Analysis of national and local energy-efficiency design standards in the public building sector in China

Energy for Sustainable Development 15 (2011) 443–450

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Energy for Sustainable Development

Analysis of national and local energy-efficiency design standards in the public building sector in China Ping Jiang ⁎ United Nations University Institute of Advanced Studies, Yokohama 220-8502, Japan

a r t i c l e

i n f o

Article history: Received 21 February 2010 Revised 1 August 2011 Accepted 1 August 2011 Available online 1 September 2011 Keywords: Energy saving design standards Public building sector Energy consumption China

a b s t r a c t The energy consumption in the building sector in China shares 25% of total energy consumption in the whole nation. The energy use in urban buildings in Chinese cities like Beijing and Shanghai share approximately 90% of whole energy consumption in buildings. Amongst these urban buildings, the energy use in public buildings is higher than other building sectors. So, the public building sector thus is an area of priority with regard to energy conservation and carbon reduction. China's Ministry of Construction has issued six energy-efficiency design standards to the building sector since 1995. The latest one is the design standards for energy efficiency in public buildings which aim to achieve 50% of the reduction of energy consumption in new and refurbished public buildings. Beijing and Shanghai governments have also issued their local energy saving standards for the public buildings with 65% and 50% of energy-saving goals. The main problems and weaknesses existing in the national and local standards in Beijing and Shanghai are assessed, and the reasons for producing the barriers to the implementation of national and two local standards are explored in this paper, they include: a) no explicit definitions of the base load energy consumption and the space conditioning energy uses are given, and only the energy savings from the base load energy consumption is considered in current standards; b) the benchmark of energy consumption selected is unreasonable and energy cuts from non technical measures are ignored; and c) the lack of effective supervision. Relevant solutions and suggestions to tackle these problems and weaknesses for the long-term energy conservation development in public buildings are discussed in this paper. © 2011 International Energy Initiative. Published by Elsevier Inc. All rights reserved.

Introduction In 2007, China's primary energy consumption was 2656 million tonnes of standard coal equivalent (or 77.825 EJ). Around 69.5% of China's primary energy comes from coal, the comprehensive GHG emission factor is higher than in western countries whose main energy sources are natural gas and oil, and since 2000 the energy consumption has been rising at 9% per annum (National Bureau of Statistics, 2008), China has become one of the largest energy consumers and green house gas (GHG) emitters in the world. China's building sector consumes 25% of the total energy in the country and with an estimated total area of over 50 billion m 2 the annual energy use was around 5500 TWh in 2007 (National Bureau of Statistics, 2008; Qiu et al., 2007). Between 2000 and 2007, the energy consumption percentage in buildings of the total energy use in China was 25% to 27%. This energy consumption includes the direct energy use in maintaining thermal comfort and normal operation and indirect embedded energy use associated with the construction of the building and including the material manufacture and transport of the materials to site. This energy consumption in China's building

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stock is associated with the emission of around 4.5 billion tonnes of CO2 equivalent (CO2e) emissions in 2007(Jiang, 2009). With a high growth in energy consumption in recent years (Fig. 1) which is expected to continue in the next decade, the consumption in the building sector plays an important role in China's long-term sustainable development strategy. In China, buildings can be divided into two categories: i). Rural buildings representing around 60% of the whole building area; ii). Urban buildings can be further divided into residential buildings and non-residential buildings (a) with heating systems in north China, and (b) without heating systems (Qiu et al., 2007). In China, the non-residential buildings are also called “public buildings” in many occasions. The public buildings comprise most of the non-residential buildings except plants and factories, such as, governmental buildings, commercial buildings (i.e. office building, hotels, restaurants and shopping malls), school buildings and gyms. The urban buildings in China, with only 40% of the total building area, were responsible for almost 90% of total energy consumption in the building sector (Qiu et al., 2007). Because energy consumption in the urban building stock is much greater than that in the countryside, in this

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P. Jiang / Energy for Sustainable Development 15 (2011) 443–450

20,000

20000

15,000

Million m2

25000

PJ

15000 10000

10,000

5,000 5000 0 0

2000

2001

2002

2003

2004

2005

2006

2000

2001

2002

2003

2007

2004

2005

2006

2007

Year

Year

Public buildings' floor area

Residnetial buildings' floor area

Fig. 1. Direct and indirect energy consumption in the building sector in China. (National Bureau of Statistics, 2008; Qiu et al., 2007).

