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Passive design principles and techniques for folk houses in Cheju Island and Ullūng Island of Korea
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aUILDII IGEnergy and Buildings 23 (1996) 207-216
Passive design principles and techniques for folk houses in Cheju Island and Ull ng Island of Korea Kyung-Hoi Lee, Dong-Wook Han, Ho-Jin Lim Department of Architectural Engineering, Yott~eiUniversity, Seoul, South Korea
Abstract
The Korean folk house has created a comfortable indoor environment with passive control of outdoor climate as an example of environmental architecture. This study aims to identify the peculiar elements of environmental architecture in folk houses in Cheju Island and U!lQng Island through field experiments. The elements of environmental control of folk houses in both islands could be developed as design elements of modern architecture. This effoa can play a major role to find the passive design principles and techniques of environmental control of the building which have been neglected in the design of modern architecture. Keywords: Environmental architecture; Passive design; Folk houses; Korea
1. Introduction
Climatic determinism ha.,; been generally accepted in the field of architectural design, even though cultural geographers began to use it as an explanation of their theory. Actually, climatic determinism does not fully explain all the characteristics of vernacular architecture. However, it is obvious that climate is one of the most important factors influencing the form of the house. Especially, with poor building techniques and the limited knowledge of environmental control, climate seems to have a major impact on the building. In such circumstances, human beings cannot dominate nature, but they have adapted themselves to the natural environment. The energy problems, since 1973, require new innovative attitudes toward architecture and planning. Review of traditional architecture in its ecological concerns suggests that human beings should adapt all their design activities to the natural order of the global system. In the light of this, environmental architecture can be the most appropriate discipline to perform the role of stabilizing the ecological system. Accordingly, the current knowledge and skills of architects, planners, designers, engineers, and industry can begin to resolve the global crisis by designing environmentally responsible architecture and urban systems. The term, environmental architecture, means the architecture adjusted to its surroundings or in harmony with nature creates a healthy 0378-7788/96/$15.00 © 1996 Elsevier Science S.A. All rights reserved
SSDI0378-7788(95)00946-U
environment for human beings by maximizing the utilization of natural energies. Korean traditional architecture has been developed by adapting to the surrounding environment which has very distinctive cultural and climatic characteristics. With proper shapes, the Korean folk house performs well in its regional climate and natural environment to provide comfortable indoor environment through site planning, space organization and using proper building materials. The environmental control principles underlying in traditional architecture to adapt to nature can be good sources for the design of modern buildings, although shape, structure, and design elements differ from each other. Folk houses in Cheju Island and Tumakgyp or a doubleenvelope house in Uli~ng Island are good examples of environmental architecture; they have the unique structure and form which have been derived from particular environmental conditions of the areas. Analysis of the relationship between these architectural characteristics and environmental conditions reveals the background of the most proper environmental control principle in the integration of architectural characteristics and climatic conditions. This study aims to find the relationship between Korean regional climate and architectural characteristics with a view to identify passive design principles of folk houses in the two islands. The implication of passive design principles of.
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environmental architecture will be discussed in the Conclusions.
2. Traditional folk house in Cheju Island 2.1. Climatic characteristics
The annual average temperature of Cheju Island, located on the South Sea about 80 mile away from the Korean peninsula, is 12-20 °C which is higher than that of the country, 8-14 °C. Analysis of the climate reveals that there is a narrow temperature range between the hottest period and the coldest period of the year. During the winter, it is relatively warm and humid as compared with the inland. The main wind direction in summer is SSE, while the wind direction in winter is NW. The average annual wind velocity is about 4 m / s which does not give any discomfort. The maximum annual wind velocity is over 13.9 m/s, and its frequency is more than 20 days per year. Because Cheju Island is on the passage of strong winds or tropical atmospheric depressions more frequently than on the inland, it tends to have high wind velocity and high frequency of strong winds. According to the above climatic characteristics, Cheju Island belongs to the temperate climate zone inclined to oceanic climate, and has rather frequently strong winds as shown in Fig. 1. 2.2. Architectural characteristics 2.2.1. Site and floor planning
In the Korean traditional architecture, according to the Fengshu order or geomancy, it is preferable to face low hills across a water to the south and being surrounded by high hills and, therefore, protected from the wind by woods to the north. .=+
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Fig. 2. Variationof outdoor air movementheated by frontcourtyard. By these means, a maximum solar heat gain and a primitive heat-loss protecting have been achieved during the winter. The slope and woods of rear hills initially decrease the velocity of north-south wind and fences reduce it furthermore. South-east wind in summer creates a comfortable indoor climate in Daechung (Maru) or the main Korean woodenfloor room during the summer. In the traditional folk house of Cheju Island the inner court, called Antui, is surrounded by the main building and boundary walls. Plants in the inner court have a wind-protecting effect and create shading areas. During the daytime, when the temperature is at its highest level, the front courtyard is exposed to sunshine. However, the air temperature in the Antui remains low because of the shade created by trees. Therefore, cool air in the Antui moves to the front courtyard due to natural convection as shown in Fig. 2, and passes through the narrow backdoor of the main wooden-floor room (Sangbang); even in hot summers, people sitting in the Sangbang feel comfortable. Floor plans in the Korean traditional folk houses vary with local climatic conditions, see Fig. 3. Houses in the northern regions show more insulated Gyupgyp style or double backto-back rooms, having less Maru (wooden floor), than those in the southern regions, mainly due to the mild climate. Notably, the houses in Cheju Island and UllQng Island show unique floor plans to protect them from strong winds or heavy snowfall, thus reflecting the local climate conditions. The traditional folk house in Cheju Island consists of Bakuri (outer quarter), Mokuri (inner quarter), Imunkan (entrance). A three-bedroom house is the standard and basic house in Cheju Island. The main elements of the floor plan are Chungji (kitchen), Sangbang (Maru, wooden floor), Gudle (bedroom), Gopang (store), Chatbang (dining room), etc. The house of Cheju Island has a characteristic unique heating system called Ondol. This special plan is for creating a comfortable living space in summer by reducing wind velocity, enhancing air-conditioning effect, and balancing interior temperature.
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Fig. 1. Climaticcharacteristicsof Cheju Island.
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Awnings in Korean traditional houses were designed to prevent sunlight from mid-April to late August when the altitude of the sun is over 63.5 ° . They were designed to gain sunlight entering the room from middle October to late Feb-
K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
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Fig. 5. Section of traditional folk house in Cheju Island.
