Experimental Study On The Thermal Characteristics Of Vertical Tube Counter-flow Dew Point Indirect Evaporative Cooling Tower

As an important auxiliary equipment in the thermal cycle of thermal power plants,cooling towers have considerable energy-saving potential.The cooling capacity of cooling towers directly related to the overall economic benefits of the power plant.The heat transfer limit of wet cooling towers is the wet bulb temperature of ambient air.However,due to the uneven distribution of air and water and the thermal resistance between the air and water phases in the project,the circulating water can not be cooled to the wet bulb temperature of the air.Traditional cooling tower cooling performance optimization methods can only make the cooling tower circulating water outlet temperature close to the inlet air wet bulb temperature.The dew point indirect evaporative cooling tower based on the dew point indirect evaporative cooling technology can cool the circulating water to below the wet bulb temperature of ambient air,which has significant energy saving potential in the field of industrial cooling systems.According to the current research status of the dew point indirect evaporative cooling technology in the field of air conditioning,the cooling efficiency of the cooler with the counter-flow flow form is the best.This paper conducts experimental research on the pilot test bench of a vertical tube counter-flow dew point indirect evaporative cooling tower.The research content includes the uniformity experiment of ventilation and water spray,the resistance characteristic experiment of the cooling tower,the influence law experiment of the cooling tower structural parameters on the performance of the cooling tower,and the cooling tower Experiment on the influence of operating parameters on the cooling performance of cooling towers.The main conclusions obtained in this paper are as follows:(1)The uniformity of water spray has a great influence on the performance of the cooling tower.Poor water spray uniformity will lead to uneven distribution of the cooling capacity of the filler,resulting in uneven distribution of water temperature at the outlet of the cooling tower and uneven distribution of air temperature at the outlet of the dry channel.After the uniformity of the cooling tower spraying water improved,the cooling performance of the cooling tower is improved,and the wet bulb efficiency is increased from 89.89% to 104.44%.(2)When the inlet water temperature is 27°C,as the length of the dry channel increases,the cooling performance gradually improves,the outlet water temperature of the cooling tower gradually decreases,and the wet bulb efficiency gradually increases.When the length of the dry channel is 2.4m,the cooling tower has the best performance;When the inlet water temperature is 32℃,as the length of the dry channel increases,the cooling performance first increases and then decreases.The outlet water temperature of the cooling tower first decreases and then rises.The wet bulb efficiency first increases and then decreases.The dry channel length is 2..0m,The performance of the cooling tower is the best;when the inlet water temperature is 40℃,as the length of the dry channel increases,the cooling performance gradually decreases.The outlet water temperature of the cooling tower gradually rises,and the wet bulb efficiency gradually decreases.The length of the dry channel is 1.6m.,The performance of the cooling tower is optimal.(3)As the wind speed of the filler section and the dry bulb temperature of the ambient air increase,the cooling performance of the cooling tower gradually improves,the outlet water temperature gradually decreases,and the wet bulb efficiency gradually increases.With the increase of inlet water temperature,spray density,and relative humidity of ambient air,the cooling performance of the cooling tower gradually decreases,the outlet water temperature gradually increases,and the wet bulb efficiency gradually decreases.