| With the city development and the people’s living standard improvement,the energy consumption is increasing,the air environment is getting worse and worse.Therefore,to improve energy efficiency and reduce pollutant emissions have become an important part of the work of the government.In the urban central heating industry,how to meet the increasing demand for heating,and the use of new clean energy to replace the traditional coal-fired heating has become the research object of many scholars and experts.This heating system with double heat source solar heat pump and central heating system refers to the double heat source solar heat pump is arranged in the central heating system in heat exchange station,the double heat source of the heat pump is used in the solar energy collector and the central heating system,heat supply through the electric driven heat pump to enhance heat source.At the same time,the heat exchanger station heat exchanger two side water supply and water supply heat pump condenser by alternating or combined heat supply network of water.This system can make up for the instability of the solar heating,but also can solve the problem of the heat source load of the central heating or the transmission capacity of the pipe network.If the central heating with high back pressure cogeneration heating unit,the system can also reduce the steam inlet temperature of the steam turbine unit,improve the operational efficiency and operational stability of the unit.Firstly,this paper introduces the system structure and operation mode,discusses the system flow of each operating mode and draws the flow chart of each operating mode and gives the energy equation.On this basis,the system operation control strategy,the start and stop conditions of each equipment are summarized.Heat storage control use temperature difference control.heating control use constant temperature control.And first consider the use of solar heat,at full load operation of solar collector and central heating system is still unable to meet the load demand for heat pump under the condition of starting.In this system,the selection calculation and application of solar collector and heat storage equipment are analyzed,and the mathematical model of each operating condition is given.Taking a district in Ji’nan of Shandong Province as an example,the paper makes the transformation scheme and makes economic analysis.First of all,combined with the local solar energy resources,climate and design standards in Ji’nan,the load is analyzed.Calculate the total heating capacity of the district is 9229.44GJ,the maximum load is 4.608GJ/h,then draw the heat load duration chart.According to local conditions,analysis of the original central heating system heating capacity and operating parameters in previous years,in the best use of the original centralized heating system on the basis of solar collector and heat pump selection calculation.The operation modes of the system after transformation are analyzed,and the running time and heating capacity are calculated.The total running time,heat supply and overall energy consumption of solar heat collection system and heat pump system are analyzed.The results show that the average daily heating capacity of the solar collector system can be increased by 28%when the primary return water and the solar heat collecting system are used together.The annual operating cost is 13.9%lower than that of the gas-fired boiler,which is lower than that of the high voltage electrode boiler by 8.5%.Compared with other reconstruction scheme,the conclusion can be the effective use of solar energy to solve many problems of city central heating system of this system,which provides a reference for the application of dual source solar heat pump assisted central heating system. |
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