The exterior wall is built up of stone to resist strong winds. The front areas except the Chatbang (dining room) of most houses in Cheju Island provide a semi-interior space called Mutdung (porch). Some other houses have surrounding wails built in order to be protected from storm winds. In addition, the Poongchae (movable eaves) is hung at the eaves and the double door called Gerchang is also attached to prevent strong storm winds, see Fig. 5. ,
Fig 3. P]oor plan of Korean traditional folk houses. ( R ) room; (K) kitchen; (D) Daechung (main wooden-flo<:,r room); (J) .leongjugan (store); (P) Gopang(store); (G) Gulmok (fire house), and (C) Chuckdam (buffer space).
ruary when the altitude of the sun is under 40 °. Also, Salchang or a grid-framed window frame acts as a sun screen in modern architecture. It offers shade in the summer and minimizes heat losses by making an air-curtain outside the window. The traditional folk house in Cheju Island is less high than the house in the inland; the roof is low and has a round shape for resisting wind (Fig. 4). The average slope of the roof is less than 4110 of that in the :inland. Also, the roof used to be tied up with thick rope to resist strong winds.
2.2.3. Characteristics of heating system: Ondol The Korean traditional heating system, Ondol, has been used for a long time as the unique residential radiant heating method in Korea, see Fig. 6. The air heated in the fire sources Butumak (the traditional kitchen range) or Agungie (fuel hole) heats the flat stones under the floor by passing through the hypocaust in such a way that the indoor air is heated. In Ondol, the thermal mass of flat stones keeps heat for six or eigth hours with vernacular firewood. Ondol also has the function of controlling the humidity, heating and natural cooling effect. The clay used in this system controls indoor humidity comfortably by emitting humidity in winter and absorbing humidity in summer. The Ondol system in Cheju Island is estimated to have been started around 1660, and it is a more primitive style and structure compared with that of the inland. Most folk houses provided with Ondol systems have only 1/3 of the hypocaust arrangements, and it has smaller fire stocks than those of the northern and middle part of the country. Once, the fire stock
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Fig. 4. Facade of the traditional folk house in Cheju Island.
Fig. 6. Section of the heating system Ondol.
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K.-H. Lee et al. / Energyand Buildings23 (1996)207-216
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Fig. 8. Lift-updoor systemin Daechungfor Maru. is lighted and the heat kept by stones, during the winter, a proper floor temperature is maintained at floor according to the regional climate conditions. On the other hand, Ondol also performs as a good natural cooling system during the summer. But the main living space during the summer is Sangbang (main wooden-floor room, Maru), see Fig. 7. The airflow under Sangbang makes the ambiant cool by intercepting direct sunlight, controlling the humidity and penetrating through the peepholes of the wooden-floor room where during the summer activities take place. This cooling effect is enhanced by Antui as explained above. Duleryulgae or the lift-up door system tends to increase the cooling effect of Daechung by inducing cross ventilation, see Fig. 8. 2.3. Field survey of thermal performance
The field survey was done in a well-preserved folk house in Cheju Island in order to evaluate the thermal performance that responds to the local climatic condition, see Fig. 9. Thermal environmental factors such as air temperature, surface temperature, global temperature, relative humidity, wind direction, wind velocity and illumination were measured in the large Gudle or the master bedroom, Maru, and outdoors. 2.3.1. Thermal environment of interior space The analysis of thermal environment of the traditional folk house in Cheju Island shows the following characteristics of each space, Table 1. In summer, the average indoor dry-bulb
Fig. 9. Planof folkhousein Cheju Island. ( 1) masterbedroom(largegudle); (2) bedroom(Gudle); (3) Maru (Sang bang); (4) store (Gopang); (5) kitchen ( Chungji) ; (6) dining room ( Chatbang), and (7) fireplace ( Gulmok). temperature in the large Gudle is 29.9 °C, and the relative humidity is 86.6% when the door is open. But a time-lag effect is found in the large Gudle. During night, the indoor air velocity is 0.3 m / s and the radiant temperature of surrounding walls is 1.6 °C lower than indoor dry temperature. However, during daytime, the indoor air velocity is more than 0.5 m/s, and the radiant temperature of surrounding walls marks 4-10 °C lower than the indoor dry-bulb temperature. By inducing cross ventilation, rooms keep comfort during summer. 2.3.2. Wind-resistant plan composition Fig. 10 indicates that there is little airflow in the large Gudle and Sangbang in winter, and the infiltration through the large Gudle opening and front opening of Sangbang is lower than that of the backside infiltration of Sangbang and the exterior airflow. This seems to be due to the characteristic of double arrayed room-type which has a windbreak effect of Mutdung and Gulmock (buffer space and fireplace). 2.3.3. Natural cooling capability of Maru According to the measurement, the temperature under Sangbang (Maru) is 0.1-1 °C lower than that of above Sangbang. The indoor temperature of Sangbang is lower than that of the large Gudle (master bedroom). Even though the air temperature of Cheju Island in summer is very high, comfortable indoor climate has been achieved by cool air under Sangbang and by the cross-ventilation effects. Folk houses in Cheju Island can provide comfortable indoor condition using cross ventilation during summer. In spite of the high opening ratio, however, modern houses do not utilize cross ventilation. Even in hot humid summers, the indoor climate of folk house is comfortable, because cool airflow under the floor space and air circulation from backyard to Sangbang. The architectural elements could support the theory of modem passive cooling system that can be applied to the designs of contemporary houses. 2.3.4. Thermal characteristics of a volcanic rock For the construction of Korean traditional folk houses, local materials are mainly used. The roofing materials are mainly clay tiles and barley straws, and wall materials are
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Table 1 Thermal performance factors at Smtgbang Place
Sangbang (Maru)
Season
Sumtr~r
Factors
Teml~'~rature ( °C )
Wind velocity (m/s)
Outdoor temperature (°C)
Temperature (°C)
Wind velocity (m/s)
Outdoor temperature (*C)
12:00 14:00 16:00 18:00 20:00 Mean value Minimum value Maximum value
30.8 29.6 31.2 29.4 28 29.8 28 31.2
I. 1 0.9 2.1 0.2 0.3 0.9 0.2 2.1
31.3 30.5 30.6 29.2 28 29.9 28 31.3
5.6 6.8 6.8 7.0 7.0 6.8 5.6 7.7
0.1 0. I 0. I 0.1 0.2 0.12 0.1 0.2
4.7 6.5 5.6 5.5 5.3 5.5 4.7 6.5
Winter
has been derived from particular environmental conditions of the area. The evaluation o f the thermal performance and the characteristics of this traditional folk house will be a useful framework to understand the environmental characteristics of the Korean traditional architecture in relation to its regional climate.
