Natural Science, 2009, 1, 37-40 NS
http://dx.doi.org/10.4236/ns.2009.11007
Discussion on low-carbon economy and low-carbon
building technology
Xiao-Gen Shuai1,2, Hui-Qiang Li2
1CNNC Hunan Taohuajiang Nuclear Power CO., LTD, Yiyan 413000, P. R. China; 2School of Civil Engineering and Mechanics,
HUST, Wuhan 430074, P. R. China.
Received 11 May 2009; revised 20 May 2009; accepted 26 May 2009.
ABSTRACT
The paper introduced low-carbon economy and
low-carbon technology, and proposed the de-
tailed technical measures of low-carbon build-
ing technology. Moreover, it has quantitatively
calculated the “implicit” CO2 emission of C40
and C50 concrete columns, aluminium curtain
wall, wall paintings and common floor decora-
tion materials. The calculation results show that
it is preferable to use high strength concrete,
reduce the usage of aluminium materials and
use wooden floor according to location. The
paper can be a reference for quantitative meas-
urement to the low-carbon technology and en-
ergy efficiency.
Keywords: Low-Carbon Economy; Low-Carbon
Technology; Building Technology; Quantitative Cal-
culation
1. INTRODUCTION
The British energy white paper “Our Energy Future-
Creating a Low Carbon Economy” firstly introduced the
concept of “Low-carbon Economy” [1]. This concept
means that the developed industrial country should use
the production technology that reduces the emission of
CO2, so as to protecting the environment while main-
taining the economic growth. The CO2 and ozone etc. in
the aerosphere can absorb the radiant heat from sun and
preventing its escape from the earth, therefore empow-
ering the aerosphere of the natural greenhouse effect.
When the density of greenhouse gases such as CO2
raises, the absorbed radiant heat will increase and the
heat given out by the earth will be reduced, thus result-
ing in global warming. Global warming will melt the
glacier, raise the sea level, reduce the continental area,
silt up harbors and destroy the marsh land and river plain,
as a result bringing great negative effects to the eco-
nomic of coastland area. Moreover, global warming will
shift the climate zone to high latitude, change the eco-
system in certain area and increase infectious diseases
and the consumption of ozonosphere [2].
White paper: China's policies and actions on climate
change [3] issued by the Chinese government has indi-
cated that, the average temperature of the earth surface
in China has increased by 1.1 during the last 100 years. ℃
For the last 30 years, the sea level has increased by
90mm on average. For example, the 《Assessment Re-
port on Climate Change of Guangdong》 [4] issued by
the weather bureau of Guangdong Province in 2007
forecast that, in the background of global warming, the
emission of greenhouse gases such as CO2 will be dou-
bled in Guangdong Province, and the sea level will in-
crease by 30cm (compared with the highest level in re-
cord), which is quite serious.
China is one of the first signing countries of 《Kyoto
Protocol》, but it has not assumed its responsibility in
reducing the emission of gas since it is still a developing
country. However, China has a growing power in the
economic world, and as a responsible major country
China has to face the question of reducing the emission
of greenhouse gases and develop a low-carbon economy
during its economic growth.
The low-carbon technology has relationships with
electricity sector, transportation sector, construction
sector, chemistry industry and many other new tech-
nologies. Price L. et al [5] and Kim Y [6] have studied
the energy demand and CO2 emission of Chinese steel
industry; and Yang J X [7] have conducted bill analysis
over the life cycle of steel industry. Low-carbon
building technology is a multi-disciplined subject.
Based on the building design and selection of building
materials, the paper adopts the life cycle assessment to
quantitatively analyze the emission of CO2 and studies
the low-carbon building technology, in expecting to
provide a brand-new angle for energy saving and green
building.

