Forced-air
A warm air heating system is heating, which keeps the heat generated without intermediate support and distributed in a building as warm air. Heat transfer is the air that heats the heater and as warm air plants with less than using gravity circulation ( warm air is lighter and rises - cold air is heavier and sinks ) is moved in larger systems using fans.
The warm room air ( exhaust air) is guided in admixture with outside air through a filter which retains any dust and odors. After air heating, a safety ensures that the system disconnects the heater temperature is too high. About adjustable supply air return air and outdoor air dampers, the room air is mixed so that it corresponds to the instantaneous requirements in terms of the amount of heat and air quality.
The air channels have been built earlier Eternit plates; today come from galvanized sheet steel made air ducts used primarily as a pipe ( spiral-seam ), for larger systems rectangular channels are used.
Since air as opposed to water heat stores very bad, the warm air heating in housing only for small heat output is suitable (for example, holiday bungalows ) and seldom used rooms. Accordingly, it is drawn in low-energy homes in consideration when heating capacities up to 10 W / m² suffice. In Central and Northern Europe, with its relatively cold winters, the warm air heating is of only limited use in the U.S., especially in the southern states, these heating but could spread.
History
In an archaeological excavation in the area of the Imperial Palace Ingelheim was 1997, a warm air heating of 12-13. Century are exposed. The heating system was south of the Throne Hall (Aula regia) found. This finding is in addition to references to plants in the Imperial Palace of Goslar ( ground floor of the Hall building, around 1180 ), the Dankwarderode castle in Braunschweig ( ground floor of the Hall building, around 1160 /70) and the Neuchâtel on Freyburg (13th century ) of the hitherto oldest evidence of such a heating system dar. Probably the heating type in Central Europe was preferred for the functional space type of the Knights' Hall (also: Hofstube ) used a single-storey, hall-like meeting room on castles.
The technical structure of the warm air heating of Ingelheimer example is divided into the functional areas of the combustion chamber, furnace shell and warm air ducts. The combustion chamber was supplied from the south side through an opening with combustible material, emptied and cleaned. In the Sandsteingewände the opening anchoring holes of an iron furnace door are still visible. The furnace walls were made of cup tiles that were layered in dense intervals in clay. This type of construction is reminiscent of stoves, which can be found on some pictures of the late Middle Ages. The dating of the furnace in 1200 founded in the form and type of goods this mug tiles. The furnace shell was sealed with clay and surrounded the oven on three sides. The fourth wall was the apse of the Aula regia. This design made it possible to save the furnace heat, even long after the end of the burning process. Through openings or channels could then be passed smoke-free to a port situated on the oven housing.
As the warm air heating on the shape, size and state of preservation is a unique technology historic monument, it was preserved permanently in 2000 by a shelter and made accessible.
A much younger, historical warm air heating is working properly visible to this day in the Villa Hügel in Essen. Krupp himself has designed this for his home, but the difference to today's systems is enormous. For example, a several hundred meter long shaft for the supply of fresh air of a space charge, which takes over the function of the heat exchanger.