The principle of chimney smoke exhaust is that in buildings and structures (such as water towers) with unobstructed circulation space from the bottom to the top, air (including smoke) quickly diffuses along the passage or is discharged from the building due to the effect of density difference, which is called stack effect.

That is to say, the smoke must be discharged from the bottom up, especially the hot smoke itself has the property of floating up, and your current chimney exit is of course not well discharged downward. With the help of stack effect, indoor organized natural ventilation and smoke exhaust can be realized.

the result of the interaction between the hot pressing caused by the indoor and outdoor temperature difference and the outdoor wind pressure is usually the former, and the hot pressing value is directly proportional to the air density difference caused by the indoor and outdoor temperature difference and the height difference of the air inlet and outlet. This shows that the higher the indoor temperature is than the outdoor temperature, the higher the building is, and the more obvious the stack effect is. At the same time, it also shows that the stack effect of civil buildings generally only occurs in winter.

Extended information:

When it is used as fuel with wood, they form creosote deposits on the walls of the structure. The deposits of this substance will interfere with the airflow, and more importantly, they are flammable. If the deposits in the chimney are ignited, it will cause dangerous chimney fires.

The heater burning natural gas greatly reduces the concentration of miscellaneous phenol caused by natural gas combustion, which is cleaner and more effective than traditional solid fuel. Although in most cases, it is not necessary to clean the chimney every year, this does not mean that other parts of the chimney will not be in disrepair.

For a class of public buildings with a building height of more than 51m and residential buildings with a building height of more than 111m, it is advisable to set up a mechanical pressurized air supply system according to the requirements of "High Code". In some projects, natural smoke exhaust is used at the same time in the above parts, which leads to the difficulty of forming positive pressure in the smoke prevention stairwell when the mechanical pressurized air supply system and the natural smoke exhaust window are opened at the same time, and the smoke prevention effect cannot be achieved.

Baidu Encyclopedia-Chimney

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