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Energy-conservation standards for buildings in China
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Energy Vol. 13, No. 3, pp. 265-214, 1988 Printedin Great Britain. All rightsreserved
$3.00 + 0.00
CopyrightfQ 1988PergamonPressplc
ENERGY-CONSERVATION STANDARDS BUILDINGS IN CHINA
FOR
ROBERT M WIRTSHA~ER Department of City and Regional Planning, University of Pennsylvania, Philadelphia, PA 19104, U.S.A. (Received 27 April 1987)
Abstract-The People’s Republic of China has recently designed an energy-conservation building standard which would require that, by 1990, the energy efficiency of new buildings be improved by 60% over existing practices. Present energy-conservation practices in China suffer from a lack of fully developed technical solutions and institutional support
infrastructure. Given the greater complexity of the Chinese economy under the new reforms, the commitment to improving the efficiency of household energy use requires a broader focus beyond the formulation of a standard. In order for the standard to be successful, China will need to devote resources that may be more effectively utilized in other sectors of the economy.
INTRODUCTION
A recently enacted energy-conservation standard for new buildings provides insight into the difficult political issues facing China amid the new economic reforms. The standard requires that by 1990 new buildings consume 60% less energy than typical existing buildings. In the past, China relied on the combination of such standards and absolute control of fuel supply to restrict energy consumption. Now, with the relaxing of central control of the economy, this approach is not sufficient. China must now develop energy policy implementation strategies compatible with its economic reforms. The energy-conservation standard is a central component of China’s residential energyconservation efforts. The implementation and enforcement of the standard face many difficult challenges, however. Some of these obstacles are unique to China’s climatic, economic, and political situation, while others are representative of both developed and developing countries. CHINESE
ENERGY
PRODUCTION
AND CONSUMPTION
The need for energy conservation in China is underscored by the severe shortage of non-coal energy resources and by the production, transportation, and environmental problems resulting from reliance on coal.lm3 In 1983, coal accounted for over 74% of the total commercial energy consumed in China. While most of this coal is used in industry (58%), 27% is for residential/commercial uses, almost all of which is burned directly in inefficient stoves and boilers, leading to unhealthy air-quality conditions in most urban areas. In rural areas, there is little coal available for residential use and, therefore, the dependence on agricultural waste for cooking and heating has resulted in degradation of soil and extensive erosion. Future projections suggest that China must radically increase its energy supply and the efficiency of use. A World Bank report demonstrates that China’s plans for modernization, in which gross value of industrial and agricultural output (GVIAO) will quadruple by the year 2000, will require a 220% increase in coal production and a 300-400% increase in oil and electricity.3g4 In an earlier World Bank publication, it was noted that China has an energy input/GDP ratio that is 2.5 times higher than that of most other developing countries.3 In order to achieve the goal of quadrupling GVIAO, this ratio must be lowered significantly. The various scenarios require reductions in the energy intensity per unit GDP of between 1.0 and 2.7% per annum.3 China’s recent progress in energy conservation has emphasized the industrial sector.5 For instance, between 1981 and 1984, energy input rose only 4% while GVIAO rose 9.4%. Most of 265
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ROEIERTMWIRTSHAFIER
this reduction in energy intensity is attributable to the restructuring of the Chinese economy from heavy to light industry.‘j During that period, the amount of energy consumption per unit of steel output dropped 12%, energy per unit of ammonia production dropped 21%, energy input per crude oil output dropped 29%, and coal in thermal power plants dropped 6%. China has accomplished these industrial energy savings by instituting a number of reforms. The recent 5-yr plans contain specific goals for reduction of energy, including mandatory and voluntary goals for major industries to meet, and designation of large energy-savings projects for immediate development. Energy-management schemes have been instituted for the major energy-consuming industries and have included audits, incentives, monitoring, and training. Economic reforms have also provided new financial impetus to conserve energy. Coupled with new emphasis on establishing market prices for energy, the relaxing of control over markets has resulted in greater efficiency and a shift away from heavy industry to less energy-intensive light manufacturing. One major obstacle is that much of Chinese industrial production comes from small factories which are difficult to reach as effectively with energy-conservation initiatives. The task is complicated by the fact that free market competition is still modest by Western standards and limited by access to raw materials and final customers. Some energy inputs are still priced below their real international market value. This is particularly the case with coal even though factories that use more coal than they are allocated by the government are now required to purchase the excess at market prices. Historically, the Chinese have relied on central control for limiting energy consumption. In the industrial sector, this control has had two components: the restriction of access to energy supplies, and the implementation of usage standards. In the residential sector, restriction of access has been the predominant means of control. As China begins to create an open market for energy, restrictions on access are weakened, necessitating the extension of standards into the residential sector. ENERGY
CONSUMPTION
IN THE
RESIDENTIAL
SECTOR
The present level of energy consumption in households is so low that little savings can be expected. China has recognized the importance of improving residential energy efficiency not for what is presently consumed, but based on the potential future consumption projections: there is concern that energy consumption increases caused by the expansion of the residential sector will absorb the resources made available by energy conservation in the industrial sector, constraining future industrial expansion. Because of the present shortage of housing, the Chinese have placed a priority on increasing the number and quality of housing units. Hu and Yang report that 1.5 billion m2 of heated residential housing will be constructed by the year 2000, quadrupling the existing 500 million m2.7 Since the modernization plans can only tolerate a doubling of the total energy for residential heating, therefore, the average usage in all buildings must be half of what it is today.8 The efficiency gain must come in large part from new housing since, new housing will account for as much as 75% of the housing to be available by the year 2000. Unfortunately, additional pressure on the energy supply can be expected as a result of the expansion of the economy. The increase in the disposable incomes of Chinese workers will most certainly result in greater demand for energy for heating. This is particularly the case when one considers the low temperatures at which Chinese homes are presently maintained. Wirtshafter and Chang report that Chinese energy consumption per home is similar to that in other developing countries, even though almost all other developing countries have essentially no heating requirements. The supply of fuel is so limited and expensive that most if not all of the fuel is needed for cooking rather than space heating.’ Since little energy is consumed for residential heating, measures for greater thermal efficiency in new buildings will contribute far more to raising temperature levels than to lowering energy use. This is the crux of a major policy dilemma in China today: whether resources should be directed toward improved standards of living, such as increased comfort levels in the home, or toward industrial expansion. Should China decide to continue to opt for
Energy-conservation standards for buildings in China
267
industrial expansion, even tighter control of energy supplies in the residential sector will be needed. If improvement in the comfort levels of homes is permitted, it is clearly preferable that this be accomplished by improving energy efficiency rather than by increasing fuel consumption.
