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Overview on Green Building Label in China
Renewable Energy 53 (2013) 220e229
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Renewable Energy journal homepage: www.elsevier.com/locate/renene
Review
Overview on Green Building Label in China Ling Ye a, *, Zhijun Cheng a, Qingqin Wang a, Wenshi Lin b, Feifei Ren a a b
China Academy of Building Research, No. 30 North 3rd Ring Road, Chaoyang District, Beijing 100013, China China Environmental Certification Center of MEP, Beijing, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 16 August 2012 Accepted 17 November 2012 Available online 23 December 2012
This paper reviews features of Green Building Label (GBL), the green building evaluation system in China, in terms of management and technology. It is followed by classified statistical analysis on 353 GBL projects issued in the four years from 2008 to 2011, in the context of evaluation agency, evaluation stage, building type, star level, regional distribution, and developer. Then it focuses on technical application of GBL projects including basic technical requirements and 32 applicable technologies, especially renewable energy utilization. Some suggestions are proposed for GBL development and revision of the Chinese national standard (Evaluation Standard for Green Building) in this paper. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Green building evaluation Green Building Label Evaluation Standard for Green Building Renewable energy China
1. Introduction Building energy saving in China started with residential buildings in northern China in the 1980s. In the 2000s, it has spread to all regions and all building types. Not only were some related laws and regulations [1e3] amended or enacted, but also many studies were implemented. Li and Yao [4] addressed the emerging issues relating to building energy consumption and building energy efficiency due to the fast urbanization, after reviewing urbanization and building energy use situation in China. Kong et al. [5] reviewed developmental routes, policies and programs for building energy efficiency in China during the Eleventh Five-Year (2006e2010), and recommended some proposals to enhance the development of building energy efficiency in the next Five-Year (2011e2015). Application of some key technologies involved with building energy efficiency was reviewed as well, such as air-to-air heat recovery, ground source heat pump, and solar energy utilization [6e9]. The concept of green building in China was developed from “Energy-Saving and Land-Saving Residential Building” required by the central government in 2004. To be specific, the green building should be energy-saving, land-saving, water-saving and materialsaving, environment-benign and pollution-reducing, summarized as “Four-Saving & One-Benign”. That is defined in a Chinese national standard enacted in 2006, the Evaluation Standard for Green Building (hereinafter referred to as ESGB) [10]. Studies on
* Corresponding author. Tel./fax: þ86 10 64517980. E-mail address: [email protected] (L. Ye). 0960-1481/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.renene.2012.11.022
green building in China were implemented in these years, such as comparison between ESGB and LEED [11], and the additional cost of green building projects [12]. However, no overview on green buildings in China can be identified, and no review on technologies related to green building either. In this paper, project quantity, regional distribution, and technical application, especially renewable energy utilization, of green buildings in China are reviewed. Based on the reviews and analysis, some suggestions on green building development and ESGB revision are proposed. 2. Green Building Label In China, green buildings are distinguished by the Green Building Labels (GBL). GBL is issued and managed by the government, and is supported technically by ESGB. 2.1. Management The governmental department in charge of GBL is the Ministry of Housing and Urban-Rural Development (MOHURD). Under its supervision, a uniform evaluation system all over China is achieved. Two evaluation agencies engaged in GBL nationwide belongs to the Center of Science and Technology of Construction of MOHURD and the Chinese Society for Urban Studies (CSUS) respectively. Moreover, about 30 local authorities are carrying on GBL evaluation in their local regions (provinces or special cities) by June 2012. But their GBL level, which is explained in a later session, is restricted to one-star and two-star. The hierarchy of GBL evaluation agencies is shown in Fig. 1.
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Fig. 1. GBL evaluation agencies.
Evaluation procedures include submission of application, formal examination, expert committee evaluation, public scrutiny and public notification, as shown in Fig. 2. Once the developer or owner of a project submits its application and proofing materials to an evaluation agency, formal examination is carried out by the agency. Then, it is followed by expert committee evaluation. Finally, state building authority (MOHURD) takes over public scrutiny and notification. A project may fail in formal examination or expert evaluation. For a failed project lacking proofing material, reexamination or re-evaluation is applicable after rectification or improvement. Objections to a project can also be raised during a public scrutiny period of 30 days. Before the procedure goes to public notification, MOHURD will take these objections into consideration, and make a judgment. After a public notification, a GBL certificate, which is as shown in Fig. 3, is issued to the project. 2.2. Technical features and ESGB GBL is applicable either for the design stage or for the operation stage. Particularly, GBL for the design stage is also known as Green Building Design Label, which has been shown in Fig. 3. Evaluation at the design stage mainly requires detailed drawings and modeling as proof. Evaluation at the operation stage can only be applied to buildings in operation for a year or longer. Whatever the stage, GBL is evaluated separately for two building types, residential projects and public projects. To be specific, public projects mainly include office buildings, retail buildings and hotel buildings. Using one-star
Fig. 3. Green Building Label (GBL) certification of China.
+, two-star ++ or three-star +++, different levels of GBL are distinguished. Three-star is the top level. According to ESGB, evaluating provisions are divided into six sections, namely land saving and ambient environment, energy saving and energy utilization, water saving and water resource utilization, material saving and material resource utilization, indoor environmental quality, and operation and management. Each section includes three provision categories, namely prerequisite provisions, optional provisions and optimal provisions. For residential buildings and public buildings, provisions are different, and hence provision quantity differs, as shown in Table 1. All prerequisite provisions must be complied regardless of GBL level, whereas optional ones and optimal ones both have different compliance requirements for each level. Furthermore, compliance quantity of optional provisions is required respectively in each section, but compliance quantity of optimal ones is required in sum for all six sections. By counting provision compliance quantity, the level of GBL could be determined according to Table 2. Considering that some provisions are not applicable before building operates, provision compliance requirement is adjusted correspondingly in case of design stage. 3. Overall status of GBL
Fig. 2. Procedures of GBL evaluation.
By the end of 2011, there have been 353 GBLs in China. Their features are analyzed as follows.
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Table 1 Provision quantity in each section. Provision category
Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
Prerequisite provisions Optional provisions Optimal provisions
8/5 8/6 2/3
3/5 6/10 2/4
5/5 6/6 1/1
2/2 7/8 2/2
5/6 6/6 1/3
4/3 7/7 1/1
Note: “a/b” represents provision numbers through “a” for residential building and “b” for public building respectively. Table 2 Provision compliance requirements for each GBL level. GBL level
+ ++ +++
Optional provisions Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
4/3 5/4 6/5
2/4 3/6 4/8
3/3 4/4 5/5
3/5 4/6 5/7
2/3 3/4 4/5
4/4 5/5 6/6
Optimal provisions
N/A 3/6 5/10
Note: “a/b” represents provision compliance requirements through “a” for residential building and “b” for public building respectively.
