Research On Energy Saving Renovation Of A Central Air Conditioning System Of A Large Public Building

At present,China's large-scale public buildings account for only 5%of China's total construction area,but its energy consumption accounts for more than 20%of the country's total urban electricity consumption.The selection of air-conditioning equipment is too large,the operating conditions are unreasonable,and the blind pursuit of indoor environment comfort is the main reason for the high energy consumption of such buildings.This paper analyzes the operation status of a large public building air conditioning system by using field measured data,and uses EnergyPlus to analyze the energy saving potential of the building.Finally,the economics of the building using different types of air conditioning systems are analyzed.Firstly,the calculation methods and simulation software of common building energy consumption are introduced.The model of chiller system in EnergyPlus and the related theory and fan coil heat transfer model are introduced,which lays a theoretical foundation for the following load simulation and system simulation..Secondly,through the analysis of the annual electricity cost of the target building and the analysis of the power consumption of each equipment,it is found that the air conditioning system is the main energy-consuming equipment in the target building,and its energy consumption exceeds 45%of the total energy consumption of the building,and in the air-conditioning system.The main energy-consuming equipment is the water-cooled unit.Through the measurement and analysis of the basic parameters of the air conditioning system,it is found that the average energy efficiency of the water cooling unit is low and needs to be cleaned;the average working efficiency of the chilled water pump is low,and there is the possibility of eccentricity and blade wear;the energy efficiency ratio of chilled water and cooling water(ER)The mean value is too high,and the selection of the chilled water pump and the cooling water pump in the conveying system is too large.Thirdly,in order to provide theoretical advice on the energy-saving retrofit of existing air-conditioning systems,EnergyPlus was used for numerical simulation.According to the analysis of the simulation results,the energy-saving effect of the external window modification is most obvious in the reconstruction of the maintenance structure.When the heat transfer coefficient is reduced from 2.69 W/(m2 K)to 1.77 W/(m2 K),the construction The total load decreased by 12.4%;the COP of the chiller has a linear relationship with the system energy saving rate,and the energy saving potential of the chilled water pump and the chilled water pump is large;the energy saving effect of the variable flow water system is the most obvious in the energy saving reform of the air conditioning system.After the water system,the energy consumption of the system is reduced by 5.45%,and the power consumption per unit area of the building is reduced by 1.88kW·h/m2.Finally,the initial investment and operating costs of the water source heat pump,VRV multi-line and chiller were calculated for the target building.According to the calculation results,the three schemes are excellent,but considering the long-term comprehensive cost,the water source heat pump system is more reasonable.The comprehensive cost of the system is about 37.55 million yuan,and the system can reduce daily maintenance.And management pressure.