THE
ENERGY-CONSERVATION
BUILDING
STANDARD
Putting aside the issue of the political priority of residential energy conservation, there remains the issue of whether the conservation standard can be implemented effectively. The Energy-conservation Design Standard in Civil Buildings was developed cooperatively by The State Planning Commission and the Ministry of Urban and Rural Construction and Environmental Protection. lo The standard specifies that residential buildings built between 1986 and 1990 reduce the overall heat loss coefficient by 30% from present practices. An additional 30% improvement must be realized in homes built between 1990 and 2000. The standard also stipulates that the improvements must add no more than 5% to present costs of construction. It is important to observe the difference between the Chinese and Western concept of a standard. A Chinese ministry will often issue a standard as a means of raising concern for a problem. Passage does not necessarily extend the standard beyond the ministry’s own jurisdiction, unless the standard is later adopted by the broader central government. The ministry’s role is somewhat analogous to that of ASHRAE or other U.S. organizations that develop standards that must be adopted by other entities to be effective. The Chinese standards tend to serve as goals to be achieved rather than as enforceable minimum levels for compliance. The standard utilizes a performance-based criterion in which heat loss from walls, roof, windows, doors, floor, and infiltration are calculated on a seasonal basis using degree days. The typical overall heat loss coefficient of homes in the region is determined. The standard then establishes a new performance value that new buildings must achieve. Actions for achieving the standard are suggested for each climatic region including recommendations for number of window glazings, volume/surface area ratio, and basement or slab treatment. The experience of the United States in trying to develop an energy-conservation standard is helpful in evaluating the Chinese standard.” The complexity of technical and political issues led to the rejection of the Building Energy Performance Standard (BEPS) as a national energy-conservation code, but the state of California has utilized a performance standard for over 5 yrs. Chief among the issues involved in the development and enforcement of building energy performance standards are the following: (i) the legitimacy of BEPS and the resulting savings estimates were questioned because the standard relied upon unvalidated engineering models drawn from studies of a few buildings. The Chinese have relied upon engineering estimates based on even less study. They have conducted few tests of actual savings from proposed energy-conservation measures. (ii) The use of prescriptive standards was deemed too inflexible for U.S. building practices. Performance-related standards were either too general or required extensive and time-consuming energy-consumption modelling. As a result, the California standard includes both prescriptive and performance options, including a simplified performance scoresheet approach. The Chinese have developed a performance-related standard, one that was easy to develop but much harder to enforce. Because the majority of past regulations have been prescriptive in nature, neither designers nor those responsible for enforcement have any experience with this type of calculation procedure. (iii) Political issues about the purpose of the standard and social accounting of its benefits were instrumental in the rejection of BEPS. The Chinese have tried to develop this standard accounting for the needs of the country as a whole. There are individuals and groups within China for whom enactment of the standard will create difficulties. Little technical, financial, and educational assistance to overcome these obstacles has been included as part of the implementation strategy. In addition, there are other specific issues that make the Chinese standard difficult to implement. China encompasses a broad range of climatic conditions. The Chinese have dealt with this issue by dividing the country into different zones depending on heating degree days
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ROBERTM WIRTSHAFI-ER
and cooling degree days. Areas with less than 1500 heating degree days “C are designated cooling only areas, and are not provided with any coal for heating purposes. Without the unqualified support of local governments in the implementation of the standard, the reductions envisioned will not materialize. For insight into implementation issues at the local level, it is useful to examine the experience in the Province of Henan. IMPLEMENTATION
PROBLEMS
IN HENAN
Henan is located in central China, in the area that is both hot in the summer (average monthly temperature for Zhengzhou, the capital, for June, July, and August is 268°C) and cold in the winter (heating degree days are 2331”C).t The combined requirements for increasing winter indoor temperatures while reducing summer indoor temperatures presents a difficult challenge for designers. Many of the passive solar heating approaches used in northern China produce unlivable summer conditions in this part of the country. Like the rest of China, Henan is undergoing a rapid construction phase in which 50 million m2 of new housing are being built each year. Eighty percent of this construction is being done in the rural areas, by peasants who pay for and build their own homes, and as such are probably not subject to the standard. As interpreted by some building officials in Henan, the standard only applies to homes built by the Ministry of Urban and Rural Construction and Environmental Protection. If this is true, then only a small fraction of the buildings in Henan will be affected directly by the code. A typical urban construction project consists of a 5-story brick apartment building with 4 staircases, with each staircase serving 3 families per floor. Although the main portion of the structure is south-facing, little care has been made to reduce summer solar heat gain. The building is made of a double layer brick wall with a thin layer of lime mortar. Roofs are made by spanning precast concrete blocks for support and then covering with a brick-supported light precast panel. Some material, usually slag removed from boilers, is used to provide some roof insulation. Windows are made with single-paned glass and a steel frame, causing a large amount of infiltration. Most homes in Zhengzhou are heated by a small portable coal stove, though many of the newest apartments are equipped with central heating systems fired by a coal boiler. The energy efficiency of present US. and Chinese practices is illustrated in Table 1. The U-values for the different components are quite large especially in comparison to current U.S. and Western practices. Because the majority of the heat loss occurs through the walls and the windows, these areas deserve the greater attention. In order to calculate the energy use required by the new standard, the present heat transfer coefficient is calculated, and then reduced by 60%. Equation (1) is used to determine the present total heat-transfer coefficient, viz.,
QH=
(1)
where Qu = total heat transfer coefficient, Q HT = total heat loss from conduction, QrNF = total heat loss from infiltration, QrH = internal heat gain, 2 = number of heating days, and AREA = total floor area. For Henan, the following values are obtained for a typical 5-story, 60-unit apartment building: 39.19 W/m2 = (257,646 + 32,244 + 25,627)/(24 x 100 x 2810).
(2)
The coal needed to supply this building is 24.7 kg/m2-yr [See Eq. (3)]. This result assumes that standard residential coal contains 8.14 x lo3 Wh/kg and that the efficiency of the boiler and delivery system are 55 and 85%, respectively. Therefore, 24.7 kg/m2-yr = (39.19 W/m’) x (2400 h/yr)/[(8.14
X lo3 Wh/kg) X 0.85 X 0.551.
(3)
tin China, degree days are only accumulated during the official heating period. For Zhengzhou, Henan, this is a 100 day period from 26 November through 5 March in which there are 1660 degree days (“C base 18).
Energy-conservation Table 1. The heat-transfer
structure
standards for buildings in China
coefficients (W/m’-K) for different construction practices. United states
Typical
Roof
0.27
1
Typical
Wall
0.44
3
Energy
Efficient
Roof
0.19
5
Energy
Efficient
Wall
0.21
7
1.
2. 3. 4. 5. 6. 7. 8.
269
China
I
Relative efficiency US/China
154 mm (6") of insulation 200 mm concrete 51.3 mm (2") by 102.6 mm (4") construction with 89.7 mm (3.5") of insulation between studs 240 mm brick, 10 mm of lime mortar 231 mm (9") of insUlatiOn 200 mm concrete, 20 mm of boiler slag 51.3 mm (2") by 154 mm (6") construction with 25.6 mm (1") insulation sheeting 240 mm brick, 20 mm perlite/lime mortar
The new standard requires a 60% improvement in the efficiency of the building so that new buildings must achieve a rating of 21.1 W/m* and a coal usage of 13.3 kg/m*-yr. The bare features of this home reflect both the material shortages experienced in China (wood is only used for window jambs and doors) and the necessity for minimizing the cost of each home so that more can be constructed. Present costs for construction are in the range of 160-170Yuan (y) per m* of floor area (1 Yuan = $0.27). Since a typical two bedroom apartment has 50m*, the total cost of the unit is 8000Yuan and, therefore, all energy improvements must be accomplished for Y400. This provision severely limits the options available to designers in trying to develop homes that meet the new thermal requirements. The implementation of the code will require answers to a number of difficult technical, economic and political questions and development of new policies. Chief among these are the following: (i) China has not developed the infrastructure for providing energy-conservation materials and services. There are few tested energy-conservation measures available on a widespread basis. There does not exist an adequate body of information about the effectiveness, economy, safety, and availability of potential energy-conservation measures. (ii) While the long-term economic benefits to the nation of this standard seem to have been established, the immediate benefits to the builders and owners is less clear. (ii) Institutional changes needed for successful implementation, including product development, training, and enforcement have not been explicated adequately. Other directives such as the extent of applicability are subject to interpretation at the local level.