Fig. 3. Floor area of public and residential buildings in China between 2000 and 2007. (National Bureau of Statistics, 2008).

paper, only energy use in the urban building stock is considered. The area of urban buildings which include residential and non-residential buildings is about 15 billion m2 which are occupied by 550 million people in China. According to the “2007 Annual Report on China Building Energy Efficiency (Qiu et al., 2007)”, per square metre energy consumption in China's non-residential building stock is three times that of the energy use in residential buildings. Especially, the energy use in the largescale non-residential building sector (i.e. the floor area of a single building is over 20,000 m 2) is about 105–15 times that energy use in residential buildings, again on a per-m 2 basis (Qiu et al., 2007). With more new public buildings, and higher comfortable and convenient levels involving the use of more equipments and appliances, the overall energy consumption (including the direct and indirect energy consumption) in the public building sector continues to increase. The current energy use in public buildings has a higher annual growth rate at 12.9% compared to 11.4% in residential buildings between 2000 and 2007 in China (Fig. 2). During the same period, the average annual growth rate of public building floor area in China was 14.3% compared with 22.4% of the growth rate of residential building floor area (Fig. 3) (National Bureau of Statistics, 2008). The energy consumption per m 2 in public and residential buildings can be seen (Fig. 4) based on the data of Figs. 2 and 3. Fig. 4 shows that the lowest level of energy use per m 2 happened in both building sectors in 2002 Then the level increased dramatically after 2002 and it reached the peak in 2005 (2.0 GJ/m 2) in public buildings, and then dropped little bit after 2005 but still kept around 1.80 to 1.87 GJ/m 2 in 2006 and 2007. However, the energy use per m 2 in residential buildings kept almost the same level (around 0.65 GJ/m 2) between 2002 and 2007. Fig. 4 shows that the overall energy consumption per m 2 in public buildings is over two times higher than that in residential buildings; and it is very clear that the increasing rate of energy use per

m 2 in public buildings is also much higher than in residential buildings from 2002 to 2007. Therefore, the public building sector should be the priority to achieve the energy conservation and the sustainable development in the whole China's building sector. Beijing and Shanghai are the two biggest cities in China, with populations of 17 million and 18 million respectively. Not only do they have the largest number of public buildings but also the highest growth rate in urban development in China and are thus good examples to explore opportunities for energy conservation and carbon dioxide emission reduction in the public building sector. Table 1 provides the information about the area of public building sector and its energy consumption situation in the two cities. Facing increasing challenges from the issues of environment protection and energy security in recent years, Chinese central and local governments have undertaken many activities which include the adoption of legislative measures to tackle these issues. This paper assesses the current energy-efficiency design standards implemented in the public building sector in China and especially in Beijing and Shanghai, and also explores the possibility of developing new standards which could be more suitable for enhancing the longterm energy conservation in the public buildings in China.

25000 20000

PJ

15000 10000 5000 0

2000

2001

2002

2003

2004

2005

2006

2007

Year Public buildings

Residential buildings

Fig. 2. Energy use in public and residential buildings in China between 2000 and 2007 (National Bureau of Statistics, 2008).

Current legislation and design standards relating to energy conservation in China's public building sector There are two main national policies designed to tackle the problems described above: one is “The Eleventh Five-Year Plan”, which was issued in March 2006, with the objective of reducing energy consumption per unit of GDP by 20% by 2010 compared to the level of energy use in 2005. According to the information from The State Council of China, 1 the energy consumption per unit of GDP was to be reduced by 14.38% by May 2010. This plan also set a goal to increase the share of renewable energy to 10%, and an objective of covering roughly 20% of the nation's land with forest by 2010 compared to the situation in 2005 (State Council of the People's Republic of China, 2007). The last White Paper of “China to Address Climate Change Policies and Actions” which was issued in November 2010, set a more ambitious objective of cutting GHG emission per unit of GDP by 40– 45% by 2020 (National Development and Reform Commission of China, 2010). There is also a law called the “Energy Conservation Law of China” which was passed by the National People's Congress in October 2007 and subsequently the revised energy conservation law came into effect on 1st April 2008. This law also includes specific rules on energy saving in the building sector. All local energy saving regulations and 1

Xinhua News Agency, 2nd September 2010.

P. Jiang / Energy for Sustainable Development 15 (2011) 443–450

445

Table 2 Energy saving design standards in the building sector in China.

