Research On Green Roof Design Based On Building Energy Consumption Evaluation

In recent years,urbanization has continued to develop,and building energy consumption has increased significantly.The roof is the envelope structure that receives solar radiation for the longest time,and has great potential for energy saving.Green roofs reduce the energy consumption of air-conditioning cooling in summer and have obvious energy-saving effects.However,in winter,the reduction in energy consumption of air-conditioning heating is relatively small^[1-2].Therefore,this thesis focuses on four key issues to study summer office buildings in Xuzhou Green the roof.First of all,the current situation of green roofs in Xuzhou is studied through actual measurement and questionnaire methods:this study investigated 13 green roof buildings in Xuzhou on the spot,and selected two office buildings for questionnaire survey and a week-long actual measurement.（1）Through SPSS analysis of the reliability and validity of the questionnaire,the reliability of the material market and Jiangsu Jiatianxia Pension Service Co.,Ltd.were 0.724 and 0.783,and the validity was0.813 and 0.798,respectively,both of which were good.66%of the respondents believe that the green roof area in Xuzhou is insufficient.（2）The actual measurement results show that,compared with no green roof,the average value of the highest indoor temperature,outer surface temperature,and inner surface temperature of the green roof building of Building No.2 of the Material Market（the highest value per day during the actual measurement period）is 0.4℃,11.5℃,and 3.9℃respectively.The average daily air conditioning cooling load per unit building area of the green roof top room is1.05k Wh/m2,which is 0.21k Wh/m2 lower than that,and the energy saving rate is16.70%.;Jiangsu Jiatianxia Elderly Service Co.,Ltd.is 0.5℃,12.0℃,4.1℃lower than it,respectively,and the average daily air conditioning cooling load per unit building area is 1.07k Wh/m2,which is 0.22k Wh/m2lower than that,and the energy saving rate is 16.9%.Secondly,through literature research to answer the energy consumption evaluation standards of office buildings:summarize and compare domestic and international public building energy consumption evaluation standards,such as CEC,EMS-Ⅱsystem,PAL,ECIPB,EUI,comprehensive energy consumption of lighting and air conditioning,etc.,and select the appropriate one Evaluation standard for energy consumption of office buildings.The air conditioning system in office buildings accounts for the largest proportion of energy consumption,so the air conditioning cooling load per unit building area and energy saving rate are selected as the evaluation criteria.The smaller the air conditioning cooling load per unit building area,the better,and the larger the energy saving rate,the better.Once again we are based on actual cases,simplify the model,and study how to optimize the design of green roofs through Energy Plus simulation method,for the Xuzhou area.The following conclusions are drawn:the soil thickness of the green roof should not exceed 0.3m;the smaller the soil thermal conductivity the better;the bigger the leaf area index the better;you can choose Crassulaceae,Carpet Grass,Photinia,Boxwood,Ligustrum lucidum,Banyan Tree,etc..Simulation results show that the suitable orientation range for green roof buildings in Xuzhou area is 30°east by south-15°west by south,the best orientation is 15°-30°from south to east;flat roofs should be selected as far as possible.If there are design requirements for sloping roofs,the roof slope should be set within 30°.Finally,I will answer how to design and practice the green roof of office buildings in Xuzhou:Take No.2 of the material market as an example,introduce the design steps of modular green roof and give a cost suggestion of about 204 yuan/m2,and use the above simulation conclusions in the design.Comparing the energy consumption results with the original bare roofs in the materials market,it is concluded that the energy-saving rates of the green roofs is 27.0%.