Analysis Of Applicable Technology Types Of Evaporative Cooling Air Conditioners In Arid Regions Of Northwest China

The research on the applicability of each technology type of evaporative cooling air conditioning is the premise to ensure the efficient and energy-saving operation of evaporative cooling air conditioning in the northwest dry area.However,in the early stage,the applicability of evaporative cooling air conditioning mainly focused on outdoor climate parameters,or further combined with the ideal indoor air supply point to form the applicability analysis model.Due to the complex building types and the climate in the arid area of Northwest China,the actual indoor state are different,and the use conditions of different units are different.It is difficult to characterize the actual indoor air-conditioning demand of different buildings only considering the theoretical cooling fraction obtained by outdoor parameters,and the operating conditions of various units are also different.Finally,the applicability of traditional evaporative cooling can not directly guide the application of evaporative cooling air conditioning in the northwest dry area.Therefore,on the basis of considering the influence of the actual cooling hours required by air conditioning in different indoor conditions,this study uses theoretical analysis,simulation calculation and other methods,combined with the diversity requirements of indoor state points and the actual use conditions of different technology types,this study analyzes the applicability of each technology type of evaporative cooling air conditioning,in order to overcome the traditional applicability analysis methods,most of them only focus on the outdoor climate parameters for climate zoning,and only study the ideal indoor state points,ignoring the impact of indoor parameters and the actual application conditions of various technologies,which is difficult to meet the requirements of indoor diversity.This study first combs the four main principles of evaporative cooling technology: the evaporative cooling fan,the evaporative air conditioner,the direct evaporative cooling unit and the indirect direct combined evaporative cooling unit,analyzes the air treatment process of the above four types of evaporative cooling technology by using the enthalpy humidity diagram,and obtains the use conditions of each technology.Combined with the existing evaporation cooling climate applicability zoning,the Energy Plus is used to calculate indoor temperature and the cooling load of each urban and rural building in the northwest arid area under different indoor state points and analyze the actual indoor state combined with the moisture content.Finally,the climate division based on the actual indoor conditions and the applicable conditions of each technology are integrated,the types of evaporative cooling technology suitable for different buildings and indoor state points are given.The main conclusions are as follows:1)Based on the study of different building types of evaporative cooling technology climate zoning,it can be found that the applicability of residential buildings is not much different from the traditional zoning method due to the use of natural ventilation cooling.For office buildings,due to the limited natural ventilation capacity and high energy consumption,even in the case of low outdoor temperature,indoor air conditioning and refrigeration are still needed due to the influence of internal heat source.As a result,the application area of evaporative cooling air conditioning is expanded compared with the traditional one only considering outdoor meteorological parameters.2)Through the analysis of the applicable conditions of the four commonly used types of evaporative cooling air conditioning technology,it is found that the cooling capacity of the evaporative cooling fan and the evaporative cooling air mechanism is relatively small,the outdoor temperature and humidity conditions are required to be high,and the range of the actual indoor state that can be achieved is large;the cooling capacity of the direct evaporative cooling unit is large,and the application conditions is strict;the cooling capacity of the indirect direct combined evaporative cooling unit is large It can handle a wide range of outdoor climate parameters and meet the requirements of a variety of indoor state points.3)By using Energy Plus software,the indoor parameters of typical urban buildings in the northwest arid area in summer of typical meteorological year are calculated.The results show that the room temperature and cooling load of residential buildings in the northwest arid area are generally large,and the room temperature of office buildings is higher than that of residential buildings.Among them,the urban cooling load of Xinjiang Uygur Autonomous Region is the largest,and most of the other cities have a difference of 10% ? 20%.However,most of the cooling loads of urban buildings vary from 10% to 20% due to strict compliance with national standards,and the cooling loads of rural buildings vary greatly due to no clear specification requirements.At the same time,the indoor moisture content of all kinds of buildings is changeable,and the complex indoor environment is formed together with the cooling load.4)The evaporative cooling fan is suitable for residential buildings with small area and low load,and its applicability decreases with the increase of building area and outdoor humidity.If the actual indoor temperature and humidity requirements are not high,the evaporative cooling fan can meet the requirements of many cities in the northwest dry area.The suitable building area of evaporative air-conditioner is increased compared with that of evaporative air-conditioner.It can be widely used in the arid area of Northwest China because of its wide range of temperature and humidity.5)When the direct evaporative cooling unit is used as an accurate refrigeration equipment,it can not be directly popularized in Northwest China because it is strictly required that the enthalpy value of outdoor state point is strictly equal to that of indoor air supply state point;as a simple cooling equipment,it can be compared with the evaporation air conditioner which will be widely used in the northwest arid area after the expansion of indoor temperature and humidity range.The indirect direct combined evaporative cooling unit can meet the refrigeration requirements by adopting two-stage and three-stage evaporative cooling in the cities of Xinjiang,Gansu and Ningxia province;some cities in the Shaanxi Province can not directly achieve accurate refrigeration due to excessive outdoor humidity.At this time,it can cooperate with dehumidification equipment for combined refrigeration.Through the above research,under different building types and indoor design parameters in the northwest arid area,the applicable technology types of evaporative cooling air conditioning are obtained,which are limited by various applicable conditions.The purpose is to provide a reference equipment selection method for the application of evaporative cooling air conditioning engineering in China,and maximize the energy-saving application of evaporative cooling.