Editor's Note:
When it was cold, the snow cellar was ice, in the era of no modern heating, how did the royals heat it? The Forbidden City not only has a splendid palace complex, but also contains many ancient court life wisdom, of which floor heating is a typical representative.
Literature and history
The front facing the main hall brazier is warmed
Regarding the heating method in the buildings of the Forbidden City, there are many rumors that "the walls in the palace are actually hollowed out 'sandwich walls', commonly known as 'fire walls'"; "The three main halls of the emperor's office (Taihe Hall, Zhonghe Hall, Bohol Hall), Yangxin Hall and some of the walls of the palace are hollow, and there are vertical and horizontal fire channels under the bricks in the hall, leading directly to the floor furnace outside the hall"... This is all wrong.
From the perspective of engineering practice, the so-called "sandwich wall" or "fire wall" has not yet been found in the ancient walls of the Forbidden City. The fire area is mainly distributed in the inner court area (living area). In the three main halls of the former dynasty, there is neither a "wall of fire" nor a "fire place". When the emperor held important events in winter, the main heating method in the three halls was charcoal pots.
Volume III of the History of the Imperial Palace states: "On the twenty-seventh day of the twenty-seventh month of the first month of the Reign of The Yongzheng Dynasty (the twenty-seventh day of October of the first year of the Yongzheng Dynasty, that is, November 24, 1723), the date of the examination of the Taihe Temple, the weather was cold, and the general manager prepared the large brazier. This passage explains that in the winter of the first year of the Yongzheng Dynasty, the Taihe Hall held a court examination, and due to the cold weather, the Taihe Hall was prepared with a large brazier.
There are also rumors that there are warm pavilions and fire pits in the Forbidden City. There are indeed two heating practices in the palace, and they are closely related to the fire.
The so-called warm pavilion, that is, in the building with a fire, uses a wooden partition to separate this part of the area from other areas of the palace building, making it a relatively closed small space, which can maintain a constant warm state. For example, the Kunning Palace, located in the inner court area, was the empress's residence in the Ming Dynasty, and its easternmost two rooms were changed into cave rooms for the emperor's wedding in the Qing Dynasty, and the transformation method was consistent with the practice of the warm pavilion, so it was called "East Warm Pavilion".
Schematic diagram of the interior of the East Pavilion of Khun Ninh Palace and the section of the fire
The kang is to use the heat source of the fire to set up wooden or brick rectangular pedestals in the building (especially in the area near the window position) to facilitate the daily living activities of the empress in winter. The ondol has always been popular in the Manchus, and it is both a facility for sleeping and heating. After ming chongzhen entered the customs in the seventeenth year (1644), the Manchu imperial family used the fire kang on a large scale in the inner court buildings of the Forbidden City, making it an important facility on the fire ground to facilitate the leisure activities of the empress.
The first day of November "Furnace Opening Festival"
During the Ming and Qing dynasties, the Beijing area was in the fourth cold period in mainland history, the "Ming and Qing Xiaoice Period", about 150 days of the year belonged to winter, and the temperature could reach minus 30 degrees Celsius at its coldest. However, even during extremely cold periods, the Interior of the Forbidden City is relatively warm because of the underground heating system.
The Ming Dynasty eunuch Liu Ruoyu wrote in the "Zhi Zhongzhi" volume 20 "Good Diet Shang Jiluo" contains: "October ... It was time and night that had gradually grown, and the inner minister began to burn the ground. "It shows that the Forbidden City already had floor heating during the Ming Dynasty." The "Qing Barnyard Banknotes" compiled by Xu Ke at the end of the Qing Dynasty and the beginning of the People's Republic of China records: "Every year on the first day of November, the palace begins to burn ondol and set up an enclosure stove, which is oldly known as the Opening Furnace Festival. Here, "open stove" begins to use the meaning of fire. The Opening Furnace Festival opened the prelude to the winter chill in the palace.
Different from the water floor heating or electric floor heating method used by modern people in winter, the floor heating of the Forbidden City is for burning fire heating, commonly known as "fire land" or "warm ground", which is the main way of heating in the buildings of the Forbidden City.
