Research On Optimal Scheduling Of CCHP System Coupled With Renewable Energy

Traditional energy system,which mainly consumes fossil energy,has become one of the focuses of energy consumption intensity control as the proposition of carbon peaking and carbon neutrality goals.Coupling renewable energy turns into an important trend of combined cooling,heating,and power（CCHP）system optimization in the future.The input of renewable energy makes CCHP system show the characteristic of multi-energy complementation on source side.However,the uncertainty of renewable energy and the diversity of demand exacerbate the contradiction between source and load side.Hence,it is necessary to optimize the configuration and operation mode of CCHP system coupled with renewable energy.In this paper,a model of CCHP system coupled with solar energy and wind energy was constructed,and the operation mode was optimized by improving the following electrical load strategy,which was one of the traditional operation modes of system.Taking the economic,environmental and energy performances of system as optimization objectives,the non-dominated sorting genetic algorithm II was adopted to optimize model,and the optimal configuration of system was determined by technique for order preference by similarity to ideal solution based on the analytic hierarchy process.In the decision-making process of operation mode,except for the economic,environmental and energy performances of system,the matching of system was still considered.Here,the matching degree between system and buildings was analyzed by comparing the thermoelectric ratio of source and load side;considering the on-site energy fraction,on-site energy matching,net interaction level and grid integration level,the matching evaluation system of CCHP system was performed to investigate the matching degree between optimization strategy and system.In the process of configuration optimization,the feasibility of reducing the influence of system uncertainty by day-ahead prediction was judged by the accuracy verification of renewable energy output prediction on the source side of system.The optimal configuration of solar energy coupled CCHP system was determined by contrasting system performance of two forms of solar thermal utilization;optimizing the configuration of wind coupled CCHP system by comparing the system performance with or without wind turbine.Sensitivity analyses of natural gas price,electricity price,photovoltaic laying area and initial investment subsidy were implemented.Finally,based on the operation and configuration optimization of CCHP system coupled with renewable energy,the interconnection optimization of different buildings was implemented.The office,residence and hotel buildings in Shijiazhuang were taken as research objects to carry out the above optimization.The optimization results show that when CCHP system run in following electrical load with photovoltaic priority strategy,the comprehensive performance of system in three types of buildings were improved by 0.61%,1.59%and 0.44%respectively than the system performance of following electrical load with internal combustion engine priority strategy.In terms of building and system matching,the hotel building obtained the highest matching degree,and the two improvement strategies had their own advantages in system and strategy matching analysis.Photovoltaic,solar collector and wind turbine coupled CCHP system was the optimal configuration of system;The economic,environmental,energy and comprehensive performances of hotel building system were increased by 2.66%,2.73%,2.73%and 2.66%respectively when the system operation state was not changed for hot and cold interconnection throughout the year.When the operation state of system was changed for interconnection optimization,the overall daily operation cost was reduced by 0.195%,the primary energy consumption was decreased by9.256%,and the CO₂ emission was diminished by 17.034%.