3.1. Annual GBL number Since the start of GBL in 2008, annual number of GBL projects increased significantly year by year. There were 10 in 2008, 20 in 2009, 82 in 2010 and 241 in 2011. Fig. 4 gives GBL annual numbers by evaluation agency, evaluation stage, building type and star level. From four paragraphs in Fig. 4, some features of GBL can be deduced: C Local agencies commenced evaluation in 2010, later than national agencies. Regardless of the year, most GBLs are evaluated by the national agencies. GBLs evaluated by local
agencies account for about 27% of the annual total both in 2010 and 2011, indicating GBLs evaluated by national agencies and local agencies increasing at approximately the same rate over the last 2 years. C The number of GBL for the design stage is 331 compared with 22 for the operation stage. By year, the ratios of GBL number for design stage to that for operation stage in 2009, 2010 and 2011, are 9, 9.5 and 19, respectively (there is no GBL for operation stage in 2008). There are complicated factors that lead to this phenomenon, such as GBL application fee, technological hurdles, sales promotion on new-construction buildings. C The numbers of GBL residential and public projects are 193 (54.7%) and 160 (45.3%) respectively. A massive rise of
Fig. 4. Annual GBL number a) By evaluation agency b) By evaluation stage c) By building type d) By star level.
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Fig. 5. City distribution of GBL.
residential projects is evident. Recent policy on social housing in China may be one reason for the large rise in residential projects, and this is expected to continue. Measured by gross floor area (GFA), residential projects could even account for a large proportion of the total than by GBL number, since a residential project usually contains several separate multifamily multi-story (even high-rise) residential buildings and has a GFA larger than 50,000 m2. C The numbers of one-star, two-star and three-star GBL are 98, 140 and 115, respectively. Their proportion of the total are 27.8%, 39.7% and 32.6%, respectively, appearing with spindle-shaped. Local agencies have been playing an important role on one-star and two-star GBL evaluation since 2010.
3.2. Regional distribution of GBL Fig. 5 gives GBL numbers of all 76 cities with at least one GBL, in descending order. Shanghai not only has the most GBL projects at 47, but also started early, with 4 GBL in 2008. Suzhou is second with 41 GBLs, and had 15 GBLs in 2010 and 24 in 2011, respectively, more than Shanghai. It is followed by Shenzhen, Tianjin, Beijing, etc. Sixteen cities on the left in Fig. 5 (accounting for 20% of all 76 cities), possess 259 GBLs (accounting for 73% of the total). Of note is the fact that Kunshan, a city much smaller than others, has 5 GBL projects which indicate that green buildings in China have begun to spread to small cities. Counted by province, autonomous region, municipality and special administrative region (SAR), GBL regional distribution is
Fig. 6. Province distribution of GBL.
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their GBL numbers. Each developer has its own GBL target and features. For examples, all GBLs of Landsea and Jindu are residential projects, and all GBLs of Landsea and Expo are three-star, etc. 4. Technical features of GBL projects 4.1. Basic technical requirements Basic technical requirements from compulsory articles in relative regulations, standards and mandatory policy documents, are cited in prerequisite provisions in ESGB. All these requirements are summarized in Table 3. Other prerequisite provisions in ESGB include contracted shape of architectural design, O&M strategies, waste sorting for both residential buildings and public buildings, daylight index, ratio of opening area to room floor area, closed waste container for residential buildings, light pollution prevention, energy sub-metering, and indoor parameter of central air-conditioning system for public buildings. Fig. 7. Regional distribution of GBL.
4.2. Applicable technologies shown in Fig. 6. There are 27 provinces (or autonomous regions, municipalities, SAR) with at least one GBL, accounting for about 80% of provincial regions in China. Jiangsu Province has the most with 84 GBLs, accounting for nearly a quarter of the total. It is followed by Guangdong Province and Shanghai Municipality. To sum up, GBL regional distribution has the following characteristics: C GBL covers a great part of provinces, autonomous regions, municipalities and SARs (i.e. Hong Kong), within not only large cities, but also a few small cities. C As shown in Fig. 7, more than three quarters of GBLs are in the east coast, which is the region with a rapid economic growth in China. Although western China accounts for two-thirds of China’s total area, its GBL proportion is less than 10%. 3.3. Developers of GBL projects More than 20 developers have had more than 1 GBL project. GBLs of these developers account for more than half of the total, and the rest are possessed by small developers, institutions and the government. Fig. 8 gives top 12 developers possessing GBL and
Besides basic technical requirements, many applicable technologies could be chosen according to building function, local resource, regional climate, economic development, social custom, etc. Most technologies applied in these GBL projects and their application proportions are listed in Table 4. The investigating sample is 57 GBL projects evaluated by CSUS by the end of 2010. Among them, 32 are residential projects, and the other 25 are public projects. From another standpoint, GBL numbers of one-star, two-star and three-star level are 11, 25 and 21, respectively. Considering that GBLs for design stage take absolute majority in all 353 GBLs, it is understandable that most technologies in Table 4 concern design. Part of these technologies are emphasized and discussed as follows, and the 16th one (renewable energy) will be studied in details in a later section. C Possible locations for planting of a building include the roof, exterior wall, etc. However, the roof has many potential functions, such as vegetation, PV panel, solar collector, and skylight. Consequently, planting area on roof is restricted. As for exterior wall, planting is not as popular as roof, especially in high-rise building. Residential buildings may be more
Fig. 8. Large developers’ GBL projects a) By building type b) By star level.
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Table 3 Part of basic technical requirements on a GBL project. Relevant section in ESGB
Requirement
Regulation, standard or document
Article No.
Land saving & ambient environment
Greening protection Residential land per capita Hours of sunshine Green space ratio Capita public green space Public facilities Environmental noise
Urban Greening Regulation GB 50180-93 (2002 version) Code of Urban Residential Areas Planning & Design
Part three 3.0.3 5.0.2.1 7.0.2.3 7.0.5 6.0.3 5.1
Construction pollution control
Energy saving & energy utilization
Thermal performance
Heating & cooling equipment efficiency Forbidden on electrical boiler or water heater Lighting power density Metering of centralized heating system
Water saving & water resource utilization
Plumbing system Water saving device Safeguard of non-traditional water source
Material saving & material resource utilization
Indoor environmental quality
Harmful substance content in building materials
Indoor air pollutants
Condensation on internal surface Maximal temperature of internal surface Indoor noise level Sound insulation performance of envelope
GB 3096-2008 Environmental Quality Standard for Noise GB 8978-1996 Integrated Wastewater Discharge Standard GB 12523-90 Noise Limits for Construction Site JGJ 26-2010 Design Standard for Energy Efficiency of Residential Buildings in Severe Cold & Cold Zones JGJ 134-2010 Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Cold Winter Zone JGJ 75-2003 Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Warm Winter Zone GB 50189-2005 Design Standard for Energy Efficiency of Public Buildings GB 50189-2005 Design Standard for Energy Efficiency of Public Buildings
Multiple 2.1 Multiple
Multiple
Multiple
Multiple 5.4.5, 5.4.8 5.4.2
GB 50034-2004 Standard for lighting design of buildings Guideline on System Reform Pilot of Centralized Heating (by Ministry of Construction in 2003) Guideline on Promoting System Reform of Centralized Heating (by Ministry of Construction in 2005) GB 50015-2003 (2009 version) Code for Design of Building Water Supply and Drainage CJ 164-2002 Domestic Water Saving Devices GB 50335-2002 Code for Design of Wastewater Reclamation and Reuse GB 50336-2002 Code of Design for Building Reclaimed Water System GB 6566-2010 Limit of Radionuclides in Building Materials GB 18580-2001, GB 18581-2009, GB 18582w18583-2008, GB18584w18587-2001 Indoor Decorating and Refurbishing Materials – Limit of Harmful Substances GB 18588-2001 Limit of Ammonia Emitted from the Concrete Admixtures GB 50325-2010 Code for Indoor Environmental Pollution Control of Civil Building Engineering GB 50176-93 Code for Thermal Design of Civil Buildings GB 50118-2010 Code for Design of Sound Insulation of Civil Buildings
suitable for vertical planting, for multiple purposes of thermal insulation, sound insulation and sun shading. C The ratio of permeable pavement area to outdoor ground area can be used as an index of site development impact. Typical values are 40%e70%. As shown in Fig. 9, the index values of public projects are more likely to lie out of the range. One potential problem of permeable pavement is performance degradation during operation, due to plugging. C As a typical way of land saving, underground space development is widely applied in GBL projects, except one public project, as shown in Fig. 10. The index in Fig. 10 is the ratio of floor area of underground space to building footprint area.