The fire pit of the Forbidden City building consists of an underground operating port located outside the window, an underground furnace cavity inside the window, a fire tunnel (a heat transfer channel) under the indoor floor tiles, and a smoke outlet on the side of the outdoor pedestal. The basic principle of heating is: service personnel (generally eunuchs) stand in the operation port, put charcoal into the underground furnace cavity to burn, heat the air; the heated air spreads along the path of the fire channel to the surroundings, during which the ground brick is heated, using the heat storage of the floor tile itself and the law of heat radiation upwards, so that the heat is conducted from bottom to top, so as to maintain the warmth of the room; after heat dissipation, the air temperature is reduced, and a small amount of smoke and dust in the charcoal fire is discharged from the smoke outlet.
The Forbidden City's underground "Centipede Road"
The principle of the Forbidden City ground fire includes three processes of heating, heat transfer and heat dissipation, of which heating, that is, the process of burning charcoal to form a heat source, is entered by the eunuch into the outdoor operation port and burned charcoal in the furnace chamber under the interior. The position between the furnace chamber and the operating port is the coal feed port, which is composed of an iron grate and a furnace door. Cast from pig iron, the iron grate has a larger cross-sectional size of the frame, with both ends fixed to the wall and the upper part supporting the wall under the sill window. The iron grate is good for preventing people from drilling into the room from the operating port.
When the furnace door is closed, the heat source is prevented from spreading outward. The upper part of the furnace chamber is made of iron frames, also made of cast iron, mainly to increase the strength of the support to bear the weight of the upper floor tiles and to withstand the high temperatures generated by the burning of charcoal. When the operation port is not in use, it is covered with a thick wooden board, which prevents small animals from burrowing in and facilitates the walking of the palace personnel. The eunuch stands in the operation mouth, can see the room through the window, which is convenient for communication with the room, increases or decreases the charcoal fire in time, and ensures that the indoor temperature is appropriate.
After heating, it is heat transfer, and the heat generated by burning charcoal spreads underground to the room, and this flue is called the main flue, and then spreads to both sides, which is called a flue. The distribution of the main and branch flues is like a centipede, so it is also commonly known as the "centipede road". Because the heat is from the bottom up, the fire source position is located at the lowest point in the room, and when the main flue extends from the fire source position to the room, its height gradually rises, and the profile is sloped. This allows the heat to spread more quickly to distant locations. In general, the main flue section is larger in size and covered with a layer of floor tiles; the section of the flue is small in size and has a buckle tile on it. In order to facilitate the spread of heat underground, the floor tiles of the main flue and the tiles of the flue are laid overhead. On the gray soil (rammed earth) erected a number of brick support piers, the ground bricks on the support piers, the seams between the surface bricks with mortar smeared tightly.
After heat transfer, it is heat dissipation, and the underground heat spreads through the main and branch flues to various locations under the interior and underground, and then discharges to the outside through the smoke outlets on the side wall of the outdoor base. Since most of the heat generated by the fire source has been diffused indoors and underground, very little heat is discharged from the smoke outlet.
The smoke outlet is equivalent to the "chimney" of the Forbidden City building, which cleverly discharges the smoke through the outdoor pedestal, which does not affect the overall appearance of the building, but also plays a good smoke exhaust effect. This practice can explain the saying that "the Forbidden City burns charcoal in winter for heating, but there is not a single chimney" (there is a chimney on the back façade of the Khun Ning Palace, which is the passage for shamanic sacrifices to exhaust smoke, which has nothing to do with winter heating). In order to avoid small animals from drilling into the indoor underground from the outlet, the outlet is often paved with hollow brick carvings with copper coins to achieve a practical and beautiful effect.
