Multi-objective Optimization Of Exterior Window System For Office Building In Guangzhou Based On Building Energy Consumption And Thermal Comfort

With the rapid development of social economy and the continuous improvement of people’s living standards,the size of urban office buildings,the building energy consumption and the people’s requirement on the environment and thermal comfort of the office space continued to grow.The office building energy consumption in Guangzhou is mainly composed of air conditioning and lighting energy consumption,which are closely related to building envelope(especially the exterior window).So the optimization of the building envelope could effectively reduce the comprehensive building energy consumption,and ensure a favorable thermal comfort simultaneously.In this paper,the exterior windows of office building in Guangzhou were selected as optimized object,the energy consumption and thermal comfort were adopted as optimization goals,then the multi-objective optimization problem was established,and finally found the analytical solution through parallel computation with EnergyPlus and GenOpt.The main works consisted of the following parts:Firstly,two typical algorithms,the traditional algorithm and genetic algorithm,for solving multi-objective optimization problems,were compared and summarized for the pros and cons.After that,the genetic algorithm based on weighted sum method was chosen as the main algorithm for solving the multi-objective optimization problem in this paper.Secondly,the control variables and optimization variables were determined and parameterized,so as to set up the mathematical model of multi-objective optimization problem of this paper.Then the impact of individual variables on building energy consumption and thermal comfort were analysed respectively.The blinds’ hourly optimal angle for each oriented room in the working days of 12 months were summed up.Based on the analytical results,the potentiality of different shade forms to reduce building total power consumption and Predicted Percentage of Dissatisfied(called PPD for short)was compared.Thirdly,the optimal solution of shading devices for different oriented rooms were found.Eight typical shade forms,including no shade,fixed interior blind,fixed exterior blind,horizontal shade,vertical shade,integrated shade,adjustable interior blind,adjustable exterior blind were analysed respectively to get the optimal solution.Finally,the compared results showed that for the south,east and west oriented rooms,the adjustable exterior blind could reduce the most total power consumption,which was about 9.4% to 14.4% compared with the rooms without any shade devices,while for the north oriented rooms,the best performer was integrated shade that could reduce about 2.6% to 4.4%.For rooms with all different orientations,the fixed exterior blind with 0° angle,whice was also called “baffle shade”,could reduce the most PPD,which was about 14.4% to 26.3%.Comprehensively,the exterior shade performed better than the interior shade,and the adjustable blind better than the fixed one.