EXAMINATION
OF FEASIBLE
CONSERVATION
MEASURES
The options available to designers in Henan are strictly limited by the cost restrictions and the limitation on the supply of materials. Wirtshafter and Chang concluded that Western-style insulation practices are inappropriate in Henan.’ They found that the materials were either not available, are not readily installed, or not economically justified. New approaches are being tried in Henan and elsewhere in China. Many of these are in the experimental stages and have yet to be tested thoroughly, The opportunities can be classified in four categories: insulation, windows, passive solar, and heating systems. Potential improvements
in insulation
The Western ideal of insulating everything has to be reevaluated when considering China. The modern insulation materials, fiberglass, polystyrene, and polyisocyandrate are not
210
ROBERTM WIRTSHAFTER
available and would be too expensive. The Chinese have begun to use boiler slag as a roof insulation material. This is the major reason that roof losses account for ~6% of the total heat loss. If the standard is to be met, improvements are needed in the walls and windows. Boiler slag appears to be available, but its density is quite high and its resistivity value is quite low. Other materials such as perlite, vermiculite, rockwool, and compressed wood-fiber, which are presently available in China, could be used, but there are serious supply issues raised. For instance, perlite, which has a resistance factor three times that of boiler slag, could replace the slag. The present price of perlite in China suggests that one-third the amount of perlite would have the same costs and the same effectiveness as the boiler slag. The main problem in insulating the walls is that there is no simple way to attach insulation to the walls. The walls are solid brick with no studs or lathing. Traditionally in northern China, walls are made thicker to increase thermal efficiency. In these cases, the creation of a cavity wall is possible. In Henan, where walls are load bearing and are only one brick length thick there is no easy or inexpensive method for constructing a cavity wall. The other possibility, to which the Chinese have devoted much attention, is improving the thermal resistance of the bricks themselves. The production of hollow bricks and of aerated masonry blocks has been expanded. China has imported a hollow brick manufacturing plant from Italy. The factory produces bricks in which small rectangular tubes are pushed through the brick before firing, leaving holes in the brick. Up to 40% of the brick can be removed, saving production costs and increasing heat resistance. China has also built over 60 factories to create masonry block. A most promising idea has been the suggestion to add perlite to the mortar used to cover the interior walls. The perlite mortar reduces the wall losses by 29%. The cost is estimated to be about Y1.00/m2 using present perlite prices. The Beijing Institute of Architectural Design has experimented with strips made from gypsum wallboard to create a cavity into which insulation can be placed. They have also created a precast concrete wall panel for curtain walls in which rockwool has been sandwiched. These experiments are not yet widely used in Beijing, and are too expensive for Henan’s purposes. Reducing window conduction and infiltration
Current construction relies on the use of single-paned, steel-framed windows. There are often large visible cracks between the window and its frame resulting in high infiltration levels. Fortunately, because even steel windows are expensive (35-48Y/m2), no more than 10% of the wall area is window. Weatherstripping for the windows is available at 4Y/m2, but it is not always specified. Aluminum windows with tighter seal and hollow frames are increasingly available, however the cost of the aluminum windows is normally prohibitive, approx. 3-4 times more expensive than steel windows. A limited supply of wood frame windows, which are of higher quality and are more efficient, are manufactured and are surprisingly sold at prices lower than the steel ones, a phenomenon that is difficult to explain given China’s severe shortages of wood. This is another example of prices being inconsistent with resource value. Storm windows are almost never utilized, partly because the leakage is so great that the benefits are minimal. The steel and especially the aluminum windows can be made with double glass thermal pane. Quality control of windows is a major concern. Despite varying quality, each factory sells its windows at the same price. The demand for windows is so great that all of the windows, be they good or bad, are immediately sold. The use of passive solar energy
The Chinese have always built their homes with an east/west orientation, with windows predominantly on the southern side in order to take advantage of solar gain and to minimize heat loss due to northerly winter winds. Unfortunately, the actual utilization of solar energy is
Energy-conservation
standards for buildings in China
271
well below optimum. The thermal collection is under-utilized because windows are covered with thick layers of dirt. Given the need to design buildings that are comfortable in the summer and in the winter, the sizing of the overhang is critical. Many homes have windows with no overhangs at all while other have windows which are completely shaded by balconies year-round. Solar designs appropriate in northern or southern China are often unsuitable in Henan’s climate, and many of the passive solar approaches used in the West are too expensive. One measure that has a lot of promise, but is seldom utilized, is the use of thermal shutters and blankets. Chinese farmers have traditionally covered their greenhouses with reed matting to keep the plants warm on cold evenings. Since there are no automatic temperature systems, Chinese take a more active role in the maintenance of indoor temperatures, and are more likely to utilize thermal blankets than their Western counterparts. Passive solar energy techniques are often introduced without full understanding of the concepts involved. Many homes do not include overhangs or sufficient thermal mass for heat storage. The potential for improvement in the rural areas is increased by the greater leeway that individual peasants have in designing their homes. For peasants, a primary motivation in design in the status gained by the inclusion of certain measures. Yet, until adequate education is made available, aesthetic improvements may be selected without consideration of energy consumption. A classic example is the status gained by a higher ceiling because it is a sign of great wealth, even though it results in greater heating requirements. Improvements in the heating systems Perhaps the most substantial savings will be realized in the potential improvements in the heating systems. Most Henan homes are heated by small stoves that burn honeycomb-shaped coal briquettes, formed from coal dust. The Chinese have been leaders in the development of more efficient stoves. They have developed new designs which have improved the typical efficiencies from 8-10% to 25-30%. Some newer buildings have central heating systems. The systems do not contain any of the energy control equipment such as thermostats and outdoor reset controls commonly included in Western systems. Usually, the boiler is manually turned on for a certain period of time each day, and then the building is expected to coast through the rest of the day. Present efficiencies for boilers are estimated to be around 40-55%. Another 5% of the energy generated is lost in the delivery system. These central systems do allow for certain economies of scale in the cost of the boiler, however the absence of controls may actually increase overall consumption. In China, measures such as automatic boiler controls, heat recovery, and cogeneration are very rarely utilized in individual apartment buildings. Also, as in the West, such centralized boilers remove the individual’s responsibility for energy bill payment and thus the incentive for reducing fuel consumption. Pollution control is a potential benefit of larger centralized systems. Since the individual stoves often have no chimney, indoor air pollution is reduced even though no specific pollution controls are included in the central systems. Natural gas or, more commonly, synthetic coal gas systems are being installed in many of the large cities to reduce pollution. District heating systems are also being expanded. By the year 2000, the Chinese hope to heat 25-30% of the urban buildings in northern China with district heating. l5 District heating in China faces the same barriers as it does in the West. For instance, unless a large industrial base is secured, the systems can only be operated in the winter. In addition, the same forces that have driven the Western power plants away from the cities are exerting themselves in China, thus separating the heat source from its end-use. THE
ECONOMIC
BARRIERS
TO GREATER
ENERGY
CONSERVATION