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3.1.1. Climatic characteristics The annual average temperature of Ullfing Island, 9.9-15.9 °C, is higher than that of the country, 8-14 °C, see Fig. 11. The climate analysis revealed that there is a narrow temperature range between the hottest and the coldest period of the year. It is warmer and more humid than the inland, with heavy snowfall during winter. Ullfing Island is located in the middle of the East Sea, being largely effected by strong winds and low atmospheric pressure. The main direction of wind is S S W in summer and NE in winter. Although the annual average wind velocity of 4 m / s give a comfortable feeling, the maximum wind velocity is over the 13.9 m / s . The frequency of wind velocity,
Fig. 10. Air-flow changes in different rooms. soil-based materials that have high thermal capacity. The thermal characteristics of these materials can decrease the room temperature by blocking strong solar radiation in summer. In winter, high thermal capacity materials can also decrease the room temperature. From the present field survey, one may observe that the thermal conduction rate of volcanic rock in Cheju Island (about 0.399-0.580 k c a l / ( r n h °C) ) is less than that of concrete, a modern construction material (about 1.1 k c a l / ( m h °C) ). Therefore, volcanic reck in Cheju Island is a relatively good insulation material.
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Tumakgyp in UllQng Island, located on the East Sea, is the traditional folk house with an unique structure and form that
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3. Tumakgyp - double-envelope house in Ullfing Island 3.1. Characteristics o f Tumakgyp
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K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
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even corn stalk. The fences have two functions: 'wind-proof and 'snow-proof, and the give also privacy to the occupants.
Fig. 12. Bird's eye view of Village Nari.
13.9 m/s, is higher than that of the inland marked 20 days per year. 3.2. Architectural characteristics 3.2.1. Site In the center of the Island, with a surface area of about 70 km 2, is a high summit called Mt. Sungin. In the north of Mt. Sungin, is Nari basin where a small village settled down, see Fig. 12. There remains 5 Tumakgyps whose preservation is not good. Some folk houses reside in a little higher land which is southwestward from the center of the basin, since the rainfall in the north of Nari Basin is very heavy. In general, folk houses are built near the farm, and the distance between folk houses is therefore not the same. The landshape is generally square, and, at the border of each land, there are fences plaited by branches of the Gore pine, beech, chestnut, maple, and
3.2.2. Floor plan Tumakgyp, a 'I'-typed and primitive double-enveloped house in UllGng Island, has the distinctive factors of Nuwagyp (single wooden- roofed house) and Gulpeegyp (single barkroofed house) which is the typical house for fire-field farmers in Kangwon Province. The house in the inner mountain area of Kangwon Province is double arrayed room-type (Gyupgyp), but Tumakgyp is a single arrayed room-type (Oitonggyp) with Udegi modified from double-envelope system, building materials are limited in UllGng Island. The floor plan of Tumakgyp in Ullfing Island is a closed style. It does not have Maru (wooden floor) that is commonly found all over the country, except in the northern regions of Korea. Most functions of the house is concentrated to the main zone. If residential space was scattered, it would be blocked between buildings during heavy snow period. Tumakgyp has concentrative spatial structure. Chukdam (buffer space) surrounded by Udegi (outer wall) al so works as passages between rooms in a building in order to obstruct snow. 3.2.3. Facade and section Guitlbyuk (log wall) and Udegi (outer wall) are remarkable characteristics of Tumakgyp, see Fig. 13. Soil filings between logs protect from infiltrated wind. Udegi (thatched outer wall) is installed to protect from wind and rain, and to block solar radiation from the top to the bottom at the outer side of the wall, like a bamboo blind. The entrance of Udegi can be opened or closed; it is made at the entrance of a room and the kitchen. Chukdam (space of width 1.2-1.6 m between outer wall, Udegi and inner log wall) is the space for living,
FRONT ELEVATION
SIDE ELEVATION
SECTION
Fig. 13. Elevation and section of Tumakgyp (without Udegi).
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K.-H. L e e et al. / E n e r g y a n d Buildings 23 (1996) 2 0 7 - 2 1 6
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activity, work, and store. The slope of the roof of Tumakgyp (about 6/10) is steeper than that of other Korean traditional folk houses (about 6/10) to reduce the snow loads.
4. Evaluation of thermal performance The field experiment was made in a well-conserved Tumakgyp to evaluate the thermal performance of the traditional folk house responding to the natural environment in UII0ng Island, see Fig. 14. Thermal environmental factors measured in the master room, Chukdam were air temperature, surface temperature, globa] temperature, relative humidity, the direction and the velocity of wind, and illumination as shown in Table 2. The results of measurement are given in Table 3. The average temperature floor surface is 22 °C. Temperatures are almost the same at't0 cm, 170 cm, and below ceiling. The floor temperature of Ondol is 7-10 °C higher than indoor air temperature. Such temperature distribution is the typical
temperature stratification of the floor-heating system. The difference between room air temperature and mean radiant temperature in the master room is more than 0.3-1.4 °C, indicating a comfort condition. The variation of daily indoor temperature is small, within a range of 4 °C, mainly due to a windowless wall or Udegi and Ondol (heating system). Relative humidity is within 4 4 50% in the room, 66% in Chukdam, 71% outdoors. The inner soil wall and Udegi control the indoor humidity. Fig. 15 shows that the temperature variation in Chukdam which is almost similar to outdoor temperature. Chukdam, acting as a thermal buffer zone, reduces the heat loss and controls strong wind to be kept below 1.2 m / s when the maximum velocity of outdoor winds reaches 14 m/s, as shown in Fig. 16. The first protection against strong outdoor winds has a great influence on the thermal environment of a building in a windy condition. At first, wind pressure around the building envelope decreases so that the infiltration rate becomes lower resulting in a small air movement in the room. The convective heat loss from the exterior surface of a building is due to the function of outdoor wind velocity. Udegi reduces the convective heat loss from the surfaces of indoor space substantially by minimizing the effect of outdoor wind velocity and outgoing radiation during the night. In addition to this, Udegi can be a good control device, for shading and ventilation; it does not provide convenient adjustability when natural lighting is necessary. The results of this evaluation can be summarized as follows:
Table 2 Evaluation of thermal performano~ Factors
Instrument
Place
Data logger Global thermometer
Outdoor, room, Chukdam Floor surface wall Room, Chukdam
Relative humidity (%)
Climomaster Hygrometer
Room, Chukdam
Wind velocity (m/s)
Climomaster Hygrometer
Room, outdoor
Illumination (Ix)
Lightmeler
Outdoor, Chukdam
Temperature (°C)
Temperature Surface temperature Global temperature
Table 3 Comparison of thermal performance factors Place
Room
Chukdarn
Outdoor
Factors
Temperature (°C)
RH (%)
Wind velocity (m/s)
MRT (*C)
Temperature (*C)
RH (%)
Wind velocity (m/s)
MRT (°C)
Temperature (°C)
RH (%)
Wind velocity (m/s)
Mean value Minimum value Maximum value
15.6 13.7 17.5
44.9 44.0 49.0
0 0 0
16.2 14.0 18.1
1.1 - 0.9 3.1
66.3 50.0 93.0
0.6 0.03 1.2
1.3 - 0.2 2.8
1.2 - 1.2 4.9
71.2 40.0 86.0
5.6 0.7 14.0
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K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
! -4)- 0utdoor a- Chukdam I + CeIing 170CM !-m-. 70Cil
35 30
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7 65
25
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(i) though Tumakgyp has a low air tightness, its daily indoor temperature range is narrow due to Udegi and the soil wall; (ii) Udegi (a primitive double-envelope) functions as a thermal buffer zone for keeping the indoor environment comfortable by protecting from climatic influences such as snow, rain and wind, and (iii) humidity control and thermal mass effect of the soil wall, and protection from wind by Udegi create a comfortable indoor climate.
