Environmental Effect And Cost Increment Of Green Roof In Life Cycle

In recent years,China’s rapid urbanization has brought many urgent problems to cities,one of which is the rapid growth of urban population.Due to the increasing urban population,the urban construction land has become tight,and due to the land construction,the corresponding green space resources are becoming more and more tight,which makes the green area decreasing.In addition,rapid urbanization makes the human cluster effect more and more obvious,which makes our cities suffer from many "diseases" : urban waterlogging,air pollution,increasingly serious urban "heat island effect",sharp reduction of biodiversity,water pollution In this context,green buildings and sponge cities,which are constantly mentioned in the development plans of various countries,can be used as one of the important forms to increase the green area and improve the urban living environment.Green plants can be planted on the roof of buildings to increase the green space of the city.In this context,green buildings and sponge cities,which are constantly mentioned in the development plans of various countries,can be used as one of the important forms to increase the green area and improve the urban living environment.Green plants can be planted on the roof of buildings to increase the green space of the city.Green roof plays a significant role in alleviating the urban heat island effect,improving the urban living environment,decorating the urban landscape and improving the quality of residents’ living environment.Greening the roof can properly alleviate the problem of energy consumption and improve the comfort of urban living environment.However,there is less analysis on the environmental and economic benefits of green roof in the existing research.This study aims to analyze the environmental and economic benefits of green roof of four modules through experiment,research and analysis,so that the green roof can be better popularized.In this thesis,a variety of green roof technologies are combined,and four combined green roofs（solar ventilation green roof,natural ventilation green roof,water storage green roof and ventilation water storage green roof）and bare roof test platforms are set up.The thermal insulation properties such as module bottom temperature,heat transfer and heat flow of the four green roofs are experimentally studied and measured,The measured data obtained from the experiment and the variation law of the data are analyzed,and the following conclusions are obtained: the four green roof modules have good heat insulation ability.The experiment shows that the lowest average temperature at the bottom is module B,the average temperature is 29.03 ℃,module A is close to it,the average temperature at the bottom of module is 29.10 ℃,the average temperature at the bottom of module C is30.80 ℃,and the average temperature at the bottom of module D is 31.53 ℃,Compared with the measurement point e of bare roof,modules A,B,C and D are lower than those of bare roof: 9.27 ℃,9.34 ℃,7.57 ℃ and 6.84 ℃.In this thesis,the application status and ecological and economic benefits of green roof technology are analyzed by the combination of literature research and experimental measurement.According to the calculation and analysis of the experimental measured data,the four green roof modules A,B,C and D are studied and analyzed,and compared with the measurement point F of the bare roof,the differences of cooling and heat insulation effect,heat transfer and heat flow,energy conservation and emission reduction of each module are obtained.At the same time,the environmental benefits of green roof are analyzed,including energy conservation and emission reduction（carbon reduction）,carbon fixation and oxygen release benefits,and air purification benefits.The annual power saving per unit area of modules A,B,C and D is obtained.Module a is 24.35 kw · h,module B is 24.58 kw · h,module C is 19.96 kw · h and module D is 18.03 kw · h.The annual carbon reduction per unit area of each module is 17.82 kg,17.99 kg,14.61 kg and 13.19 kg.Then,the cost accounting of the four green roof modules in the whole life cycle is carried out respectively,and the economic analysis of their cumulative income and cost is carried out.It is concluded that module C can reach the balance of revenue and expenditure in only 1.17 years,and the four modules can enter the revenue period in an average of only 1.305 years.Therefore,it is concluded that the green roof has good economic benefits.Finally,according to the research results,put forward relevant development suggestions.