The range of potential technical solutions to improving energy efficiency in Chinese buildings is limited by economic constraints. Not only are many of the raw materials in short supply, but
272
ROBERTM WIRTSHAFTER
there is also no developed conservation market infrastructure. In a sense, the standard must serve as the impetus for the development of an energy-conservation product and service industry. Without government assistance, products and services will not be available to help builders meet the new standards. The development of energy efficient stoves illustrates the complexities involved in trying to develop new energy-conservation products. There are strong direct benefits to the users of more efficient stoves. In rural areas, peasants will be able to reduce time spent gathering fuel, return a greater portion of their agricultural residue to the soil, remove less vegetation and thus reduce erosion, and/or improve health and comfort by having a greater amount of available energy. In urban areas, families will be able to increase their comfort levels, reduce their purchases of supplemental fuel, and/or sell a portion of their monthly coal quota to others. In spite of these strong economic incentives to the stove user, the use is far from universal. One obstacle to the universal adoption of new efficient stoves is the lack of differentiation between products, preventing the consumer from making an educated purchase. Testing and product rating is currently under way to provide the necessary information to potential purchasers. Finally, an ambitious promotional effort in the countryside has been instituted with an initial success in the deployment of over 40 million stoves, and a goal of reaching 60% of the rural households by 1990, the end of the 7th Five Year Plan.13 Successful development of the energy-conservation industry is even less straightforward than the development of stoves, particularly because the benefits may not be as clear-cut. For most individual families, energy conservation may not actually result in the savings of any fuel or money at all. This is because so little energy is used for heating in the first place. In Zhengzhou only 6.1% of the total energy consumed in the residential sector is used for heating. In many other parts of the country, there are insufficient fuel resources to meet cooking demands. This means that energy conservation will result in little fuel savings. This factor raises a difficult policy issue for those promoting the new standard. The immediate benefits to the individual Chinese families from the inclusion of energy conservation will probably be an increase in the comfort level of their homes, but little or no savings in energy. The extent of this can be seen by reexamining the standard. Equation (3) calculates that each apartment building presently uses 69,643 kg of coal per yr [(24.7 kg/m’) X (2810 m”)]. A 60% improvement in efficiency, as required by the standard, would reduce energy consumption to 37,373 kg/yr, or a saving of 32,090 kg/yr. At present in Zhengzhou, the coal consumption for heating an apartment building, based on the average coal use for the city, is 7440 kg of coal per yr [(124 kg/yr-family) x 60 families)]. In other words, the standard proposes to save over four times more energy than is currently consumed. The standard calculates energy savings assuming indoor temperatures of 18°C while actual indoor temperatures are considerably lower. As a result of the discrepancy in indoor temperatures, the short-term benefits envisioned by improved building efficiency are drastically overestimated. The question is, if there are no immediate energy savings from the standard, can the Chinese afford to implement the standard at this time? The Chinese assume that in the future, their citizens will demand higher indoor winter temperatures as a measure of their increased standard of living. These greater temperatures can be achieved by increasing coal consumption or by increasing building efficiency. It seems unrealistic, however, to calculate the benefits of conservation assuming indoor temperature equivalent to present Western practices. Instead, the benefits of conservation should be evaluated allowing for far more modest indoor temperature improvements. Only in this way can the real priority of energy efficiency in buildings be determined correctly. In one important sense, the designers of the standard recognized the real priority of conservation in buildings by limiting conservation investment to ~5% of building costs. The problem is that due to the lack of competition to meet consumer demands, the immediate prospect of raising indoor temperature levels does not provide sufficient economic incentive to the individual or institution responsible for building the structure. The government may have to give additional incentives to reconcile the long-term benefits to the country, whatever they really are, with the immediate expenditures forced on the homebuilders. Adding
Energy-conservation
standards for buildings in China
273
to the problem is the fact that the standard does not appear to be applicable to the rural areas where individual peasants build and own their own houses. This is a significant weakness, since 80% of the housing construction is now being done in the rural areas, and it is in the rural areas where present fuel shortages are most severe. These issues are all the more important when it is considered that the government is simultaneously losing some of its control over the supply of fuel. The development of secondary fuel markets, where individuals can purchase additional supplies of fuel, increases the likelihood that more fuel will be burned to increase indoor temperatures. Unfortunately, while the economic reforms seem to have freed the supply of fuel, they do not seem to have affected the materials and products used in energy conservation. As noted above, perlite, which is not heavily used now, is priced rather low relative to the international market price. Yet if demand increased, it is not clear that supply would keep pace regardless of the price charged. Other products such as hollow bricks and rockwool, which have high development costs are priced high even though the initial cost will eventually be spread over a large production volume. Reliance on the market to promote energy conservation in Chinese housing raises another major issue. The likelihood that a free market for fuel will lead to greater inequity in the distribution of fuel supplies is a large political concern in China. This phenomenon can already be seen in wealthy villages in Henan where energy consumption per household is several times greater than that in rural households in general.
CONCLUSION
The building standard addresses only one of the many serious resource issues confronting China. According to Fingar, the recent search for and discussion of these problems has created an information overload.16 He warns that it is important that each of these problems be given a relative priority. The issue of energy supply is critical to China’s modernization plans, but energy currently used in buildings for heating is small, and is therefore, only a minor area of that concern. Future gains in income and wealth will probably increase the desire of the Chinese to use more energy for heating, raising the temperature at which they maintain their buildings. Should this trend become too strong it could jeopardize China’s other modernization plans, plans that are already dependent on a decrease in the consumption of energy per household. Unfortunately, the new economic reforms have created an impasse for the Chinese. The success of the reforms has fueled the desires for improvements in living standards and has reduced China’s ability to control household access to coal. As long as the Chinese continue rapidly to build new housing, every effort should be made to optimize the level of energy efficiency. Unfortunately, the infrastructure for delivering energy conservation is extremely immature. Energy conservation in the residential market is unlikely to be pursued without a continued effort by government organizations. While the new standard alone cannot be effective in solving China’s monumental energy problems, the standard can be a useful step towards development of a conservation strategy. In the long run the standard must become a component in a broader effort to develop new energy-conservation products, more effective means of education about energy-conservation measures and approaches, and training of energy service personnel. The Chinese will need to find a way to control energy demand, either through a return to direct control or through energy pricing policies. Thus the eventual role of the standard depends upon the resolution of much larger political and economic questions now facing China.
Acknowledgements-Partial funding for this research was made available by the University of Pennsylvania Research Foundation. The author wishes to thank Chang Song-Ying, Robert P. Taylor, Stephen Sawyer, and Agatha Andrews for their contributions to this article.
