How the Ondol was used to create the World’s First Active Greenhouse
The tremendous benefit of the ondol underfloor smokeless heating system does just end at providing efficient heating through the winter season. Seeing a good thing, of course, Koreans will find ways to bring additional life improvements that no other culture could conceive in the ancient times.
Clear traces of ondol system found in North Korea from 1000 B.C. is a long time for Koreans to consider the possibilities. From farmer to the king, all Koreans benefited from the unique benefits of ondol.
The story of how much ondol as a smokeless radiative underfloor heating system has benefited all Korean people since Gojoseon times does not just end with staying warm through the winter.
With the propensity to find innovation with prime technology, Koreans from farmers to royal scientists have found ways to expand the use of ondol’s heating properties to enhance ancient life in Korea.
The heated house environment allowed Korean women to enhance the fermentation of foods. Soybeans, makgeolli wine, bean sprouts were left on the warmest floor with a blanket tossed over to utilize the elevated heat to enhance fermentation. Meju blocks could be hung up high over a warm floor to allow fermentation through the winter.
The humble varied uses of ondol in addition to heating found a most inventive use in the world’s first active greenhouse from the early Joseon era. A royal court physician compiled a cookbook, the Sanga Yorok, and included instructions for how to build a greenhouse.
The Annals of the Joseon Dynasty records that fresh flowers were offered to the king in the dead of winter, flowers that were raised in a specially constructed greenhouse (ancient proof of concept demonstration).
Since King Sejong’s time, the Joseon greenhouse was constructed before the winter season and was practical for raising vegetables to continue providing essential nutrition for the king. Oiled hanji paper covered a roof frame that allowed translucent light transmission. The floor consisted of an ondol system to keep the greenhouse actively warm through the winter cold. During the day, the translucent lattice roof could be opened to vent excess heat. Of course, the ondol firing could be adjusted to increase or reduce heating. Moreover, water was boiled in the furnace room and the moist steam vapor brought humidity into the greenhouse.
Thus, light, temperature, and humidity could be all regulated actively!
Europeans attribute ancient Romans as being first to develop the greenhouse. But this so called Roman greenhouse involved planting cucumber type plants on cart that were wheeled outdoors during the day then wheeled back indoors at night, not exactly a fixed “house” for raising plants.
Even by Napolean’s time when the first practical French greenhouse was built for growing oranges during winter, the active (versus passive) heating greenhouse existed in Joseon hundreds of years earlier.
Ancient Koreans developed another first in inventions, the world’s first active greenhouse system thanks to ondol!
Greenhouse
https://en.m.wikipedia.org/wiki/Greenhouse#History
Jump to History — The French botanist Charles Lucien Bonaparte is often credited with building the first practical modern greenhouse in Leiden, Holland, during the 1800s to grow medicinal tropical plants. … The French called their first greenhouses orangeries, since they were used to protect orange trees from freezing.
The idea of growing plants in environmentally controlled areas has existed since Roman times. The Roman emperor Tiberius ate a cucumber-like vegetable daily.[3] The Roman gardeners used artificial methods (similar to the greenhouse system) of growing to have it available for his table every day of the year. Cucumbers were planted in wheeled carts which were put in the sun daily, then taken inside to keep them warm at night. The cucumbers were stored under frames or in cucumber houses glazed with either oiled cloth known as specularia or with sheets of selenite (a.k.a. lapis specularis), according to the description by Pliny the Elder.[4][5]
The first description of a heated greenhouse is from the Sanga Yorok, a treatise on husbandry compiled by a royal physician of the Joseon dynasty of Korea during the 1450s, in its chapter on cultivating vegetables during winter. The treatise contains detailed instructions on constructing a greenhouse that is capable of cultivating vegetables, forcing flowers, and ripening fruit within an artificially heated environment, by utilizing ondol, the traditional Korean underfloor heating system, to maintain heat and humidity; cob walls to insulate heat; and semi-transparent oiled hanji windows to permit light penetration for plant growth and provide protection from the outside environment. The Annals of the Joseon Dynasty confirm that greenhouse-like structures incorporating ondol were constructed to provide heat for mandarin orange trees during the winter of 1438.[6]
The World’s First ‘Active’ Greenhouse
London Korean Links
https://londonkoreanlinks.net/2019/11/2 … reenhouse/
The World’s First ‘Active’ Greenhouse | London Korean Links
The greenhouse is an ancient invention, dating back 2,200 years. Modern ‘active’ greenhouses are distinguished from older ‘passive’ ones by the fact that they allow for the adjustment of air and soil temperature. Previously, the first such greenhouses were believed to have been built in Germany in 1619, using a stove to regulate air temperature, and later developed in England in 1691.
