Archaeologists in Basel have uncovered an exceptionally rare medieval heating system hidden beneath the remains of a former monastery for centuries.
The exceptionally well-preserved hot-air system was discovered during archaeological work at Petersgraben 52, at what was once the refectory (or dining hall) of the Gnadental Monastery. Experts believe the installation dates back to the 13th or 14th century and say discoveries like this are extremely rare in Switzerland.
The sophisticated system was based on an underground stone chamber filled with fieldstones that could absorb and maintain heat. Under this was a fire channel constructed from stone blocks and bricks. Archaeologists also discovered two pointed arches that remain in their original positions.
When a fire was lit, warm air entered the chamber and warmed the stones. The heat was then channeled upward through eight openings in the ceiling that could be opened or closed to regulate the flow of warm air into the dining hall above.
Smoke produced by the fire was allowed to escape before the heated air entered the room, enabling the system to warm the refectory primarily through circulating hot air. The design demonstrates a surprisingly sophisticated approach to indoor heating during the Middle Ages.
A glimpse into medieval life
The Gnadental Monastery was founded in the 13th century, when the site stood outside Basel’s city walls. Its buildings were subsequently occupied by several monastic communities.
Following the Reformation, the monastery complex gradually disappeared, leaving relatively little visible evidence of its former structures. The latest discovery therefore offers archaeologists valuable new information about both medieval architecture and the technologies used to make large communal buildings more comfortable.
The remains were uncovered during excavations connected with the construction of the new University Library in Basel.
Researchers have documented the heating system using conventional archaeological techniques while also producing a detailed three-dimensional model of the structure.
The digital reconstruction will allow specialists to examine and measure the system long into the future, even if parts of the archaeological remains eventually have to be covered or removed as construction proceeds.
Authorities are now examining how the unusual medieval heating installation can be preserved for the long term.
Sources : Magyar Hirlap