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ROBERTM WIRTSHAFI-ER REFERENCES
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Energy and Economic Growth,” in “China Economy Looks Toward the Year 2000, Volume 2. Economic Openness in Modernizing China”, U.S. Government Printing Office, Washington, DC (21 May 1986). Hu Lin and Yang Shau-gin, “Brief Introduction of Tentative Design Standard on Energy Conservation in New Residential Buildings,” Institute of Building Physics Chinese Academy of Building Research, Beijing, Xerox. Xia Wu-Xiang, Vice President, China Engineering Technology Development Corp., personnel conversation. R. M Wirtshafter and Chang Song-ying, Energy Pol. 15, 158 (April 1987). Chinese Architectural Scientific Research Institute, “Energy Conservation Design Standard in Civil Buildings,” Beijing, 3186, in Chinese. W. S. Fleming and H. Misuriello, ASHRAE J. 22, 31 (June 1980). World Bank, China Long-Term Development Zssues and Options, Johns Hopkins University Press, Baltimore, MD (1985). Regional Office for Asia and the Pacific, FAO, “Chinese Fuel Saving Stoves,” Maliwan Mansion, Phra Atit Rd., Bangkok, Thailand (1986). “First International Symposium on Fuel-Efficient Stoves,” Zhang Jigao ed., China Academy of Agricultural Engineering Research and Planning, Beijing, China (November 1986). Xinhua “Government Calls For More Central Heating in Cities,” in Survey of World Broadcasts, Far East IV1378 Al6 (18 Feb. 1986). T. Fingar, “Overview Energy in China,” in “China’s Economy Looks Towards the Year 2000, Volume 2. Economic Openness in Modernizing China,” 4, U.S. Government Printing Office, Washington, DC (21 May 1986).
Energy Vol. 13, No. 3, pp. 265-214, 1988 Printedin Great Britain. All rightsreserved
$3.00 + 0.00
CopyrightfQ 1988PergamonPressplc
ENERGY-CONSERVATION STANDARDS BUILDINGS IN CHINA
FOR
ROBERT M WIRTSHA~ER Department of City and Regional Planning, University of Pennsylvania, Philadelphia, PA 19104, U.S.A. (Received 27 April 1987)
Abstract-The People’s Republic of China has recently designed an energy-conservation building standard which would require that, by 1990, the energy efficiency of new buildings be improved by 60% over existing practices. Present energy-conservation practices in China suffer from a lack of fully developed technical solutions and institutional support
infrastructure. Given the greater complexity of the Chinese economy under the new reforms, the commitment to improving the efficiency of household energy use requires a broader focus beyond the formulation of a standard. In order for the standard to be successful, China will need to devote resources that may be more effectively utilized in other sectors of the economy.
INTRODUCTION
A recently enacted energy-conservation standard for new buildings provides insight into the difficult political issues facing China amid the new economic reforms. The standard requires that by 1990 new buildings consume 60% less energy than typical existing buildings. In the past, China relied on the combination of such standards and absolute control of fuel supply to restrict energy consumption. Now, with the relaxing of central control of the economy, this approach is not sufficient. China must now develop energy policy implementation strategies compatible with its economic reforms. The energy-conservation standard is a central component of China’s residential energyconservation efforts. The implementation and enforcement of the standard face many difficult challenges, however. Some of these obstacles are unique to China’s climatic, economic, and political situation, while others are representative of both developed and developing countries. CHINESE
ENERGY
PRODUCTION
AND CONSUMPTION
The need for energy conservation in China is underscored by the severe shortage of non-coal energy resources and by the production, transportation, and environmental problems resulting from reliance on coal.lm3 In 1983, coal accounted for over 74% of the total commercial energy consumed in China. While most of this coal is used in industry (58%), 27% is for residential/commercial uses, almost all of which is burned directly in inefficient stoves and boilers, leading to unhealthy air-quality conditions in most urban areas. In rural areas, there is little coal available for residential use and, therefore, the dependence on agricultural waste for cooking and heating has resulted in degradation of soil and extensive erosion. Future projections suggest that China must radically increase its energy supply and the efficiency of use. A World Bank report demonstrates that China’s plans for modernization, in which gross value of industrial and agricultural output (GVIAO) will quadruple by the year 2000, will require a 220% increase in coal production and a 300-400% increase in oil and electricity.3g4 In an earlier World Bank publication, it was noted that China has an energy input/GDP ratio that is 2.5 times higher than that of most other developing countries.3 In order to achieve the goal of quadrupling GVIAO, this ratio must be lowered significantly. The various scenarios require reductions in the energy intensity per unit GDP of between 1.0 and 2.7% per annum.3 China’s recent progress in energy conservation has emphasized the industrial sector.5 For instance, between 1981 and 1984, energy input rose only 4% while GVIAO rose 9.4%. Most of 265
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this reduction in energy intensity is attributable to the restructuring of the Chinese economy from heavy to light industry.‘j During that period, the amount of energy consumption per unit of steel output dropped 12%, energy per unit of ammonia production dropped 21%, energy input per crude oil output dropped 29%, and coal in thermal power plants dropped 6%. China has accomplished these industrial energy savings by instituting a number of reforms. The recent 5-yr plans contain specific goals for reduction of energy, including mandatory and voluntary goals for major industries to meet, and designation of large energy-savings projects for immediate development. Energy-management schemes have been instituted for the major energy-consuming industries and have included audits, incentives, monitoring, and training. Economic reforms have also provided new financial impetus to conserve energy. Coupled with new emphasis on establishing market prices for energy, the relaxing of control over markets has resulted in greater efficiency and a shift away from heavy industry to less energy-intensive light manufacturing. One major obstacle is that much of Chinese industrial production comes from small factories which are difficult to reach as effectively with energy-conservation initiatives. The task is complicated by the fact that free market competition is still modest by Western standards and limited by access to raw materials and final customers. Some energy inputs are still priced below their real international market value. This is particularly the case with coal even though factories that use more coal than they are allocated by the government are now required to purchase the excess at market prices. Historically, the Chinese have relied on central control for limiting energy consumption. In the industrial sector, this control has had two components: the restriction of access to energy supplies, and the implementation of usage standards. In the residential sector, restriction of access has been the predominant means of control. As China begins to create an open market for energy, restrictions on access are weakened, necessitating the extension of standards into the residential sector. ENERGY
CONSUMPTION
IN THE
RESIDENTIAL
SECTOR
The present level of energy consumption in households is so low that little savings can be expected. China has recognized the importance of improving residential energy efficiency not for what is presently consumed, but based on the potential future consumption projections: there is concern that energy consumption increases caused by the expansion of the residential sector will absorb the resources made available by energy conservation in the industrial sector, constraining future industrial expansion. Because of the present shortage of housing, the Chinese have placed a priority on increasing the number and quality of housing units. Hu and Yang report that 1.5 billion m2 of heated residential housing will be constructed by the year 2000, quadrupling the existing 500 million m2.7 Since the modernization plans can only tolerate a doubling of the total energy for residential heating, therefore, the average usage in all buildings must be half of what it is today.8 The efficiency gain must come in large part from new housing since, new housing will account for as much as 75% of the housing to be available by the year 2000. Unfortunately, additional pressure on the energy supply can be expected as a result of the expansion of the economy. The increase in the disposable incomes of Chinese workers will most certainly result in greater demand for energy for heating. This is particularly the case when one considers the low temperatures at which Chinese homes are presently maintained. Wirtshafter and Chang report that Chinese energy consumption per home is similar to that in other developing countries, even though almost all other developing countries have essentially no heating requirements. The supply of fuel is so limited and expensive that most if not all of the fuel is needed for cooking rather than space heating.’ Since little energy is consumed for residential heating, measures for greater thermal efficiency in new buildings will contribute far more to raising temperature levels than to lowering energy use. This is the crux of a major policy dilemma in China today: whether resources should be directed toward improved standards of living, such as increased comfort levels in the home, or toward industrial expansion. Should China decide to continue to opt for
Energy-conservation standards for buildings in China
267
industrial expansion, even tighter control of energy supplies in the residential sector will be needed. If improvement in the comfort levels of homes is permitted, it is clearly preferable that this be accomplished by improving energy efficiency rather than by increasing fuel consumption.
