Integration Research Of Building Cooling Heating And Power System Coupling Biomass,solar And Geothermal Energy

As one of the three major energy consumption sectors in China,building energy consumption is of importance.The safety,durable and stable energy supply is not only related to the economic development of China,but also have an impact on social stability and development.The combined cooling,heating and power generation system(CCHP)combines the energy resources with buildings,which can make the energy supply more efficient and safety.At the same time,the CCHP system combined with renewable energy resources not only realize the complementary integration of diversity energy,but also can adjust the energy structure,alleviate the energy shortage and reduce environmental pollution problems.Biomass,solar and geothermal energy are attracting more and more attention due to the environment frendily and abundant reserves.Therefore,it is necessary to investigate the building cooling heating and power system(BCHP)integrated with biomass,solar and geothermal energy.This study is expected to reveal the integration mechanism of biomass,solar and geothermal energy;put forward the coupling energy supply systems and investigate the performances of systems in terms of thermodynamics and exergoeconomics.In addition,a multi-objective optimization model of coupling energy supply system is established,which contributes to optimize the operation of energy supply system.The main contents of this dissertation are as follows:Firstly,the investigation of biomass partial gasification process is carried out according to the principle of moderate reaction.Through controlling the reaction time and temperature of partial gasification process,the carbon conversion ratio(CCR)of biomass decreases which realizes the biomass partial gasification,and the investigation of exergy destruction of partial gasification can verify its feasibility.According to the principle of cascade utilization of physical energy and chemical energy,the mechanism of upgrading energy level from solar thermal energy to bio-gas is studied on the basis of concept of energy level.Moreover,the correlation characterstics between temperature of warm water derived from condenser of ground source heat pump(GSHP)and its coefficient of performance(COP)are also investigated,the decrease in temperature of warm water derived from condenser contributes to improve the COP of GSHP and decrease the exergy destruction of condenser.The application of above innovative methods provides various novel ideas for the energy complementary integrated system.Secondly,based on the mechanism of upgrading energy level from solar thermal energy to bio-gas,a building cooling heating and power system integrated with biomass and solar enegy is put forward.By help of Aspen Plus software,thermodynamic performances of coupling system are completed in terms of the first law of thermodynamics and the second law of thermodynamics.The influence characters of key integrated parameters of coupling system are analyzed.Namely,the influences of air equivalence ratio(ER),steam/biomass ratio(SBR)and solar collected temperature on system performances are studied.The Sankey diagram is adopted to analyze exergy flow of coupling system so as to analyze the energy utilization efficiency and exergy destruction of equipments clearly,which can provide guidance for further energy saving.In addition,the advantages and disadvantages between coupling system and reference separated system are carried out from the point of view of energetic,economic and environmental aspects.Next,according to the mechanism of biomass partial gasification and water temperature upgrading of ground source heat pump,a building heating and power system integrated with biomass and geothermal enegy is presented.By help of Aspen Plus process simulation software,the thermodynamic performances of coupling system are completed in terms of the first law of thermodynamics.The influence characters of key integrated parameters of coupling system are analyzed.Namely,the influences of carbon conversion ratio(CCR),and temperature of warm water on system performances are investigated.At the same time,the exergoeconomic performance of coupling system is also studied through the establishment of exergetic analysis and exergoeconomic analysis model.Namely,the variations of equipment economy and product cost of coupling system are presented.Finally,the multi-objective optimization model is developed,which take the building heating and power system integrated with biomass and geothermal as research objective.In the model,the three key parameters: prime mover capa city,carbon conversion ratio and temperature of warm water are considered as optimized variables,and the primary energy saving ratio(PESR),annual total cost saving ratio(ATCSR)and CO2 emission reduction ratio(CO2ERR)are selected as the optimized objective.The optimized problem is solved by help of genetic algorithm(GA)in MATLAB program.And the influence characters of key integrated parameters on performances of coupling system are analyzed,which contributes to verify the reliability of the results of genetic algorithm in the optimization processes.In addition,the influences of biomass price,natural gas price and electricity price on performances of coupling system and equipment capacity are also studied.