architecture yunnan china

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Building and Environment 41 (2006) 687–697 An ecological assessment of the vernacular architecture and of its embodied energy in Yunnan, China Wang Renping , Cai Zhenyu School of Architecture and Urban Planning, Tongji University, Shanghai, China Received 1 November 2003; received in revised form 5 January 2005; accepted 25 February 2005 Abstract This article engages ecological architectural concepts to evaluate the traditional dwellings of the Lancang River Valley, Yunnan Province, China. By discovering the implied interpretation of nature and assessing the energy consumption of vernacular houses, this research establishes certain advantages of vernacular building in light of a modern environmentally aware evaluation. r 2005 Elsevier Ltd. All rights reserved. Keywords: Vernacular dwellings; Interpretation of nature; Embodied energy; Ecological concept 1. Overview of existing challenges Undeniably one of the most beautiful landscapes in the world, the southwestern Chinese province of Yunnan is visually stunning not only due to its picturesque limestone mountains. Many small towns and villages in Yunnan collectively contain some of the best-preserved and aesthetically delightful traditional architecture in all of China. This traditional architecture integrates naturally into its setting, rather than being an artificial imposition upon it. It is due to a heartfelt desire to both learn from these ancient buildings, and also to consider ways of preserving them, that, during the fall of 2000 and spring of 2001, I participated in a broad survey, of vernacular habitats in the Lancang River Valley. This paper is largely based on my findings during this period. The Langchan River Valley covers almost the entire western portion of Yunnan, nearly one-third of the province. While conducting my research, I was always touched by the charm of this magnificent red land, Yunnan. This homeland to 26 ethnic minorities possesses a fascinating geography, history and culture. But as an architect, it was the vernacular architecture and traditional settle- ments, which impressed me the most. I gasped in admiration—but also felt deeply saddened. When old traditional buildings and villages are being torn down one by one, architects, photographers and artists pick up their tools hastily for capturing a portrait of the doomed. However, what else can we do regarding our heritage, one might ask, except record and preserve an image? What else does our traditional architecture possess, except aesthetic and cultural values? (Fig. 1) Firstly, what are the environmental challenges con- fronting this area? Yunnan faces frequent natural disasters: earthquakes, land-slides, flooding and so on. According to the Water and Soil Protection Bureau of Yunnan, since the 1950s, 31.3% of the topsoil of the Lancang River Valley has been lost to erosion. Rates of soil erosion are generally affected by four factors, namely, topography, geology, rainfall pattern, and type and degree of plant cover. But actually, unsustainable agricultural practices and ruthless industrialization combined with runaway and unregulated construction have displaced all natural factors as the primary causes of soil erosion and environmental degradation. Despite the natural inevitability of frequent earth- quakes, turbulent weather and massive rainfall, Yunnan ARTICLE IN PRESS www.elsevier.com/locate/buildenv 0360-1323/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.buildenv.2005.02.023 Corresponding author. E-mail address: [email protected] (W. Renping).

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Page 1: architecture Yunnan China

ARTICLE IN PRESS

0360-1323/$ - se

doi:10.1016/j.bu

�CorrespondE-mail addr

Building and Environment 41 (2006) 687–697

www.elsevier.com/locate/buildenv

An ecological assessment of the vernacular architecture andof its embodied energy in Yunnan, China

Wang Renping�, Cai Zhenyu

School of Architecture and Urban Planning, Tongji University, Shanghai, China

Received 1 November 2003; received in revised form 5 January 2005; accepted 25 February 2005

Abstract

This article engages ecological architectural concepts to evaluate the traditional dwellings of the Lancang River Valley, Yunnan

Province, China. By discovering the implied interpretation of nature and assessing the energy consumption of vernacular houses,

this research establishes certain advantages of vernacular building in light of a modern environmentally aware evaluation.

r 2005 Elsevier Ltd. All rights reserved.

