A future bamboo-structure residential building prototype in China: Life cycle assessment of energy use and carbon emission
Highlights
• A bamboo-structure residential building is analyzed based on energy and carbon flows. • It has lower embodied energy and carbon than an alternative brick-concrete building. • Three scenarios are designed based on the LEED standard and available technologies. • The largest potential is recycling, followed by use of recycled-content material. • The practical effect significantly depends on level of management and technologies.
Introduction
More and more evidences show that excessive consumption of fossil fuels leads to global warming, of which the most influential factor is carbon emission. In China, construction industries consume about 40% of the natural resources, representing 20–30% of the national energy requirements and 30–40% of all the urban materials generated [1], [2]. Embodied energy of a building typically accounts for 20% of its energy use during a 50-year life cycle and is equivalent to 10–20 times its annual energy use [3]. Therefore, it is necessary to study the energy and carbon flows over the life cycle of a building and develop strategies for their reductions in energy use and carbon emission.
At present, life cycle assessment (LCA) is used as a tool to assess the environmental impacts of product systems and services, accounting for the emissions and resource uses during the production, distribution, use, and disposal of a product [4]. The method is also applied to buildings to see which phase of the life cycle of buildings and which type of buildings consumes more energy and have more greenhouse gas emission [5]. In fact, some countries or organizations have already developed and implemented their life cycle CO2 assessment programs, for example, SUSB classified the life cycle of buildings into a construction stage, an operation stage, a maintenance stage and a dissolution/disposal stage; and provided a simple analogy method of evaluating CO2 emissions of an apartment house based on five standard apartment houses in South Korea [6]. However, Sartori and Hestnes [7] reviewed that only a few studies included the recycling of building materials after demolition, even fewer during construction, although most of the literatures analyzed the embodied energy and/or carbon based on the building life cycle assessment. In the past few years, recycling of the building waste generated over the building life cycle has been a feature of some building life cycle studies in Europe. Thormark [8] investigated 20 apartments in four two-storey rows in Sweden and found that the recycling potential of building waste was between 35% and 40% of the embodied energy. Gustavsson et al. [9] systematically analyzed the energy and carbon balance of the recovery of wood residues from forest harvest, wood processing, and construction and demolition activities over the life cycle of an eight-storey wood-frame apartment. Dodoo et al. [10] investigated the effects of post-use material management on the life carbon of buildings. He compared the carbon balance of a concrete-frame building to that of a wood-frame building, and calculated the carbon flows associated with fossil fuel used for material production, substitution of fossil fuels by recovered wood residues, recycling of steel, and fossil fuel used for post-use material management.
In terms of building types and materials, Gustavsson et al. [11] compared the net carbon emission from the construction of concrete- and wood-framed buildings, and found that the lifecycle emission difference between the two types of buildings ranged from 30 to 130 kg C per m2 of floor area. Brad Upton et al. [12] analyzed the greenhouse gas and energy impacts of using wood instead of alternatives in residential construction in the United States based on CORRIM data, and concluded that, over a 100-year period, houses with wood-based wall systems required 15–16% less total energy for non-heating/cooling purposes than thermally comparable houses employing alternative steel- or concrete-based building system, and net greenhouse gas emissions associated with wood-based houses were 20–50% lower than emissions associated with thermally comparable houses employing steel- or concrete-based building systems. However, the energy use and carbon emission of bamboo-structure buildings were hardly investigated and quantified, although van der Lugt et al. [13] analyzed the general environmental loads of bamboo culms divided into each phase of processing, preservation and transportation through the TWIN2002 model.
In this paper, first, the bamboo-structure building is compared with an alternative brick-concrete building to distinguish intrinsic differences of the embodied energy and carbon emission between them. Second, a comprehensive assessment over the life cycle is conducted along material flows based on the technical potentials and the current LEED standard [14], which involves practical factors on use of recycled-content materials and recycling of construction and demolition waste.
Section snippets
Prototype descriptions
The bamboo-structure residential building prototype is built to optimally integrate traditional architectural design concepts with innovative insulation technologies. The aim is to build one of different types of sustainable residential buildings for the future in China if appropriate.
The building with a standing seam roofing system consists of a living room, a bedroom and a washroom with a total floor area of about 52 m2. The sustainable, hard and durable bamboo is used as supporting structures
Method
The method of life cycle assessment (LCA) is applied, which assesses environmental impacts associated with all the phases of the building from raw material extraction through materials processing, manufacture, transportation, use, and disposal or recycling. It is noted that the energy use and carbon emission are analyzed based on material flows, and not discussed in the operation phase of the building in this study.
The bamboo-structure vs. brick-concrete building
Before the bamboo-structure building is assessed, a general basis should be defined to quantify the difference between them. No matter what type of building it is, the purpose is to provide a good, durable and reliable place to live or work with some representative functions, especially envelope insulation and structure supporting. Consequently, the assessment of the energy use and carbon emission should be conducted within the boundary of the functional requirements of the building.
A typical
Discussion and conclusions
The study reveals where and how the material-based energy use and carbon emission are reduced over the life cycle of the bamboo-structure building, and reaches the following conclusions:
- (1)
The bamboo-structure residential building prototype with innovative insulation technologies has lower embodied energy and carbon than an alternative brick-concrete building with identical functional requirements, i.e., envelope insulation and structure supporting. It implies that the bamboo-structure building
Acknowledgements
The author gratefully acknowledges the support provided by Science and Technology Commission of Shanghai Municipality (Project number: 09dZ1202603) and like to thank anonymous reviewers, Dr. Zhi Zhuang, Dr. Naiping Gao and Kyle Griffith for their constructive comments and recommendations.
References (22)
- et al.
Life cycle assessment of buildings: a review
Renewable and Sustainable Energy Reviews
(2011) - et al.
The development of apartment house life cycle CO2 simple assessment system using standard apartment houses of South Korea
Renewable and Sustainable Energy Reviews
(2011) - et al.
Energy use in the life cycle of conventional and low-energy buildings: a review article
Energy and Buildings
(2007) A low energy building in a life cycle-its embodied energy, energy need for operation and recycling potential
Building and Environment
(2002)- et al.
Life cycle primary energy use and carbon emission of an eight-storey wood-framed apartment building
Energy and Buildings
(2010) - et al.
Carbon implication of end-of-life management of building materials
Resources, Conservation and Recycling
(2009) - et al.
The greenhouse gas and energy impacts of using wood instead of alternatives in residential construction in the United States
Biomass and Bioenergy
(2008) - et al.
An environmental, economic and practical assessment of bamboo as a building material for supporting structures
Construction and Building Materials
(2006) - et al.
Analysis of embodied energy use in the residential building of Hong Kong
Energy
(2001) - et al.
On-site sorting of construction and demolition waste in Hong Kong
Resources, Conservation and Recycling
(2001)