مصرف انرژی گنجانده شده ی ایجاد مهندسی ساخت و ساز : مطالعه موردی در شهر الکترونیکی، پکن

Presented in this paper is a detailed embodied energy consumption evaluation framework for building construction engineering. The building construction engineering comprises nine sub-projects, which are Structure and outside decoration engineering, Primary decoration engineering, Electrical engineering, Water supply and drainage engineering, HVAC engineering, Civil engineering, Municipal electrical engineering, Municipal water supply and drainage engineering and Gardening engineering. Our study chooses the construction engineering of a cluster of landmark commercial buildings in E-town, Beijing (Beijing Economic-Technological Development Area, BDA) as a case. As far as we know, this study is the first attempt to account the embodied energy consumption for building construction engineering based on the most exhaustive first-hand project data with about 1000 input items in the Bill of Quantities (BOQ). The embodied energy consumption of construction engineering is quantified as 7.15E+14 J. Structure and outside decoration engineering contributes more than half of the total embodied energy consumption, followed by Primary decoration engineering's 23% and Electrical engineering's 3%, respectively. As for the input items, the sum of the embodied energy consumption by steel, cement, lime and metal products is more than 3/4 of the total embodied energy consumption.

According to Energy Information Administration (EIA), building-related energy consumption (5.3 million tons of standard coal) accounts for about 29% of the global energy consumption in 2007 (17.9 million tons of standard coal) [1], while the proportions for many developed countries are even larger [2] and [3]. In China, about 1/4 of the total energy consumption is due to building construction in 2007 [4], [5], [6] and [7]. The earliest building energy consumption accounting only considered the direct energy consumption in the construction and operation process of buildings. Along with the introduction of the life cycle concept, some researchers began to consider the indirect energy consumption which occurred during the building materials’ production [8], in which some major indirect energy consumption caused by some key inputs were traced, such as energy consumed by the electricity generation and iron and steel smelting. Most of the existing studies employed the process analysis method to investigate the indirect energy consumption of buildings [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20] and [21]. For instance, the energy consumption of an eight-story wood-frame apartment building in Sweden and a six-story building in the campus of the University of Michigan was measured [14] and [18], and the energy consumption of some building materials was analyzed [8]. These efforts have contributed significantly to the development of the energy consumption assessment for buildings. However, several limitations, especially the truncation errors, are also observed in the process based studies [22]. In recognition of the limitations of the process analysis, some researchers tried to assess the energy consumption of buildings on the basis of input–output analysis, under which all buildings in the same country or region are analyzed as an economic sector. Nässén et al. used input–output analysis to evaluate the direct and indirect energy consumption of Swedish construction industry and compared the accounting results of the top-down and bottom-up methods [23]. A linear mathematical model similar to input–output analysis was established by Ziębik et al. to calculate the coefficients of cumulative energy consumption in complex buildings [24]. Although providing a complete economy modeling can avoid the truncation error of process analysis, the input–output analysis tends to be applied to macro analysis, i.e., it is not applicable for specific building's energy consumption accounting.

An embodied energy consumption evaluation framework for building construction engineering in terms of nine sub-projects of six commercial buildings in E-town (BDA, Beijing) is presented in this paper. The hybrid method as a combination of process and input–output analyses is applied. This study is the first attempt to account the embodied energy consumption for building construction engineering based on the most exhaustive first-hand project data with about 1000 input items in the BOQ. The results show that the total embodied energy consumption of construction engineering is 7.15E+14 J, with an intensity of Structure and outside decoration engineering as 9.74E+09 J/m2. It is comparable to the results in the similar studies. The embodied energy consumption of Structure and outside decoration engineering shares the greatest proportion of the total embodied energy consumption, followed by Primary decoration engineering and Electrical engineering. The curtain wall related products contribute about 4/5 of the energy consumption of Primary decoration engineering and 1/5 of the whole construction engineering. To achieve the goal of energy conservation, the curtain wall systems with the thermal insulation materials, e.g. Low-E glass, are suggested to be applied in buildings. As far as materials and products are concerned, steel products from Rolling of steel sector rank first and account for more than 30% of the overall embodied energy consumption of construction engineering, followed by concrete products from Manufacture of cement lime and plaster sector. The results indicate that building construction industry is an indispensable driving force for promoting the other industries, especially Rolling of steel sector, Manufacture of cement lime and plaster sector and Manufacture of metal products sector. The energy-saving measures in steel and concrete industry could play an important role in reducing the energy consumption of the building construction industry.