Keywords: Vernacular dwellings; Interpretation of nature; Embodied energy; Ecological concept

1. Overview of existing challenges

Undeniably one of the most beautiful landscapes inthe world, the southwestern Chinese province ofYunnan is visually stunning not only due to itspicturesque limestone mountains. Many small townsand villages in Yunnan collectively contain some of thebest-preserved and aesthetically delightful traditionalarchitecture in all of China. This traditional architectureintegrates naturally into its setting, rather than being anartificial imposition upon it. It is due to a heartfelt desireto both learn from these ancient buildings, and also toconsider ways of preserving them, that, during the fall of2000 and spring of 2001, I participated in a broadsurvey, of vernacular habitats in the Lancang RiverValley. This paper is largely based on my findings duringthis period. The Langchan River Valley covers almostthe entire western portion of Yunnan, nearly one-thirdof the province.

While conducting my research, I was always touchedby the charm of this magnificent red land, Yunnan. Thishomeland to 26 ethnic minorities possesses a fascinating

e front matter r 2005 Elsevier Ltd. All rights reserved.

ildenv.2005.02.023

ing author.

ess: [email protected] (W. Renping).

geography, history and culture. But as an architect, itwas the vernacular architecture and traditional settle-ments, which impressed me the most. I gasped inadmiration—but also felt deeply saddened.

When old traditional buildings and villages are beingtorn down one by one, architects, photographers andartists pick up their tools hastily for capturing a portraitof the doomed. However, what else can we do regardingour heritage, one might ask, except record and preservean image? What else does our traditional architecturepossess, except aesthetic and cultural values? (Fig. 1)

Firstly, what are the environmental challenges con-fronting this area? Yunnan faces frequent naturaldisasters: earthquakes, land-slides, flooding and so on.According to the Water and Soil Protection Bureau ofYunnan, since the 1950s, 31.3% of the topsoil of theLancang River Valley has been lost to erosion. Rates ofsoil erosion are generally affected by four factors,namely, topography, geology, rainfall pattern, and typeand degree of plant cover. But actually, unsustainableagricultural practices and ruthless industrializationcombined with runaway and unregulated constructionhave displaced all natural factors as the primary causesof soil erosion and environmental degradation.

Despite the natural inevitability of frequent earth-quakes, turbulent weather and massive rainfall, Yunnan

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Fig. 1. Yunnan, China Source: http://www.lib.utexas.edu/maps/middle_east_and_asia/china_pol01.jpg.

Fig. 2. View of Lancang River.

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697688

has been a desirable area for human habitation andproduced a vernacular architectural tradition welladapted, both functionally and aesthetically, to itsdramatic setting. However, the rapid development ofthis area, especially since the 1980s, has been detrimentalto the traditions of the past and ignored their relevancein meeting the challenges of the future. Not only over-population but over-exploitation of the natural re-sources has already run out the ‘‘capital’’ of ourdescendants, while a great number of people are stillstruggling at the edge of poverty.

Without underestimating the aesthetic, historical andcultural values of traditional architecture, I feel that it istoday crucial to re-survey vernacular architecture inlight of up-to-date environmental and ecological con-cepts (Fig. 2).

2. The distribution and typology of ethnic vernacular

dwellings

The lay of the land of Yunnan inclines from north-west to southeast, the altitude decreasing from morethan 7600 to 76m. This area is characterized by asegmented topography. There can be a 1000–3500mdifference in elevation between the valley floor and thejutting mountain tops that surround it. Various climatic

zones affected by topography, altitudes and latitudes aredistributed according to season and location forging acomplex tri-dimensional climatic character. A veritablejigsaw puzzle of microclimates, climatic zones changefrom valley floor to the mountain summits and from thesunny to the shady side of hills. A local ballad depictsthis as ‘‘Four seasons within a mountain, a differentclimate within 10 miles’’. The climatic character in thisone river valley area varies from northern tropic, sub-tropic, to southern temperate zones.

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Fig. 6. Waterfront village.

