Life Cycle Assessment Of Office Buildings

With industrialization and urbanization in the past several decades, the development of architecture is rapid in expectation. The consumption of natural resource of construction industry is tremendous, and the consumption of electricity, water, natural gas, etc. in the operation stage of buildings account for 30% of the total energy consumption of the whole society, the solid waste productions created after building demolish stage account more than 300 million tons, and the re-utilization rate of these construction garbage in China is extremely low, this not only cause huge waste of resources in our country, but also result in the serious environmental influence of land and water resources.The life cycle assessment approach is applied in this study, we choose a green office building in Beijing and a normal office building in Ningxia as two case studies. In the model of "from cradle to cradle" and based on the life cycle assessment software, named "Simapro", we calculate the energy consumption, environmental impact, environmental benefits of different energy conservation and emissions reduction measures of the three building stages, building material production stage, building operation stage, and building material re-utilization stage.From the results of this study, we conclude that building operation stage is the biggest contributor to the total energy consumption and environmental impacts of office building, even we only consider the electricity consumption and central heating in the operation stage. The energy consumption and environmental impact in the building material production stage are appreciable, and steel, concrete, glass, aluminium alloy have greater contribution than other materials, which regarded as main materials. We also choose the four materials for waste disposal scene.The environmental impacts can be reduced by7.3%, 1.6% and 0.8% by using 30% gas-fired electricity generation, increasing the summer indoor temperature by 1°C and switching off office equipment and lighting during lunchtime, respectively. Similarly, by reusing 80% of the selected materials when the building is finally demolished, the three major adverse environmental impacts of human health, ecosystem quality and resource depletion can be reduced by 11.3%,12.7% and 7.1% respectively. At the same scenarios, these environmental impacts of the normal office building will reduce 11.9%,20.6% and 4.2%. The calculation of payback period show that when the service time of the green building achieved 6 years, the static incremental cost of the use of green buildings can returned, and the dynamic incremental cost need 8 years as life span. The sensitivity coefficients of the electricity consumption are much bigger than those of the application amount of the chosen materials. And the longer the service time the building is, the smaller the total energy consumption, and the environmental impact is.