6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6 e
e
Multiple Multiple 1.0.5, 7.0.3 1.0.10, 5.4.1, 5.4.7, 6.2.18, 8.1.1, 8.1.3, 8.1.6 Multiple Multiple
Multiple 6.0.4
4.3.1 5.1.1 4.1.1 4.2.1, 4.2.2, 4.2.5
Unlike the area ratio of permeable pavement, the performance of land saving may not get better as the underground space area ratio gets higher. Different projects have different ratios. C A few public projects adopt thermal storage. In southern China, ice storage systems are common. No heat storage system or water cooling storage system in the sample can be found. C There are two ways to recover waste heat, namely heat recovery on exhaust air, and condenser heat recovery. The former is very suitable for severe cold and cold zone, due to large temperature difference between indoor and outdoor air
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Table 4 Applicable technologies and their application proportion in GBL projects. No.
Applicable technology
Application proportion in GBL projects Residential project
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 211 22 23 24 25 26 27 28 29 30 31 32
Simulation optimization on ambient wind environment Vertical planting Multi-storied planting by native plants Permeable pavement Underground space development Reuse of existing building Energy sub-metering Air-tight window Energy efficient lighting & controls Energy efficient cooling & heating equipment and distribution system Improvement on part-load efficiency of HVAC system Energy efficient elevator Thermal storage Heat recovery Distributed combined cooling, heating and power (CCHP) Renewable energy Simulation optimization on energy use Water efficient appliance Water sub-metering Non-traditional water source Water efficient irrigation High performance structure material Reusable, recyclable & recycled material Structure system optimization Full decoration Sound isolation & noise control (including simulation optimization) Nature ventilation (including simulation optimization) Day lighting (including simulation optimization) Control of indoor air parameters Mechanical ventilation & indoor air quality (IAQ) monitoring Adjustable sun shading Building automation
84%
96%
0 100% 100% 100% 0 100% 100% 100% 13%
64% 100% 92% 96% 12% 100% 100% 100% 100%
N/A
100%
28% N/A 19% N/A
80% 12% 84% 4%
56% 44% 100% N/A 97% 94% 35% 84% 9% 50% 100%
76% 64% 100% 96% 100% 92% 54% 100% 36% 72% 100%
100%
92%
100% 59% 31%
96% 100% 84%
28% 94%
48% 100%
in winter. However, it is not so common in GBL projects. Those public projects with swimming pools can heat water by condenser heat recovery, from either steam or refrigerant vapor in the cooling source. However, this technology is not
Fig. 9. Area ratio of permeable pavement to outdoor ground of GBL projects.
Relevant section in ESGB
Public project Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
suitable for residential projects without central heating or airconditioning. C Distributed combined cooling, heating and power (CCHP) system can only be found in one GBL project of public building. It is
Fig. 10. Area ratio of underground space to building footprint of GBL projects.
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Table 5 Residential projects in different solar energy area. Sunlight hours (Unit: h/a)
Solar irradiation (Unit: W/m2a)
Projects applying SWH/all GBL projects One-star
Two-star
Three-star
Total
3000e3200 1400e3000 1000e1400 Sum
5400e6700 4200e5400 ＜4200
N/A 2/7 0/2 2/9
1/3 8/10 N/A 9/13
2/3 3/7 N/A 5/10
3/6 13/24 0/2 16/32
Note: “a/b” represents GBL project numbers through “a” for those applying SWH and “b” for all respectively.
C
Fig. 11. Non-traditional water source (NTWS) proportion of GBL projects.
C
C
C Fig. 12. Recyclable material mass proportion of GBL projects note: points equal to zero represent projects which have not provided ratio value when applying for GBL.
Fig. 13. Installed cooling/heating capacity of GSHP in residential projects.
more suitable in regions rich in natural gas, but not in hot summer and warm winter zone. For all projects in dry regions, non-traditional water source (NTWS) is most likely to be reclaimed water. On the other hand, rainwater is the NTWS of most projects in wetter regions. The NTWS proportions of GBL projects are shown in Fig. 11. It could be seen that, the only way of meeting threshold value of 30% in ESGB for residential building, is utilization of municipal reclaimed water. Similarly, nearly half of public projects with the NTWS proportion larger than 60% utilize municipal reclaimed water. For high-rise buildings with reinforced concrete (RC) structure, high performance structure material may be applied. Projects applying high strength steel bar of HRB400 and above are more than those applying high strength concrete of C50 and above. On the whole, more public projects apply these materials than residential projects. ESGB sets 10% as the threshold proportion (by mass) of recyclable material (not recycled material) for all building materials. As a result, the proportions of most GBL projects concentrate in the range of 10%e15%. It can be seen in Fig. 12 that recyclable material proportion for some projects accurately fit the threshold value. Another phenomenon is that the proportion for public projects is on the whole higher than that of residential projects. This indicates a greater technical difficulty of using recyclable material in residential buildings comparing with public buildings. Fully furnished house has been advocated since 1999 in China, but is adopted only by half residential projects and two thirds public projects for now. It is accepted that this technology is a material-saving mode. But a tenant or buyer in China may still prefer decoration in his or her own way.
Fig. 14. Solar collector area of residential projects.
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Fig. 16. Power generation of PV in public projects.
Fig. 15. Installed cooling capacity of GSHP in public projects.
C Just like the complementary relationship between day lighting and artificial lighting, mechanical ventilation is needed when weather conditions are not suitable for natural ventilation. Unlike residential buildings, indoor air quality (IAQ) monitoring is necessary in public buildings, due to their higher occupation density (in many cases), and larger spaces. C Nowadays in China, curtains are popular to prevent solar heat from entering the interior. Despite of a large expenditure, adjustable sun shading is more efficient to bring down aircondition load in summer. However, Chinese users are still concerned about its strength, controllability, useful life, etc. 4.3. Renewable energy utilization Due to the differences between residential projects and public projects, this technology is studied according to building type. 4.3.1. Residential projects There are 18 GBL residential projects (about 56% of all GBL residential projects) with renewable energy utilization. To be specific, 16% of residential projects use ground source heat pump (GSHP), and 50% of residential projects use solar water heater (SWH). These data suggest that 10% of residential projects make use of both geothermal energy and solar energy. No residential project uses PV panels. GSHP is applied in 2 two-star projects and 3 three-star projects, which mostly are 7e9 story building. Fig. 13 gives GFA, units and installed cooling/heating capacity of the 5 projects. Obviously, the number of residential units increases with GFA. The size of dark green circle indicates installed cooling capacity of project in hotsummer and cold-winter zone, whereas that of light green one indicates installed heating capacity of the project in cold zone. The
Table 6 Public projects in different solar energy area. Sunlight hours (Unit: h/a)
3000e3200 1400e3000 Sum
Solar irradiation (Unit: W/m2a)
5400e6700 4200e5400
Projects applying SWH or PV/all GBL projects One-star
Two-star
Three-star
Total
N/A 0/2 0/2
2/3 4/9 6/12
2/2 7/9 9/11
4/5 11/20 15/25
Note: “a/b” represents GBL project numbers through “a” for those applying SWH or PV and “b” for all respectively.