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697 689

The ecosystem of the Lancang River Valley shows aprominent characteristic: diversity. The area is composedof independent, self-enclosed microregions, due to thespecial mountain geography and climate. This diversityand independence has encouraged the development ofunique and varied ethnic cultures and dwellings. Overall,the distribution of particular ethnic communities corre-sponds to the topographical character of the areas thatthey have chosen for settlement. As a local ballad says‘‘Miao people live at the top of hills, Yao people live inwetland areas (where indigo grows), Yi people live on theslopes, Dai and Zhuang people live at the edge of water,Han and Hui people live on the flat.’’ (Figs. 3–6).

Tribal groups have, through their efforts over thousandsof years, created rich and colourful styles of vernaculararchitecture, responding to local environments. These reflectan evolved response to geography, climate, distribution ofethnic peoples, and vernacular architectural traditions.

Fig. 3. Flat lan

Fig. 4. Village in mou

Fig. 5. Village on

Nevertheless, we can separate the traditional dwelling intofour broad categories: (1) courtyard house, (2) high stilthouse, (3) low stilt house, (4) log house. The distribution ofthe four house types is shown in the map (Fig. 7).

d villages.

ntainous setting.

the slopes.

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Fig. 7. Distribution of the various types of houses.

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697690

Courtyard house with wall-enclosed courtyard, typi-cal house of Han, Bai and Hui people, is the most wide-spread type and dispersed in the whole Lancang RiverBasin. Its main area of distribution, however, is in sub-tropic monsoon plateau area. This area is characterizedby strong winds from the northwest in winter andsouthwest in summer. High stilt house, the typical Daipeoples house, is distributed in wet and hot weatherareas, such as Xishuanbanna and Simao, the southern-most part of the Lancang River Valley. This area iscomposed of low-altitude flatlands, slopes, wetlands andriver and lake banks. This is a low-wind area with a hot,humid and rainy climate. Low stilt houses, typical of theWa, Laku, Bulang and Ani dwellings, are distributed inthe low mountainous areas of Simao and Lingchang,located in southwestern part of the Valley. There aremany variations of this kind of house. Local people havevivid names for them such as ‘‘wooden palm’’ house,‘‘chicken net’’ house and ‘‘hanging wall’’ house. Ignor-ing their unique picturesque shapes, what constitutestheir shared character is their low raised platform. Loghouses, typical of Pumi and Bai people of Eryuan, aredistributed in the upland area forming the northern partof the Lancang River Basin. This is a mountainous areaof high altitude, cold weather, and frequent smallearthquakes.

3. The wisdom of interpretations of nature implicit in the

vernacular architecture

While most of the local architects and intellectualshave been interested in the traditional building styles,

shapes and ornaments, only few of them have turnedtheir attention to the local people’s wisdom in theinterpretations of nature as expressed in their houses.How do the vernacular dwellings respond to theirsurroundings? And in which way do they express therelationship of man and nature?

3.1. Courtyard house

The typical courtyard house is characteristic of theBai people’s dwellings in the scenic town of Dali. Dali,on the shore of crystalline Erhai Lake and surroundedby the green Cangshan Mountains, features neat dwell-ings with white walls and blue-tiled roofs. Dwellingwalls employ both stone and wood in their structure.Locals say, ‘‘Dali has three treasures: One is thecobblestones to build walls that never collapsey’’.Since ancient times, locals have used stones to buildhouses. These courtyard dwellings have various floorplan arrangements. Despite the differing layouts, theprominent character of these dwellings is that they areclosed-in on four sides either with rooms or walls, with acourtyard in the centre. This is a direct response to thestrongly windy weather.

On the back and side walls, the dwelling usually hasonly few small windows. There are no overhang roofs onthe side and back walls, for the strong wind wouldpossibly lift the roofs away. Most of the main rooms areset to face south. The southern wall of the main roomusually has wide windows and doors opening to thecourtyard, in order to receive southern sunshine andwarm breeze. The local people have truly createdsophisticated construction details to adapt to the localweather: for instance, ‘‘tiles cloth’’, a sheet of bambooweave, protects the tiles from falling down, and ‘‘fei-huostone’’, special thin stones, are used to protect theoverhangs.