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5. Elements of environmental control in T U M A K G Y P Examination of the thermal performance of Tumakgyp (the traditional folk house in Ull0ng Island) has brought about the following architectural elements related to passive design principles that can be used in modern architecture, see Fig. 17.
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outer walls and the inner walls. Chukdam was utilized for outdoor activities away from the snow and performed as a thermal buffer zone. Although the air temperature inside Chukdam did not show much difference from the outdoor air temperature, Udegi performed well as a climatic filter by reducing air movement inside Chukdam. In summary, Chukdam performs multi-functions in terms of behavioral and thermal environmental controls.
5.3. Ondol 5.1. Double envelope Double-envelope structure as a modern passive solar system is the system to circulate the heated air in south-facing greenhouse through double-envelope space. Tumakgyp is responsive to climate by circulating warm air, produced in the kitchen, through the double envelope to maximize the insulation effect. During summer, it promotes a cooling effect by natural ventilation and by blocking the direct solar radiation that penetrates into the space.
5.2. Buffer zone By the double-envelope system with Udegi or outer walls, Tumakgyp creates Chukdam which is the space between the
Structurally Tumakgyp comes with Ondol floor-heating system instead of wooden floor. Structure and heating efficiency of Ondol are closely related to the regional climate. Therefore, peculiar indoor temperature, building structure, and materials, etc., have been applied according to climatic regions.
5.4. Openings for cross ventilation Most of the Korean traditional folk houses have emphasized the design of openings. The comfortable indoor condition can be created during summer by these openings for cross ventilation, though the whole opening ratio is about
K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
215
Fig. 17. Elements of thermal environmental control in Tumakgyp.
Tumakgtp as a double envelop structure
Modem double envelope structure
Fig. ! 8. T u m a k g y p vs. modem double-envelope structure.
10%. Cross ventilation is the most useful factor in cooling during summer and keeping the healthy indoor air quality.
excellent double-envelope structure system, such as a modern utilization of passive design principle.
5.5. Utilization of vernacular building materials Tumakgyp has a structure of Guitlgyp ( Korean log house). Log house is made of woc~l produced in Ullfing Island, the humidity control function and the low thermal conductivity of wood give a comfortable indoor climate. By filling logs up with mud, humidity control is strengthened and its infiltration is protected so that a more comfortable thermal environment can be created by its thermal mass effect.
5. 6. Double-envelope system development Tumakgyp has several characteristic elements related to the control of thermal environment, Fig. 18. Satjari (bamboo mat) played a great role in keeping a comfortable environment when the floor is overheated in winter or when humidity is high in summer. Gomibanja (ceiling insulation) reduces the heat loss by outgoing radiation during night. If it is developed into an attached sun space structure by replacing southfacing Udegi with transparent material, it could be an
6. Conclusions
The Korean traditional folk house, designed as a unique example of environmental architecture, has been developed in relation to the natural environment and has created a comfortable indoor climate condition through passive design principles. The traditional folk houses in Cheju Island and Tumakgyp in Ullfing Island show their own unique housetype which is distinguished from that of the other areas in terms of climatically responsive architecture. Environmental architectural elements of the traditional folk house in Cheju Island reflect the application of local building materials, the consideration of good ventilation for cooling during summer, and the unique Ondol system in which iocalc fuel is used. The construction of the folk house in Cheju Island, based on the characteristics of winds, is a good example of wind-proof design, and passive cooling design.
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The most peculiar elements of environmental architecture of Tumakgyp are Udegi and the utilization of local building materials of mud and log. Though it is different from doubleenvelope structure of modern passive solar system, the double-envelope structure of Tumakgyp controls effectively the severe outdoor environment. Self-control of humidity by logs and mud and its thermal property have been well performed for making a pleasant indoor environment. The difference between the traditional folk house in Cheju Island and Tumakgyp in Ullfing Island is the definite sample that proves how local climatic factors influence the architectural characteristics. The former is for windy and warm-humid climate, the latter is for snowy and cold climate. The difference is very significant even though they are classified into the same category of Korean traditional folk house. These environmental elements and the passive design principle of Korean folk houses can be one of the fundamental solutions for the problem-solving of contemporary architecture faced to the critical environmental problem of today, environmental architecture being based on empirical and natural philosophy. For these purposes, scientific and systematic
study of traditional architecture as a climatic filter should be reconsidered as an essential need.
Bibliography G.Z. Brouw, Sun, Wind, and Light, Wiley, USA, 1985. G.Z. Brown, J.S. Reynolds and M.S. Ubbelohde, Insideout, Wiley, USA, 1982. B.-W. Jang, Korean Folk Houses, Bojinjae, Seoul, South Korea, 1981. K.-H. Lee, Architectural Environmental Planning, Munun-Dang, Seoul, South Korea, 1990. K.-H. Lee, D.-W. Hart and H.-J. Lim, Evaluation of Thermal Performance of Traditional House in Ullang Island, Korea, Proc. 11th Int. PLEA Conf., Dead Sea, Israel. A. OIgyay and V. Olgyay, Design with climate, Princeton University Press, USA, 1956. A. Olgyay and V. Olgyay, Solar Control and Shading Devices, Princeton University Press, USA, 1957. Watson Labs, Climatic Design, McGrawhill, New York, 1983.