2.5

GJ/m2

2 1.5 1

Issued Name year

Description

1995

For heating residential buildings only For existing heating residential buildings only

2000

0.5 0 2000

2001

2002

2003

2004

2005

2006

2007

2001

Year Public buildings

001

Residential buildings

2

Fig. 4. Energy use per m in public and residential buildings in China between 2000 and 2007.

design standards relevant to the building sector are to be compliant to this law (Standing Committee Meeting, 2007). The policies and laws presented above will fundamentally influence China's overall energy conservation and GHG emission reduction in all sectors, including the building sector. The Chinese Construction Ministry has recently been renamed the Ministry of Housing and Urban and Rural Development (MOHURD). A new legislation relating to energy performance in civil buildings was enacted on 1st October 2008 (Ministry of Housing and Urban and Rural Development, 2008) which aims to promote energy conservation in maintaining thermal comfort and normal operation (i.e. the direct energy use) in general terms. More specific requirements relevant to energy efficiency in the building sector have been issued by China's central and local governments in a series of energy saving and efficiency standards since 1995, they are listed in Table 2. The national Public Buildings Energy-efficiency Design Standards (hereafter called the National Standards or GB50189-2005) which were issued on 4th April 2005 and came into effect on 1st July 2005 (Chinese Construction Ministry, 2005) is analysed in this paper, and the relevant local standards in Beijing and Shanghai are also assessed in subsequent content. Five geographical zones in China are defined in the National Standards according to different climate conditions in the different regions of China, they are: • • • • •

chilly, cold, hot summer and cold winter, hot summer and warm winter, mild zones.

According to the National Standards, Beijing belongs to the cold zone, Shanghai is located in the hot summer and cold winter zone. (Chinese Construction Ministry, 2005). All new and refurbished public buildings should now be conforming to the energy saving requirements under the standards of GB50189-2005. The key aim of these standards is to achieve a 50% reduction in energy consumption, compared to the performance of

Table 1 Area of public building sector and its energy consumption in Shanghai and Beijing (Shanghai Statistical Bureau, 2008 and Beijing Statistical Bureau, 2007). City

Shanghai (in 2007)

Beijing (in 2006)

Total area of building stock Area of public buildings Public buildings' area as a percentage of whole sector Energy use in public buildings as a percentage of whole sector

749 m2 294 m2 37%

543 m2 232 m2 43%

70%

72%

2003

2005

Residential Building Energy Saving Design Standards(JGJ26-95) Existing Heating Residential Building Energy Saving Refurbishment Technological Criterion (JGJ129-2000) Building Energy Saving Design Standards in Hot Summer and Cold Winter Zone, (JGJ134-2001) Heating Residential Building Energy Saving Assessment Standards (JGJ1322001) Building Energy Saving Design Standards in Hot Summer and Warm Winter Zone (JGJ75-2003) Public Buildings Energy-efficiency Design Standards (GB50189-2005)

For buildings located in hot summer and cold winter zone only. For heating residential buildings only. For buildings located in hot summer and warm winter zone only For all public buildings.

public buildings in the 1980s. That means the energy consumption for the normal operation and thermal comfort in public buildings in the 1980s was selected as the “benchmark” against which to measure a 50% reduction in energy consumption under the standards of 2005 (Chinese Construction Ministry, 2005). The national energy-efficiency design standards can be divided into three main sections, they are: • The standards for indoor thermal comfort and environment. In the standards, different parameters are given to different public buildings for indoor temperatures, relative humidity, and ventilation, etc. For example, the standard specifies that the indoor temperature in hotels should be 20 °C in winter and 25 °C in summer (when there is an airconditioning system). • The National Standards for the thermal transmittance (U-value) of the building envelope. The building thermal envelope comprises the doors, windows, external walls, roof, etc. According to different climate zones, the U-value standards are different. For example, in Beijing's public/commercial buildings, the U-value of external walls is set at no more than 0.6 W/m²K compared to 1.70 W/m²K in the 1980s in new buildings (Beijing Construction Bureau, 2005). In Shanghai's public/commercial buildings, however, the corresponding U-value is to be no more than 1.0 W/m²K half that of 2.00 W/m²K in the 1980s. Thus the standards of thermal performance are stricter in Beijing than they are in Shanghai. • The National Standards for heating, air-conditioning and ventilation systems. These standards give a detailed description for the technical and equipment parameters for improving energy efficiency. Generally, based on the standards, the aim of 50% in energy consumption reduction compared to the energy performance in the 1980s can be broken down as in Table 3. In the table, each item is given a certain range of the improvement, but the overall energy efficiency should reach at least 50% with regard to the standards. In Beijing, the local municipal government has issued its own latest public building energy saving design standards for all new and refurbished public buildings based on the national standards. These are the Beijing Public Building Energy Saving Design Standards (hereafter called the Beijing Standards, Beijing Construction Bureau, 2005) which came into effect on 3rd June 2006. In these Beijing Standards, the energy saving design standards are set for thermal comfort, envelope structure/fabric, heating, air-conditioning and ventilation systems. All the specific design standards in the Beijing Standards are designed to achieve the core energy saving objective of a 65% reduction in energy consumption by 2010 compared to the energy use in the same public building sector in the 1980s (Beijing Construction Bureau, 2005). In order to achieve this higher goal in Beijing's public

