Energy Saving and Carbon Reduction in the Operation Stage of Cross Laminated Timber Residential Buildings in China

Abstract

This paper focused on energy consumption and carbon emission for heating and cooling during a building's operation stage, and examined the energy effects of using Cross Laminated Timber (CLT) as an alternative building material to reinforced concrete (RC) in China's 31 key cities located in different climate zones. The authors designed two seven-story residential buildings, which were constructed with RC framed and CLT systems, separately. This was followed by simulating the energy consumption using commercialized software IES TM under the different climate zones and calculating the carbon emissions. Comparisons were made between RC and CLT systems buildings on the basis of simulation data. The results show that the estimated energy consumption and carbon emission in CLT buildings are much lower than that of RC buildings in all studied cities, which indicates that CLT systems have good potential in reducing carbon emission and saving energy consumption compared to RC. The energy consumptions and carbon emissions in both concrete and CLT buildings are closely related to the climate zones. Buildings in Severe Cold and Cold Regions consumed the most energy and released more carbon. At the national level, the estimated energy consumption at the operation stage, in the studied building with RC frames and CLT system was approximately 465.1 MJ/m 2 and 332.6 MJ/m 2 per annum, respectively. Despite vast differences in China's climate zones, the effects of energy saving and carbon reduction potentials of CLT buildings show little relationship to the climate zone. CLT buildings may result in a weighted 29.4% energy saving, which equals 24.6% carbon reductions, compared with RC buildings at the operation stage at national level, although it may vary in different climate zones.

A Comparison of the Energy Saving and Carbon Reduction Performance between Reinforced Concrete and Cross-Laminated Timber Structures in Residential Buildings in the Severe Cold Region of China

“…When comparing carbon emissions, the former is 8.7% more than the latter. In the severe cold region of China, the energy required for space cooling, appliances and space heating accounts for approximately 78% of total energy consumption in Northeast China [17,33]. It is estimated that, on average, total energy consumption in residential building with RC frames and CLT system is approximately 665.1 MJ/m 2 and 610.6 MJ/m 2 per annum, respectively, during the operational stage.…”

“…CLT production rose from 25,000 m 3 in 1996 to 340,000 m 3 in 2010. In 2014, the global annual production of CLT was 600,000 cubic metres, and this is expected to reach 1,000,000 cubic metres by 2016 [17]. CLT was introduced to the UK in 2001 and the material use is growing at a rate of 25% per annum [1].…”

“…During the operational phase, Guo et al pointed out that, in China, the effects of energy saving and carbon reductions by CLT buildings show little relationship to the climate zone. On a national level, a seven-storey CLT building may result in a 29.4% energy saving, which is equivalent to a 24.6% carbon reduction, when compared with a concrete building in the operational stage [17]. Liu et al made comparisons between two seven-storey buildings constructed using RC and CLT in the severe cold region of China.…”

“…(2) The energy consumption of the building materials are from the existing references [27], which are presented in Table 8. (3) The carbon sequestration of CLT is considered in the assessment with the assumption that one cubic meter of timber would store 800 kg of CO 2 [17]. The mass and volume of CLT buildings are presented in Table 9.…”

“…(4) According to previous studies, in the severe cold region of China, approximately 78% of total energy is used for space heating, space cooling and appliances in the residential buildings [17,33]. …”