Application And Research Of Oil-free Centrifugal Chillers In Public Buildings

The national policy promotes the air conditioning industry to make continuous progress and produces oil-free centrifugal chillers.oil-free chillers actual operation energy efficiency and technical economy are controversial,which has aroused widespread concern in the society.It is necessary to evaluate it comprehensively and apply it to the actual project according to the operation characteristics of chillers,so as to give full play to the performance advantages of oil-free chillers and promote development of the technology.Based on the actual operating data of chillers of five public buildings in Qingdao,this paper compares the operation efficiency of oil-free centrifugal chillers and conventional chillers in the same refrigeration season,and reasonably evaluates the energy efficiency of oil-free chillers.The air-conditioning system is built on the basis of TRNSYS software,and energy consum Ption of oil-free air conditioning system is simulated.The specific research contents are as follows:According to the performance parameters of different types of chillers provided by domestic and foreign manufacturers,the performance characteristics of oil-free chillers and conventional chillers are compared and analyzed.The COP of oil-free chillers is 6and IPLV is 11,which meets the first class energy efficiency standard of national chillers.Compared with the traditional chillers,oil-free chillers shows higher energy efficiency under partial load and low cooling water return temperature.According to the measurement of many public construction projects in Qingdao area,the energy consum Ption,temperature,pressure and flow rate of air conditioning equipment are collected every 5 minutes by the data acquisition system,and the load of the building and power consum Ption,COP and EER are calculated.According to the data analysis and evaluation of the operation energy efficiency of the oil-free chillers,the typical problems existing in the air conditioning system are diagnosed and analyzed.The COP of oil-free chillers reaches 7.11,the modified COP is 5.51,oil-free chillers fails to match the building load well,and the modified COP is lower than the conventional chiller.Theenergy saving effect of high efficiency chillers is offset by the selection of auxiliary equipment,which leads to the reduction of the overall energy efficiency of air conditioning system.To improve the overall operation energy efficiency of air conditioning system,the chillers and auxiliary equipment should be selected according to the building load,and the reasonable control strategy should be used to keep chillers running under the condition of high efficiency.In view of the fact that the energy consum Ption of auxiliary equipment in the project is too high and the overall energy efficiency of oil-free air conditioning system is low.This paper puts forward the idea of o Ptimal control strategy of cold and heat source equipment and system based on load forecasting.By analyzing the historical data of air conditioning,the load change and demand of air conditioning system at the next time are predicted,and the o Ptimal operation strategy which is more beneficial to the energy saving of air conditioning system is put forward to promote the popularization and application of oil-free chillers.In this paper,TRNSYS is established through a large number of actual operation data,and the application of oil-free chillers and frequency centrifugal chiller in different types of buildings under the same control strategy is simulated,and the more suitable building types of oil-free chillers are studied.The development of this technology.The simulation results show that the operation energy efficiency of oil-free chillers is higher than that of variable frequency centrifuge in the same type of building,the COP of oil-free chillers in office building is 6.7% higher than that of frequency conversion centrifuge,and 7.2% in hotel building.In different types of buildings,the COP of the oil-free chillers in the office building is 6.58,the energy efficiency EER of air conditioning system is 4.26,the COP of the oil-free chillers in the hotel is 7.51,and the EER is 4.37.The operation energy efficiency of oil-free chillers in hotel is 12.4% higher than that in hotel,and the energy saving effect is more obvious.It can be seen that oil-free chillers is more suitable for hotel.