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Table 3 Percentage of contribution in different measures to overall energy savings according under the National Standards compared to the energy performance in public buildings in the 1980s(Chinese Construction Ministry, 2005). Item

Energy saving rate

U-value improvement in envelope structure/fabric

Energy efficiency improvement in heating, air-conditioning and ventilation systems

Other energy efficiency improvement

13 to 25%

16 to 20%

7 to 18%

buildings than required in the national standards, stricter and additional standards have been added in the Beijing Standards. Comparing these with the national Standards, the main differences are as follows: • Firstly, in the Beijing Standards, public buildings are put into two categories: Type A and type B. Type A refers to single public buildings whose area is more than 20,000 m 2. The rest belong to type B. Type A buildings should meet all the design standards in the Beijing Standards. In type B buildings, if some of the Beijing Standards cannot be met, the national Standards can be used for design and demonstrating compliance. • Secondly, for the structure and U-value of the envelope, the Beijing Standards give some specific requirements. For example, in type A buildings the shape coefficient 2 should not be more than 0.4 and the window to wall area ratio should be less than 0.7. Neither of these requirements is present in the National Standards. • Thirdly, for heating and energy recovery through air-conditioning and ventilation systems, the Beijing Standards add requirements for the water heating system's energy efficiency design. Shanghai is one of only a few Chinese cities that issued relevant design standards before July 2005 when the national standards came into effect. The Shanghai Public Buildings Energy Efficiency Design Standards (hereafter called the Shanghai Standards) came into effect in October 2003 (Shanghai Construction Bureau, 2003), almost 2 years before the National Standards. The Shanghai Standards were tailored to the local climatic conditions and the actual development of energy saving in Shanghai. The Shanghai Standards encompassed all aspects relating to energy performance of new and refurbished public buildings and provided many calculation factors (e.g. for calculating the thickness of insulation, and the capacity of air-conditioning equipment, etc.) and formulations, which made the design process more complex. Otherwise, the Shanghai Standards had two main characteristics: • The Shanghai Standards were not enforced, they just acted as a reference for energy saving design for public buildings. • The Shanghai Standards did not set a target on energy saving. After July 2005, when the National Standards were issued, the Shanghai municipal government worked out a governmental mandate named the Shanghai Buildings Energy Efficiency Management Measures which wasissued on 13th June 2005 and came into effect on 15th July 2005 (hereafter called the Shanghai Measures, Shanghai Municipal Government, 2005). The Shanghai Measures apply to all residential buildings and public buildings. Considering the weaknesses in the Shanghai Standards, the later Shanghai Measures are an improvement and the main differences may be summarised as: • Firstly, in the Shanghai Measures, a clear statement has been made that all national design standards and local design standards relating to energy saving in new and refurbished public buildings should be enforced in Shanghai after 15th July 2005. • The objective of energy consumption reduction in new and refurbished public buildings in Shanghai should reach 50% compared to the energy consumption level in public buildings in the 1980s. The MOHURD and local Commissions of Housing and Urban and Rural Development in Beijing, Shanghai and other cities are 2 The Shape coefficient of a building is defined as the ratio between the external skin surfaces and the inner volume of the building.

(Artificial lighting, etc.)

responsible for carrying out the job of supervising the implementation of all standards. Basically, the National Standards, Beijing Standards and Shanghai Measures are mainly focused on saving energy through adopting technical measures, such as the improvement of insulation of the building envelope and energy efficiency of air-conditioning, lighting, heating systems, etc. However, some non-technical measures such as improvement of energy management and changing people's behaviour are overlooked.

