Bio Building

Chimney, how it works


How does a flue and how is it made? In the article dedicated toventless stoveswe have seen that this element has been replaced by a structure only a few millimeters long, as well as the devices mounted on these stoves, there are alternatives to flue. Let's see what it is.

What is a chimney for
Some heating or cooking systems are equipped withflue, it is a vertical structure suitable for discharging the fumes produced during combustion. Therefluecollects the fumes produced by the combustion chamber and takes them outside through the chimney.

How a chimney is made
To allow the passage of smoke, it must develop - compatible with the building structure - as vertically as possible. Although externally thechimneyto us, the internal section of theflueit is circular; a vertical section favors the formation of vortices designed to convey the hot air outside. The diameter of thefluemust be strictly proportional to the type of heating system (or cooking): the calculation of the right section takes into account the power of the firebox, the length of the barrel and the presence of any curves, even the geographical altitude and the prevailing temperatures can play a role in determining thedraftof aflue. To give a practical example, in order to optimize the draft, between a mountain home and one at sea level, the section of theflueof the first must be 50% higher than the one implanted above sea level.

In order to make thefluemore efficient, this must be well insulated so as to prevent the fumes from condensing before reaching the chimney: the water vapor, mixed with soot and residues from combustion, forms creosote, a sort of tar that encrusts the barrel reducing it in section , onefluewell insulated, it minimizes this formation, avoiding any risk of fire.

Thechimneyis the terminal part of theflue, this structure also plays a decisive role: it protects the inside of the system from wind and atmospheric agents. The chimney pot may differ according to the needs, in fact the shape of the cap is chosen to disperse the fumes even in the presence of strong winds; an efficient chimney has a double section compared to that offlue.

As seen with flue-less stoves, or if it is impossible to install a chimney pot (buildings that are too high and landscape or condominium constraints), you can have blocks that are then plastered after drowning a reinforcement mesh.


Video: How to not use a Charcoal Chimney Starter (October 2020).