Application Of Typical Meteorological Season For Direct Evaporative Cooling Air Conditioning

Direct evaporative cooling(DEC)air conditioning is often regarded as “green air conditioning”,which reduces energy consumption by about 25% and costs by about 20% compared to conventional air conditioning systems.It has been widely used in arid regions of northwest China.DEC air conditioning is greatly affected by outdoor meteorological parameters,so it is necessary to have corresponding typical meteorological year data to provide design meteorological parameters for direct evaporative cooling air conditioning system.But at present,there is no research on the typical meteorological year of DEC air conditioning,and the typical meteorological years of building energy consumption are not suitable for DEC air conditioning.Therefore,in this paper,it explored the construction of a typical meteorological season for direct evaporative cooling air conditioning systems.In this paper,it analyzed the sensitivity of the energy efficiency ratio(EER)of direct evaporative cooling air conditioning system to the changes of outdoor meteorological parameters.The results show that the average annual EER of the direct evaporative cooling air conditioning system and the rated EER of the equipment can’t be used as the design basis.A set of meteorological representative data is needed to evaluate the operation of the DEC air conditioning system during the cooling season.Therefore,in this paper,according to the characteristics of DEC air conditioning system,which is affected greatly by the change of dry and wet bulb temperature,it selected daily average value,daily maximum value,daily minimum value and daily difference of the dry bulb temperature and wet bulb temperature as the construction of typical meteorological season.The weights determined for typical meteorological season are: the average is set to 0.2,and the remaining six factors are all 0.1.Taking the Urumqi region as the research object,it constructed a typical meteorological season for evaluating the performance of the DEC air conditioning system by Sandia method,CSWD method and Danish method.The error analysis results show that the dry-wet bulb temperature of the typical meteorological season constructed by the three methods is close to the monthly cumulative distribution of the dry-wet bulb temperature for 30 years.The absolute deviations of the monthly average dry bulb and wet bulb temperature and the long-term monthly average dry bulb and wet bulb temperature for the typical month selected by the three methods are all within 1 °C,and the relative standard deviations are all within 5%.Moreover,it’s pointed out that the relative standard deviations of the monthly average EER value of the typical meteorological month and the 30-year long-term monthly average EER value are all within 10%,by calculating the reflection accuracy of the long-term average energy efficiency ratio of the direct evaporative cooling air conditioner.The typical meteorological season constructed by the three methods is not only representative of the climatic characteristics of the Urumqi region of Xinjiang,but also can represent the monthly variation characteristics of the actual operation performance of the DEC air conditioner.The results of this paper also show that the average and minimum EER calculated by the typical meteorological season can be used as the key basis for economic evaluation indicators and equipment selection of direct evaporative cooling air conditioning systems.According to the long-term average EER of the DEC air conditioning system and the predicted deviation of the frequency distribution,it’s pointed out that the most accurate method is Danish method when comparing the accuracy of the direct evaporative cooling meteorological year by different methods.Therefore,Danish method can be selected as the first choice for the construction of a typical meteorological season for the direct evaporative cooling air conditioning system in Urumqi,Xinjiang.