Problems and weaknesses existing in the energy saving design standards in the public building sector in China Policies and regulations on energy conservation have been issued in China. And specific energy saving design standards relevant to the different building types have also been made for improving efficiency in energy performances. According to Fig. 2, the energy consumption is growing at a much higher rate in the public building sector than in the residential building sector, and the energy consumption per m 2 in public buildings is over two times higher than residential buildings (Fig. 4). Qiu et al. (2007) predicts that energy consumption in public buildings will keep the current level for the coming decades in China. Regarding the important role that public buildings play in overall energy conservation in the whole sector, questions are being raised about whether current national and local Standards are sound and work effectively, and what improvements could be made for enhancing the existing standards' availability and operability. There are two kinds of energy used in a public building. One is the space conditioning energy consumption which is mainly focused in maintaining thermal comfort and lighting. This depends on building design and construction. Another is the base load energy consumption for equipment (e.g. office equipment, drinks machines, cooking equipment, etc.) that are installed in the building. The latter does not depend on building design and is not covered by building construction standards. One finding in the author's research shows that the base load energy use in the building is an important aspect for overall energy saving in public buildings because working conditions have increased dramatically since the 1980s in China with the use of more and more computers, lifts, fridges and water heaters. The author has assessed the energy consumption in 20 public buildings in Beijing and Shanghai. The results show that the base load energy use accounts for more than half of total energy consumption in these public buildings. Two typical samples which are located in Shanghai and Beijing respectively of these buildings are used as examples for analysing the base load energy use as follows. One building is a university campus building which is located close to the central area of Shanghai. It is a multi-functional building which contains offices, classrooms, libraries and meeting rooms, etc. It has a central air-conditioning system and its floor area is 120,000 m 2. Electricity is the only energy source which is used for heating, cooling, lighting, and base load energy use. When the energy consumption is plotted against the mean external temperature two different trends are seen as shown in Fig. 4, two separate trend lines A–B and C–D can be made and they represent the energy requirements in the heating and cooling seasons respectively as the external temperature falls and rises. The gradients of the two trend lines are related to the heat loss/

P. Jiang / Energy for Sustainable Development 15 (2011) 443–450

gain coefficient (in W°C −1) indicating additional energy requirements per degree change in outside temperature. The electricity use in February was much lower than would normally be expected as this coincided with the extended Chinese New Year Holiday when most classrooms and offices close completely. Therefore, data for February were not used in subsequent analyses. The consumption level at the intersection of the two trend lines indicates the basic base load energy requirements for the building i.e. for lighting, hot water, appliances and equipment, etc. The gradient of the heating trend line is 42.1 kW°C −1 (if data for February are excluded) while that of the cooling line is 37.0 kW°C −1. The monthly energy consumption in month i in the heating season (Hi) is given by: …………::

Hi = 1073−42:1Ti

ð1Þ

where Ti is the mean temperature in month i. The corresponding relationship in the cooling season (Ci) is given by: Ci = 37:0Ti −279:3

…………::

ð2Þ

Monthly energy consumption (MWh)

Solving the simultaneous equations of the trend lines to determine the crossing point of the two lines allows this base load energy consumption to be estimated at 353.5 MWh per month or 30.0 kWh/m 2/annum. At the same time the base or neutral temperature at which no heating or cooling is required maybe estimated as 17.1 °C. Deducting the base load energy use (i.e. 353.5 MWh) from the actual consumption in each month provides an estimate of the electricity needed to control the thermal comfort. This indicates a total space heating energy requirement of about 1606 MWh per annum and 1828 MWh for cooling giving a total of 3434 MWh per annum. This means that of the total energy consumption of 7675 MWh in 2008, 44.7% of the annual electricity consumption in this building was associated with the provision of adequate heating and cooling), while 55.3% of annual electricity use was related to the base load energy consumption. Another sample building is located in downtown Beijing, it is an office building with central air-conditioning system, it has a floor area of 8900 m 2 .The space heating in winter is provided by the district hot water supply system with a fixed tariff for the heating period. A plot of the electricity consumption data against the mean external temperature is made in Fig. 5. As the building is heated by district heating, there is little difference in electricity consumption from 1 month to the next during the heating season, the electricity consumption during heating season as demonstrated by the line A–B is approximately constant. The trend C–D relates to the energy requirements in the cooling season as the external temperature rises.

1000 800 600 Heating season

400

Cooling season

200 0 0.0 -200

February

10.0

20.0

30.0

40.0

-400

Mean monthly external temperature

Fig. 5. Variation of monthly electricity use with monthly mean temperature for a university campus building in Shanghai in 2008 (Jiang, 2009).