circle in the lower left corner represents the only high rise building. The high rise building contains both residential and commercial premises. Apart from this project, cooling load of residential building in hot-summer and cold-winter zone is estimated between 30 W/m2 and 35 W/m2. Heating load of the residential project in cold zone is about 63 W/m2. SWH is applied in half of residential projects, as shown in Table 5. There are 2 one-star projects (including a social housing project) applying SWH, suggesting that renewable energy utilization is not the distinguishing feature of high-level GBL projects. Linear correlation between solar collector area and units served by SWH can be found in Fig. 14. A solar collector area of 2.09 m2 is installed for one unit on average. 4.3.2. Public projects There are 19 GBL public projects (about 76% of all GBL public projects) with renewable energy utilization. To be specific, the percentages of projects applying GSHP, SWH and PV panel or facade in all public projects are 48%, 44% and 32%, respectively. There are even four projects applying all three systems. GSHP is applied in 4 two-star projects and 7 three-star projects. Among them, one three-star project is ground water heat pump (GWHP); another is district heating and cooling (DHC) system using sea water heat pump (SWHP); the other 9 projects are groundcoupled heat pump (GCHP) systems. Despite various functions of public projects, linear correlation between installed cooling capacity and GFA can be deduced from Fig. 15 as well. The cooling load of public building is about 54.8 W/m2. Eleven projects applying SWH and 8 projects applying PV are summarized in Table 6. In certain area, the more the solar energy available, the more projects there are applying SWH or PV. What is more, the higher the GBL level, the more projects there are applying SWH or PV. Without exception, electricity generated by PV panel is put into electricity grid at low-voltage. Fig. 16 gives the power generation and PV area of public projects, and the size of circle indicates GFA of the project. Power generation per unit area of most projects is in the range of 100 Wp/m2 to 200 Wp/m2. 5. Discussion and conclusions Based on investigations above, discussion on GBL development and ESGB revision are proposed as follows: C Although the annual number of GBL projects has increased rapidly year by year, the total amount of GBL projects is much
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C
C
C
C
less than that of other green building assessment systems such as LEED and BREEAM in other countries. One decisive factor is that GBL started much later than the others. In April 2012, the policy to encourage green building development was launched by the Ministry of Finance and MOHURD, for the very first time. GBL annual number has been found to maintain an upward trend. However, more attention should be paid to marketing and promotion of GBL as well. Currently, the regional distribution of GBL is very uneven, with the east coast the most important region for GBL. Fullscale popularization of green building is still needed. Under current western development strategy, construction projects will increase sharply in western China. It is a good chance to popularize GBL from east to west. In addition, there is an increase in construction in rural areas. The spread from large cities into small cities, towns and villages, is another approach to popularizing GBL. GBL numbers for design stage and operation stage differ widely. Developers are understandably passionate about GBL for design stage, before the sale. After this, GBL for operation stage becomes useless for them. Since GBL evaluation for design stage only requires detailed drawings and modeling as proof, some designed technologies might be changed or ever canceled during building construction. Furthermore, operational performance of a system or device may be worse than design. Thus, GBL for design stage is suggested to be encouraged, by reducing application fee, simplifying proofing materials, financial rewarding, etc. It is not detailed enough for ESGB, dividing GBL evaluation into two building types, residential building and public building. Some threshold values need to be set separately for office building, retail building and hotel building, and more building types, such as industrial building and hospital building, need to be taken into consideration. As far as LEED or BREEAM is concerned, there are about 10 versions for different building types. ESGB should extend its application to more building types. Meanwhile, evaluation index system in ESGB should be refined for each different building type. For six sections in ESGB, there are corresponding technologies applied in GBL projects respectively. In a sense, “Four-Saving & One-Benign” could be achieved at the same time, by requiring all prerequisite provisions in six sections and compliance quantity of optional provisions in each section respectively in ESGB. However, some technologies are applied widely, and others are seldom used. Technical and economic comparison among technologies should be implemented when revising ESGB. Technologies with different difficulties deserve different rewards. Weighting different evaluating indices may be a solution.
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The government is playing a key role in GBL evaluation. This is one of the distinguishing features of green building development in China. Although some policies boosting GBL spread have been launched, policy makers should take improvement on GBL evaluation into consideration. For the certification, GBL for operation stage is suggested to be encouraged. For the standard, ESGB is suggested to cover more building types and be more specific to each building type. In addition, index weighting may be introduced into technical evaluation. Last but not the least, marketing and promotion could be introduced into GBL development. Acknowledgments The authors would like to express their gratitude to the Chinese Society for Urban Studies (CSUS), for providing GBL project profiles and the annual reports on green building. Heartfelt thanks also goes out to Dr Andrew Wright of De Montfort University, UK, Mr. Haiyan Lin of China Academy of Building Research, and Ms. Ning Li of Hong Kong Polytechnic University, for the valuable suggestions and English language improvements. This study is supported by National Key Technology R&D Program of the People’s Republic of China (No. 2012BAJ10B02). References [1] Law of the People’s Republic of China on Energy Conservation. Standing committee of the national people’s congress, http://www.npc.gov.cn/ englishnpc/Law/2009-02/20/content_1471608.htm; 2007 [accessed 01.07.12]. [2] Regulation on energy conservation in civil buildings. The State Council, http:// www.gov.cn/flfg/2008-08/07/content_1067062.htm; 2008 [accessed 01.07.12, in Chinese]. [3] Regulation on energy conservation by public institutions. The State Council, http://www.gov.cn/zwgk/2008-08/11/content_1069566.htm; 2008. [4] Li B, Yao R. Urbanisation and its impact on building energy consumption and efficiency in China. Renewable Energy 2009;34:1994e8. [5] Kong X, Lu S, Wu Y. A review of building energy efficiency in China during “Eleventh Five-Year Plan” period. Energy Policy 2012;41:624e35. [6] Zhong K, Kang Y. Applicability of air-to-air heat recovery ventilators in China. Applied Thermal Engineering 2009;29:830e40. [7] Gao Q, Li M, Yu M, Spitler JD, Yan YY. Review of development from GSHP to UTES in China and other countries. Renewable and Sustainable Energy Reviews 2009;13:1383e94. [8] Li ZS, Zhang GQ, Li DM, Zhou J, Li LJ, Li LX. Application and development of solar energy in building industry and its prospects in China. Energy Policy 2007;35:4121e7. [9] Peng C, Huang Y, Wu Z. Building-integrated photovoltaics (BIPV) in architectural design in China. Energy and Buildings 2011;43:3592e8. [10] Evaluation standard for green building (GB/T 50378-2006). Ministry of Construction, General Administration of Quality Supervision, Inspection and Quarantine; 2006 [in Chinese]. [11] Chen J, Zhao P, Wang X. The research on sino-US green building rating system. Energy Procedia 2011;5:1205e9. [12] Zhang X, Platten A, Shen L. Green property development practice in China: costs and barriers. Building and Environment 2011;46: 2153e60.
