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Chinese Net Zero Architecture from Life Carbon Assessment (LCA)

The issue of climate change has become a critical priority, with the architecture industry being a significant contributor to global CO2 emissions, accounting for 38% of energy-related emissions. To address this, the Paris Agreement of 2015 set a goal to limit global warming to less than 2 degrees above pre-industrial levels, with a target of no more than 1.5 degrees.



This requires the architecture industry to achieve net zero carbon emissions by 2050. China, at the 75th session of the United Nations General Assembly in September 2020, announced its commitment to peak carbon emissions before 2030 and achieve carbon neutrality by 2060, as part of its efforts to effectively address global climate and environmental concerns.


Life Cycle Assessment (LCA) is a comprehensive approach for evaluating the environmental impact of a product throughout its entire lifecycle, from sourcing raw materials to production, transportation, use, and disposal. In the context of architecture, LCA is used to assess the carbon emissions generated by the materials, construction, and use of a building over its entire lifecycle, including demolition and disposal

© Xiaohang Hou

By considering all stages of a building's lifecycle, LCA provides a more complete picture of its environmental impact and can help identify opportunities for reducing emissions. Along with conventional architectural and technological approaches, such as optimizing natural light and increasing insulation, exploring methods to reduce emissions throughout every stage of the building's lifecycle is key to achieving net-carbon buildings.

 
1. Product stage:

When developing a building, it is important to take into account the carbon emissions associated with the sourcing and transportation of materials. One way to mitigate these emissions is by using materials sourced from nearby locations, rather than transporting them from far away. This requires careful consideration of materials and their sourcing during the early stages of a building's development.


Additionally, utilizing local resources can also help to reduce the carbon footprint associated with the gathering and transportation of materials. The first step towards achieving this goal is to make rational and sustainable choices about the materials used in a building's construction.


Changqi Stadium Bamboo Corridor:
© Jiancong Chen

The project is located in Changqi Ancient Village, Lubao, Foshan, Guangdong Province. Changqi Village is one of the first batches of ancient villages recognized in Guangdong Province and Lubao Town is well-known for its bamboo weaving tradition. The project was to renovate an old basketball court located between the village's wind pond and the village's ancient buildings.


Atelier cnS decided to use local materials to construct a bamboo corridor for the basketball court. The bamboo corridor is built using modular modules, which can be easily adapted to the village's growth and demands and can be removed and recycled in the future. The project is surrounded by Moso bamboo, which is abundant in the bamboo village behind the ancient village.

 
2. Constructure process stage:

Prefabricated assembly buildings have gained popularity in recent years, as they have been shown to have significant advantages in terms of construction efficiency, energy savings, and pollution reduction when compared to traditional building methods.


By minimizing the use of raw materials and energy during construction, prefabricated buildings can lead to significant reductions in carbon emissions associated with waste. In fact, studies have shown that prefabricated buildings can save up to 24.99% in carbon emissions compared to typical cast-in-place buildings.


Lakeside Plugin Tower:
© Weiqi Jin

The Lakeside Plugin Tower is a 480-square-meter mixed-use development that serves as a prototype for the Xiong'an New Area. Developed in collaboration with the Shenzhen Institute of Building Research, a world-renowned organization in sustainable building design and urban planning, the tower aims to minimize its impact on the environment. One of the ways this is achieved is through its design, which utilizes a distributed concrete pier base, which helps to reduce the building's influence on its surroundings.

 
3. Use stage:

Carbon emissions during the use and maintenance phase of a building primarily come from heating, cooling, and power generation, with heating and cooling accounting for about 22% of a building's total energy consumption. To reduce these emissions, the focus must be on energy efficiency and the use of renewable energy sources.


This can be achieved by using energy-efficient lighting in buildings, and by implementing renewable energy sources such as solar, wind, and geothermal energy to replace fossil fuels. These measures can help to significantly reduce emissions and contribute to a more sustainable future.


Nanjing Green Light House:
© Archiland International

The Nanjing Green Lighthouse is designed with the goal of reducing energy consumption as the primary principle. This is achieved through "intelligent design" which reduces energy consumption to 60% of the Chinese standard demand baseline. The building's design includes precise calculations to achieve maximum energy efficiency through the top and perimeter lighting, a novel ground-source heat pump system for cooling and heating, and a "variable air volume" fresh air system for ventilation.


Additionally, the design maximizes the use of renewable energy, reducing energy demand by approximately 20% through active design and the incorporation of renewable energy sources such as rainwater and wind energy. The building also has solar photovoltaic arrays installed on top and around it.

 
4. End-of-life stage:

In addition to prolonging the useful life of a building, improved resource optimization and the reuse of waste can help to reduce carbon emissions at the end-of-life stage. According to the inverted waste disposal pyramid, the best option is to reuse waste components after demolition.


For example, scrap windows, doors, and steel constructions can be recycled and reused. Additionally, recycling involves collecting and processing waste to be used again. The goal is to reduce the amount of waste sent to landfills and minimize the environmental impact of building demolition and disposal.


Zero Pavilion: A Zero Carbon Garden:
© Ren Jun, He Zhihan

Creating a zero-carbon garden involves several steps, the first of which is to utilize plants' ability to sequester carbon for carbon fixation and oxygen release. Another method is offsetting carbon emissions generated during the construction process through the use of renewable energy. Additionally, using scrap or recycled materials can help minimize material consumption and contribute to a carbon-neutral landscape garden. By taking these steps, a garden can be designed and constructed to have a minimal impact on the environment.


The design phase of a building project should take into account all stages of the building's lifecycle, including material selection, construction, use, and end-of-life waste management. By considering all of these factors early in the design process, it is possible to create a building that ultimately achieves net zero architecture. It's important to be comprehensive and make decisions that are sustainable for the entire life cycle of the building to achieve the goal of net zero.

 
While there are a number of challenges associated with the implementation of LCA in China, such as lack of standardization and data, the increasing demand for new buildings and availability of sustainable materials and construction methods presents significant opportunities for net zero architecture in the country.
 

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