447

The annual electricity consumption was 14,851 MWh. During the cooling season, only 2058 MWh (or 13.9%) of electricity use was associated with cooling. According to the “2007 Annual Report on China Building Energy Efficiency (Qiu et al., 2007)”, the average energy requirements for heating in the heating season in Beijing is around 50 kWh/m 2 per annum. If we consider the heating energy used (i.e. 4450 MWh per annum), the total energy consumption for heating and cooling in this building was 6508 MWh. So, the whole space conditioning energy use was 43.8% of annual energy consumption in 2006, in other words, the percentage of the annual base load energy use was 56.2%. The author's research has also assessed the energy performance in the public building sector in Beijing and Shanghai after 2005, the results show that the base load energy consumption share is more than half of total energy use in many public buildings (Jiang, 2009). Thus as the heating and cooling energy is a low proportion of overall consumption, greater returns in energy saving and carbon dioxide emission reduction could be achieved by reducing the base load energy consumption. However, in current national and local energyefficiency design standards in the public sector, this kind of energy saving has been significantly overlooked. Two different energy consumption categories are not clearly defined and addressed in the energy saving design standards, the absence of an adequate description of base load energy consumption in the current standards and also in the benchmark and how it can be determined means that the objective of a 50% (or 65%) reduction in energy use will be unsound and probably unachievable. It is true that the base load energy consumption (for the operation of computers and other appliances) could leads to high internal thermal gains, which may reduce the space conditioning energy demand for heating in winter. However, this kind of thermal gains could need more cooling demands in summer. Furthermore, the benchmark will run into difficulties when considering energy reduction associated with the provision of adequate thermal comfort. In the 1980s, few public buildings in China's cities used air-conditioning systems in summer and instead relied on fans and natural ventilation systems. It is also needed to point out that there were few appliances like computers, fridges, printers and drinks machines, etc. used in public buildings in the 1980s. In other words, the base load energy consumption was much lower in public buildings in the 1980s than now. As a consequence the benchmark is ill defined as there is little if any data on which to base a benchmark. Buildings without airconditioning use in summer and also with less adoption of appliances will clearly have lower energy consumption than those which do, and it will be impossible to achieve the required reductions on the situation in the 1980s. Associated with the above issue, another weakness in the National Standards and two local standards is that there was no accurate data for energy performance in the 1980s in certain zones/cities, e.g. the value of energy consumption for the heating, lighting and other appliances, or the value of per square metre energy use in public buildings per annum. This lack of accurate benchmark of energy use in the 1980s creates confusion for those designing new buildings and more importantly those checking for compliance of the new standards. This lack of clarity may result in differences in interpretation and mean that any saving achieved could be much less than those expected in the standards. As pointed out previously, the current National and Beijing Standards and Shanghai Measures mainly focus on the technical measures for reducing the energy consumption. Non technical measures such as effective energy management with functions of promoting people's environmentally friendly awareness raising and behaviour change which can reduce energy consumption and CO2 emissions costeffectively are significantly overlooked (Jiang and Tovey, 2009). The Energy Conservation Law of 2007 described above also encourages the improvement of energy management and enhancement of relevant education and trainings (Standing Committee Meeting, 2007). Fig. 6

P. Jiang / Energy for Sustainable Development 15 (2011) 443–450

1200

1800 1600

Electricity use (kWh)

Monthly energy consumption (MWh)

448

1400 1200 1000 800 600 Heating

400

800

F3

600 400 200 0

0 0.0

-10.0

10.0

20.0

30.0

Week 1

Week 2

Week 3

Week 4

April 2005

Mean monthly external temperature (oC)

Fig. 6. Variation of monthly electricity use with monthly mean temperature for an office building in Beijing in 2006 (Jiang, 2009).

shows a plot of energy consumption against external temperature from a low energy building at the University of East Anglia which was completed in 2003 and won the low Energy Building of the year award in 2005. The building, as new, and operated in accordance with the original specifications, demonstrated an energy consumption shown by the line A–B. However after adopting an effective management for not only improving the energy efficiency of the systems such as lighting, heating, ventilation systems, but also encouraging occupants' awareness raising and behaviour change, a significant saving in energy requirement was demonstrated as shown by line C–D. This improved operation was achieved by the end of the second year of operation and represents solely an achievement from improved management. Noteworthy is the achievement of 57% of energy saving compared to the energy consumption for heating in the first year (Fig. 7) (Tovey and Turner, 2006). Another example from Tovey (2006) shows in April 2005, the electricity use in student dormitories at the University of East Anglia (Fig. 8). In the first two Fridays (Points F1 and F2), the data of electricity use was collected and it showed that it was around 1000 kWh. In week 3, an energy saving campaign which aimed to raise students' awareness on energy conservation was carried out on campus, the data of electricity use on that Friday (Point F3) shows that the electricity consumption was reduced by about 30%. Regarding the analysis and examples above show that significant savings can be achieved largely by non technical measures especially by reducing the base load energy use, as large as 50% of savings (Jiang, 2009). However, this scope for substantial energy savings has not been addressed so far in current standards and measures in China. In China, another serious issue is the lack of building control and supervision during the construction of new buildings. Furthermore the evidence from some of the public buildings studied in Jiang (2009)

Heating Requirement (kWh/day)

F2

season

200

A

1000 800 600 C

400 B

200 0 -4

F1

1000

D

-2

0

2

4

6

8

10

12

14

Mean External Temperature ( oC)

16

18

Fig. 7. Energy demand of low energy building after construction (line A–B) and after adaptive management (line C–D). The energy consumption at any temperature was reduced by 57% (Tovey and Turner, 2006).