Contents lists available at SciVerse ScienceDirect
Renewable Energy journal homepage: www.elsevier.com/locate/renene
Review
Overview on Green Building Label in China Ling Ye a, *, Zhijun Cheng a, Qingqin Wang a, Wenshi Lin b, Feifei Ren a a b
China Academy of Building Research, No. 30 North 3rd Ring Road, Chaoyang District, Beijing 100013, China China Environmental Certification Center of MEP, Beijing, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 16 August 2012 Accepted 17 November 2012 Available online 23 December 2012
This paper reviews features of Green Building Label (GBL), the green building evaluation system in China, in terms of management and technology. It is followed by classified statistical analysis on 353 GBL projects issued in the four years from 2008 to 2011, in the context of evaluation agency, evaluation stage, building type, star level, regional distribution, and developer. Then it focuses on technical application of GBL projects including basic technical requirements and 32 applicable technologies, especially renewable energy utilization. Some suggestions are proposed for GBL development and revision of the Chinese national standard (Evaluation Standard for Green Building) in this paper. Ó 2012 Elsevier Ltd. All rights reserved.
Keywords: Green building evaluation Green Building Label Evaluation Standard for Green Building Renewable energy China
1. Introduction Building energy saving in China started with residential buildings in northern China in the 1980s. In the 2000s, it has spread to all regions and all building types. Not only were some related laws and regulations [1e3] amended or enacted, but also many studies were implemented. Li and Yao [4] addressed the emerging issues relating to building energy consumption and building energy efficiency due to the fast urbanization, after reviewing urbanization and building energy use situation in China. Kong et al. [5] reviewed developmental routes, policies and programs for building energy efficiency in China during the Eleventh Five-Year (2006e2010), and recommended some proposals to enhance the development of building energy efficiency in the next Five-Year (2011e2015). Application of some key technologies involved with building energy efficiency was reviewed as well, such as air-to-air heat recovery, ground source heat pump, and solar energy utilization [6e9]. The concept of green building in China was developed from “Energy-Saving and Land-Saving Residential Building” required by the central government in 2004. To be specific, the green building should be energy-saving, land-saving, water-saving and materialsaving, environment-benign and pollution-reducing, summarized as “Four-Saving & One-Benign”. That is defined in a Chinese national standard enacted in 2006, the Evaluation Standard for Green Building (hereinafter referred to as ESGB) [10]. Studies on
* Corresponding author. Tel./fax: þ86 10 64517980. E-mail address: [email protected] (L. Ye). 0960-1481/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.renene.2012.11.022
green building in China were implemented in these years, such as comparison between ESGB and LEED [11], and the additional cost of green building projects [12]. However, no overview on green buildings in China can be identified, and no review on technologies related to green building either. In this paper, project quantity, regional distribution, and technical application, especially renewable energy utilization, of green buildings in China are reviewed. Based on the reviews and analysis, some suggestions on green building development and ESGB revision are proposed. 2. Green Building Label In China, green buildings are distinguished by the Green Building Labels (GBL). GBL is issued and managed by the government, and is supported technically by ESGB. 2.1. Management The governmental department in charge of GBL is the Ministry of Housing and Urban-Rural Development (MOHURD). Under its supervision, a uniform evaluation system all over China is achieved. Two evaluation agencies engaged in GBL nationwide belongs to the Center of Science and Technology of Construction of MOHURD and the Chinese Society for Urban Studies (CSUS) respectively. Moreover, about 30 local authorities are carrying on GBL evaluation in their local regions (provinces or special cities) by June 2012. But their GBL level, which is explained in a later session, is restricted to one-star and two-star. The hierarchy of GBL evaluation agencies is shown in Fig. 1.
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Fig. 1. GBL evaluation agencies.
Evaluation procedures include submission of application, formal examination, expert committee evaluation, public scrutiny and public notification, as shown in Fig. 2. Once the developer or owner of a project submits its application and proofing materials to an evaluation agency, formal examination is carried out by the agency. Then, it is followed by expert committee evaluation. Finally, state building authority (MOHURD) takes over public scrutiny and notification. A project may fail in formal examination or expert evaluation. For a failed project lacking proofing material, reexamination or re-evaluation is applicable after rectification or improvement. Objections to a project can also be raised during a public scrutiny period of 30 days. Before the procedure goes to public notification, MOHURD will take these objections into consideration, and make a judgment. After a public notification, a GBL certificate, which is as shown in Fig. 3, is issued to the project. 2.2. Technical features and ESGB GBL is applicable either for the design stage or for the operation stage. Particularly, GBL for the design stage is also known as Green Building Design Label, which has been shown in Fig. 3. Evaluation at the design stage mainly requires detailed drawings and modeling as proof. Evaluation at the operation stage can only be applied to buildings in operation for a year or longer. Whatever the stage, GBL is evaluated separately for two building types, residential projects and public projects. To be specific, public projects mainly include office buildings, retail buildings and hotel buildings. Using one-star
Fig. 3. Green Building Label (GBL) certification of China.
+, two-star ++ or three-star +++, different levels of GBL are distinguished. Three-star is the top level. According to ESGB, evaluating provisions are divided into six sections, namely land saving and ambient environment, energy saving and energy utilization, water saving and water resource utilization, material saving and material resource utilization, indoor environmental quality, and operation and management. Each section includes three provision categories, namely prerequisite provisions, optional provisions and optimal provisions. For residential buildings and public buildings, provisions are different, and hence provision quantity differs, as shown in Table 1. All prerequisite provisions must be complied regardless of GBL level, whereas optional ones and optimal ones both have different compliance requirements for each level. Furthermore, compliance quantity of optional provisions is required respectively in each section, but compliance quantity of optimal ones is required in sum for all six sections. By counting provision compliance quantity, the level of GBL could be determined according to Table 2. Considering that some provisions are not applicable before building operates, provision compliance requirement is adjusted correspondingly in case of design stage. 3. Overall status of GBL
Fig. 2. Procedures of GBL evaluation.
By the end of 2011, there have been 353 GBLs in China. Their features are analyzed as follows.
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Table 1 Provision quantity in each section. Provision category
Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
Prerequisite provisions Optional provisions Optimal provisions
8/5 8/6 2/3
3/5 6/10 2/4
5/5 6/6 1/1
2/2 7/8 2/2
5/6 6/6 1/3
4/3 7/7 1/1
Note: “a/b” represents provision numbers through “a” for residential building and “b” for public building respectively. Table 2 Provision compliance requirements for each GBL level. GBL level
+ ++ +++
Optional provisions Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
4/3 5/4 6/5
2/4 3/6 4/8
3/3 4/4 5/5
3/5 4/6 5/7
2/3 3/4 4/5
4/4 5/5 6/6
Optimal provisions
N/A 3/6 5/10
Note: “a/b” represents provision compliance requirements through “a” for residential building and “b” for public building respectively.
3.1. Annual GBL number Since the start of GBL in 2008, annual number of GBL projects increased significantly year by year. There were 10 in 2008, 20 in 2009, 82 in 2010 and 241 in 2011. Fig. 4 gives GBL annual numbers by evaluation agency, evaluation stage, building type and star level. From four paragraphs in Fig. 4, some features of GBL can be deduced: C Local agencies commenced evaluation in 2010, later than national agencies. Regardless of the year, most GBLs are evaluated by the national agencies. GBLs evaluated by local
agencies account for about 27% of the annual total both in 2010 and 2011, indicating GBLs evaluated by national agencies and local agencies increasing at approximately the same rate over the last 2 years. C The number of GBL for the design stage is 331 compared with 22 for the operation stage. By year, the ratios of GBL number for design stage to that for operation stage in 2009, 2010 and 2011, are 9, 9.5 and 19, respectively (there is no GBL for operation stage in 2008). There are complicated factors that lead to this phenomenon, such as GBL application fee, technological hurdles, sales promotion on new-construction buildings. C The numbers of GBL residential and public projects are 193 (54.7%) and 160 (45.3%) respectively. A massive rise of
Fig. 4. Annual GBL number a) By evaluation agency b) By evaluation stage c) By building type d) By star level.