THE
ENERGY-CONSERVATION
BUILDING
STANDARD
Putting aside the issue of the political priority of residential energy conservation, there remains the issue of whether the conservation standard can be implemented effectively. The Energy-conservation Design Standard in Civil Buildings was developed cooperatively by The State Planning Commission and the Ministry of Urban and Rural Construction and Environmental Protection. lo The standard specifies that residential buildings built between 1986 and 1990 reduce the overall heat loss coefficient by 30% from present practices. An additional 30% improvement must be realized in homes built between 1990 and 2000. The standard also stipulates that the improvements must add no more than 5% to present costs of construction. It is important to observe the difference between the Chinese and Western concept of a standard. A Chinese ministry will often issue a standard as a means of raising concern for a problem. Passage does not necessarily extend the standard beyond the ministry’s own jurisdiction, unless the standard is later adopted by the broader central government. The ministry’s role is somewhat analogous to that of ASHRAE or other U.S. organizations that develop standards that must be adopted by other entities to be effective. The Chinese standards tend to serve as goals to be achieved rather than as enforceable minimum levels for compliance. The standard utilizes a performance-based criterion in which heat loss from walls, roof, windows, doors, floor, and infiltration are calculated on a seasonal basis using degree days. The typical overall heat loss coefficient of homes in the region is determined. The standard then establishes a new performance value that new buildings must achieve. Actions for achieving the standard are suggested for each climatic region including recommendations for number of window glazings, volume/surface area ratio, and basement or slab treatment. The experience of the United States in trying to develop an energy-conservation standard is helpful in evaluating the Chinese standard.” The complexity of technical and political issues led to the rejection of the Building Energy Performance Standard (BEPS) as a national energy-conservation code, but the state of California has utilized a performance standard for over 5 yrs. Chief among the issues involved in the development and enforcement of building energy performance standards are the following: (i) the legitimacy of BEPS and the resulting savings estimates were questioned because the standard relied upon unvalidated engineering models drawn from studies of a few buildings. The Chinese have relied upon engineering estimates based on even less study. They have conducted few tests of actual savings from proposed energy-conservation measures. (ii) The use of prescriptive standards was deemed too inflexible for U.S. building practices. Performance-related standards were either too general or required extensive and time-consuming energy-consumption modelling. As a result, the California standard includes both prescriptive and performance options, including a simplified performance scoresheet approach. The Chinese have developed a performance-related standard, one that was easy to develop but much harder to enforce. Because the majority of past regulations have been prescriptive in nature, neither designers nor those responsible for enforcement have any experience with this type of calculation procedure. (iii) Political issues about the purpose of the standard and social accounting of its benefits were instrumental in the rejection of BEPS. The Chinese have tried to develop this standard accounting for the needs of the country as a whole. There are individuals and groups within China for whom enactment of the standard will create difficulties. Little technical, financial, and educational assistance to overcome these obstacles has been included as part of the implementation strategy. In addition, there are other specific issues that make the Chinese standard difficult to implement. China encompasses a broad range of climatic conditions. The Chinese have dealt with this issue by dividing the country into different zones depending on heating degree days
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and cooling degree days. Areas with less than 1500 heating degree days “C are designated cooling only areas, and are not provided with any coal for heating purposes. Without the unqualified support of local governments in the implementation of the standard, the reductions envisioned will not materialize. For insight into implementation issues at the local level, it is useful to examine the experience in the Province of Henan. IMPLEMENTATION
PROBLEMS
IN HENAN
Henan is located in central China, in the area that is both hot in the summer (average monthly temperature for Zhengzhou, the capital, for June, July, and August is 268°C) and cold in the winter (heating degree days are 2331”C).t The combined requirements for increasing winter indoor temperatures while reducing summer indoor temperatures presents a difficult challenge for designers. Many of the passive solar heating approaches used in northern China produce unlivable summer conditions in this part of the country. Like the rest of China, Henan is undergoing a rapid construction phase in which 50 million m2 of new housing are being built each year. Eighty percent of this construction is being done in the rural areas, by peasants who pay for and build their own homes, and as such are probably not subject to the standard. As interpreted by some building officials in Henan, the standard only applies to homes built by the Ministry of Urban and Rural Construction and Environmental Protection. If this is true, then only a small fraction of the buildings in Henan will be affected directly by the code. A typical urban construction project consists of a 5-story brick apartment building with 4 staircases, with each staircase serving 3 families per floor. Although the main portion of the structure is south-facing, little care has been made to reduce summer solar heat gain. The building is made of a double layer brick wall with a thin layer of lime mortar. Roofs are made by spanning precast concrete blocks for support and then covering with a brick-supported light precast panel. Some material, usually slag removed from boilers, is used to provide some roof insulation. Windows are made with single-paned glass and a steel frame, causing a large amount of infiltration. Most homes in Zhengzhou are heated by a small portable coal stove, though many of the newest apartments are equipped with central heating systems fired by a coal boiler. The energy efficiency of present US. and Chinese practices is illustrated in Table 1. The U-values for the different components are quite large especially in comparison to current U.S. and Western practices. Because the majority of the heat loss occurs through the walls and the windows, these areas deserve the greater attention. In order to calculate the energy use required by the new standard, the present heat transfer coefficient is calculated, and then reduced by 60%. Equation (1) is used to determine the present total heat-transfer coefficient, viz.,
QH=
(1)
where Qu = total heat transfer coefficient, Q HT = total heat loss from conduction, QrNF = total heat loss from infiltration, QrH = internal heat gain, 2 = number of heating days, and AREA = total floor area. For Henan, the following values are obtained for a typical 5-story, 60-unit apartment building: 39.19 W/m2 = (257,646 + 32,244 + 25,627)/(24 x 100 x 2810).
(2)
The coal needed to supply this building is 24.7 kg/m2-yr [See Eq. (3)]. This result assumes that standard residential coal contains 8.14 x lo3 Wh/kg and that the efficiency of the boiler and delivery system are 55 and 85%, respectively. Therefore, 24.7 kg/m2-yr = (39.19 W/m’) x (2400 h/yr)/[(8.14
X lo3 Wh/kg) X 0.85 X 0.551.
(3)
tin China, degree days are only accumulated during the official heating period. For Zhengzhou, Henan, this is a 100 day period from 26 November through 5 March in which there are 1660 degree days (“C base 18).
Energy-conservation Table 1. The heat-transfer
structure
standards for buildings in China
coefficients (W/m’-K) for different construction practices. United states
Typical
Roof
0.27
1
Typical
Wall
0.44
3
Energy
Efficient
Roof
0.19
5
Energy
Efficient
Wall
0.21
7
1.
2. 3. 4. 5. 6. 7. 8.