Suffering from frequent minor earthquakes, localbuilders have developed a functional and flexibletechnique of timber structure. There are two maintechniques, namely, the ‘‘wooden lock’’ and the‘‘enclosure lintel’’. The rabbets technique is used forthe connections, without any screws or nails, whichallows the wooden structure to resist the horizontalforces from earthquake. The structure may incline butwill not collapse. Local carpenters have developed acomplex method of locking all the main connections ofbeams and columns, small beams and joists. There arethree enclosure lintels on the top, middle and bottomlevel of a house to improve the earthquake resistance(Figs. 8–10).

3.2. High stilt house

The traditional Dai stilt house simply and admirablycorresponds to the hot, wet, and rainy surroundings.

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Fig. 8. Courtyard houses.

Fig. 9. Wood lock (left).

Fig. 10. Three Lintels rabbet (right).

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697 691

Typical Dai tilt houses are empty on the ground floorfor storing tools. The first floor is arranged with livingroom, bedrooms, balcony, kitchen, dining, or working

spaces. The roof sometimes has several layers and eachlayer has a large overhang protecting interior space fromexposure to summer sunshine. In hot humid weather,the airflow is the main consideration in order to achievecomfort. Natural ventilation is the main approach torelease excessive heat. The interior space of a traditionalDai house is usually a completely open place. Wind canblow through this open space easily. At the same timethe crevices in the floor, roof and walls enable hot air torise up and cool air to sink down, which creates a mildand pleasing internal microclimate.

The roof of a Dai house is usually very steep, whichhelps rain to drain away quickly. Dai people love to livebeside the water, despite the frequent natural occurrence

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of flooding in Xishuanbanna. High columns support thewhole house and elevate it above moisture and floodwater. Floors and walls are made of movable woodenboards. People can easily take off some pieces of board,when the force of the flood is getting too strong, andthen put them back after water levels have subsided.

3.3. Low stilt houses

Villages and houses of Wa people are mostly locatedon the southwest slope to receive cooling wind from theIndian ocean. Perhaps because of the similar hot, rainyweather and ethnic culture, this low stilt house sharessome characteristics with the Tai house, for instance:steep roof, open space, raised ground floor, which,however, can be just several inches above the ground.Distribution is mostly in the region inhabited by Wapeople in the Changyuan Awa Mountain, Ximen, andMenlian districts, and regions inhabited by Bulangpeople surrounding Bulang Mountain, a less-developedarea of Yunnan. Local people’s houses are quite simple,humble and coarse. Some houses still utilize the mostprimitive colligation, instead of the more advancedrabbets technique.

As a Chinese proverb says ‘‘there are orchids underwormwood.’’ This lower tilt house also has someshinning points from an ecological point of view, despiteits primitiveness. First, its lifted floor minimizes thestructural damage to the site, protects the originalecosystem on the earthen surface and potentially reducesland slides. Second, local mountain resources are used inbuilding. Even the roof is made of a special kind ofgrass. Moreover, local material and simple constructionendows it with a kind of purity and rustic beauty.

3.4. Log house

Due to the availability of wood in the northwesternmountainous area, the traditional log houses are builtwith timber frames for the walls, floors and roof. Wallsare composed of logs laid horizontally one on the top ofthe other. The roof is made of wooden tiles, or localslate. There are three environmental advantages:(1) taking advantage of local wood and stone resources,while reducing the energy involved in transportation;(2) log walls provide good insulation in cold weather;(3) they are solid and make for a good anti-seismicstructure.

The wisdom of interpreting nature in the traditionaldwellings discussed above involves a deep respect for thesurroundings, shaping the building form for the localclimate, and utilizing natural materials to obtain anorganic expression. Nowadays, we do not see manytraditional houses being built. Farmers, with a mis-conceived notion of progress, prefer a modern stylehouse instead of the traditional house of their fore-

fathers. So cubic houses made of concrete, which iseasily available, are now built everywhere, creating adepressing monotonous human-made environment,with little consideration for the natural settings. Ancientwisdom seems to be largely ignored. We saw, inXishuanbanna, traditional high stilt houses beingreplaced by the new cubic houses. When floods came,a high cost was paid for this neglect of tradition.

