What is Ondol?
Ondol Summary
Ondol is a traditional Korean house heating method. It is also called Banggudeul. Heating method is make a fire at the fuel hole, and heating is done when hot smoke contained heat which was generated at the fuel hole passes through the Gudeuljang(room floor), and the said smoke is gone out into the chimney at the end of the Gudeuljang. A typical device of similar concept with Ondol is Hypocaust which is a Roman era's large bathhouse warm water supply method of primitive type (only comprised of fuel hole and Gorae) that Bulmok(the warmest part of the heated floor) or Gaejari is none. Furthermore we can also take a Gloria which was used for heating device of medieval castle that was derived from Hypocaust.
Heat Method around the world
Hearth of West and Irori of Japan and so on are the heating apparatus directly using the heat source, while Ondol has a feature that use the generated 'indirect radiant heat' warming up the Gudeuljang and Gorae under the Gudeuljang by the heat. That's why if a certain Gudeuljang was well made, heat of the Gudeuljang relatively keeps up for long time even if got rid of the direct heat source from the fuel hole. Condition of the good Gudeuljang depends on how long this 'remaining warmth' would be lasting. Demerit is that once Gudeul (room floor) is split or broken, smoke comes up and carbon monoxide poisoning could be happened. As problem of the heat efficiency can be taken, it tends to heat excessively beyond necessity to pass overnight with the remaining warmth after making a fire before sleeping. Another demerit is that temperature difference between the place on the Ondol floor nearest the fireplace and the upper side of the floor away from the fireplace is occurred under the structure of Ondol.
Ondol History
Backje Dynasty Era Ondol Relics Backje Dynasty Era Ondol Relics Ondol cal also be seen at the Neolithich Age relics of around B.C.5000 and was also painted on the Goguryo Dynasty tomb fresco of Anak No. 3 Tomb in Whanghae-Do around 4 century. Pattern of the Tong Gudeul that Ondol was made into room began to appear from the end of the Goryo Dynasty. It was mainly used by rich class and mainly used for room of the patient or the aged. Considered difficulty of making or management and fuel consumption, it was deemed luxurious heating method. - There is a record on the True Record of the Joseon Dynasty of May 14 King Taejong 17th years (1417) that directed to make a one Ondol room for the sick persons among the Confucian scholars of Sunggyunkwan whose establish meant was not passed long. When sees this, we can recognize that they did not use the Ondol room completely. Afterwards King Sejong 7th years (1425) directed to increase the Ondol of Sunggyunkwan by 5 rooms and were entirely become the Ondol room only when 16 century sets in. In general all used bed and were wooden floor. According to the Joseon Dynasty King Myungjong 18th years (1563) of February 4 there was a fire accident in the bed of the King and among the situation explanations at that time it describes that made a small Ondol structure on the bed of the King and warmed up the place. Further it mentions that at that time put the stone wrong through carelessness and heat of fire approached to the bed then burnt. According to the True Record of the Joseon Dynasty of March 5 on King Injo 2nd years (1624), since a story is appeared that even rooms where servants of the gentry dwells in were already all Ondols from the Kwanghaegun ruling period and rooms of the lady attendants too in the royal palace were changed into the Ondol rooms as it is not good that lady attendants in the royal palace dwells in the board-framed house, we can learn that spread of the Ondol to the royal palace were completed. Passing by the 16 century 17 century which is even called Small Glacial Epoch whose weather is exceptionally cold, Ondol was gradually spread and at the latter half of the Joseon Dynasty Ondol was widely used to even thatched cottage of the ordinary folks.
Fuel of Ondol
Traditional Ondol mainly used straw or wood as fuel of the cooking fireplace. Mr. Duckki Kim at the time of the King Sukjong used to make fuel (firewood) made of horse dung in Dongrae and used to use charcoal. However, traditional Ondol consumed too many woods as fuel and used to be a reason destructing environment. [1] Fuel in the Joseon Dynasty was the most important living article along with cotton, rice. After 1960's major fuel was substituted to briquette and now boiler that is using the oil was spread a lot. Hostage-held- advisor(其人) who provides Shimok(fuel) under tribute in the royal palace provided fuel and charcoal, and ordinary boys in civilian society did play a great deal of firewood gatherer role.
