative humidity,followed by hot water flow.And pointed out the weak links in the system,which is the direction of further optimization of the system.In this paper,the characteristics of the solution dehumidification evaporative cooling fresh air system were studied,the results of the study to improve the system performance and system optimization have a guiding significance.