38 X. G. Shuai et al. / Natural Science 1 (2009) 37-40
2. ENERGY SAVING AND EMISSIONS
REDUCTION
Energy saving in buildings relates to building planning,
building design, retaining structure, heating system, air-
conditioning system design, lighting system and many
other sectors [8]. At present, many energy saving meth-
ods have been carried out in construction projects, in-
cluding heat preventing technology in surrounding
structure, usage of solar power and wind power, energy
saving in temperature control, and enhancing energy
saving management; they all have a positive impact on
energy saving and emission reduction [9,10,11]. How-
ever, the author of this article feels that all these works
are “explicit” energy saving and carbon reducing works;
for example, the heat preventing technology in sur-
rounding structure puts more attention to the energy
saving during the running of buildings. But they have
not considered the massive consumption of building
materials and energy during the construction of the pro-
ject, the massive emission of greenhouse gases such as
CO2 during the collection, artificial work and transporta-
tion process. Low-carbon emission measures should also
be taken to them, and these measures can be called “im-
plicit” carbon reducing measures. In this sense, low-
carbon building technology should take into considera-
tion of both the “explicit” and “implicit” low-carbon
technology.
3. LOW-CARBON BUILDING
TECHNOLOGY
From the point of low-carbon building technology, it
should be taken into consideration of choosing materials
and components with lower carbon emission during the
designing and construction process.
3.1. Low-Carbon Technology in Structure
Designing
The paper takes the ground floor structure of a five-story
frame structure industrial workshop of a chemical fac-
tory as the example. It compares the C40 concrete with
the C50 concrete through the PKPM structure designing
software, both of which are under the same structure
load and seismic designing requirement. And the change
in sectional area are shown in Figure 1, when C40 has
(a) C40 (b) C50
Figure 1. Section of concrete columns.
been upgraded to C50 with the same amount of rein-
forcements; and the length of each side in section has
been reduced by 50mm in most of columns.
The mixed ratios of concrete used by this article have
been listed in Table 1. The CO2 emission of concrete
production is 1041.6kg CO2/t [12]. According to the in-
vestigation of building materials procurement in Wuhan,
the transportation distance of concrete used by the con-
crete batching plant is 50km~200km; which is taken as
100km for the convenience of following calculation. The
transportation distance for sand and gravels is 50km, and
the distance for concrete from the concrete batching
plant to the construction site is 50km; moreover, ac-
cording to references [13], the energy consumption of
sand and gravel is 13.89 kw·h/t, and that of concrete is 2
kw·h/m3. All the materials will be transported by 5 t
trucks, and the amount of CO2 emission during the
transportation and electricity production is referred to
reference [14]. The CO2 emission calculation of 1m3
concrete in using the bill analysis (a type of life cycle
assessment method) under the two strength levels have
been listed as follows.
Through the calculation, when the columns in ground
floor using the C40 concrete, the quantity consumed is
30.996m3, and the CO2 emission is 15994kg; when using
the C50 concrete, the quantity consumed is 25.389m3,
and the CO2 emission is 15 193kg. The consumption of
concrete has been reduced by 5.607m3, or 18.1%; and
CO2 consumption has been reduced by 801kg, or 5.0%.
In increasing the strength of concrete, the consumption
of concrete and CO2 emission can be largely reduced.
Therefore, high strength concrete should be preferable,
with the satisfaction to structure safety and designing
requirement.
Table 1. Mixed ratio of concrete.
Mixed ratio/(kg/m3)
Concrete
Strength Level
Cement
grade cement sand crushed rockwater
C40 525 460 720 1080 185
C50 525 540 655 1070 185
Table 2. CO2 emission of C40 and C50 concrete columns(kg/m3).
