Research On Coordinated Optimal Scheduling Of CCHP Micro Energy Grid Based On Building Phase Change Energy Storage

In the context of the transformation of global energy production and consumption patterns,concepts such as integrated energy system and various types of energy networks have been proposed.The micro energy grid system is an extension of the concept of "micro grid",which is a kind of energy Internet.Through the unified planning and scheduling of multiple types of energy in the network,the waste of resources in the network can be reduced,new energy can be absorbed locally,and energy utilization can be improved.CHP units are responsible for cooling and heating tasks in summer and winter.Because CHP units themselves have rigid constraints of "setting power by heat" or "setting power by cold",it will lead to serious electric heating or electric cooling demand conflict,resulting in a large number of wind and light abandonment and environmental pollution.Energy storage technology is an important technical means to achieve energy decoupling and new energy consumption.In this paper,a phase change material energy storage integrated into the building wall is adopted to study the optimal scheduling of the combined cooling,heat and power generation micro energy network with phase change energy storage.The main research contents are as follows:Firstly,a micro energy grid model of Combined Cooling,Heating and Power(CCHP)with phase change energy storage is constructed.On this basis,the operation characteristics and mathematical model of each distributed micro source in the micro energy network are analyzed in detail,and the mathematical model including wind motor,photovoltaic cell,cogeneration system of cold and heat and power,and air source heat pump is established.In terms of energy storage,phase change energy storage technology can solve the micro energy grid energy supply and demand in time,space and strength does not match the contradiction,by comparing a variety of thermodynamic performance of phase change material itself,the phase transition temperature of composite phase change materials after winter and summer indoor temperature control requirements,based on the composite phase change materials building phase change wall model is set up,and each node based on the thermal resistance model of thermal heat balance equation obtained network parameters,as the theoretical foundation for further research.Secondly,to verify the construction phase change energy storage in reducing operation cost and peak sharpening effect,to optimize the cycle system operation cost minimum as the objective function is established,photovoltaic cells,cold hot electric installations,including wind motor system(gas turbine,waste heat boiler,gas boiler,heat exchange device),air source heat pump,and phase change energy storage type CCHP micro energy grid optimization model.The CPLEX solver in Yalmip toolbox was used to solve the model in MATLAB environment,and the optimal output of each distributed micro source,the energy storage state of the phase change energy storage system and the total operating cost of the system were obtained,which were compared with the micro energy network scheduling model without heat pump and phase change energy storage.The results show that the scheduling model established in this paper can relax the thermoelectric ratio of CCHP unit itself,reduce the total cost of system operation,increase the flexibility of the system,and can replace the air conditioning in function while realizing "peak load reduction and valley filling".Finally,based on the existing CCHP micro energy network model,considering that the user side can shift,transfer and reduce the flexible electric heating load to participate in the demand response scheduling,the optimal scheduling model of micro energy network is established with the goal of minimizing the total operating cost of the system.The CPLEX solver in the Yalmip toolbox was used to solve the model,and the optimization results of the flexible load participating in the scheduling were compared with those of the scenarios where the flexible load did not participate in the interaction and the electrothermal independent scheduling.The dispatching results show that the participation of electro-thermal flexible load can reduce the peaking and valley difference between electrical and thermal loads,smooth the load curve,and effectively reduce the system operation cost,so as to achieve the economic scheduling goal of minimizing the operation cost of the micro-energy network system.