Modern Ondol
Entering into 1970's, warm water boiler that made the best use of the Ondol pattern was developed and is being used until now, so as to reduce the carbon monoxide poisoning damage as well as solve the heat efficiency problem. Warm water boiler, which is currently main force of the home heating method, is widely being used in replace of traditional Ondol. Today, we can hardly see the traditional Ondol in the region where fuel supply & demand for Ondol like urban area etc is difficult, and instead various methods such as warm water boiler, Ondol floor, electric Ondol used midnight electricity etc. are being used. It is on account of convenience, supply problem of traditional fuel, safety reason like gas poisoning etc., easiness of installation and management. Present warm water boiler uses various energies such as briquette, coal, oil, electricity etc., and can mix various kinds of fuel depending on the case, and new design of cost saving type considered heat efficiency and convenience such as semi-automatic replacement of briquette or coal, use of midnight electricity etc. is continuously being researched developed. Even today traditional Ondol is being executed in the region where not get big hindrance to the fuel purchase does for the Ondol though, strict execution standard and execution supervision item pursuant to the relevant laws & regulations are applied to the building etc. in which people resides. Besides the house in which people lives, Ondol of traditional design pattern that use fuel(straw and wood or briquette) that can relatively get easily at a farmhouse as a heating method of stall and greenhouse is also used. Furthermore, in the back country, high mountainous district, islands etc. where installation of the warm water boiler is not suitable because of frozen-burst of the warm water pipe or difficulty in managing, and continuous supply of coal, oil and gas etc. is difficult, still traditional Ondol is frequently executed and used.
Structure
Ondol design structure has a slight difference depending on the era and region. If make Ondol meeting with the most basic requirement only, its structure is make a fire at the fuel hole and heat of that fuel hole is gone out into the chimney passing through the Gorae of the Gudeuljang. Sequence to pass by the smoke which contained the heat of fire is as follows.
Fuel hole of cooking fireplace: It is a place to make a fire and generate heat.
In case that room is small, Woebang Gudeul is connected to a one fuel hole (or two fuel holes).
Couple of fuel holes used to stick and connect to a one Gudeul(room), and couple of Gudeuls used to connect to a one fuel hole, depending on the room size or house structure etc.
Small house is comprised of a one with a cooking fireplace of the kitchen, and in the big house a separate heating fuel hole used to put every room or building.
Since fuel hole of the cooking fireplace is supposed to put lower than the Gudeul, floor of the kitchen belongs to the lowest height area in the house.
As the fire burning from the fuel hole of the cooking fireplace combines a heating a and a cooking, there are lots of cases that cooking fireplace height of the conventional kitchen despite kitchen floor is low is under the waist extent. This is a design to cause inconvenience of user when in cooking labor.
Bulmok : (Bulgogae, buneomki or bunangki): It is a place where make the heat generated from the fuel hole enter into the room floor(Gudeul).
It is a passage of the heat connected to the Gorae under the Gudeuljang beginning from the cooking fireplace wall face that hangs up a kettle.
It is a hilly space where pass the heat enetered through the fuel hole rear side(Hulungi) to the Gudeulgaejari and Gorae. It should make controlling its width and height in order for the strong heating power to suck in orderly fashion.
Prop a stone above the Bulmok, and can control the inflow amount of the heat as adjust width of the Bulmok by this.
In severe cold area such as North Korea or Manchuria etc shape of the Bulmok is formed with a wide big structure close to the Dunduck so as to receive much heat.
If Hulungi and Bulmok are too narrow, heat is not sucked, entered in orderly fashion.
If Hulungi and Bulmok are too wide, when heat of fire is none, Gudeul gets cold fast since air of the outside kitchen is flowed in as it is.
Bulmok gives a big influence to heat efficiency such as fuel volume when make a fire and 'remaining warmth' of the whole Gudeul after the fire is extinguished and so on.
Gudeulgaejari: It corresponds to the room's first part and this upper part is corresponded to the place on the Ondol floor nearest the fireplace.
It exists before the Gorae begins, and is a combined place of both air and heat that are deeply dug than the Gorae.
It is a practical first introductory part that drops the heat speed transmitted from the Bulmok and that gives a help to heating when heat is mixing, spreading with a relatively cold air in the Gudeul.
Gudeuljang of this part (place on the Ondol floor nearest the fireplace) is thickly laid than the Gudeuljang of the upper side of the floor away from the fireplace.