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Fig. 5. City distribution of GBL.
residential projects is evident. Recent policy on social housing in China may be one reason for the large rise in residential projects, and this is expected to continue. Measured by gross floor area (GFA), residential projects could even account for a large proportion of the total than by GBL number, since a residential project usually contains several separate multifamily multi-story (even high-rise) residential buildings and has a GFA larger than 50,000 m2. C The numbers of one-star, two-star and three-star GBL are 98, 140 and 115, respectively. Their proportion of the total are 27.8%, 39.7% and 32.6%, respectively, appearing with spindle-shaped. Local agencies have been playing an important role on one-star and two-star GBL evaluation since 2010.
3.2. Regional distribution of GBL Fig. 5 gives GBL numbers of all 76 cities with at least one GBL, in descending order. Shanghai not only has the most GBL projects at 47, but also started early, with 4 GBL in 2008. Suzhou is second with 41 GBLs, and had 15 GBLs in 2010 and 24 in 2011, respectively, more than Shanghai. It is followed by Shenzhen, Tianjin, Beijing, etc. Sixteen cities on the left in Fig. 5 (accounting for 20% of all 76 cities), possess 259 GBLs (accounting for 73% of the total). Of note is the fact that Kunshan, a city much smaller than others, has 5 GBL projects which indicate that green buildings in China have begun to spread to small cities. Counted by province, autonomous region, municipality and special administrative region (SAR), GBL regional distribution is
Fig. 6. Province distribution of GBL.
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their GBL numbers. Each developer has its own GBL target and features. For examples, all GBLs of Landsea and Jindu are residential projects, and all GBLs of Landsea and Expo are three-star, etc. 4. Technical features of GBL projects 4.1. Basic technical requirements Basic technical requirements from compulsory articles in relative regulations, standards and mandatory policy documents, are cited in prerequisite provisions in ESGB. All these requirements are summarized in Table 3. Other prerequisite provisions in ESGB include contracted shape of architectural design, O&M strategies, waste sorting for both residential buildings and public buildings, daylight index, ratio of opening area to room floor area, closed waste container for residential buildings, light pollution prevention, energy sub-metering, and indoor parameter of central air-conditioning system for public buildings. Fig. 7. Regional distribution of GBL.
4.2. Applicable technologies shown in Fig. 6. There are 27 provinces (or autonomous regions, municipalities, SAR) with at least one GBL, accounting for about 80% of provincial regions in China. Jiangsu Province has the most with 84 GBLs, accounting for nearly a quarter of the total. It is followed by Guangdong Province and Shanghai Municipality. To sum up, GBL regional distribution has the following characteristics: C GBL covers a great part of provinces, autonomous regions, municipalities and SARs (i.e. Hong Kong), within not only large cities, but also a few small cities. C As shown in Fig. 7, more than three quarters of GBLs are in the east coast, which is the region with a rapid economic growth in China. Although western China accounts for two-thirds of China’s total area, its GBL proportion is less than 10%. 3.3. Developers of GBL projects More than 20 developers have had more than 1 GBL project. GBLs of these developers account for more than half of the total, and the rest are possessed by small developers, institutions and the government. Fig. 8 gives top 12 developers possessing GBL and
Besides basic technical requirements, many applicable technologies could be chosen according to building function, local resource, regional climate, economic development, social custom, etc. Most technologies applied in these GBL projects and their application proportions are listed in Table 4. The investigating sample is 57 GBL projects evaluated by CSUS by the end of 2010. Among them, 32 are residential projects, and the other 25 are public projects. From another standpoint, GBL numbers of one-star, two-star and three-star level are 11, 25 and 21, respectively. Considering that GBLs for design stage take absolute majority in all 353 GBLs, it is understandable that most technologies in Table 4 concern design. Part of these technologies are emphasized and discussed as follows, and the 16th one (renewable energy) will be studied in details in a later section. C Possible locations for planting of a building include the roof, exterior wall, etc. However, the roof has many potential functions, such as vegetation, PV panel, solar collector, and skylight. Consequently, planting area on roof is restricted. As for exterior wall, planting is not as popular as roof, especially in high-rise building. Residential buildings may be more
Fig. 8. Large developers’ GBL projects a) By building type b) By star level.
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Table 3 Part of basic technical requirements on a GBL project. Relevant section in ESGB
Requirement
Regulation, standard or document
Article No.
Land saving & ambient environment
Greening protection Residential land per capita Hours of sunshine Green space ratio Capita public green space Public facilities Environmental noise
Urban Greening Regulation GB 50180-93 (2002 version) Code of Urban Residential Areas Planning & Design
Part three 3.0.3 5.0.2.1 7.0.2.3 7.0.5 6.0.3 5.1
Construction pollution control
Energy saving & energy utilization
Thermal performance
Heating & cooling equipment efficiency Forbidden on electrical boiler or water heater Lighting power density Metering of centralized heating system
Water saving & water resource utilization
Plumbing system Water saving device Safeguard of non-traditional water source
Material saving & material resource utilization
Indoor environmental quality
Harmful substance content in building materials
Indoor air pollutants
Condensation on internal surface Maximal temperature of internal surface Indoor noise level Sound insulation performance of envelope
GB 3096-2008 Environmental Quality Standard for Noise GB 8978-1996 Integrated Wastewater Discharge Standard GB 12523-90 Noise Limits for Construction Site JGJ 26-2010 Design Standard for Energy Efficiency of Residential Buildings in Severe Cold & Cold Zones JGJ 134-2010 Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Cold Winter Zone JGJ 75-2003 Design Standard for Energy Efficiency of Residential Buildings in Hot Summer and Warm Winter Zone GB 50189-2005 Design Standard for Energy Efficiency of Public Buildings GB 50189-2005 Design Standard for Energy Efficiency of Public Buildings
Multiple 2.1 Multiple
Multiple
Multiple
Multiple 5.4.5, 5.4.8 5.4.2
GB 50034-2004 Standard for lighting design of buildings Guideline on System Reform Pilot of Centralized Heating (by Ministry of Construction in 2003) Guideline on Promoting System Reform of Centralized Heating (by Ministry of Construction in 2005) GB 50015-2003 (2009 version) Code for Design of Building Water Supply and Drainage CJ 164-2002 Domestic Water Saving Devices GB 50335-2002 Code for Design of Wastewater Reclamation and Reuse GB 50336-2002 Code of Design for Building Reclaimed Water System GB 6566-2010 Limit of Radionuclides in Building Materials GB 18580-2001, GB 18581-2009, GB 18582w18583-2008, GB18584w18587-2001 Indoor Decorating and Refurbishing Materials – Limit of Harmful Substances GB 18588-2001 Limit of Ammonia Emitted from the Concrete Admixtures GB 50325-2010 Code for Indoor Environmental Pollution Control of Civil Building Engineering GB 50176-93 Code for Thermal Design of Civil Buildings GB 50118-2010 Code for Design of Sound Insulation of Civil Buildings
suitable for vertical planting, for multiple purposes of thermal insulation, sound insulation and sun shading. C The ratio of permeable pavement area to outdoor ground area can be used as an index of site development impact. Typical values are 40%e70%. As shown in Fig. 9, the index values of public projects are more likely to lie out of the range. One potential problem of permeable pavement is performance degradation during operation, due to plugging. C As a typical way of land saving, underground space development is widely applied in GBL projects, except one public project, as shown in Fig. 10. The index in Fig. 10 is the ratio of floor area of underground space to building footprint area.