The first ‘active’ greenhouse to be built, as was discovered by chance in 2001 in a historical document, was in 15th century AD Korea. On the basis of the surviving document, entitled ‘Growing Vegetables During Winter’, a reconstruction of the greenhouse was made, and it was found to combine traditional heating technology with sophisticated heat retention features and control of condensation.
- The exterior of the Sanga Yorok Greenhouse
The greenhouse described in this book was designed to regulate the temperature and humidity requirements of plants and crops in a very precise manner. Heat was supplied by means of a kudle (구들), a traditional Korean method of heating. The oiled hanji paper made it possible to raise the inner temperature and control ventilation and humidity. However, the extent to which these methods alone could regulate the temperature was limited. The additional inflow of steam from the cauldron had the effect of raising both the temperature and humidity.
One feature of the greenhouse that particularly impressed horticulturalists and academics is the process by which the kudle would automatically raise the temperature of the soil as the boiling water from the cauldron warmed the air.
Vegetables were planted in the new greenhouse, the temperature and humidity levels of the greenhouse were monitored over a space of 20 days. At first, the subterranean temperature outside was 8.6ºC, while the soil inside the greenhouse was at an ideal temperature of 26ºC. The radish and lettuce sprouted after three days, the other vegetables soon afterwards, and after two weeks they had all grown to full size.
The soil above the kudle always remained at 20ºC or higher, and the air temperature at 10ºC minimum. During the night, the soil temperature inside and outside differed by more than 25ºC, proving that the greenhouse was generating adequate heat. Although humidity was as low as 40% at the hottest time of the day (1 p.m), it was otherwise kept at 70%, a level suitable for growth.
- The interior of the Sanga Yorok Greenhouse
This remarkable control was made possible by the oiled Hanji paper used for the walls of the greenhouse, as well as the heating system. Hanji paper when oiled has a high transmission ratio for incident solar rays, and low one for infrared rays. It also diffuses a large proportion of the transmitted rays, and its tensile and tear strength are also high. It retains the droplets of condensation that naturally form on the surface of the walls, allowing them to flow down to the floor. This is necessary to prevent them falling directly on to the plants, and potentially causing damage or introducing impurities.
Thanks to the discovery of a single volume in the corner of an old bookshop, forgotten for hundreds of years, the horticultural world has discovered a missing chapter in its history!
How was this active greenhouse constructed? The design plans appear in a cookbook manual Sanga Yorok written in the Joseon times by a royal physician. YTN Science did a computer model reconstructing the Joseon era design. This website has screen captures highlighting how oiled hanji paper allowed light and retention of warm air while the ondol heated the floor beneath during winter.
Just extraordinary ancient Korean “smart” technology!
Korean History Series 1. The Invention of Heated Greenhouse
https://medium.com/@ilovemeca/the-inven … a50b38479d
— — To the flowers that bloomed in the winter night six hundred years ago
Joseon Dynasty has long been considered as a golden era of the Korean peninsula where the history has witnessed an unprecedented development in the Korean civilization. It was in this period of time, the Korean characters have been invented, Korean poetry has started to blossom, and the world’s first greenhouse has been constructed and put into use.