Fig. 8. Energy demand of low energy building at the University of East Anglia after construction (line A–B) and after adaptive management (line C–D). The energy consumption at any temperature was reduced by 57% (Tovey and Turner, 2006).

demonstrates that the quality of energy management is poor, although in some public buildings it is relevantly good. There is clearly a need for the training of key personnel to ensure that the best possible approaches to energy management are implemented. According to the relevant policies and regulations relating to energy saving in the building sector, the Ministry of Housing and Urban and Rural Development (MOHURD) and the Commissions of Housing and Urban and Rural Development in the local government regions are responsible for supervising and managing building control. However, there is no system in place for effective supervision (Xue, 2007). The reasons for this are: • Not enough effective supervision in the design process or construction process for new and refurbished buildings; • Lack of skilled and professional people who are responsible for supervision and management; • Corruption makes the activities of supervision and management weak and ineffectual, • There is a lack of legal support to those carrying out energy saving supervision and management in the building sector. Without this kind of support, any energy saving standards cannot be enforced effectively and successfully. The problems highlighted above regarding energy saving standards apply not only to the public building sector in Beijing and Shanghai, but also to the whole of the building sector in China. Conclusions and recommendations Since energy saving design standards at both the national and city level directly affect the energy use and CO2 emissions in the building sector and there are several issues which should be addressed in revised legislation for overcoming the existing problems and weaknesses including: • A clear distinction between the issues of space conditioning and base load energy performance and how these two components are addressed to ensure compliance with commitments to reduce carbon dioxide emissions. The research of Jiang (2009) and the analysis above show that the base load energy use shares a significant proportion (even more than half) of total energy consumption in public buildings. More energy saving can be actually achieved from cutting the base load energy consumption than the space conditioning energy use through effective energy management, awareness raising and behaviour change, and yet current standards address only space conditioning energy use, and even there greater clarity is needed. • A more rational approach to ensure high standards could focus on the overall energy performance in buildings which can contain both functional and space conditioning energy uses. This kind of new

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energy performance based standards can address not only the energy cuts from the technical measures, but also energy savings from non technical measures such as effective energy management, awareness raising and behaviour change. In addition to the assessment of overall energy performance parameters, the unit area carbon dioxide emissions could also be determined (i.e. kg CO2/m 2/annum), because any improvement in energy performance with the same fuel mix provision will show the same improvement in CO2 emissions. Relevant data bases which include history and current energy performance in the building sector in certain climate zones can be set up and issued regularly to the public by governments as future references and for monitoring the implementation of standards. • The choice of the level of energy consumption in public buildings in the 1980s as the chosen benchmark in both national and city energy saving design standards is questionable and will lead to confusion and misinterpretation the only likely outcome of which will be an energy performance well below the target and indeed in some cases a degradation of the performance. The problem arises as the energy consumption level in similar buildings of the 1980s only concentrates on the space conditioning energy consumption, at a time when thermal comfort and lighting conditions were inferior to those now, and there was less widespread use of office equipments, appliances, centralised air-conditioning, ventilation and heating systems. All of these issues bring into question the choice of the 1980s benchmark. Noting the changes in living standards in the last 25 years it would be more appropriate to set a benchmark which is more relevant relating say to the year 2004 or the average over the period say 2000–2004 and base any improvements relative to this more recent benchmark and a period when thermal comfort conditions within these large buildings were comparable to the current situation. Indeed in the UK the Code for Sustainable Homes launched in May 2008 specifies improvement in the domestic sector in the UK based on the baseline of 2005 with stringent targets of improvements including even a 100% improvement in carbon dioxide emission (i.e. zero emission) by 2016 (Department for Communities and Local Government, 2008). Besides sound regulations and laws, the reasonable and valid standards are a priority to the effective implementation of energy conservation in the public building sector in Beijing and Shanghai and other places in China. Effective building control supervision during construction and during operation of the building is another key aspect which is needed to be in place to promote energy conservation activities and achieve sustainable development. The Ministry of Housing and Urban and Rural Development (MOHURD) and the Commissions of Housing and Urban and Rural Development in Beijing and Shanghai governments play an important role in supervising energy conservation in the building sector however it is essential that the legislation under which they operate is tightened and that the personnel carrying out the necessary supervision are adequately trained. The capacity of supervision can be strengthened through the approaches below: • Effective enhancement of the current policies, regulations and standards on the lines discussed above are needed. • More effective supervision is needed. • More skilled and professional staff to carry out the supervision activities is needed. • There is a need for transparency in the operation of supervision. China's building sector consumes one quarter of total energy consumption in the whole country. On a per square metre basis, energy use and CO2 emissions are much higher in public buildings than in residential buildings. Several key policies which focus on the energy conservation and sustainable development strategy have been issued. The Chinese Ministry of Construction has issued six energy saving design standards

