Temperature Field Simulation And Experimental Study Of Direct Evaporative Cooler

Since entering the21th century, mankind is facing increasingly serious energy and environmental problems, and building as a major energy consumption is particularly valued. In building energy consumption, air conditioning accounted for the proportion of more than50%,however, air conditioning caused a heavy burden on the grid in the summer peak period. Therefore, providing a kind of air conditioning with low power consumption and low pollution is an effective way to solve these problems. Evaporative cooling technology is a kind of energy conservation and environmental protection cooling methods that water as its energy source to prompt evaporation of between air and water. In recent years, scholars of air conditioning industry have done a lot of research on evaporative cooling technology, and achieved many results.Lanzhou is a city with petroleum, chemical, metallurgy and machinery manufacturing as its pillar industry in northwest China. Currently, this region’s civil and industrial construction cooling in summer is still mainly adopts the traditional mechanical refrigeration. During the "Twelfth Five-Year Guideline" energy consumption per unit output value will achieve the goal of3.66%reduction in Lanzhou city, and actively carry out a series of low energy consumption, environmental protection of construction projects. Lanzhou is located in China’s inland dry areas, the climate in this region have characteristics of higher dry bulb temperature, lower wet bulb temperature, bigger temperature difference between day and night, less precipitation in summer this kind of climate is very favorable for direct evaporative cooling.The research progress of direct evaporative cooling technique both at home and abroad were introduced in this paper, according to the current environmental and energy problem and advantages of direct evaporative cooling technology in the aspect of energy consumption, environmental pollution and application, elaborate the necessity of direct evaporative cooling air conditioning technology research, propose the purpose and research content of this paper. Based on climatic conditions in Lanzhou, set up a direct evaporative cooling test bench to study its actual running performance. Through the experimental test and numerical simulation method to analysis the direct evaporative cooler thermodynamic performance under different outdoor air state parameters, right against the face wind velocity.(1) By analyzing the basic principle of direct evaporative cooling——heat and mass transfer of the mechanism when air in direct contact with water and according to the calculation equation for heat and mass transfer, obtained the main factors influencing the performance of direct evaporative cooler.(2) In the basis of the literature, the basic theory and the relevant specification of direct evaporative cooling technology, set up a direct evaporative cooling test bench that include filtering section, direct evaporative cooling section and supply section, introduce the type selection and design of each function and air flow test device. Expounding the test principles of measuring point arrangement and distribution, introducing the experiment instrument and the theoretical basis of the test. Through the analysis of test results, realizing the direct evaporative cooler cooling effect, as well as outdoor air state parameters, the spray water temperature on the influence of the direct evaporative cooler thermodynamic performance.(3) According to the structure characteristics of the direct evaporative cooler, established and the simplified physical model of the test bench. To facilitate the numerical simulation, some relevant assumptions were based on direct evaporative cooling of heat and mass transfer mechanism and packing physical model, study heat and mass transfer between air and water during the process of direct evaporative cooling by the water film channel. According to the heat and mass transfer and fluid mechanics theory, established the mathematical model of the direct evaporative cooler, introduce the control equations, boundary conditions and concrete operation process of direct evaporative cooling numerical simulation. Through comparing simulation results with the test result, it could be known that the errors between simulation value and the test results are basically in the prescribed scope. And analysis the direct evaporative cooler thermodynamic performance that influence by the inlet air dry bulb temperature, wind velocity of packing through the numerical simulation.