6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6 e
e
Multiple Multiple 1.0.5, 7.0.3 1.0.10, 5.4.1, 5.4.7, 6.2.18, 8.1.1, 8.1.3, 8.1.6 Multiple Multiple
Multiple 6.0.4
4.3.1 5.1.1 4.1.1 4.2.1, 4.2.2, 4.2.5
Unlike the area ratio of permeable pavement, the performance of land saving may not get better as the underground space area ratio gets higher. Different projects have different ratios. C A few public projects adopt thermal storage. In southern China, ice storage systems are common. No heat storage system or water cooling storage system in the sample can be found. C There are two ways to recover waste heat, namely heat recovery on exhaust air, and condenser heat recovery. The former is very suitable for severe cold and cold zone, due to large temperature difference between indoor and outdoor air
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Table 4 Applicable technologies and their application proportion in GBL projects. No.
Applicable technology
Application proportion in GBL projects Residential project
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 211 22 23 24 25 26 27 28 29 30 31 32
Simulation optimization on ambient wind environment Vertical planting Multi-storied planting by native plants Permeable pavement Underground space development Reuse of existing building Energy sub-metering Air-tight window Energy efficient lighting & controls Energy efficient cooling & heating equipment and distribution system Improvement on part-load efficiency of HVAC system Energy efficient elevator Thermal storage Heat recovery Distributed combined cooling, heating and power (CCHP) Renewable energy Simulation optimization on energy use Water efficient appliance Water sub-metering Non-traditional water source Water efficient irrigation High performance structure material Reusable, recyclable & recycled material Structure system optimization Full decoration Sound isolation & noise control (including simulation optimization) Nature ventilation (including simulation optimization) Day lighting (including simulation optimization) Control of indoor air parameters Mechanical ventilation & indoor air quality (IAQ) monitoring Adjustable sun shading Building automation
84%
96%
0 100% 100% 100% 0 100% 100% 100% 13%
64% 100% 92% 96% 12% 100% 100% 100% 100%
N/A
100%
28% N/A 19% N/A
80% 12% 84% 4%
56% 44% 100% N/A 97% 94% 35% 84% 9% 50% 100%
76% 64% 100% 96% 100% 92% 54% 100% 36% 72% 100%
100%
92%
100% 59% 31%
96% 100% 84%
28% 94%
48% 100%
in winter. However, it is not so common in GBL projects. Those public projects with swimming pools can heat water by condenser heat recovery, from either steam or refrigerant vapor in the cooling source. However, this technology is not
Fig. 9. Area ratio of permeable pavement to outdoor ground of GBL projects.
Relevant section in ESGB
Public project Land saving & ambient environment
Energy saving & energy utilization
Water saving & water resource utilization
Material saving & material resource utilization
Indoor environmental quality
Operation & management
suitable for residential projects without central heating or airconditioning. C Distributed combined cooling, heating and power (CCHP) system can only be found in one GBL project of public building. It is
Fig. 10. Area ratio of underground space to building footprint of GBL projects.
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Table 5 Residential projects in different solar energy area. Sunlight hours (Unit: h/a)
Solar irradiation (Unit: W/m2a)
Projects applying SWH/all GBL projects One-star
Two-star
Three-star
Total
3000e3200 1400e3000 1000e1400 Sum
5400e6700 4200e5400 ＜4200
N/A 2/7 0/2 2/9
1/3 8/10 N/A 9/13
2/3 3/7 N/A 5/10
3/6 13/24 0/2 16/32
Note: “a/b” represents GBL project numbers through “a” for those applying SWH and “b” for all respectively.
C
Fig. 11. Non-traditional water source (NTWS) proportion of GBL projects.
C
C
C Fig. 12. Recyclable material mass proportion of GBL projects note: points equal to zero represent projects which have not provided ratio value when applying for GBL.
Fig. 13. Installed cooling/heating capacity of GSHP in residential projects.
more suitable in regions rich in natural gas, but not in hot summer and warm winter zone. For all projects in dry regions, non-traditional water source (NTWS) is most likely to be reclaimed water. On the other hand, rainwater is the NTWS of most projects in wetter regions. The NTWS proportions of GBL projects are shown in Fig. 11. It could be seen that, the only way of meeting threshold value of 30% in ESGB for residential building, is utilization of municipal reclaimed water. Similarly, nearly half of public projects with the NTWS proportion larger than 60% utilize municipal reclaimed water. For high-rise buildings with reinforced concrete (RC) structure, high performance structure material may be applied. Projects applying high strength steel bar of HRB400 and above are more than those applying high strength concrete of C50 and above. On the whole, more public projects apply these materials than residential projects. ESGB sets 10% as the threshold proportion (by mass) of recyclable material (not recycled material) for all building materials. As a result, the proportions of most GBL projects concentrate in the range of 10%e15%. It can be seen in Fig. 12 that recyclable material proportion for some projects accurately fit the threshold value. Another phenomenon is that the proportion for public projects is on the whole higher than that of residential projects. This indicates a greater technical difficulty of using recyclable material in residential buildings comparing with public buildings. Fully furnished house has been advocated since 1999 in China, but is adopted only by half residential projects and two thirds public projects for now. It is accepted that this technology is a material-saving mode. But a tenant or buyer in China may still prefer decoration in his or her own way.
Fig. 14. Solar collector area of residential projects.
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Fig. 16. Power generation of PV in public projects.
Fig. 15. Installed cooling capacity of GSHP in public projects.
C Just like the complementary relationship between day lighting and artificial lighting, mechanical ventilation is needed when weather conditions are not suitable for natural ventilation. Unlike residential buildings, indoor air quality (IAQ) monitoring is necessary in public buildings, due to their higher occupation density (in many cases), and larger spaces. C Nowadays in China, curtains are popular to prevent solar heat from entering the interior. Despite of a large expenditure, adjustable sun shading is more efficient to bring down aircondition load in summer. However, Chinese users are still concerned about its strength, controllability, useful life, etc. 4.3. Renewable energy utilization Due to the differences between residential projects and public projects, this technology is studied according to building type. 4.3.1. Residential projects There are 18 GBL residential projects (about 56% of all GBL residential projects) with renewable energy utilization. To be specific, 16% of residential projects use ground source heat pump (GSHP), and 50% of residential projects use solar water heater (SWH). These data suggest that 10% of residential projects make use of both geothermal energy and solar energy. No residential project uses PV panels. GSHP is applied in 2 two-star projects and 3 three-star projects, which mostly are 7e9 story building. Fig. 13 gives GFA, units and installed cooling/heating capacity of the 5 projects. Obviously, the number of residential units increases with GFA. The size of dark green circle indicates installed cooling capacity of project in hotsummer and cold-winter zone, whereas that of light green one indicates installed heating capacity of the project in cold zone. The
Table 6 Public projects in different solar energy area. Sunlight hours (Unit: h/a)
3000e3200 1400e3000 Sum
Solar irradiation (Unit: W/m2a)
5400e6700 4200e5400
Projects applying SWH or PV/all GBL projects One-star
Two-star
Three-star
Total
N/A 0/2 0/2
2/3 4/9 6/12
2/2 7/9 9/11
4/5 11/20 15/25
Note: “a/b” represents GBL project numbers through “a” for those applying SWH or PV and “b” for all respectively.
