Application Of Evaporative Cooling Air Conditioning Technology In Residential Buildings In Dry Areas

The climate in the northwest of China is hot and dry,and the economic level is relatively backward.In the hot summer,some areas mainly rely on electric fans to cool the room.Therefore,it is very necessary to analyze and research a kind of air-conditioning cooling method suitable for residents of residential buildings in dry areas in northwestern China.Nowadays,the deficiency of traditional air conditioners has become more and more obvious.It consumes a lot of energy in the process of running,making the interior dry and polluting the environment.However,the application of direct and indirect evaporative cooling air conditioning technology in residential buildings in the Northwest China can clearly avoid the above three shortcomings.Therefore,I have studied the application of evaporative cooling air-conditioning technology in residential buildings in dry areas,and conducted experiments on two aspects of direct and indirect evaporative cooling air-conditioning technology,and conducted research and analysis.The direct evaporative air conditioner was installed in a university dormitory in Xi'an and was actually tested in summer.When the outdoor dry-bulb temperature is 32? and the relative humidity is 22%,the air-dried dry-bulb temperature after the air conditioner treatment is 23?,and the temperature difference between the inlet and outlet air is about9?.The temperature in the dormitories gradually decreased and eventually stabilized at approximately 28?.The indoor temperature was relatively low,and there was a temperature drop of about 5?.Since the direct evaporative cooling air conditioner uses a direct-flow air supply,the concentration of particulates in the dormitories is significantly reduced during the operation.The concentrations of PM2.5,PM4,and PM10 particulates were just 47.0?g/m~3,61.3?g/m~3,and 119.5?g/m~3,respectively.The concentrations of PM2.5,PM4,and PM10 after startup were reduced to 22.5?g/m~3,28.8?g/m~3 and44.1ug/m~3 respectively.During the test,three people smoked in the dormitory.The smoke produced was able to be discharged to the outside smoothly.The indoor air quality was good and there was no strong pungent odor.Using the enthalpy difference laboratory to simulate different temperature and humidity environments,the composite dew point indirect evaporative cooling air conditioning unit was analyzed.When the relative humidity of the air at the inlet of the unit is within a certain range,the air dry bulb temperature at the air inlet and the wet bulb efficiency and the cooling rate are linearly related to y=0.607x-8.152(R~2=0.924)and y=2.367x-14.50(R~2=0.799)respectively.When the air dry bulb temperature at the inlet of the unit is within a certain range,the air relative humidity,wet bulb efficiency,and cooling rate at the air inlet are linearly related to y=-0.485x-101.0(R~2=0.455)and y=-0.215x-16.93(R~2=0.956)respectively.After the test,it was found that when the unit's wet bulb efficiency is the highest,the cooling rate is not the maximum during the test.Therefore,the unit's wet-bulb efficiency is not the only factor to measure the use of evaporative cooling air-conditioning technology in the region,but also consider the local meteorological parameters,air temperature and other parameters of the unit.The experiment simulated the meteorological parameters of cities in the northwest region and conducted experiments.Among them,in the regions of Urumqi,Karamay and Turpan,the cooling efficiency of the dew point units was 108%,108%and 119%,respectively,and the cooling rates were 16.3?,17.8? and 19.2?,respectively.This shows that the use of dew point indirect evaporative cooling air-conditioning units in such dry areas is particularly effective,and has the advantage of mechanical refrigeration compression air-conditioning can not be replaced.Combined with dew point unit cooling efficiency,the number of hours that can be used is counted.In Urumqi,Xinjiang,the number of hours when the outlet air temperature is less than or equal to 18? is 4399 hours,accounting for 99.62%of the total hours in May-May.From May to May,Urumqi,Karamay and Turpan in Xinjiang,the unit's air temperature reached below 23?.In the Ankang area,the dew point indirect evaporative cooling air conditioning unit cooling effect is relatively poor compared to the Xinjiang region.In 5-10 months,the unit outlet air temperature is less than or equal to 18? for 1473 hours,accounting for 33.36%of the total hours from May to October.