Experimental Study On Spray Atomization Technology Of Evaporative Condenser For Air Conditioning

Air-cooled air-conditioners are widely used in buildings for the advantages of easy installation and low initial investment.However,when the outdoor temperature rises in summer,the heat transfer efficiency of the condenser decreases and the energy consumption of the compressor in the air-conditioning system increases.For water-cooled air-conditioners,although the air-conditioning system compressors consume less energy,it requires a large amount of water.In addition,it needs to be equipped with cooling tower,cooling water pump and other equipments,which will increases initial investment.The evaporative condenser has the advantages of high heat exchange efficiency,energy saving,water saving,and compact structure.If the evaporative condensation technology is applied to the air-cooled air-conditioning system,the problem of excessive energy consumption in summer can be solved.At present,there are extensive amounts of research work related with evaporative condensers.However,most studies focus on vertical spray evaporative condensers and rather few researches have been performed on horizontal spray atomization.In this paper,experimental research is carried out on horizontal spray atomization evaporative condensers.It can provide basic data for further study on the application of horizontal spray in evaporative condenser for air conditioning.Firstly,the relevant parameters of the nozzle are determined through experiments.Then,the influence of the air inlet temperature(simulated summer outdoor air temperature),air inlet velocity(air velocity flowing through the condenser),air inlet rheumatism(simulated summer outdoor air humidity),spray water volume and spray angle on compressor power consumption is obtained according to orthogonal and single factor experiments.The evaporation rate of the water film outside the tube was calculated by experimental data.The main conclusions are as follows:(1)The aperture of 1.2 mm was selected by choosing spray nozzles with different apertures,adjusting the distance between the nozzle and the condenser,observing the spray atomization condition.Futhermore,the distance between the nozzle and the condenser is set as 150 mm,and two nozzles at the windward surface of the condenser are arranged,The distance between the nozzles is 210 mm and the height of the nozzle is 375 mm.At this condition,the best coverage of spray atomizing water on the condenser is achieved(2)Orthogonal experiments show the factors affecting the power consumption of the compressor are,in turn,inlet air temperature,spray water volume,spray angle,air inlet speed,and inlet air humidity.(3)The power consumption of the compressor decreases with the increase of the spray angle firstly.When the spray angle increases to a certain extent,the decreasing rate of the power consumption of the compressor gradually slows down,and the optimal spray angle is 60°.The power consumption of compressor decreases with the increase of spray water and increases with the increase of inlet air temperature.Considering the power consumption of spray atomization pump,the energy-saving efficiency of the system increases firstly and then decreases with the increase of spray water volume.Under the condition of lower inlet air temperature,the energy-saving effect of evaporative condenser is not obvious,while at higher inlet air temperature,the energy-saving efficiency of evaporative condenser system will be improved significantly.(4)The evaporation rate of the water film on the wall of evaporative condenser is 0.37-0.46g/(m2·s)when the inlet air temperature is 30-38℃.With the increase of the inlet air temperature,the evaporation rate of the water film on the outer wall of heat exchanger coil increases gradually.