Ancient Korea Use of the
ondol has been found at archaeological sites in present-day North Korea. A
Neolithic Age archaeological site, circa 5000 BC, discovered in
Sonbong,
Rason, in present-day
North Korea, shows a clear vestige of gudeul in the excavated dwelling (). The main components of the traditional
ondol are an
agungi (
firebox or
stove) accessible from an adjoining room (typically kitchen or master bedroom), a raised
masonry floor underlain by horizontal smoke passages, and a vertical, freestanding
chimney on the opposite exterior wall providing a draft. The heated floor, supported by stone piers or baffles to distribute the smoke, is covered by stone slabs, clay and an impervious layer such as oiled paper. Early
ondols began as
gudeul that provided the heating for a home and for cooking. When a fire was lit in the furnace to cook rice for dinner, the flame would extend horizontally because the flue entry was beside the
furnace. This arrangement was essential, as it would not allow the smoke to travel upward, which would cause the flame to go out too soon. As the flame would pass through the flue entrance, it would be guided through the network of passages with the smoke. Entire rooms would be built on the furnace flue to create ondol floored rooms. Ondol had traditionally been used as a living space for sitting, eating, sleeping and other pastimes in most Korean homes before the 1960s. Koreans are accustomed to sitting and sleeping on the floor, and working and eating at low tables instead of raised tables with chairs. The furnace burned mainly rice paddy straws, agricultural crop waste,
biomass or any kind of dried firewood. For short-term cooking, rice paddy straws or crop waste was preferred, while long hours of cooking and floor heating needed longer-burning firewood. Unlike modern-day water heaters, the fuel was either sporadically or regularly burned (two to five times a day), depending on frequency of cooking and seasonal weather conditions.
Ancient Rome and Greece ,
Province of Palencia (
Castile and León, Spain) The ancient Greeks originally developed central heating. The
temple of Ephesus was heated by
flues planted in the ground and circulating the heat which was generated by fire. Some buildings in the
Roman Empire used central heating systems, conducting air heated by
furnaces through empty spaces under the floors and out of
pipes (called
caliducts) in the walls—a system known as a
hypocaust. The Roman hypocaust continued to be used on a smaller scale during
late Antiquity and by the
Umayyad caliphate, while later Muslim builders employed a simpler system of
underfloor pipes. After the collapse of the
Roman Empire, overwhelmingly across Europe, heating reverted to more primitive fireplaces for almost a thousand years. In the early medieval Alpine upland, a simpler central heating system where heat travelled through underfloor channels from the furnace room replaced the Roman hypocaust at some places. In
Reichenau Abbey a network of interconnected underfloor channels heated the 300 m2 large assembly room of the monks during the winter months. The degree of efficiency of the system has been calculated at 90%. In the 13th century, the
Cistercian monks revived central heating in
Christian Europe using river diversions combined with indoor wood-fired furnaces. The well-preserved
Royal Monastery of Our Lady of the Wheel (founded 1202) on the
Ebro River in the
Aragon region of
Spain provides an excellent example of such an application.
Modern central heating systems The three main methods of central heating were developed in the late 18th to mid-19th centuries.
Hot air William Strutt designed a new mill building in
Derby with a central hot air furnace in 1793, although the idea had been already proposed by
John Evelyn almost a hundred years earlier. Strutt's design consisted of a large stove that heated air brought from the outside by a large underground passage. The air was ventilated through the building by large central ducts. In 1807, he collaborated with another eminent engineer,
Charles Sylvester, on the construction of a new building to house Derby's Royal Infirmary. Sylvester was instrumental in applying Strutt's novel heating system for the new hospital. He published his ideas in
The Philosophy of Domestic Economy; as exemplified in the mode of Warming, Ventilating, Washing, Drying, & Cooking, ... in the Derbyshire General Infirmary in 1819. Sylvester documented the new ways of heating hospitals that were included in the design, and the healthier features such as self-cleaning and air-refreshing toilets. The infirmary's novel heating system allowed the patients to breathe fresh heated air whilst old air was channeled up to a glass and iron dome at the centre. Their designs proved very influential. They were widely copied in the new mills of the
Midlands and were constantly improved, reaching maturity with the work of de Chabannes on the ventilation of the
House of Commons in the 1810s. This system remained the standard for heating small buildings for the rest of the century.
Steam , a noted engineer and authority on central heating systems in the early 19th century The English writer
Hugh Plat proposed a steam-based central heating system for a greenhouse in 1594, although this was an isolated occurrence and was not followed up until the 18th century. Colonel Coke devised a system of pipes that would carry steam around the house from a central boiler, but it was
James Watt the Scottish inventor who was the first to build a working system in his house. A central boiler supplied high-pressure steam that then distributed the heat within the building through a system of pipes embedded in the columns. He implemented the system on a much larger scale at a textile factory in
Manchester.
Robertson Buchanan wrote the definitive description of these installations in his treatises published in 1807 and 1815.
Thomas Tredgold's work
Principles of Warming and Ventilating Public Buildings, delineated the method of the application of hot steam heating to smaller, non-industrial buildings. This method had superseded the hot air systems by the late 19th century.
Hot water in
St. Petersburg had an early system of
hydrologic central heating. Early hot water systems were used in
Ancient Rome for heating the Thermæ. Another early hot water system was developed in
Russia for central heating of the
Summer Palace (1710–1714) of
Peter the Great in
Saint Petersburg. Slightly later, in 1716, came the first use of water in Sweden to distribute heating in buildings.
Mårten Triewald, a Swedish engineer, used this method for a
greenhouse at
Newcastle upon Tyne. Jean Simon Bonnemain (1743–1830), a French architect, introduced the technique to industry on a
cooperative, at Château du Pêcq, near
Paris. However, these scattered attempts were isolated and mainly confined in their application to
greenhouses. Tredgold originally dismissed its use as impractical, but changed his mind in 1836, when the technology went into a phase of rapid development. Early systems had used low pressure water systems, which required very large pipes. One of the first modern hot water central heating systems to remedy this deficiency was installed by
Angier March Perkins in
London in the 1830s. At that time central heating was coming into fashion in Britain, with steam or hot air systems generally being used. 1838 Patent Perkins' 1832 apparatus distributed water at 200 degrees
Celsius (392 °F) through small diameter pipes at high pressure. A crucial invention to make the system viable was the thread screwed joint, that allowed the joint between the pipes to bear a similar pressure to the pipe itself. He also separated the boiler from the heat source to reduce the risk of explosion. The first unit was installed in the home of
Governor of the Bank of England John Horsley Palmer so that he could grow
grapes in
England's cold climate. His systems were installed in factories and churches across the country, many of them remaining in usable condition for over 150 years. His system was also adapted for use by bakers in the heating of their ovens and in the making of paper from wood pulp.
Franz San Galli, a Prussian-born Russian businessman living in
St. Petersburg, invented the
radiator between 1855 and 1857, which was a major step in the final shaping of modern central heating. The Victorian
cast iron radiator became widespread by the end of the 19th century as companies, such as the
American Radiator Company, expanded the market for low cost radiators in the US and Europe. ==Energy sources==