Study Of Heat And Moisture Transfer Process Of A Dew Point Evaporative Cooler

The latent heat absorbed by natural evaporation of water is used for air cooling,and the air can be cooled to its dew point temperature in the limit state,which is a green refrigeration technology suitable for air conditioning.Although a lot of research work has been done by domestic and foreign scholars,and the efficiency of dew point air cooler has been effectively improved,the cooling capacity per unit volume of the device is still relatively low.On the basis of previous research,this paper tries to find the way to further optimize the equipment and improve the refrigeration efficiency,and verifies it theoretically and experimentally.Therefore,on the basis of in-depth literature research,this paper found the evaporating medium and equipment structure as the breakthrough point,carried out experimental testing and structural optimization design,and carried out simulation research on the new design.First of all,in order to make clear the water system test standard which is the basis of the evaluation of the evaporative cooling equipment performance,this paper makes an in-depth analysis of the domestic and foreign industry standards,and establishes the applicable test method and calculation formula of the evaporation efficiency and water use efficiency.Then,the moisture absorption and moisture dispersion properties of COOLMAX hygroscopic and quick-drying fiber materials were measured experimentally.The experimental results verified and quantified the water absorption and evaporation performance of the material,which laid a foundation for subsequent structural design innovation.Moreover,in order to further verify the practicability of the material,this paper proposes and experimentally verifies a new material thermal composite processing technology,which is used for the processing and molding of Cool Max fiber material and metal heat exchange plate.On the basis of verifying the forming process of the core heat and humidity exchanger of the dew point air cooler,a new dew point air cooler with COOLMAX as the wet surface material is designed in this paper.Different from the traditional evaporative cooler,this structure arranges the water system in the way of immersion,and cancels the general necessary water pump and water distribution system,reduces the power consumption of the unit,and optimizes the water and air distribution of the system.Finally,in order to understand the rules of heat and humidity process inside the new structure,this paper uses the multi-physical field simulation software COMSOL to conduct modeling and performance simulation research,mainly simulating and analyzing the temperature field,velocity field and humidity field of dry-wet channel coupling.Through the simulation analysis of the heat and humidity exchange process in the channel,it is found that the evaporation is active at 0.6 m before the wet channel,and the latent heat is mainly exchanged.After that,the air in the wet channel tends to be saturated,and the evaporation is not obvious,and a simple sensible heat exchange is carried out.This conclusion is very important for optimizing the length of heat and moisture exchange channel and the structure of heat exchanger.The results show that the best air passage spacing is 4～5 mm,and the best cooling condition can be achieved when the working air ratio is 0.3.