269
China
I
Relative efficiency US/China
154 mm (6") of insulation 200 mm concrete 51.3 mm (2") by 102.6 mm (4") construction with 89.7 mm (3.5") of insulation between studs 240 mm brick, 10 mm of lime mortar 231 mm (9") of insUlatiOn 200 mm concrete, 20 mm of boiler slag 51.3 mm (2") by 154 mm (6") construction with 25.6 mm (1") insulation sheeting 240 mm brick, 20 mm perlite/lime mortar
The new standard requires a 60% improvement in the efficiency of the building so that new buildings must achieve a rating of 21.1 W/m* and a coal usage of 13.3 kg/m*-yr. The bare features of this home reflect both the material shortages experienced in China (wood is only used for window jambs and doors) and the necessity for minimizing the cost of each home so that more can be constructed. Present costs for construction are in the range of 160-170Yuan (y) per m* of floor area (1 Yuan = $0.27). Since a typical two bedroom apartment has 50m*, the total cost of the unit is 8000Yuan and, therefore, all energy improvements must be accomplished for Y400. This provision severely limits the options available to designers in trying to develop homes that meet the new thermal requirements. The implementation of the code will require answers to a number of difficult technical, economic and political questions and development of new policies. Chief among these are the following: (i) China has not developed the infrastructure for providing energy-conservation materials and services. There are few tested energy-conservation measures available on a widespread basis. There does not exist an adequate body of information about the effectiveness, economy, safety, and availability of potential energy-conservation measures. (ii) While the long-term economic benefits to the nation of this standard seem to have been established, the immediate benefits to the builders and owners is less clear. (ii) Institutional changes needed for successful implementation, including product development, training, and enforcement have not been explicated adequately. Other directives such as the extent of applicability are subject to interpretation at the local level.
EXAMINATION
OF FEASIBLE
CONSERVATION
MEASURES
The options available to designers in Henan are strictly limited by the cost restrictions and the limitation on the supply of materials. Wirtshafter and Chang concluded that Western-style insulation practices are inappropriate in Henan.’ They found that the materials were either not available, are not readily installed, or not economically justified. New approaches are being tried in Henan and elsewhere in China. Many of these are in the experimental stages and have yet to be tested thoroughly, The opportunities can be classified in four categories: insulation, windows, passive solar, and heating systems. Potential improvements
in insulation
The Western ideal of insulating everything has to be reevaluated when considering China. The modern insulation materials, fiberglass, polystyrene, and polyisocyandrate are not
210
ROBERTM WIRTSHAFTER
available and would be too expensive. The Chinese have begun to use boiler slag as a roof insulation material. This is the major reason that roof losses account for ~6% of the total heat loss. If the standard is to be met, improvements are needed in the walls and windows. Boiler slag appears to be available, but its density is quite high and its resistivity value is quite low. Other materials such as perlite, vermiculite, rockwool, and compressed wood-fiber, which are presently available in China, could be used, but there are serious supply issues raised. For instance, perlite, which has a resistance factor three times that of boiler slag, could replace the slag. The present price of perlite in China suggests that one-third the amount of perlite would have the same costs and the same effectiveness as the boiler slag. The main problem in insulating the walls is that there is no simple way to attach insulation to the walls. The walls are solid brick with no studs or lathing. Traditionally in northern China, walls are made thicker to increase thermal efficiency. In these cases, the creation of a cavity wall is possible. In Henan, where walls are load bearing and are only one brick length thick there is no easy or inexpensive method for constructing a cavity wall. The other possibility, to which the Chinese have devoted much attention, is improving the thermal resistance of the bricks themselves. The production of hollow bricks and of aerated masonry blocks has been expanded. China has imported a hollow brick manufacturing plant from Italy. The factory produces bricks in which small rectangular tubes are pushed through the brick before firing, leaving holes in the brick. Up to 40% of the brick can be removed, saving production costs and increasing heat resistance. China has also built over 60 factories to create masonry block. A most promising idea has been the suggestion to add perlite to the mortar used to cover the interior walls. The perlite mortar reduces the wall losses by 29%. The cost is estimated to be about Y1.00/m2 using present perlite prices. The Beijing Institute of Architectural Design has experimented with strips made from gypsum wallboard to create a cavity into which insulation can be placed. They have also created a precast concrete wall panel for curtain walls in which rockwool has been sandwiched. These experiments are not yet widely used in Beijing, and are too expensive for Henan’s purposes. Reducing window conduction and infiltration
Current construction relies on the use of single-paned, steel-framed windows. There are often large visible cracks between the window and its frame resulting in high infiltration levels. Fortunately, because even steel windows are expensive (35-48Y/m2), no more than 10% of the wall area is window. Weatherstripping for the windows is available at 4Y/m2, but it is not always specified. Aluminum windows with tighter seal and hollow frames are increasingly available, however the cost of the aluminum windows is normally prohibitive, approx. 3-4 times more expensive than steel windows. A limited supply of wood frame windows, which are of higher quality and are more efficient, are manufactured and are surprisingly sold at prices lower than the steel ones, a phenomenon that is difficult to explain given China’s severe shortages of wood. This is another example of prices being inconsistent with resource value. Storm windows are almost never utilized, partly because the leakage is so great that the benefits are minimal. The steel and especially the aluminum windows can be made with double glass thermal pane. Quality control of windows is a major concern. Despite varying quality, each factory sells its windows at the same price. The demand for windows is so great that all of the windows, be they good or bad, are immediately sold. The use of passive solar energy
The Chinese have always built their homes with an east/west orientation, with windows predominantly on the southern side in order to take advantage of solar gain and to minimize heat loss due to northerly winter winds. Unfortunately, the actual utilization of solar energy is
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standards for buildings in China
271
well below optimum. The thermal collection is under-utilized because windows are covered with thick layers of dirt. Given the need to design buildings that are comfortable in the summer and in the winter, the sizing of the overhang is critical. Many homes have windows with no overhangs at all while other have windows which are completely shaded by balconies year-round. Solar designs appropriate in northern or southern China are often unsuitable in Henan’s climate, and many of the passive solar approaches used in the West are too expensive. One measure that has a lot of promise, but is seldom utilized, is the use of thermal shutters and blankets. Chinese farmers have traditionally covered their greenhouses with reed matting to keep the plants warm on cold evenings. Since there are no automatic temperature systems, Chinese take a more active role in the maintenance of indoor temperatures, and are more likely to utilize thermal blankets than their Western counterparts. Passive solar energy techniques are often introduced without full understanding of the concepts involved. Many homes do not include overhangs or sufficient thermal mass for heat storage. The potential for improvement in the rural areas is increased by the greater leeway that individual peasants have in designing their homes. For peasants, a primary motivation in design in the status gained by the inclusion of certain measures. Yet, until adequate education is made available, aesthetic improvements may be selected without consideration of energy consumption. A classic example is the status gained by a higher ceiling because it is a sign of great wealth, even though it results in greater heating requirements. Improvements in the heating systems Perhaps the most substantial savings will be realized in the potential improvements in the heating systems. Most Henan homes are heated by small stoves that burn honeycomb-shaped coal briquettes, formed from coal dust. The Chinese have been leaders in the development of more efficient stoves. They have developed new designs which have improved the typical efficiencies from 8-10% to 25-30%. Some newer buildings have central heating systems. The systems do not contain any of the energy control equipment such as thermostats and outdoor reset controls commonly included in Western systems. Usually, the boiler is manually turned on for a certain period of time each day, and then the building is expected to coast through the rest of the day. Present efficiencies for boilers are estimated to be around 40-55%. Another 5% of the energy generated is lost in the delivery system. These central systems do allow for certain economies of scale in the cost of the boiler, however the absence of controls may actually increase overall consumption. In China, measures such as automatic boiler controls, heat recovery, and cogeneration are very rarely utilized in individual apartment buildings. Also, as in the West, such centralized boilers remove the individual’s responsibility for energy bill payment and thus the incentive for reducing fuel consumption. Pollution control is a potential benefit of larger centralized systems. Since the individual stoves often have no chimney, indoor air pollution is reduced even though no specific pollution controls are included in the central systems. Natural gas or, more commonly, synthetic coal gas systems are being installed in many of the large cities to reduce pollution. District heating systems are also being expanded. By the year 2000, the Chinese hope to heat 25-30% of the urban buildings in northern China with district heating. l5 District heating in China faces the same barriers as it does in the West. For instance, unless a large industrial base is secured, the systems can only be operated in the winter. In addition, the same forces that have driven the Western power plants away from the cities are exerting themselves in China, thus separating the heat source from its end-use. THE