4. Embodied energy of the vernacular houses

4.1. The necessity of applying an embodied energy

analysis

I read an article in a local architectural magazine inwhich the author boldly declares ‘‘the development ofnew vernacular building should keep traditional archi-tectural styles, but completely replace traditional mate-rials with modern materials.’’ Yet, traditional naturalmaterials, for instance, wood, bamboo, stone, raw earth,psychologically speaking, are closer to the human heart.And can one really achieve the same feeling andaesthetic result when substituting modern materials? Interms of ecology, traditional materials possess clearadvantages because of their local availability, lowenvironmental impact in their production, renewabilityand even natural dissolution.

Energy and resources are critical issues in our modernsociety. In environmental architectural studies, specialattention is paid to the energy consumption in coolingand heating. But the initial energy that the creationconsumed of the buildings is often neglected. There is amere 101 difference between average summer and wintermean temperatures in Lancang River Basin. Supple-mental mechanical heating and cooling are not reallynecessary if a house has a good passive design. So inassessing energy consumption of a building in this area,the assessment of the embodied energy consumptionshould be the first and most important task.

The General Energy Requirement (GER) includes allthe resources and energy, which were expended into abuilding, from processing, transportation, up to thecompletion of its construction. However, GER of abuilding as embodied energy coefficient, it is hard toachieve accuracy, due to its complexity. Transportationenergy consumption has a big range of variety,depending on the situation, and does not constitute areliable or general figure. And though constructionenergy consumption represents a valid figure, it isrelatively small, roughly 10–15% of GER. So, in energycomparative analysis, Processing Energy Requirement(PER) is a more reliable and feasible factor for theevaluation of the embodied energy of a building. PER isthe energy consumption involved in the exploitation and

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Table 1

Materials of main components

Bai house Dai house New house

Roof layer and roof truss Ceramic tile, wood roof truss Ceramic tiles, wood roof truss Concrete and steel

Walls Stone wall Wooden wall Brick wall

Floor Ceramic brick Wood Concrete & steel

Fig. 11. High stilt houses.

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697 693

processing of a building material. Energy coefficient iscalculated as Mg/kg.1

4.2. Energy density of typical houses—case studies

As mentioned above, there are many types oftraditional houses. Their materials and constructionsare quite different. Even within each type, individualhouses vary widely in style. So, I have chosen the mosttypical cases with reference to each kind. Due to thecomplexity of the size, structure and construction ofvarious houses, I prefer to compare the main compo-nents of each building, instead of taking the house as awhole. Data and material are collected from mypersonal fieldwork, on the basis of measuring the actualbuildings, interviewing local workmen, and readingrelated literature. I have aimed at accuracy. Data andconclusions are the result of personal quantitativeanalysis.

A house is composed of three main components: roof,wall, and floor. First, the weight of a component persquare meter is calculated according to the constructionof each member. Then, by multiplying the material’sweight and its energy coefficient (MJ/kg), we will get thetotal energy per square meter, which is the density ofenergy of the main components. This format and the

1[1, pp. 6,7].

data of energy coefficient are mostly derived from themethod outlined in the book Architectural Material,

Energy and Environment: Towards Ecological Oriented

Development, by Dr. Bill Lawson and David Rudder,Australia (2000).

Some houses, although they are unique in buildingforms, share similar materials and construction, whichmeans that they would have similar embodied energy.Specifically, this is the case with high stilt and low stilthouses. So, only three unique typical houses are chosenas samples: (1) #226, Shangmo west village, Dali, atypical Bai courtyard house; (2) # 58Manben village,Xishuanbanna, a typical Dai high tilt house; (3) #82,Shangmo village, Dali, a new concrete house (Table 1).