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ELSEVIER
aUILDII IGEnergy and Buildings 23 (1996) 207-216
Passive design principles and techniques for folk houses in Cheju Island and Ull ng Island of Korea Kyung-Hoi Lee, Dong-Wook Han, Ho-Jin Lim Department of Architectural Engineering, Yott~eiUniversity, Seoul, South Korea
Abstract
The Korean folk house has created a comfortable indoor environment with passive control of outdoor climate as an example of environmental architecture. This study aims to identify the peculiar elements of environmental architecture in folk houses in Cheju Island and U!lQng Island through field experiments. The elements of environmental control of folk houses in both islands could be developed as design elements of modern architecture. This effoa can play a major role to find the passive design principles and techniques of environmental control of the building which have been neglected in the design of modern architecture. Keywords: Environmental architecture; Passive design; Folk houses; Korea
1. Introduction
Climatic determinism ha.,; been generally accepted in the field of architectural design, even though cultural geographers began to use it as an explanation of their theory. Actually, climatic determinism does not fully explain all the characteristics of vernacular architecture. However, it is obvious that climate is one of the most important factors influencing the form of the house. Especially, with poor building techniques and the limited knowledge of environmental control, climate seems to have a major impact on the building. In such circumstances, human beings cannot dominate nature, but they have adapted themselves to the natural environment. The energy problems, since 1973, require new innovative attitudes toward architecture and planning. Review of traditional architecture in its ecological concerns suggests that human beings should adapt all their design activities to the natural order of the global system. In the light of this, environmental architecture can be the most appropriate discipline to perform the role of stabilizing the ecological system. Accordingly, the current knowledge and skills of architects, planners, designers, engineers, and industry can begin to resolve the global crisis by designing environmentally responsible architecture and urban systems. The term, environmental architecture, means the architecture adjusted to its surroundings or in harmony with nature creates a healthy 0378-7788/96/$15.00 © 1996 Elsevier Science S.A. All rights reserved
SSDI0378-7788(95)00946-U
environment for human beings by maximizing the utilization of natural energies. Korean traditional architecture has been developed by adapting to the surrounding environment which has very distinctive cultural and climatic characteristics. With proper shapes, the Korean folk house performs well in its regional climate and natural environment to provide comfortable indoor environment through site planning, space organization and using proper building materials. The environmental control principles underlying in traditional architecture to adapt to nature can be good sources for the design of modern buildings, although shape, structure, and design elements differ from each other. Folk houses in Cheju Island and Tumakgyp or a doubleenvelope house in Uli~ng Island are good examples of environmental architecture; they have the unique structure and form which have been derived from particular environmental conditions of the areas. Analysis of the relationship between these architectural characteristics and environmental conditions reveals the background of the most proper environmental control principle in the integration of architectural characteristics and climatic conditions. This study aims to find the relationship between Korean regional climate and architectural characteristics with a view to identify passive design principles of folk houses in the two islands. The implication of passive design principles of.
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environmental architecture will be discussed in the Conclusions.
2. Traditional folk house in Cheju Island 2.1. Climatic characteristics
The annual average temperature of Cheju Island, located on the South Sea about 80 mile away from the Korean peninsula, is 12-20 °C which is higher than that of the country, 8-14 °C. Analysis of the climate reveals that there is a narrow temperature range between the hottest period and the coldest period of the year. During the winter, it is relatively warm and humid as compared with the inland. The main wind direction in summer is SSE, while the wind direction in winter is NW. The average annual wind velocity is about 4 m / s which does not give any discomfort. The maximum annual wind velocity is over 13.9 m/s, and its frequency is more than 20 days per year. Because Cheju Island is on the passage of strong winds or tropical atmospheric depressions more frequently than on the inland, it tends to have high wind velocity and high frequency of strong winds. According to the above climatic characteristics, Cheju Island belongs to the temperate climate zone inclined to oceanic climate, and has rather frequently strong winds as shown in Fig. 1. 2.2. Architectural characteristics 2.2.1. Site and floor planning
In the Korean traditional architecture, according to the Fengshu order or geomancy, it is preferable to face low hills across a water to the south and being surrounded by high hills and, therefore, protected from the wind by woods to the north. .=+
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Fig. 2. Variationof outdoor air movementheated by frontcourtyard. By these means, a maximum solar heat gain and a primitive heat-loss protecting have been achieved during the winter. The slope and woods of rear hills initially decrease the velocity of north-south wind and fences reduce it furthermore. South-east wind in summer creates a comfortable indoor climate in Daechung (Maru) or the main Korean woodenfloor room during the summer. In the traditional folk house of Cheju Island the inner court, called Antui, is surrounded by the main building and boundary walls. Plants in the inner court have a wind-protecting effect and create shading areas. During the daytime, when the temperature is at its highest level, the front courtyard is exposed to sunshine. However, the air temperature in the Antui remains low because of the shade created by trees. Therefore, cool air in the Antui moves to the front courtyard due to natural convection as shown in Fig. 2, and passes through the narrow backdoor of the main wooden-floor room (Sangbang); even in hot summers, people sitting in the Sangbang feel comfortable. Floor plans in the Korean traditional folk houses vary with local climatic conditions, see Fig. 3. Houses in the northern regions show more insulated Gyupgyp style or double backto-back rooms, having less Maru (wooden floor), than those in the southern regions, mainly due to the mild climate. Notably, the houses in Cheju Island and UllQng Island show unique floor plans to protect them from strong winds or heavy snowfall, thus reflecting the local climate conditions. The traditional folk house in Cheju Island consists of Bakuri (outer quarter), Mokuri (inner quarter), Imunkan (entrance). A three-bedroom house is the standard and basic house in Cheju Island. The main elements of the floor plan are Chungji (kitchen), Sangbang (Maru, wooden floor), Gudle (bedroom), Gopang (store), Chatbang (dining room), etc. The house of Cheju Island has a characteristic unique heating system called Ondol. This special plan is for creating a comfortable living space in summer by reducing wind velocity, enhancing air-conditioning effect, and balancing interior temperature.
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Awnings in Korean traditional houses were designed to prevent sunlight from mid-April to late August when the altitude of the sun is over 63.5 ° . They were designed to gain sunlight entering the room from middle October to late Feb-
K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
209
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Fig. 5. Section of traditional folk house in Cheju Island.
