Energy-Saving Diagnosis And Transformation Of Public Buildings

With the rapid development of domestic economy,the number and volume of public buildings are increasing in recent years.The design requirements of public buildings for their air conditioning systems are increasing.A complete set of air conditioning systems,including design,construction,commissioning and operation management,will lead to high energy consumption in operation once some problems arise,such as unreasonable selection of equipment,lack of construction quality,imperfect system debugging process and improper operation management.To sum up,the air conditioning system of large public buildings has considerable potential for energy saving,and it is also the key direction of building energy saving reconstruction.The air conditioning system of large public buildings includes cold and heat source unit,transmission and distribution system,terminal and other links.Each link is highly coupled with each other,and the design is very difficult.The old design easily causes the system to fail to arrive at the design parameter,energy waste and so on.Therefore,we need to diagnose the air conditioning system.This paper takes an office building in Sichuan as the research object.Through investigation and test,this paper makes a comprehensive statistical record of the status and problems of the office building's air-conditioning operation,and checks the problems of the system equipment which can not be put into operation because of the failure of the hardware facilities and the imperfect construction.The analysis of the operation of the cold and heat source unit in summer is based on the data in the data record table of the machine room history,and the operation of the boiler in winter is recorded and analyzed by the field test.Through the analysis of the results,I found that both summer and winter,the cooling and heat source of the air conditioning system in the office building,there is a "large flow,small temperature difference" in the water supply temperature difference during the operation of the cooling and heat source unit of the air conditioning system of the office building,while some problems such as the high temperature of the return water and the unreasonable number of units opening the unit in the summer part of the summer are also found.In view of these problems,the author combines the actual operation failure and unreasonable analysis of the system that the non frequency conversion of the pump and the nonlinear characteristics of the pipe system of the fan coil system controlled by the open type valve are the main causes of the "large flow and small temperature difference" in the system.In addition,through the investigation and analysis,it is found that the increase of air conditioning area in the office building,the increase of the number of terminal coil and the increase of water system resistance,the water flow of the system is less than the design flow,and the temperature of the return water is too high.Besides,this paper also focuses on the measurement and analysis of the running efficiency of the fresh air heat recovery unit located on the roof of the office building.Through the previous investigation,the author finds that the operation of the full thermal recovery unit is short of debugging and control strategy,which leads to the opening of the heat recovery wheel and the failure of the motor drive belt,which causes the wheel motor not to drive the runner and is in a state of empty rotation,not only can not achieve the purpose of energy recovery.The energy consumption of the system is also increased.After the operation failure of the unit was eliminated,the new exhaust temperature and humidity of the whole heat recovery unit was tested.Because the test time was winter,the humidity control was not considered in the office building in winter,so only the sensible heat recovery part of the total heat recovery unit was analyzed.From the analysis results,it is found that the thermal efficiency of the unit during the test is fluctuating between 30%-40% and the heat exchange efficiency is not required by the standard.However,this paper finds that the energy saving effect is still considerable even if the heat recovery efficiency is not high.At the end of the article,the author puts forward some suggestions on the problems of the air conditioning system.According to the data of the machine room operation record and the test data of the whole heat recovery unit,the scheme of the system optimization is put forward,and the operation control strategy of the whole heat recovery unit is analyzed and formulated,and the consummation of energy consumption is put forward in combination with the comprehensive inspection of the equipment of the air conditioning system.The scheme of monitoring system makes the operation of the unit more efficient and energy saving,and the office building air conditioning system achieves the purpose of truly intelligent control.