Thermal Performance Calculation And Optimization Design Tool Development Of Phase Change Heat Storage Wall

With the development of building energy consumption increasing dramatically,building energy conservation has become an important part of sustainable development.Improving thermal performance of building envelope is the foundation and important guarantee of building energy conservation.Thermal insulation performance and thermal storage performance of walls play an important role in maintaining stable indoor thermal environment.As a result,new building envelopes(such as phase change thermal storage wall)emerge gradually in engineering.Because of variable physical properties of phase change materials,it is necessary to use nonlinear equation of variable physical parameters to describe heat transfer process.On the other hand,Thermal design of phase change thermal storage wall should be adapted to the regional climate.Phase change temperature,thickness,and the type and thickness of insulation material are also different in different regions.It is necessary to optimize the design of phase change thermal storage wall.In this paper,first,from the perspective of thermal calculation and optimal design of phase change thermal storage wall,heat transfer calculation program of phase change thermal storage wall is developed on the basis of investigation on the field in domestic and foreign literatures.The verifications of the model are carried out and the integrated application of DeST is completed.Second,the evaluation index(J)of energy saving performance of free-running building is put forward.The calculation program of indoor air temperature and the evaluation index is written.Last,based on genetic algorithm,the multivariate single-objective and multi-objective optimization models are established and the optimal design program is developed.The main research work is as follows:(1)This paper investigates the advantages and disadvantages of heat transfer calculation model for phase change heat storage wall in domestic and foreign literatures and mainstream softwares.On this basis,the heat capacity mathematical model,finite difference method and successive over relaxation iteration algorithm are used to develope heat transfer calculation program of phase change heat storage wall by MATLAB.Theoretical validation,EnergyPlus validation and scale model experiment validation have been carried out from three verification aspects.Based on FMI(functional mock up interface)and FMU(functional mock up unit),the dynamic coupling of heat transfer calculation of phase change heat storage wall and energy consumption simulation is achieved in DeST.This work is of great significance to quantitatively evaluate the effect of phase change thermal storage wall.(2)On the analysis of the characteristics of energy saving performance evaluation index in the existing standards and literatures,it is clear about the influence factors of energy saving contribution evaluation index of the room with phase change heat storage wall.Based on human thermal adaptation model,from the perspective of degree hours between annual indoor or outdoor air temperature and comfortable temperature,building envelope energy saving contribution evaluation method is proposed and the concepts of the benchmark degrees hours,design degrees hours and adjustment degree hours of building envelope are defined.A trade-off method is established based on energy saving contribution evaluation index of building envelope.Selecting the living room as the research object,the application effect of BioPCMs in seven cities in cold region is evaluated.This work can provide reference for the evaluation of energy saving performance of building envelope.(3)The process,the basic principle of genetic algorithm and MATLAB genetic algorithm toolbox are introduced.The single-objective optimization model is established based on genetic algorithm with construction parameters as design variables and adjustment degree hours of building envelope as objective function,and the multiobjective optimization model is established by combining with PWF economic index.The multi-variable single-objective and multi-objective optimization design programs are developed.A design case of the room with phase change material illustrates the practice of the program.The heat transfer calculation and optimization tool is introduced in structure,interfaces,and main functions.The tool can be used to analyze regional climate suitability of phase change heat storage wall.It is convenient for architects to optimize the design of phase change thermal storage wall in engineering practice.