The exterior wall is built up of stone to resist strong winds. The front areas except the Chatbang (dining room) of most houses in Cheju Island provide a semi-interior space called Mutdung (porch). Some other houses have surrounding wails built in order to be protected from storm winds. In addition, the Poongchae (movable eaves) is hung at the eaves and the double door called Gerchang is also attached to prevent strong storm winds, see Fig. 5. ,
Fig 3. P]oor plan of Korean traditional folk houses. ( R ) room; (K) kitchen; (D) Daechung (main wooden-flo<:,r room); (J) .leongjugan (store); (P) Gopang(store); (G) Gulmok (fire house), and (C) Chuckdam (buffer space).
ruary when the altitude of the sun is under 40 °. Also, Salchang or a grid-framed window frame acts as a sun screen in modern architecture. It offers shade in the summer and minimizes heat losses by making an air-curtain outside the window. The traditional folk house in Cheju Island is less high than the house in the inland; the roof is low and has a round shape for resisting wind (Fig. 4). The average slope of the roof is less than 4110 of that in the :inland. Also, the roof used to be tied up with thick rope to resist strong winds.
2.2.3. Characteristics of heating system: Ondol The Korean traditional heating system, Ondol, has been used for a long time as the unique residential radiant heating method in Korea, see Fig. 6. The air heated in the fire sources Butumak (the traditional kitchen range) or Agungie (fuel hole) heats the flat stones under the floor by passing through the hypocaust in such a way that the indoor air is heated. In Ondol, the thermal mass of flat stones keeps heat for six or eigth hours with vernacular firewood. Ondol also has the function of controlling the humidity, heating and natural cooling effect. The clay used in this system controls indoor humidity comfortably by emitting humidity in winter and absorbing humidity in summer. The Ondol system in Cheju Island is estimated to have been started around 1660, and it is a more primitive style and structure compared with that of the inland. Most folk houses provided with Ondol systems have only 1/3 of the hypocaust arrangements, and it has smaller fire stocks than those of the northern and middle part of the country. Once, the fire stock
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Fig. 4. Facade of the traditional folk house in Cheju Island.
Fig. 6. Section of the heating system Ondol.
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K.-H. Lee et al. / Energyand Buildings23 (1996)207-216
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Fig. 8. Lift-updoor systemin Daechungfor Maru. is lighted and the heat kept by stones, during the winter, a proper floor temperature is maintained at floor according to the regional climate conditions. On the other hand, Ondol also performs as a good natural cooling system during the summer. But the main living space during the summer is Sangbang (main wooden-floor room, Maru), see Fig. 7. The airflow under Sangbang makes the ambiant cool by intercepting direct sunlight, controlling the humidity and penetrating through the peepholes of the wooden-floor room where during the summer activities take place. This cooling effect is enhanced by Antui as explained above. Duleryulgae or the lift-up door system tends to increase the cooling effect of Daechung by inducing cross ventilation, see Fig. 8. 2.3. Field survey of thermal performance
The field survey was done in a well-preserved folk house in Cheju Island in order to evaluate the thermal performance that responds to the local climatic condition, see Fig. 9. Thermal environmental factors such as air temperature, surface temperature, global temperature, relative humidity, wind direction, wind velocity and illumination were measured in the large Gudle or the master bedroom, Maru, and outdoors. 2.3.1. Thermal environment of interior space The analysis of thermal environment of the traditional folk house in Cheju Island shows the following characteristics of each space, Table 1. In summer, the average indoor dry-bulb
Fig. 9. Planof folkhousein Cheju Island. ( 1) masterbedroom(largegudle); (2) bedroom(Gudle); (3) Maru (Sang bang); (4) store (Gopang); (5) kitchen ( Chungji) ; (6) dining room ( Chatbang), and (7) fireplace ( Gulmok). temperature in the large Gudle is 29.9 °C, and the relative humidity is 86.6% when the door is open. But a time-lag effect is found in the large Gudle. During night, the indoor air velocity is 0.3 m / s and the radiant temperature of surrounding walls is 1.6 °C lower than indoor dry temperature. However, during daytime, the indoor air velocity is more than 0.5 m/s, and the radiant temperature of surrounding walls marks 4-10 °C lower than the indoor dry-bulb temperature. By inducing cross ventilation, rooms keep comfort during summer. 2.3.2. Wind-resistant plan composition Fig. 10 indicates that there is little airflow in the large Gudle and Sangbang in winter, and the infiltration through the large Gudle opening and front opening of Sangbang is lower than that of the backside infiltration of Sangbang and the exterior airflow. This seems to be due to the characteristic of double arrayed room-type which has a windbreak effect of Mutdung and Gulmock (buffer space and fireplace). 2.3.3. Natural cooling capability of Maru According to the measurement, the temperature under Sangbang (Maru) is 0.1-1 °C lower than that of above Sangbang. The indoor temperature of Sangbang is lower than that of the large Gudle (master bedroom). Even though the air temperature of Cheju Island in summer is very high, comfortable indoor climate has been achieved by cool air under Sangbang and by the cross-ventilation effects. Folk houses in Cheju Island can provide comfortable indoor condition using cross ventilation during summer. In spite of the high opening ratio, however, modern houses do not utilize cross ventilation. Even in hot humid summers, the indoor climate of folk house is comfortable, because cool airflow under the floor space and air circulation from backyard to Sangbang. The architectural elements could support the theory of modem passive cooling system that can be applied to the designs of contemporary houses. 2.3.4. Thermal characteristics of a volcanic rock For the construction of Korean traditional folk houses, local materials are mainly used. The roofing materials are mainly clay tiles and barley straws, and wall materials are
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Table 1 Thermal performance factors at Smtgbang Place
Sangbang (Maru)
Season
Sumtr~r
Factors
Teml~'~rature ( °C )
Wind velocity (m/s)
Outdoor temperature (°C)
Temperature (°C)
Wind velocity (m/s)
Outdoor temperature (*C)
12:00 14:00 16:00 18:00 20:00 Mean value Minimum value Maximum value
30.8 29.6 31.2 29.4 28 29.8 28 31.2
I. 1 0.9 2.1 0.2 0.3 0.9 0.2 2.1
31.3 30.5 30.6 29.2 28 29.9 28 31.3
5.6 6.8 6.8 7.0 7.0 6.8 5.6 7.7
0.1 0. I 0. I 0.1 0.2 0.12 0.1 0.2
4.7 6.5 5.6 5.5 5.3 5.5 4.7 6.5
Winter
has been derived from particular environmental conditions of the area. The evaluation o f the thermal performance and the characteristics of this traditional folk house will be a useful framework to understand the environmental characteristics of the Korean traditional architecture in relation to its regional climate.