Length and breadth are smaller than the 1 piece Gudeuljang stone plate, and depth is approx 30cm extent from the Gorae floor though, its size and depth differs depending on the regional temperature and other design. For severe cold region, shallow Gudeulgaejari and big Bulmok are designed.
Gudeuljang
Ancestors of Korea primarily used mica for the Gudeuljang.
They used white mica out of it because white mica is that heat preservation time was big, and was an insulator.
Mineral which is mainly called mica is mostly contained in other rocks being used for the Gudeuljang.
Types of Ondol
Rauchhaus' of Austria
It is primitive as one of the 3 evils of the house is called 'smoke'
European people in 12~13centuries lived with cattle under one roof supplementing body temperature to each other and put a 'fire place' in the middle of the house and made a bonfire. (Picture 1) By this they did cooking and did overcome coldness too.
Fire place was made putting with fence, using pots or bricks and made a fire thereon though, smoke was discharged through hole of the gable or entrance exit under the eaves. Thus the air in the house was always thick with smoke.
German language area, particularly Austria called this kind of house 'Rauchhaus'.
If translate literally, it is a 'smoke house'. As the proverb of German language area around 11 century says that '3 evils in the house are the roof raining in, nagging wife and smoke', heating of Rauchhaus method was primitive.
At a certain region suffered from smoke a shape which made the roof over the fire place with funnel form so that could make the smoke go out was appeared. By the way its size was gigantic to occupy as much as the whole roof.
Smoke discharge facility of that funnel form was called 'Rauchhaus'. 'Rauchhaus' form was prevailed in mountainous area of the Alps especially in 17~18 centuries.
This shape of heating system eased smoke agony as smoke got out of the house well while a big drawback was seen.
It is because why heating effect was not good enough. Because heat in the house too got out of together through the passage that smoke gets out of.
'Suvibogenhelt' of Germany
Blocks left & right of the fire place by bricks so that enhances the heating effect.
Fire place of Rauchhaus, which chimney is none, that looks like a stove, was evolved into a ' Suvibogenhelt '.
(Picture 2) It is a shape that made a fence with bricks and set up a windbreak wall at left & right of the fire place and blocked the upper side as well so that helped prevent sparks rise high.
Nevertheless chimney was none yet.
It is because why once just make a fire, smoke is spread into the inside of the room through the upper side hole and then discharged properly to the outside. It was a shape that there is none that changed except that the fire place was just more safe and solid.
Another problem was there. Wall used to split and crumble when fire contacts with wall.
Thus made, attached a plate with iron on the wall of the fire place rear side to help prevent this later on.
Heating effect became stronger since it prevented the wall and heat was more reflected into the room.
This shape became the one that is being seen a lot in German agricultural area in 18~19 centuries.
'Hearth' used in West Europe
A system that controls burning speed and heating power
Hearth is a heating type used a lot in West Europe such as Spain, France, and UK etc. where climate is relatively mild in Europe.
It is the one even now being regularly used, but its first advent is around 8~9 centuries.
Since it was made attaching to the wall at first, name was just called hearth and it did little differ from the foresaid Rauchhaus as it did not have a separate chimney.
Mostly it was used at monastery or castle where ceiling is high and room is spacious, smoke was not so much problematic.
However, it was effective to endure the cold only at the place where is close to the fire since heating effect is small for the space is big enough.
More than 200 years were taken for this kind of hearth to spread into ordinary folks.
History and principles of fireplaces
''Franklin Hearth' change process- Hearth devised at first was a shape that simply put 2 steel plates in a diagonal direction (left), and later made the steel plate move (right) so that made it play a heat proof role.
Fire and smoke in the hearth was a one body. People pondered about how can the smoke be sent and can the heat be held. An architect named 'Louis Sabo' produced an idea around 1640.
It was that raised the hearth floor by 10cm extent and made a space leaving a gap between the floor and the fire rear side wall.
It is because why, if so, air in that empty space was warmed up and subsequently heat loss through the hearth floor was reduced.
If we think now, we see that it is nothing particular, but it was an innovation in those days.
Benjamin Franklin who is a meritorious retainer at the founding of USA and renowned for inventing a lightning rod began to remodel the hearth whole by himself around 1740 judging the hearth is neither warm nor good to health.
He installed 2 steel plates in a diagonal direction to 15cm extent so that made the flame and smoke enter into this gap.