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to the building sector since 1995. The latest one is the Design Standard for Energy Efficiency of Public Buildings (GB50189-2005) which requires all new and refurbished public buildings to achieve 50% of cutting energy consumption comparing the level energy performance in public buildings in the 1980s. Other Chinese cities like Beijing and Shanghai have also issued their local energy-efficiency design standards for public buildings, and 65% and 50% of saving objectives have been established in Beijing Standards and Shanghai Measures respectively compared to the level of energy consumption in public buildings in the 1980s. Several problems and weaknesses existing in the current national standards and local standards in two cities cannot make the energy efficiency in public building sector continuously improved, and this trend would prevent the public buildings from achieving the longterm goal of energy conservation in the future. Three main problems existing in the national and local energy saving design standards are: • The base load energy use which has shared a higher proportion in the whole energy consumption in public buildings is overlooked, and no explicit and sound definitions of the base load energy consumption and the space conditioning energy consumption in public building sector make the objective of 50% (or 65%) of energy reduction compared to the energy performance in the 1980s is unreasonable. • The selection of the benchmark of energy consumption in similar public buildings in the 1980s is not reasonable. • The cost-effective energy savings through effective energy management, people's environmental-friendly awareness raising and behaviour change are not addressed by current technical based standards and measures. • Lack of effective supervisions and management during the process of design and construction is an obstacle to implementing the energy saving design standards. In order to tackle the problems and weaknesses described above, besides making clear definitions of two different categories of energy use and selecting a reasonable energy consumption benchmark, the new energy performance based standards could also be considered, and enhancing supervision is a necessary action needed to be carried out at the moment. Only sound and reasonable standards are formed and the goal of the reduction of energy consumption and carbon dioxide emissions can be achieved. There is no doubt that the central and local governments will play key roles in the process of improving and implementing all energy saving design standards in the building sector in China. References Beijing Construction Bureau. Design standard for energy efficiency of public buildings. China Architecture and Building Press; 2005. [Online] http://bbs.topenergy.org/ redirect.php?tid=31891&goto=lastpost [Accessed on Nov. 8, 2009] (in Chinese). Beijing Statistical Bureau. Beijing statistical yearbook. China Statistics Press; 2007. ISBN/ ISSN: 978-7-5037-5378-7, 2007. [Online] http://www.bjstats.gov.cn/tjnj/2007tjnj/ [Acceded on Oct. 3, 2009] (in Chinese). Chinese Construction Ministry. Design standard for energy efficiency of public buildings (GB50189-2005). China Architecture and Building Press; 2005. in Chinese. Department for Communities and Local Government (UK). The Code for Sustainable Homes, 2008. p. 68. [Online] http://www.greenspec.co.uk/documents/drivers/ codeforhomes08.pdf, [Accessed on Nov. 8, 2009]. Jiang P. A low carbon sustainable strategy using CDM methodological approach to large commercial buildings in Beijing and shanghai. PhD Thesis. University of East Anglia, 2009. Jiang P, Tovey K. Opportunities for low carbon sustainability in large commercial buildings in China. Energy Policy 2009;37(11):4949–58. Ministry of Housing and Urban and Rural Development (MOHURD). Civil Building Energy Efficiency Regulations, 2008. [Online] http://www.cin.gov.cn/ZCFG/xzfg/ 200808/t20080815_176550.htm. [Accessed on Nov. 8, 2009] (in Chinese). National Bureau of Statistics. China Statistical Yearbook. China Statistics Press; 2008. ISBN 978-7-5037-5530-9/F.2757, 2008. [Online] http://www.stats.gov.cn/tjsj/ndsj/ 2008/indexch.htm [Accessed on Nov. 8, 2009] (in Chinese). National Development and Reform Commission of China. China to address climate change policies and actions. Chinese government; 2010 [Online] http://www. ccchina.gov.cn/WebSite/CCChina/UpFile/File927.pdf [Accessed on Dec. 31, 2010] (in Chinese).

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