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3.1.1. Climatic characteristics The annual average temperature of Ullfing Island, 9.9-15.9 °C, is higher than that of the country, 8-14 °C, see Fig. 11. The climate analysis revealed that there is a narrow temperature range between the hottest and the coldest period of the year. It is warmer and more humid than the inland, with heavy snowfall during winter. Ullfing Island is located in the middle of the East Sea, being largely effected by strong winds and low atmospheric pressure. The main direction of wind is S S W in summer and NE in winter. Although the annual average wind velocity of 4 m / s give a comfortable feeling, the maximum wind velocity is over the 13.9 m / s . The frequency of wind velocity,
Fig. 10. Air-flow changes in different rooms. soil-based materials that have high thermal capacity. The thermal characteristics of these materials can decrease the room temperature by blocking strong solar radiation in summer. In winter, high thermal capacity materials can also decrease the room temperature. From the present field survey, one may observe that the thermal conduction rate of volcanic rock in Cheju Island (about 0.399-0.580 k c a l / ( r n h °C) ) is less than that of concrete, a modern construction material (about 1.1 k c a l / ( m h °C) ). Therefore, volcanic reck in Cheju Island is a relatively good insulation material.
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K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
212
even corn stalk. The fences have two functions: 'wind-proof and 'snow-proof, and the give also privacy to the occupants.
Fig. 12. Bird's eye view of Village Nari.
13.9 m/s, is higher than that of the inland marked 20 days per year. 3.2. Architectural characteristics 3.2.1. Site In the center of the Island, with a surface area of about 70 km 2, is a high summit called Mt. Sungin. In the north of Mt. Sungin, is Nari basin where a small village settled down, see Fig. 12. There remains 5 Tumakgyps whose preservation is not good. Some folk houses reside in a little higher land which is southwestward from the center of the basin, since the rainfall in the north of Nari Basin is very heavy. In general, folk houses are built near the farm, and the distance between folk houses is therefore not the same. The landshape is generally square, and, at the border of each land, there are fences plaited by branches of the Gore pine, beech, chestnut, maple, and
3.2.2. Floor plan Tumakgyp, a 'I'-typed and primitive double-enveloped house in UllGng Island, has the distinctive factors of Nuwagyp (single wooden- roofed house) and Gulpeegyp (single barkroofed house) which is the typical house for fire-field farmers in Kangwon Province. The house in the inner mountain area of Kangwon Province is double arrayed room-type (Gyupgyp), but Tumakgyp is a single arrayed room-type (Oitonggyp) with Udegi modified from double-envelope system, building materials are limited in UllGng Island. The floor plan of Tumakgyp in Ullfing Island is a closed style. It does not have Maru (wooden floor) that is commonly found all over the country, except in the northern regions of Korea. Most functions of the house is concentrated to the main zone. If residential space was scattered, it would be blocked between buildings during heavy snow period. Tumakgyp has concentrative spatial structure. Chukdam (buffer space) surrounded by Udegi (outer wall) al so works as passages between rooms in a building in order to obstruct snow. 3.2.3. Facade and section Guitlbyuk (log wall) and Udegi (outer wall) are remarkable characteristics of Tumakgyp, see Fig. 13. Soil filings between logs protect from infiltrated wind. Udegi (thatched outer wall) is installed to protect from wind and rain, and to block solar radiation from the top to the bottom at the outer side of the wall, like a bamboo blind. The entrance of Udegi can be opened or closed; it is made at the entrance of a room and the kitchen. Chukdam (space of width 1.2-1.6 m between outer wall, Udegi and inner log wall) is the space for living,
FRONT ELEVATION
SIDE ELEVATION
SECTION
Fig. 13. Elevation and section of Tumakgyp (without Udegi).
213
K.-H. L e e et al. / E n e r g y a n d Buildings 23 (1996) 2 0 7 - 2 1 6
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activity, work, and store. The slope of the roof of Tumakgyp (about 6/10) is steeper than that of other Korean traditional folk houses (about 6/10) to reduce the snow loads.
4. Evaluation of thermal performance The field experiment was made in a well-conserved Tumakgyp to evaluate the thermal performance of the traditional folk house responding to the natural environment in UII0ng Island, see Fig. 14. Thermal environmental factors measured in the master room, Chukdam were air temperature, surface temperature, globa] temperature, relative humidity, the direction and the velocity of wind, and illumination as shown in Table 2. The results of measurement are given in Table 3. The average temperature floor surface is 22 °C. Temperatures are almost the same at't0 cm, 170 cm, and below ceiling. The floor temperature of Ondol is 7-10 °C higher than indoor air temperature. Such temperature distribution is the typical
temperature stratification of the floor-heating system. The difference between room air temperature and mean radiant temperature in the master room is more than 0.3-1.4 °C, indicating a comfort condition. The variation of daily indoor temperature is small, within a range of 4 °C, mainly due to a windowless wall or Udegi and Ondol (heating system). Relative humidity is within 4 4 50% in the room, 66% in Chukdam, 71% outdoors. The inner soil wall and Udegi control the indoor humidity. Fig. 15 shows that the temperature variation in Chukdam which is almost similar to outdoor temperature. Chukdam, acting as a thermal buffer zone, reduces the heat loss and controls strong wind to be kept below 1.2 m / s when the maximum velocity of outdoor winds reaches 14 m/s, as shown in Fig. 16. The first protection against strong outdoor winds has a great influence on the thermal environment of a building in a windy condition. At first, wind pressure around the building envelope decreases so that the infiltration rate becomes lower resulting in a small air movement in the room. The convective heat loss from the exterior surface of a building is due to the function of outdoor wind velocity. Udegi reduces the convective heat loss from the surfaces of indoor space substantially by minimizing the effect of outdoor wind velocity and outgoing radiation during the night. In addition to this, Udegi can be a good control device, for shading and ventilation; it does not provide convenient adjustability when natural lighting is necessary. The results of this evaluation can be summarized as follows:
Table 2 Evaluation of thermal performano~ Factors
Instrument
Place
Data logger Global thermometer
Outdoor, room, Chukdam Floor surface wall Room, Chukdam
Relative humidity (%)
Climomaster Hygrometer
Room, Chukdam
Wind velocity (m/s)
Climomaster Hygrometer
Room, outdoor
Illumination (Ix)
Lightmeler
Outdoor, Chukdam
Temperature (°C)
Temperature Surface temperature Global temperature
Table 3 Comparison of thermal performance factors Place
Room
Chukdarn
Outdoor
Factors
Temperature (°C)
RH (%)
Wind velocity (m/s)
MRT (*C)
Temperature (*C)
RH (%)
Wind velocity (m/s)
MRT (°C)
Temperature (°C)
RH (%)
Wind velocity (m/s)
Mean value Minimum value Maximum value
15.6 13.7 17.5
44.9 44.0 49.0
0 0 0
16.2 14.0 18.1
1.1 - 0.9 3.1
66.3 50.0 93.0
0.6 0.03 1.2
1.3 - 0.2 2.8
1.2 - 1.2 4.9
71.2 40.0 86.0
5.6 0.7 14.0
214
K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
! -4)- 0utdoor a- Chukdam I + CeIing 170CM !-m-. 70Cil
35 30
--
7 65
25
8
20
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Weak W,nd
14 12
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(i) though Tumakgyp has a low air tightness, its daily indoor temperature range is narrow due to Udegi and the soil wall; (ii) Udegi (a primitive double-envelope) functions as a thermal buffer zone for keeping the indoor environment comfortable by protecting from climatic influences such as snow, rain and wind, and (iii) humidity control and thermal mass effect of the soil wall, and protection from wind by Udegi create a comfortable indoor climate.
