2. Description of the Case Studies Buildings and Environment
2.1. Weather Regions of Harbin and Xi’an
2.2. Concrete Structures
2.3. CLT Substitution Design
3. Life-Cycle Assessment Framework
3.1. The Framework
3.2. Materialisation Stage
- Energy consumed and carbon emission produced by decoration of concrete structures were neglected.
- Fasteners for construction of CLT were not considered due to the small amount of volume when compare with CLT panels.
- The carbon sequestration of CLT is considered in the assessment with the assumption that 1 cubic metre of timber would store 800 kg of CO2.
- Erection of CLT buildings is set to be 20 MJ/m2 .
- The boundary of the materials including concrete, sand, cement, steel and brick start from the extraction of the raw materials, whereas that for CLT starts from harvesting the tree.
3.3. Operation Stage (Modelling Approach and Its Assumptions)
- Only energy used for heating, cooling and lighting is simulated.
- The locations of windows are not changed when altering CLT from concrete and therefore the lighting requirements are not changed.
- The indoor temperature is controlled between 18 °C and 26 °C in all rooms except for balconies. The lights were assumed to be switched on in bedrooms between 21:00–24:00 and in living rooms between 18:00 to 21:00.
- Internal heat gain was assumed to be 90 W per person
- Areas for staircases are not heated or cooled.
- The ventilation rate is assumed to be 30 m3 per hour per person.
- Electricity is used for cooling and lighting whereas coal is used for heating. This is the current practice in China.
3.4. End-of-Life Stage
4. Results and Discussion
4.1. Quality of Data and Uncertainties of the Assessment
4.2. Energy Consumptions and CO2 Emissions
4.3. Forest Resource Distribution in China
4.4. Legal Implementations
Conflicts of Interest
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|Xi’an (GJ/m2)||Harbin (GJ/m2)|
|CLT Recycling Ratio||Material||Xi’an (t/m2)||Harbin (t/m2)|
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