By doing like this it was able to reduce a draft coming into the chimney and decrease the smoke too. Franklin developed this system so that changed to make the steel plate hang up vertically and move.
By doing like this it was able to control volume of the draft and subsequently it was able to play a heatproof plate role.
Franklin produced a third idea again. After making a groove vertically on the both sides inner wall in front of the hearth and inserting the steel plate therein, controlled burning speed and heating power to an extent that push this steel plate upward or downward.
Furthermore he made an air inlet that is helpful for combustion in frontal part of the hearth and got out of several bricks under the floor so that prepared a passage that can make a fresh air come into the inner empty space of the hearth then warm up.
This is the very 'Franklin Hearth'.(Picture 3)
'Steel Stove' of Germany
Liberated from suffering of smoke at last
A stove made of casting, namely steel stove was appeared in 1475.
(Picture 4) In 'Siegerland' area and 'Eifel' area in Germany steel production and casting factory were gathered a lot, and it was made in these areas then primarily used in north-east Europe such as Northern Germany and Scandinavian peninsular etc.
As this stove, which is quite different from the existing hearth, heated up leaving the fire between the walls and separa ting from the kitchen or corridor, smoke was not generated indoors.
History & Principal
As an early stage steel casting stove was in lack of technology, made a square plate, assembled as if attaching with a box shape and then used.
There were 2 holes up & down on the wall rear face, and it was a system that smoke comes out from the upper hole once burn the fire at the lower hole. Upper hole was mostly passed to kitchen or hall through which smoke was flown away to the entrance exit or gap of the eaves.
As the steel stove was in general attached to the wall, it was called '5 pieces plate stove' for the 5 pieces of the steel plate were used, but later a case that hang up the stove on the wall and leave an uniform interval was also happened.
Since at that time it becomes a '6 pieces plate stove', it was a structure that gets heat even a little bit more because air is scudding to the rear face of the stove and then heat generation space is becoming wide.
Since the stove was far away from the wall, a stovepipe was needed. While stovepipe is attaching to the stove, people paid attention to a one phenomenon.
It was such a fact that can take heat much more if make the stovepipe as many as possible and bend zigzag then plait long.
'Warm Water Radiator' of USA
Makes the best use of zigzag stovepipe of the stove to help prevent heat loss
Current warm water heating method is a universal heating method that can see any part of the world. This radiator heating was appeared in 17~18 centuries. (Picture 5) At the outset it was the one which is used for equipment that make pump or transportation machine by using vapor not warm water.
When mines industry becomes prosperous especially in 17 century, this method took good effect in digging underground water.
History
Afterwards British garden architect 'Hue Plan' devised for the first time 'low pressure steam heating'.
As he is a garden architect, it goes without saying that it is for the greenhouse heating.
Afterwards 'William Cooke' produced an idea in 1745 to make the low pressure steam heating use for the residential vapor heating though, could not attract significant attention at that time.
When James Watt, originator of steam engine, who is well known to us, installed steam heating in his workroom in 1784 and attracted people's attention.
However, since steam heating has a fatal disad vantage to have been exploded in case of not controlling the pressure properly, drifted apart from people's memory. Heating by using warm water thereafter was conducted experimentally in UK, Switzerland etc though, was not known for general heating.
Shape of the radiator today was appeared in 1830, regrettably who is the inventor was not known. It was too cumbersome to install the warm water radiator in the existing house. The momentum that the warm water radiator was widely spread was the Second World War.
Almost all houses were destructed by war and had to newly build a house after war and this time was the momentum that induced the radiator heating method.
At that time made the best use of the steel stove method that was used in previous era. In other words, realized that zigzag stovepipe of the steel stove is advantageous to heating and the radiator that inserted crease was appeared.
Kotatsu, a Japanese heating appartus
As a winter season heating apparatus of a shape that put a heat radiation apparatus under the table and put a quilt thereon, people used to have a friendly talk or reading etc putting their feet into the quilt under the table.
That is not so familiar article to Korean people though it is the very Kotatsu which is an indispensable article in passing the winter to Japan where underfloor heating device like Korea is none.
Kotatsu, a traditional Japanese heating apparatus, is an article to have been installed a wooden frame called Yagura on a small vessel to keep insulation by using the electricity and put a quilt thereon in modern times.
