| The combined application of various forms of cold and heat sources is an important technical means for building energy systems to achieve higher energy conservation and emission reduction goals,to meet the heating and cooling needs of large public buildings or building groups and to improve the energy efficiency of air conditioning systems under the conditions of load and resource fluctuations.Because the air-conditioning system with combined cold and heat sources involves many subsystems and its composition is complex;The coupling degree of each subsystem is high and there are many key parameters.There are technical bottlenecks in the simulation,evaluation,design and operation of the coupling system.The existing research scenarios of the coupling system are not clear,and the system simulation model is lack of engineering data verification;The systematic evaluation involves many influencing factors and the mainstream methods are subjective;For the problems such as the lack of optimal configuration method and control system of complex composite cold and heat source system,this paper has carried out multiple studies on the composite system simulation model,evaluation system,optimal configuration and operation control,with a view to comprehensively optimizing and improving the coupling performance of the composite system under the guidance of the new evaluation system.The main research contents and results are summarized as follows:(1)In this study,the application forms of the composite cold and heat source air conditioning system are studied by means of literature research and questionnaire survey.The system forms with promotion value are summarized by means of expert scoring,and five typical scenarios are proposed as the main research objects of this paper.(2)In this study,the mathematical models of key components such as heat pump unit and system hydraulic calculation are developed,and five typical system dynamic simulation platforms are constructed to realize the fast and accurate simulation of typical composite cold and heat source air conditioning system.Compared with the engineering test and monitoring data,the error of the simulation results of the calculation platform is less than 10%.The dynamic calculation platform established can be extended to the simulation of similar systems,and establishes a basic platform for the theoretical calculation of typical composite cold and heat source air conditioning systems.(3)In this study,a qualitative and quantitative evaluation method is proposed to solve the problem of the lack of a unified evaluation method for the composite cold and heat source air conditioning system.Firstly,based on the multi-dimensional system cost,economic operation and environmental impact,a comprehensive evaluation index including 30 influencing factors is proposed;Secondly,the Monte Carlo simulation method is introduced to analyze and calculate the sensitivity of different influencing factors in the typical system,to eliminate the interference of subjective factors,and the analytic hierarchy process is used to build a comprehensive evaluation index system.On the premise that the number of samples is sufficient and the survey subject is comprehensive enough,the results of sensitivity analysis and analytic hierarchy process are in good agreement,and the maximum deviation is only 13.8%.The combination of sensitivity analysis and analytic hierarchy process makes qualitative and quantitative analysis compare and correct each other,and improves the scientificity and preciseness of the comprehensive evaluation system.(4)Based on the hybrid optimization algorithm and comprehensive evaluation system,this study proposes a goal oriented optimization method to solve the capacity allocation problem of each subsystem of the combined cold and heat source air conditioning system.Based on the large scale of the complex energy system,many types of equipment,many parameters involved in the optimization problem,highly nonlinear constraints,large amount of computation under the traditional algorithm,and difficult convergence,this study proposes a particle swarm optimization?Hooke-Jeeves hybrid algorithm with fast convergence and high accuracy.Compared with the traditional single optimization algorithm,the calculation speed of the hybrid algorithm is increased by more than 30%.Then a system optimization allocation method aiming at the above comprehensive evaluation indicators is proposed,and the differences of optimization results under different objectives are analyzed and compared.The results show that the optimization results under the guidance of comprehensive evaluation indicators are more comprehensive.Compared with LCC as the optimization objective,for example,the initial investment of the optimized system is only increased by 4.22%,but the renewable energy utilization rate is increased by 11.86%,and the carbon emission reduction is increased by 8.57%,It can better take into account economic and environmental benefits.(5)In this study,a hierarchical control system architecture suitable for the compound cold and heat source air conditioning system is proposed,which realizes the multi-level in-depth optimization of the system and the efficient coupling linkage control between different levels,and provides a method basis for the operation optimization research and application of this kind of system.In this study,the hierarchical control architecture of upper level-load forecasting,intermediate level-equipment start / stop priority and lower level-equipment control is proposed,and the simulation of different operation control strategies of typical systems is carried out under the guidance of comprehensive evaluation indicators.The optimal scheduling scheme,control optimization measures and target values of key control parameters are studied and summarized,and the operation control strategies suitable for typical systems are obtained.Compared with only intermediate or lower level control strategies,the hierarchical control strategies proposed in this study save energy by 13.75% and 5.98% respectively.This research focuses on the key technologies in the planning,design,operation and other processes of the composite cold and heat source air conditioning system.Through theoretical analysis and practical engineering verification,a comprehensive technical method system from simulation,evaluation,design to operation is proposed,which provides technical support for the evaluation and optimization of the composite cold and heat source air conditioning system,helps to improve its operating energy efficiency and further enhance its environmental benefits,and has important theoretical and application value. |
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