An Adaptive Research For Water-side Free Cooling In Guizhou

Currently,with the accelerated process of industrialization and urbanization,the contradiction between energy and environment has become increasingly prominent.Urban agglomeration as a new product of industrialization and urbanization,whether the energy structure of the industrial park is reasonable or not and the level of energy utility rate will directly relate to the development direction of China’s energy industry.Adopting efficient energy-saving measures in urban agglomeration is one of the key measures to solve above problems.Water-side free cooling systems(also known as tower cooling systems),as one of the energy-saving method to normal air-conditioning system in off-seasons,are steadily gaining attentions in the minds of system designers.First of all,this paper gives an brief introduction on the cooling theory of the water-side free cooling system and several applications forms of the system based on a large number of domestic and foreign literatures.It analyzes the operation of the equipment,cooling tower,plate-frame heat exchanger,air conditioning terminal equipment etc.Also,it discusses the applicable conditions of the tower cooling system,including the meteorological terms,building types and the load characteristics.Then,based on the actual project,the hourly cooling and heating load throughout the year of the buildings is simulated using De ST software.According to the result,the summer peak cooling load is 11429.46 k W and the winter peak heating load is8562.39 k W.On the basis of analyzing the load characteristics,the features of tower cooling provided by the manufacturer are analyzed and the results show that the lower outdoor wet-bulb temperature and the smaller operation flow,the better the energy saving effect.In addition,detailed analysis was made on the outdoor wet-bulb temperature of 1464 hours in the off-season of Guiyang in April and may,which shows that there are 640 hours when the outdoor wet-bulb temperature is less than or equal to14℃,accounting for 43.72%.When outdoor wet-bulb temperature rises from 13℃ to14 ℃,the growth rate is as high as 12.50% and the time increases by 183 hours.Obviously,the increase of the switching temperature can significantly increase annual operation hours,which also means that in the running time of air conditioningthroughout the year,is falling,and energy consumption of refrigeration units will also decrease.Therefore,on the premise of ensuring the cooling effect,it is possible to choose a higher cooling tower switching temperature and extend the cooling hours,and to better realize energy saving potential.According to this project,the switching temperature is determined to be 14℃ and the energy saving efficiency of this project is calculated and analyzed,which lays a theoretical foundation for the application of this technology.Finally,four representative cities including Guiyang,Zunyi,Weining,Xingyi are selected from the four climate partition,where the switching temperature and cooling hours are discussed,we can see the total theory cooling hours,monthly hours cooling and the proportion of theoretical cooling hours throughout the year and month.What is more,outdoor wet-bulb temperature of 8760 hours based on the switching temperature4℃,9℃ and 14℃respectively is analyzed.When the switching temperature is 14℃,the annual operation hours is 2175h、2232h、2339h、3858h respectively in Guiyang,Zunyi,Weining and Xingyi,of which Weining has a absolute advantage.These data provides a design basis and data support for the application of tower cooling in Guizhou province.