4.2.1. Case 1: Bai house #226, Shangmo Village, Dali

The design and construction of each house has to becarefully examined, in order to calculate their energydensity. Plan and elevation of house is shown in Fig. 11,construction is shown in Figs. 12 and 13.

Energy density of stone wall (MJ):stone density: 2700 kg/m3;weight of stone wall per square meter: 1� 0.6(thickness)� 2700 ¼ 1620 kg/m2;energy coefficient of stone: 1MJ/kg;2

2[1,

pp. 8,9].
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Fig. 12. Low stilt houses.

Fig. 13. Log house.

660 6603500 3500380015900

3800

600

600

6300

7200

5000

2200

Fig. 14. Floor plan and elevation.

Fig. 15. Roof and floor construction.

3

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697694

energy density of stone wall: 1620�1.0 ¼ 1620MJ.

Energy coefficient of ceramic tile in China is not available. This

factor is referred to the factor in Australia, [1, pp. 166].4Energy coefficient of wood in China is referred to [1, pp. 8].

Energy density of roof of ceramic tiles:weight of tile roof per square meter: 49 kg/m2;

energy coefficient of tiles: 2.5MJ/kg;3

energy density of tile roof: 4.9� 2.5 ¼ 123MJ.

Energy density of wooden floor (MJ):

energy density of wooden board (thickness:30mm) (MJ/m2):

weight of wooden board per-square meter:1� 0.03� 500 ¼ 15 kg/m2;energy coefficient of wood: 3.5MJ/kg;4

energy density of wooden board: 15�3.5 ¼ 52.2MJ.

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Energy density of wooden beam (MJ):beam log diameter: 100mm, space between rows:500mm;wood volume per square meter: pR2

� 2 ¼ 3.14�(0.1/2)2� 2 ¼ 0.0157m3;weight of wooden beam per square meter:0.0157� 500 ¼ 7.85 kg/m2;energy coefficient of wood: 3.5MJ/kg (See foot-note 4);

CORRIDOR & GUEST AREA+2500

DOWNDINING & LIVING AREA

KITCHEN

BED ROOM 1 BED ROOM 2

±0.000

PATION

0 1M 2M 3M

DAI HOUSE SOUTH ELEVATION

DAI HOUSE MAIN FLOOR PLAN

Fig. 16. Case 2 plan and elevation.

Fig. 17. Construction detail of the ma

energy density of wooden beam: 7.85� 3.5 ¼27.475MJ;Total energy density of wooden floor: 52.2+27.475 ¼ 79.675MJ (Figs. 14–18).

in com

ponents of a Dai house.

BRICK HOUSE NORTH ELEVATION

BRICK HOUSE FIRST FLOOR PLAN

N

0 2M 3M1M

BED ROOM 1

BED ROOM 2LIVING ROOMBED ROOM 3

±0.000

KITCHEN

COURT YARD

Fig. 18. Case 3 plan and elevation.

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According to the format above, the tables of therelevant data are as follows: Tables 2–4.

4.3. Comparison of the studied cases (Table 5)

As we see in the table, energy densities of all the mainstructural components of a new concrete house are

Table 4

Case3: New concrete house #82 Shangmoa

Components Construction Square (m)b Volume (m3) Density

(kg/m3)

Wall Brick 240� 115� 53 1 0.24 1700

Floor Concrete (80mm) 1 0.08 2400

Roof Concrete (100mm) 1 0.1 2400

Steel net 1

aEnergy coefficient of the materials are referred to [1, pp. 8,9].b[1, pp. 8,9].

Table 2

Energy density of #226 Bai house

Components Construction Square (m)a Volume (m3) Density

(kg/m3)

Wall Stone(600mm) 1 0.06 2700

Up floor Wooden board

(30mm)

1 0.03 500

Log beam

+100@500mm

1 0.0157 500

Ground floor Concrete (80mm) 1 0.08 2400

Roof Wooden rafter

+80@220mm

1 0.0228 500

Ceramic tiles 1 49

a[1, pp. 8,9].bEnergy coefficient of the materials are referred to [1, pp. 8,9].

