Key Technology Research On Energy Consumption Monitoring And Diagnosis For Air Conditioning System Of Large Public Building

Along with the national economic development and social progress,the issue of energy consumption which is created by the operation of air-conditioning system in large public buildings is paid more and more attention.Nowadays,the energy consumption of air-conditioning system has already accounted for over 50% of the energy consumption of public buildings in China,and there is still a growing trend.How to reduce the energy consumption in large public buildings has been a hot issue in the field of building and energy applications.This paper is taken the energy consumption monitoring and diagnosis of air-conditioning system in Shenyang sixth people’s hospital as background,which makes a design on the basis of RS-485 bus of energy consumption monitoring system of hospital air-conditioning system.Energy consumption monitoring system can collect data from each sensor in air-conditioning system through RS-485 bus,at the same time,the system will connect with database server and workstation via Ethernet,which can upload the actual consumption data into database.The energy consumption monitoring system can realize visit of database in order to make the real-time monitoring of energy consumption in hospital air-conditioning system through JDBC.According to the energy consumption results in air-conditioning system obtained from energy consumption monitoring system in hospital,the temperature and running flow of chilled water and cooling water under the actual operating conditions of the chiller were firstly diagnosed,which concluded that there exists the problem of “large flow small temperature difference “in chiller.Through the calculation of Unit performance coefficient COP,it can be found that the maximum performance coefficient of unit is 3.943 under the actual operation,which is lower than the minimum value regulated in standard.Then,the actual operation efficiency of circulating pump is diagnosed,it is found that the actual operation efficiency of chilled water pump is 57.45%,the actual operation efficiency of cooling water pump is48.13%,both of them are lower than the rated power.The actual efficiency ratio of air conditioning system is 1.852 through the calculation of energy efficiency ratio of energy consumption in air conditioning system,which has a discrepancy of 40.25% by comparingwith the minimum valve of energy efficiency regulated in standard,it is proved that the actual operating efficiency in air-conditioning system is much lower.What’s more,while making the diagnosis of energy consumption in air-conditioning system,it happens to find that the hospital has great natural ventilation potential in summer night.Finally,according to the diagnosis results of energy consumption in air-conditioning system,the energy saving system for cold and heat source has been reformed.After reformation,the summer power consumption had decreased from 394,100 kWh to 212,800 kWh,saving 835,500 yuan for heating cost in winter.At the same time,under the different weather conditions during the summer nights,by using FLUENT,the test has been made under the condition of natural ventilation and mechanical ventilation in hospital summer night,analyzing the case whether the indoor comfort meets the requirements under the condition of reducing the running time of air-conditioning system.