Hypocaust

A hypocaust or hypocausts (Greek: ὑποκαίειν hypokaíein " including kindle, burn among them", of which: ὑπόκαυστος, ον hypókaustos, -on " blown from the bottom ( ὑπό ) / heated ( καυστός ) )" is a warm air heating ( Hypokaustenheizung ) when a solid body is flowed through by hot air, but in comparison with a radiator having a lower surface temperature. As a massive heat transfer especially floors or walls are used, but also massive benches or other components.

This form of hot air comes from the ancient Roman times and was first used in Roman houses then only in spas, later general.

Ancient construction

The construction consists of a kiln (Latin praefurnium ), a below- floor boiler room (Latin hypocaustum ) and deductions for the hot air and exhaust gas. The kiln was usually outdoors. The boiler was made at an interval of about 30 to 40 cm stacked about 30 to 60 cm high brick tower of square or round plate, which initially carried a larger cover plate. On this record, lay the great support plate on which the screed was applied. The entire construction of the floor was about 10 to 12 cm thick and required at least several hours if not a day or two until the complete heat penetration. The hot air from the heated space located under the boiler room flowed into the wall channels ( tubules ) that in this way the walls heated. Only then the air came out into the open. The Roman Caius Sergius Orata ( 90 BC) is considered the inventor in ancient Europe.

A further development for buildings with relatively low heat demand is the Roman duct heating.

A reconstruction there are, for example, in the Reiss- Engelhorn Museums in Mannheim, but also in almost every museum provincial Roman legacy.

Roman underfloor heating ( Roman Open Air Museum Hechingen -Stein )

Sudelfels at him

Tubules of the wall heater in the Terme del Foro at Ostia Antica

Copy in clean home

Reconstruction of the Roman Museum Schwarzenacker

Reconstruction of the bath in Carnuntum

Modern construction

Nowadays, one sees the same thing under a Hypokaustenheizung in principle. The air is not always a furnace, but also by means of solar energy, such as Air collectors, heated. Modern hypocaust are concreted for example as pipes in ceilings or brick directly as limestone walls.

Hypocaust be used as alternative heating. These have a larger surface area than a stand- radiator, thus they need for the same room temperature, a lower surface temperature (about 30 degrees Celsius ), which generates less convection. This quieter heat climate is perceived as pleasant and dries the air out less.

Since ancient times and still the Korean Ondolheizung the hypocaust is a similar type of floor heating.

In winter gardens a so-called " Hypo exchanger " system is sometimes used with the overheating problems or drafts can be avoided. In the warm air in the winter garden water evaporates ( irrigation water fountain or water), the Ascended moist air is exhausted at the highest point of the conservatory and passed through hypocaust pipes on cold ground. Where the water vapor condenses, and the liberated heat of condensation is discharged to the ground. The moist poor but not necessarily more cold air is then fed back into the conservatory to cool the winter garden in the circuit.