!
5. Elements of environmental control in T U M A K G Y P Examination of the thermal performance of Tumakgyp (the traditional folk house in Ull0ng Island) has brought about the following architectural elements related to passive design principles that can be used in modern architecture, see Fig. 17.
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outer walls and the inner walls. Chukdam was utilized for outdoor activities away from the snow and performed as a thermal buffer zone. Although the air temperature inside Chukdam did not show much difference from the outdoor air temperature, Udegi performed well as a climatic filter by reducing air movement inside Chukdam. In summary, Chukdam performs multi-functions in terms of behavioral and thermal environmental controls.
5.3. Ondol 5.1. Double envelope Double-envelope structure as a modern passive solar system is the system to circulate the heated air in south-facing greenhouse through double-envelope space. Tumakgyp is responsive to climate by circulating warm air, produced in the kitchen, through the double envelope to maximize the insulation effect. During summer, it promotes a cooling effect by natural ventilation and by blocking the direct solar radiation that penetrates into the space.
5.2. Buffer zone By the double-envelope system with Udegi or outer walls, Tumakgyp creates Chukdam which is the space between the
Structurally Tumakgyp comes with Ondol floor-heating system instead of wooden floor. Structure and heating efficiency of Ondol are closely related to the regional climate. Therefore, peculiar indoor temperature, building structure, and materials, etc., have been applied according to climatic regions.
5.4. Openings for cross ventilation Most of the Korean traditional folk houses have emphasized the design of openings. The comfortable indoor condition can be created during summer by these openings for cross ventilation, though the whole opening ratio is about
K.-H. Lee et al. / Energy and Buildings 23 (1996) 207-216
215
Fig. 17. Elements of thermal environmental control in Tumakgyp.
Tumakgtp as a double envelop structure
Modem double envelope structure
Fig. ! 8. T u m a k g y p vs. modem double-envelope structure.
10%. Cross ventilation is the most useful factor in cooling during summer and keeping the healthy indoor air quality.
excellent double-envelope structure system, such as a modern utilization of passive design principle.
5.5. Utilization of vernacular building materials Tumakgyp has a structure of Guitlgyp ( Korean log house). Log house is made of woc~l produced in Ullfing Island, the humidity control function and the low thermal conductivity of wood give a comfortable indoor climate. By filling logs up with mud, humidity control is strengthened and its infiltration is protected so that a more comfortable thermal environment can be created by its thermal mass effect.
5. 6. Double-envelope system development Tumakgyp has several characteristic elements related to the control of thermal environment, Fig. 18. Satjari (bamboo mat) played a great role in keeping a comfortable environment when the floor is overheated in winter or when humidity is high in summer. Gomibanja (ceiling insulation) reduces the heat loss by outgoing radiation during night. If it is developed into an attached sun space structure by replacing southfacing Udegi with transparent material, it could be an
6. Conclusions
The Korean traditional folk house, designed as a unique example of environmental architecture, has been developed in relation to the natural environment and has created a comfortable indoor climate condition through passive design principles. The traditional folk houses in Cheju Island and Tumakgyp in Ullfing Island show their own unique housetype which is distinguished from that of the other areas in terms of climatically responsive architecture. Environmental architectural elements of the traditional folk house in Cheju Island reflect the application of local building materials, the consideration of good ventilation for cooling during summer, and the unique Ondol system in which iocalc fuel is used. The construction of the folk house in Cheju Island, based on the characteristics of winds, is a good example of wind-proof design, and passive cooling design.
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The most peculiar elements of environmental architecture of Tumakgyp are Udegi and the utilization of local building materials of mud and log. Though it is different from doubleenvelope structure of modern passive solar system, the double-envelope structure of Tumakgyp controls effectively the severe outdoor environment. Self-control of humidity by logs and mud and its thermal property have been well performed for making a pleasant indoor environment. The difference between the traditional folk house in Cheju Island and Tumakgyp in Ullfing Island is the definite sample that proves how local climatic factors influence the architectural characteristics. The former is for windy and warm-humid climate, the latter is for snowy and cold climate. The difference is very significant even though they are classified into the same category of Korean traditional folk house. These environmental elements and the passive design principle of Korean folk houses can be one of the fundamental solutions for the problem-solving of contemporary architecture faced to the critical environmental problem of today, environmental architecture being based on empirical and natural philosophy. For these purposes, scientific and systematic
study of traditional architecture as a climatic filter should be reconsidered as an essential need.
Bibliography G.Z. Brouw, Sun, Wind, and Light, Wiley, USA, 1985. G.Z. Brown, J.S. Reynolds and M.S. Ubbelohde, Insideout, Wiley, USA, 1982. B.-W. Jang, Korean Folk Houses, Bojinjae, Seoul, South Korea, 1981. K.-H. Lee, Architectural Environmental Planning, Munun-Dang, Seoul, South Korea, 1990. K.-H. Lee, D.-W. Hart and H.-J. Lim, Evaluation of Thermal Performance of Traditional House in Ullang Island, Korea, Proc. 11th Int. PLEA Conf., Dead Sea, Israel. A. OIgyay and V. Olgyay, Design with climate, Princeton University Press, USA, 1956. A. Olgyay and V. Olgyay, Solar Control and Shading Devices, Princeton University Press, USA, 1957. Watson Labs, Climatic Design, McGrawhill, New York, 1983.