Energy Saving Analysis And Energy Consumption Analysis Of Air Conditioning System In Public Buildings Based On Field Measurement

With the increasing shortage of traditional energy resources,energy conservation has become an increasing concern topic.Construction industry has received more and more attention characterized by high efficiency,energy saving and environmental protection.Large public buildings provide a comfortable environment for people.At the same time,it also poses a serious problem of energy consumption.According to the literature,the area of large-scale public buildings in China accounts for about 4%of the total building area in China,but its power consumption accounts for 20%of the total building electricity consumption.Above,the rapid development of the construction industry has led to the rapid development of other auxiliary equipment mainly for construction.In the overall energy consumption of buildings,the air-conditioning system accounts for a large proportion of power consumption,which accounts for about 40%of the total building energy consumption.Because of the vast space of large public buildings adequate equipment layout space,so it has more central air-conditioning system,the use of all-air system of air supply,the whole air system to effectively eliminate the indoor air mass operation of the indoor heat load,but its control and management lacks the awareness of energy conservation,the process targeted control is difficult to be implemented on operation and management of the process,if the optimal control of the air-conditioning system is strengthened,and start the program targeted planning,the entire air-conditioning system will be able to develop a huge energy saving potential.This paper takes an example of large-scale public buildings air-conditioning system in the south of District,Qingdao City for the test case transformation,based on the test data of air-conditioning system to analysis of the impact of system power consumption factors.At the early stage of the test,first understand the basic situation of the building and the status ratio of energy use.Conduct a survey and summarize the building energy consumption and local charges,and then conduct a detailed test and analysis of the energy consumption of the air-conditioning system,including the refrigeration side of the refrigeration unit,cooling water inlet and outlet temperature,flow,chilled water pump and cooling pump actual head,power and flow,as well as the cooling tower coefficient of transmission and wind water ratio,etc.,then compared and analyzed the test results for the chiller COP low,low efficiency pump proposed reasonable improvement program.For the low COP of refrigeration unit,the improvement is started with controllable factors,such as improving the bypass status of the cooler without refrigeration,controlling the opening strategy of the refrigerator with load changes,and controlling the outlet temperature of the frozen water,so as to analyze the effect of inlet and outlet temperature and flow on the energy efficiency of the system.At the same time,according to the COP of the unit,the limited flow range of the pump frequency conversion system is controlled.The phenomenon of "large flow rate and small temperature difference" is improved,and then the system’s energy efficiency is also improved.As for the pump and cooling towers,the problem of lower transmission coefficient transmission and distribution system is implemented,according to the pump performance curve,the operating conditions point is analysis to determine whether it is operating at the best conditions about 20%range,and use Origin software to fit the curve of its operating conditions,analyze its operating status,compared with the actual operating curve,and frequency its conversion transformation,making the pump flow decrease with the end of the load decreases,and clean the cooling tower into the wind to increase their wind water ratio or to replace the packing to increase its heat exchange efficiency.Finally,the genetic algorithm in MATLAB is used to model and optimize the power consumption of the whole air conditioning system.According to the optimization theory of genetic algorithm,the genetic variation of each progeny gene and its genetic evolution are established.The power consumption is the objective function.The model equations with the evaporator side and the condenser side flow as the control variables are used to optimize and control the water flow on the evaporator side and the condenser side by simulating and analyzing the power consumption under different load rates.According to model the genetic algorithm,with the end of the required load decreases,get the minimum air-conditioning system’s overall power consumption.Taking this analysis method as the starting point,taken targeted solutions to different buildings and put forward practical and feasible analytical methods and efficient energy-saving methods for building energy saving in China.