In the Annals of the Joseon Dynasty (fig.1), one sees the record of tributes of flowers in the winter to the royal family. Those records indicated that the Korean people somehow were able to defy the law of nature and grow plantation according to their own needs. To delve into the detailed manual of the construction of the advanced agricultural technology, Sanga yorok (fig.2) has to be referred. It is a cookbook written by Jeon soon in 1459 by the royal family doctor which also contains descriptions of farming. As one may notice while reading through the manual, the oil-coated paper, and the ondol system are the secret lying behind the structure.
Figure.1 Annals of the Joseon Dynasty | Figure 2. Sanga yorok — Images from YTN
Following the steps written in the manual, attempts can be made to reconstruct the world first greenhouse. First of all, the greenhouse is built from a normal storage-like structure with internal walls covered with oil-coated paper (hanji) on three sides–east, west, and north. (fig.3) Here, the oil-coated paper is used to maximize the reflection of sunlight. On the south facade, a largely tilted grid-window consists entirely of oil-coated paper shall be laid on top of the structure. (fig.4)
Figure 3. Basic structure of the greenhouse | Figure 4. The oil-paper employed on the south facade — Images from YTN
The properties of the oil-coated paper, while guaranteeing the ventilation of air; also enable the maximum amount of sunshine available, prevent the water vapour in the air from condensing and dropping on the plantations, and have further merit in preserving the heat inside the greenhouse. Nevertheless, the true genius of the greenhouse structure lies in the employment of the pre-existing floor heating system that has been invented and started to put into domestic use from the 4th century AD.–ondol. Ondol is an indoor floor heating system. Normally, a fireplace would be set up in the kitchen or on the outside wall to generate heat. The heat then spreads under the household in a conducted tunnel built up underneath the floor. (fig.5)
Figure.5 Examples for Ondol system — Images from YTN
To start with the construction of an ondol system in the greenhouse, a layer of flat stone should be placed on to the floor. (fig.6) Then, on top of the flat stone, the cradle of plantations–soil is layered with a width of 45 cm. (fig.7)
Figure 6. Flat stone | Figure 7. Soil of 45cm
As the ordinary ondol system, a fireplace is set up in the next room to the greenhouse. (fig.8) While the heat is utilized to heat up the place, the water vapor is also collected and used as a means to adjust the humidity of the greenhouse. The effort to condition the humidity speaks of the fact that the Korean people back in the 15th c have already had a fair knowledge of agriculture and plantations.
Figure 8. Ondol system in the greenhouse — Images from YTN
The appearance of the world’s first greenhouse was not an abrupt brand-new invention but a result of a mixture of pre-existing technology available in the Korean peninsula. Admiration should be given to not only those intelligent Korean people but also to those flowers which bloomed bravely in the greenhouse.
The Sangayorok was discovered in a used book store by chance, for some reason its cover removed. Unfortunately, many Korean historical texts were deliberately confiscated and destroyed under Japanese colonial rule, so the missing cover might be to hide the book. How many historical documents were scattered and lost/burned and stolen erasing documentation of ancient Korea’s technological accomplishments?
Here is the YTN Science video, very informative. A working reconstruction was demonstrated following the detailed instructions in the Sangayorok at an agricultural center is covered in the video. The oiled hanji paper was compared to glass and plastic for thermal insulation properties, where oiled hanji proved to be slightly better at insulating. The light transmissibility of oiled hanji, critical for photosynthesis, was also investigated with modern analysis. Moreover, oiled hanji removed the problem of morning condensation due to permeability. Morning photosynthesis is a critical cycle for plants, and modern plastic greenhouses suffer from condensation falling from the sheeting, dropping cold water onto the plants below as well as blocking morning light. Such a morning condensation problem was nonexistent in the Joseon greenhouse and the video explains clearly the reason. Our ancient Korean ancestors got everything right!
What is most interesting in the video is how Koreans in the modern times through trial and error came to develop modern greenhouses with direct soil heating greatly improves plant growth, a principle that ancient Koreans had already understood long ago.
All proof that ancient Koreans developed technologies that all could come together into remarkable innovations, the sum whole being even greater than the parts.
[Exploring Korean History] 03 Greenhouse of Joseon | YTN Science
https://youtu.be/DiHL4hlmoqo