"People have short winter days, I love long winter nights"
Despite the cold outside in winter, the Ming and Qing emperors who used the fire felt very warm and comfortable. The History of the Ming Palace, written by the Ming Dynasty scholar Lü Yi, volume 1 contains "Mao Qin Dian, the Emperor of the Heavenly Revelation built the kang here, Heng Lin Xingzhi"; volume 4 contains "(indoors) full of food and living, nothing to do". It is described that the emperors of the Ming Dynasty liked to go to the interior with a fire in winter, and in the winter night, the heat provided by the fire made the room warm and comfortable. The Qianlong Emperor of the Qing Dynasty wrote in the poem "Winter Nights Are Occasionally Formed": "People suffer and winter days are short, and I love long winter nights... Knocking on the poem does not feel cold, leaking forever in the night. Because of the warmth of the room, the Qianlong Emperor actually liked the long winter nights and expressed his happy mood through poetry. The Daoguang Emperor wrote in the Complete Collection of Yangzheng Bookstore: "The fine cloth of the flower bricks is good at strange work, and the dark and hot pine branches are baked underground." Meditation is only suspicious of spring, and when you close your eyes, you often feel that your body is flushed. He sat in the warm room, feeling the melting warmth coming from the ground, praising the exquisite layout and excellent heating effect of the fire.
Jin Yi and Shen Yiling's "Records of the Palace Women's Talks on the Past" review the history of the Forbidden City in the late Qing Dynasty from the perspective of the palace maid He Rong'er. The chapter "Hand Paper and Official Houses" records the heating methods of the Forbidden City buildings in the Qing Dynasty: "Thousands of houses have no chimneys. The palace was afraid of fire, and it was not allowed to burn coal, let alone burn chopped wood, and all burned charcoal. The palace buildings were all suspended, like the current buildings with basements. In winter, iron ruts (iron trains), charcoal is burned, and the basement is pushed into the basement for heating, and people in the house are like on ondol. This passage not only confirms the heating method of the fire in the Forbidden City, but also reflects that the fire has a good heating effect.
Slightly aromatic red charcoal
The fuel used for fire heating in the Forbidden City is mostly red charcoal, which has excellent texture, produces high heat and smoke, and has a slight aroma. Volume 16 of the "ZhizhongZhi" (内府衙門知 palm) records the origin of the red charcoal: "All those who use red charcoal in the palace are fired from the mountains around Yizhou, transported to the red kiln factory, sawn off according to the size, woven into small round thorn baskets, and served with laterite brush baskets, so the name 'red basket charcoal' is also known." Each root is about a foot long, the round longitude (diameter) is two or three inches, the air is warm and durable, gray and white without explosion. This passage shows that the name of red charcoal comes from the fact that the charcoal is placed in a basket coated with laterite pulp, and the charcoal is produced in Yizhou (present-day Yixian County, Hebei), made of mountain hardwood, transported to the red basket factory (near the Dahong Luochang Street in the xicheng district of Beijing) for preservation, and is processed into small sections about 1 foot long; the red charcoal does not burst when used, and the heat is sufficient and long. In the poem "Ballad of Fire" composed by the Qianlong Emperor, there is a description of "the earth furnace is sharp and the temperature is plucked, and the white gray and red charcoal can be a friend". Here "榾柮" refers to charcoal, and "黁" refers to aroma. It can be seen that the Qianlong Emperor greatly appreciated the excellent material properties of red charcoal.
According to volume 17 of the "History of the Palace of the State Dynasty" compiled by Ertai and Zhang Tingyu of the Inner Court University in the Qing Dynasty, due to the scarcity of the amount of red charcoal, its supply quantity has different regulations according to different identities in the palace: 40 jin of the empress dowager, 20 jin of the empress, 15 kg of the imperial concubine, 15 kg of the noble concubine, 10 kg of the concubine, 8 kg of the concubine, 5 kg of the nobleman, often in nothing, promised no, 5 kg of the prince (princess), 10 kg of the crown prince Fujin, and 10 kg of the prince's side room Fujin. In addition to the supply of red charcoal in the palace, there is also black charcoal, and black charcoal can be used when there is no red charcoal ration or when the red charcoal is not enough.
According to the "Hand Paper and Official Room" chapter of the "Lady of the Palace", the charcoal ash produced by the burning of the red charcoal was collected and used for the liner in the toilet and bedpan.
Author Affilications:Palace Museum