Table 3

Case 2: Dai house #58 Manban Village, Xishuanbana

Components Construction Square (m)a Volume (m3) Density

(kg/m3)

Wall Wooden board

(20mm)

1 0.02 500

Floor Wooden board

(20mm)

1 0.02 500

Log beam

+60@250

1 0.0113 500

Roof Wooden rafter +60@360

1 0.0078 500

Ceramic tiles 1 49

a[1, pp. 8,9].bEnergy coefficient of the materials are referred to [1, pp. 8,9].

greater than those of the traditional Dai and Bai house.The Dai house has the smallest energy density. Thisindicates that traditional houses possess a significantadvantage in terms of embodied energy consumption.Traditional materials still possess an intrinsic vigor or‘‘life force’’ not present in highly processed ‘‘modern’’materials. Their attractiveness is especially apparent

Weight (kg) Energy

coefficient

(MJ/kg)

Energy density

(MJ/m)bTotal

(MJ/m)b

408 5 2040 2040

192 2.3 441.6 441.6

240 2.3 552 639.5

2.5 35 87.5

Weight (kg) Energy

coefficient

(MJ/kg)b

Energy density

(MJ/m)aTotal

(MJ/m)a

1620 1 1620 1620

15 3.5 52.2 79.7

7.85 3.5 27.48

192 2.3 441.6 441.6

11.418 3.5 39.96 163.0

49 2.5 123

Weight (kg) Energy

coefficient

(MJ/kg)b

Energy density

(MJ/m)aTotal

(MJ/m)a

10 3.5 35 35

10 3.5 35 54.78

5.652 3.5 19.78

3.928 3.5 13.75 136.75

49 2.5 123

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Table 5

Comparison of the studied cases

Energy density of Bai house (MJ/m)a Energy density of Dai house (MJ/m)a Energy density of new concrete house (MJ/m)a

Wall 1620 35 2040

Floor 79.7 54.78 441.6

Roof 163.0 136.75 639.5

a[1, pp. 8,9].

W. Renping, C. Zhenyu / Building and Environment 41 (2006) 687–697 697

when we consider China’s increasing shortages of energyand resources. The data above constitute a rationalground for rejecting the claims that ‘‘traditional materialsshould be completely replaced’’. Although these dataform a rough estimation, it is hoped that this analysis willgive architects the general understanding of the embodiedenergy and ecological value of our vernacular architec-tural heritage and will contribute to the search for a moresustainable method of development.

Through re-assessing our traditional dwellings underan ecological prism, we appreciate the wisdom embo-died in the vernacular architecture in its relationto nature and its distinct advantage in low energydensity. Unfortunately, those potentials remain un-known or neglected. Nowadays, ecological and environ-mental awareness in architectural design and planningcan not be just a slogan or fashionable term. It has areal influence on our living environment. It is notenough to keep discussing architectural style, form,and genre. Now we have to allow ‘‘environment, energyand resource’’ to become genuine topics in thearchitectural field, for the sake of a more rationalrelation to the natural environment in which we exist,work and create.

Acknowledgements

Support from Canada–China Scholar’s ExchangeProgram is greatly appreciated. I would like to thank

Professor Constantine Georgiadis of McMaster Uni-versity, Hamilton, Canada, for his suggestions. Myhusband Alex kindly edited my English usage.

References

[1] Lawson Bill, Rudder David [Australian]. Architectural material,

energy and environment: towards ecologically oriented develop-

ment. Translated by Zhang, Mingshun, China Environmental

Science Press, 2000 .

Further reading

[2] Wang Renping. Sustainable development of traditional villages

and their architecture in the Lancang River Basin, Yunnan, China.

The Kunming University of Science and Technology; 2002.

[3] Jiang, Gaocheng, Culture of ethnic dwellings of Yunnan, 1997 .

[4] Economy plan Committee of Yunnan, China Territory

Plan of The Lancang lower River Basin

.