Optimal Control Of The Variable Cooling Water Flow System In The Direct Expansion Air Conditioning System Of Subway Station

The direct expansion type air conditioner has the advantages of high heat exchange efficiency,light pipeline pressure and small volume.Compared with the conventional Metro air conditioning system,it has the advantages of small occupation and low energy consumption.At present,the conventional subway air conditioning system includes the cooling water system,chilled water system and cooling water unit.The cooling water system is rarely used in frequency control,but this part is the future of the new subway air-conditioning system is very important.From the theoretical structure of the new subway air-conditioning system by analyzing the importance of the cooling water flow system and necessity.,Recoding chiller,cooling capacity,energy consumption,COP records and other data through the experiment of the screw compressor,and the the data fitting into the approximate mathematical model,the mathematical model according to the actual project changes and the cooling water flow scheme adopted in practical engineering simulation.In the Nancun station as the research object,the simulation of sumner climate typical load rate of 100%load rate,75%and 50%load rate,of the variable flow control method,prediction of energy saving effect.From the simulation results,variable flow control method is conducive to energy saving,in the high load by 5 degree temperature control,in the low load,the use of 40 degree of water temperature can save more enengy.