Research On The Applicability Of Building Combined Cooling Heatig And Power In Cold Region

In our country’s energy development strategic plan,it is pointed out that in the future,China will implement the green and low-carbon development strategy in order to accelerate the development of low-carbon energy,reduce the proportion of coal utilization,and increase the proportion of natural gas consumption.Incre--asing the proportion of non-fossil energy consumption is the direction of energy structure.With the wide use of natural gas,new forms of energy utilization--CCHP,will also be widely concerned.The CCHP system realizes the cascade utilization of energy,reduces the excessive consumption of primary energy,and reduces the emission of pollutants compared with the traditional energy supply method.At present,there are few examples of using distributed energy system in China,and few successful cases.Because Changchun is in the cold area,the climate is unique and the heat and cold load varies greatly,so the applicability of the distributed energy system in the cold region is studied in this eassay.In this eassay,the configuration scheme of distributed system is described,and the mathematical models of each device in the configuration scheme are established.Secondly,in order to better study the application of distributed energy system in cold area,this paper simulates the hourly heat and cold electric load of a hospital and an office building in Changchun area by using Dest simulation software,and summarizes the law of cooling and heating electricity load in the whole year.The characteristics of typical daily load variation are studied.At the same time,this paper establishes a mathematical model with the maximum daily operation benefit as the objective function,and analyzes the operation optimization of the system,and draws the conclusion that the system generator can run under the load rate of about 90% most of the time in the optimal operation mode.Then,the primary energy utilization ratio,relative energy saving rate and the efficiency based on the second law of thermodynamics are selected to compare and analyze the energy efficiency of the system,which is based on the first law of thermodynamics.The primary energy utilization ratio of the gas combustion engine and gas turbine system with hospital as the research object can reach 83% and 74%,which is higher than that of the traditional distribution system,and the energy saving of the joint supply system with the same load is about 30% than that of the supply system.The results show that the energy saving performance of the joint supply system is better than that of the split supply system.Finally,the economy of CCHPin cold region is analyzed and compared.This eassay selects the value economic evaluation index--net present value and annual cost value;the efficiency economic evaluation index--net present value rate and the internal rate of return;the mixed economic evaluation index-static investment payback period and the dynamic investment payback period.The economy of the system is studied from the above three aspects.Taking the hospital as the object of study,the annual total income of the co-supply system is 7.4million yuan,while the share system is-4.92 million yuan.The co-supply system is in the state of profit every year,and the distribution system is in the st ate of loss.The real internal rate of return of the joint supply system is 13.6% higher than the benchmark yield of 9%.The initial investment and the 12.5-year dynamic investment recovery period of the system indicated that,although the system was always profitable,the initial investment was large,and the investment recovery period was longer.