Concrete Strength Level C40 C50
Cement production 479.1 562.5
Cement transportation 1.1 1.3
Aggregate acquisition 28.5 27.3
Aggregate transportation 2.1 2.1
Concrete mixing 2.3 2.3
Concrete transportation 2.9 2.9
Total 516.0 598.4

X. G. Shuai et al. / Natural Science 1 (2009) 37-40 39
3.2 Low-carbon Technology in Building
Materials
The building components can be made from various
building materials, while the “implicit” CO2 emission
differs during the production of different building mate-
rials. The paper adopts the BEES assessment software
developed by National Institute of Standards and Tech-
nology to calculate the “implicit” CO2 impact of differ-
ent building materials. BEES (Building for Environ-
mental and Economic Sustainability, BEES) is a com-
prehensive evaluation software over the construction
environment and sustainability, and has been supported
by the Association of American Environment Protection
and U. S. Government [15]. It uses the Life Cycle As-
sessment (LCA) to quantitatively assess the environ-
mental performance of building materials.
3.2.1. Comparison Between Aluminium Curtain
wall and wall Paintings
There are enormous consumption of fossil fuel and CO2
emission in the production process of aluminium materi-
als, and the energy consumption is 435GJ/t while carbon
emission is 8700kg/t; but the figures in the production of
steel materials are only 35GJ/t and 700kg/t, both of
which are 1/12 of that of aluminium materials [16].
Therefore, the usage of aluminium materials should be
reduced, and other green materials should be adopted.
This article has conducted a calculation over the alu-
minium curtain wall of a university refectory project,
and has analyzed the difference of CO2 emission by
switching to common wall paintings.
The “implicit” CO2 emission of 1m2 aluminium cur-
tain wall and common wall paintings have been calcu-
lated out by BEES software. For the convenience of
calculation, it has been assumed that the transportation
distance for both of them are 200km with a life span of
50 years, then the quantity of CO2 emission are shown as
follows.
As a result, the CO2 emission of aluminium curtain
wall is far larger than that of common wall paintings.
The quantity of aluminium curtain wall in this refectory
project is 2519m2, but if using the common wall paint-
ings it will reduce 34476kg CO2 with an 85% reduction
rate.
Table 3. Comparison between aluminium curtain wall and wall
paintings (gCO2/m2).
life cycle
stage
Raw
materials Manufacturing TransportationTotal
aluminium
curtain wall 14131 1878 40 16050
wall paintings 1755 566 42 2364
Table 4. Comparison of floor decoration materials (gCO2/m2).
life cycle
stage
Raw
materials Manufacturing TransportationTotal
Composite
marble tile25953 334 1679 27966
Terrazzo
flooring 26878 0 947 27836
Wool
carpet tile415673 2314 237 418213
Natural
cork tile 6006 3262 301 9580
3.2.2. Indoor Floor Decoration Materials
Floor decoration material has been a major part of the
total consumption and cost of a decoration project, thus
the choices of materials have a close relationship with
the “implicit” CO2 emission and indoor environment.
This article has selected several common indoor floor
decoration materials, and used the BEES software to
calculate the “implicit” CO2 emission of 1m2 indoor
floor decoration materials for 50 years life span. For the
convenience of calculation, it has been assumed that, the
transportation distance of the material is 400km with a
life span of 50 years, then the quantity of their CO2
emission are as follows.
It is obvious to see the advantage of wooden floor in
carbon reduction, while other materials have given out
much CO2 in their whole life cycle; the animal-made
materials have the most serious situation. Therefore,
wooden materials should be selected if the local forests
can sustainable provide the resources.
4. CONCLUSIONS
The paper has discussed the Low-carbon economy and
Low-carbon building technology, and has proposed de-
tailed technical measures of Low-carbon building tech-
nology. In satisfying the structure load and seismic de-
signing requirements, the “implicit” CO2 emission can
be reduced by approximately 5% if replace C40 concrete
by C50 concrete; the quantity of CO2 emission of the
aluminium alloy curtain wall during the whole life cycle
is 15% of that of the wall paintings with the same area;
wooden floor has a much smaller quantity of “implicit”
CO2 emission than other indoor floor decoration materi-
als. The above measures and calculation results are of
value as a reference for energy saving, emission reduc-
tion and low-carbon building technology.
ACKNOWLEDGEMENTS
This work is supported by the Special Research Foundation of Doc-
toral Subjects in University of China (No. 20050487017).
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