circle in the lower left corner represents the only high rise building. The high rise building contains both residential and commercial premises. Apart from this project, cooling load of residential building in hot-summer and cold-winter zone is estimated between 30 W/m2 and 35 W/m2. Heating load of the residential project in cold zone is about 63 W/m2. SWH is applied in half of residential projects, as shown in Table 5. There are 2 one-star projects (including a social housing project) applying SWH, suggesting that renewable energy utilization is not the distinguishing feature of high-level GBL projects. Linear correlation between solar collector area and units served by SWH can be found in Fig. 14. A solar collector area of 2.09 m2 is installed for one unit on average. 4.3.2. Public projects There are 19 GBL public projects (about 76% of all GBL public projects) with renewable energy utilization. To be specific, the percentages of projects applying GSHP, SWH and PV panel or facade in all public projects are 48%, 44% and 32%, respectively. There are even four projects applying all three systems. GSHP is applied in 4 two-star projects and 7 three-star projects. Among them, one three-star project is ground water heat pump (GWHP); another is district heating and cooling (DHC) system using sea water heat pump (SWHP); the other 9 projects are groundcoupled heat pump (GCHP) systems. Despite various functions of public projects, linear correlation between installed cooling capacity and GFA can be deduced from Fig. 15 as well. The cooling load of public building is about 54.8 W/m2. Eleven projects applying SWH and 8 projects applying PV are summarized in Table 6. In certain area, the more the solar energy available, the more projects there are applying SWH or PV. What is more, the higher the GBL level, the more projects there are applying SWH or PV. Without exception, electricity generated by PV panel is put into electricity grid at low-voltage. Fig. 16 gives the power generation and PV area of public projects, and the size of circle indicates GFA of the project. Power generation per unit area of most projects is in the range of 100 Wp/m2 to 200 Wp/m2. 5. Discussion and conclusions Based on investigations above, discussion on GBL development and ESGB revision are proposed as follows: C Although the annual number of GBL projects has increased rapidly year by year, the total amount of GBL projects is much
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less than that of other green building assessment systems such as LEED and BREEAM in other countries. One decisive factor is that GBL started much later than the others. In April 2012, the policy to encourage green building development was launched by the Ministry of Finance and MOHURD, for the very first time. GBL annual number has been found to maintain an upward trend. However, more attention should be paid to marketing and promotion of GBL as well. Currently, the regional distribution of GBL is very uneven, with the east coast the most important region for GBL. Fullscale popularization of green building is still needed. Under current western development strategy, construction projects will increase sharply in western China. It is a good chance to popularize GBL from east to west. In addition, there is an increase in construction in rural areas. The spread from large cities into small cities, towns and villages, is another approach to popularizing GBL. GBL numbers for design stage and operation stage differ widely. Developers are understandably passionate about GBL for design stage, before the sale. After this, GBL for operation stage becomes useless for them. Since GBL evaluation for design stage only requires detailed drawings and modeling as proof, some designed technologies might be changed or ever canceled during building construction. Furthermore, operational performance of a system or device may be worse than design. Thus, GBL for design stage is suggested to be encouraged, by reducing application fee, simplifying proofing materials, financial rewarding, etc. It is not detailed enough for ESGB, dividing GBL evaluation into two building types, residential building and public building. Some threshold values need to be set separately for office building, retail building and hotel building, and more building types, such as industrial building and hospital building, need to be taken into consideration. As far as LEED or BREEAM is concerned, there are about 10 versions for different building types. ESGB should extend its application to more building types. Meanwhile, evaluation index system in ESGB should be refined for each different building type. For six sections in ESGB, there are corresponding technologies applied in GBL projects respectively. In a sense, “Four-Saving & One-Benign” could be achieved at the same time, by requiring all prerequisite provisions in six sections and compliance quantity of optional provisions in each section respectively in ESGB. However, some technologies are applied widely, and others are seldom used. Technical and economic comparison among technologies should be implemented when revising ESGB. Technologies with different difficulties deserve different rewards. Weighting different evaluating indices may be a solution.
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The government is playing a key role in GBL evaluation. This is one of the distinguishing features of green building development in China. Although some policies boosting GBL spread have been launched, policy makers should take improvement on GBL evaluation into consideration. For the certification, GBL for operation stage is suggested to be encouraged. For the standard, ESGB is suggested to cover more building types and be more specific to each building type. In addition, index weighting may be introduced into technical evaluation. Last but not the least, marketing and promotion could be introduced into GBL development. Acknowledgments The authors would like to express their gratitude to the Chinese Society for Urban Studies (CSUS), for providing GBL project profiles and the annual reports on green building. Heartfelt thanks also goes out to Dr Andrew Wright of De Montfort University, UK, Mr. Haiyan Lin of China Academy of Building Research, and Ms. Ning Li of Hong Kong Polytechnic University, for the valuable suggestions and English language improvements. This study is supported by National Key Technology R&D Program of the People’s Republic of China (No. 2012BAJ10B02). References [1] Law of the People’s Republic of China on Energy Conservation. Standing committee of the national people’s congress, http://www.npc.gov.cn/ englishnpc/Law/2009-02/20/content_1471608.htm; 2007 [accessed 01.07.12]. [2] Regulation on energy conservation in civil buildings. The State Council, http:// www.gov.cn/flfg/2008-08/07/content_1067062.htm; 2008 [accessed 01.07.12, in Chinese]. [3] Regulation on energy conservation by public institutions. The State Council, http://www.gov.cn/zwgk/2008-08/11/content_1069566.htm; 2008. [4] Li B, Yao R. Urbanisation and its impact on building energy consumption and efficiency in China. Renewable Energy 2009;34:1994e8. [5] Kong X, Lu S, Wu Y. A review of building energy efficiency in China during “Eleventh Five-Year Plan” period. Energy Policy 2012;41:624e35. [6] Zhong K, Kang Y. Applicability of air-to-air heat recovery ventilators in China. Applied Thermal Engineering 2009;29:830e40. [7] Gao Q, Li M, Yu M, Spitler JD, Yan YY. Review of development from GSHP to UTES in China and other countries. Renewable and Sustainable Energy Reviews 2009;13:1383e94. [8] Li ZS, Zhang GQ, Li DM, Zhou J, Li LJ, Li LX. Application and development of solar energy in building industry and its prospects in China. Energy Policy 2007;35:4121e7. [9] Peng C, Huang Y, Wu Z. Building-integrated photovoltaics (BIPV) in architectural design in China. Energy and Buildings 2011;43:3592e8. [10] Evaluation standard for green building (GB/T 50378-2006). Ministry of Construction, General Administration of Quality Supervision, Inspection and Quarantine; 2006 [in Chinese]. [11] Chen J, Zhao P, Wang X. The research on sino-US green building rating system. Energy Procedia 2011;5:1205e9. [12] Zhang X, Platten A, Shen L. Green property development practice in China: costs and barriers. Building and Environment 2011;46: 2153e60.