ECONOMIC
BARRIERS
TO GREATER
ENERGY
CONSERVATION
The range of potential technical solutions to improving energy efficiency in Chinese buildings is limited by economic constraints. Not only are many of the raw materials in short supply, but
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there is also no developed conservation market infrastructure. In a sense, the standard must serve as the impetus for the development of an energy-conservation product and service industry. Without government assistance, products and services will not be available to help builders meet the new standards. The development of energy efficient stoves illustrates the complexities involved in trying to develop new energy-conservation products. There are strong direct benefits to the users of more efficient stoves. In rural areas, peasants will be able to reduce time spent gathering fuel, return a greater portion of their agricultural residue to the soil, remove less vegetation and thus reduce erosion, and/or improve health and comfort by having a greater amount of available energy. In urban areas, families will be able to increase their comfort levels, reduce their purchases of supplemental fuel, and/or sell a portion of their monthly coal quota to others. In spite of these strong economic incentives to the stove user, the use is far from universal. One obstacle to the universal adoption of new efficient stoves is the lack of differentiation between products, preventing the consumer from making an educated purchase. Testing and product rating is currently under way to provide the necessary information to potential purchasers. Finally, an ambitious promotional effort in the countryside has been instituted with an initial success in the deployment of over 40 million stoves, and a goal of reaching 60% of the rural households by 1990, the end of the 7th Five Year Plan.13 Successful development of the energy-conservation industry is even less straightforward than the development of stoves, particularly because the benefits may not be as clear-cut. For most individual families, energy conservation may not actually result in the savings of any fuel or money at all. This is because so little energy is used for heating in the first place. In Zhengzhou only 6.1% of the total energy consumed in the residential sector is used for heating. In many other parts of the country, there are insufficient fuel resources to meet cooking demands. This means that energy conservation will result in little fuel savings. This factor raises a difficult policy issue for those promoting the new standard. The immediate benefits to the individual Chinese families from the inclusion of energy conservation will probably be an increase in the comfort level of their homes, but little or no savings in energy. The extent of this can be seen by reexamining the standard. Equation (3) calculates that each apartment building presently uses 69,643 kg of coal per yr [(24.7 kg/m’) X (2810 m”)]. A 60% improvement in efficiency, as required by the standard, would reduce energy consumption to 37,373 kg/yr, or a saving of 32,090 kg/yr. At present in Zhengzhou, the coal consumption for heating an apartment building, based on the average coal use for the city, is 7440 kg of coal per yr [(124 kg/yr-family) x 60 families)]. In other words, the standard proposes to save over four times more energy than is currently consumed. The standard calculates energy savings assuming indoor temperatures of 18°C while actual indoor temperatures are considerably lower. As a result of the discrepancy in indoor temperatures, the short-term benefits envisioned by improved building efficiency are drastically overestimated. The question is, if there are no immediate energy savings from the standard, can the Chinese afford to implement the standard at this time? The Chinese assume that in the future, their citizens will demand higher indoor winter temperatures as a measure of their increased standard of living. These greater temperatures can be achieved by increasing coal consumption or by increasing building efficiency. It seems unrealistic, however, to calculate the benefits of conservation assuming indoor temperature equivalent to present Western practices. Instead, the benefits of conservation should be evaluated allowing for far more modest indoor temperature improvements. Only in this way can the real priority of energy efficiency in buildings be determined correctly. In one important sense, the designers of the standard recognized the real priority of conservation in buildings by limiting conservation investment to ~5% of building costs. The problem is that due to the lack of competition to meet consumer demands, the immediate prospect of raising indoor temperature levels does not provide sufficient economic incentive to the individual or institution responsible for building the structure. The government may have to give additional incentives to reconcile the long-term benefits to the country, whatever they really are, with the immediate expenditures forced on the homebuilders. Adding
Energy-conservation
standards for buildings in China
273
to the problem is the fact that the standard does not appear to be applicable to the rural areas where individual peasants build and own their own houses. This is a significant weakness, since 80% of the housing construction is now being done in the rural areas, and it is in the rural areas where present fuel shortages are most severe. These issues are all the more important when it is considered that the government is simultaneously losing some of its control over the supply of fuel. The development of secondary fuel markets, where individuals can purchase additional supplies of fuel, increases the likelihood that more fuel will be burned to increase indoor temperatures. Unfortunately, while the economic reforms seem to have freed the supply of fuel, they do not seem to have affected the materials and products used in energy conservation. As noted above, perlite, which is not heavily used now, is priced rather low relative to the international market price. Yet if demand increased, it is not clear that supply would keep pace regardless of the price charged. Other products such as hollow bricks and rockwool, which have high development costs are priced high even though the initial cost will eventually be spread over a large production volume. Reliance on the market to promote energy conservation in Chinese housing raises another major issue. The likelihood that a free market for fuel will lead to greater inequity in the distribution of fuel supplies is a large political concern in China. This phenomenon can already be seen in wealthy villages in Henan where energy consumption per household is several times greater than that in rural households in general.
CONCLUSION
The building standard addresses only one of the many serious resource issues confronting China. According to Fingar, the recent search for and discussion of these problems has created an information overload.16 He warns that it is important that each of these problems be given a relative priority. The issue of energy supply is critical to China’s modernization plans, but energy currently used in buildings for heating is small, and is therefore, only a minor area of that concern. Future gains in income and wealth will probably increase the desire of the Chinese to use more energy for heating, raising the temperature at which they maintain their buildings. Should this trend become too strong it could jeopardize China’s other modernization plans, plans that are already dependent on a decrease in the consumption of energy per household. Unfortunately, the new economic reforms have created an impasse for the Chinese. The success of the reforms has fueled the desires for improvements in living standards and has reduced China’s ability to control household access to coal. As long as the Chinese continue rapidly to build new housing, every effort should be made to optimize the level of energy efficiency. Unfortunately, the infrastructure for delivering energy conservation is extremely immature. Energy conservation in the residential market is unlikely to be pursued without a continued effort by government organizations. While the new standard alone cannot be effective in solving China’s monumental energy problems, the standard can be a useful step towards development of a conservation strategy. In the long run the standard must become a component in a broader effort to develop new energy-conservation products, more effective means of education about energy-conservation measures and approaches, and training of energy service personnel. The Chinese will need to find a way to control energy demand, either through a return to direct control or through energy pricing policies. Thus the eventual role of the standard depends upon the resolution of much larger political and economic questions now facing China.
Acknowledgements-Partial funding for this research was made available by the University of Pennsylvania Research Foundation. The author wishes to thank Chang Song-Ying, Robert P. Taylor, Stephen Sawyer, and Agatha Andrews for their contributions to this article.
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ROBERTM WIRTSHAFI-ER REFERENCES
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