Condensation in the Ventilation of a Private House or Garage.
Condensation in the Ventilation of a Private House or Garage.
Hello.
Let's say the air in our bathroom has the following parameters:
Air temperature + 25 ° С, we mark the corresponding straight line on the diagram;
Relative air humidity 70%, mark the corresponding curve on the diagram;
Place point 1 at the intersection of these lines.
Knowing a specific point on the diagram, we can determine the remaining parameters of our air, such as moisture content (this is an absolute parameter, in contrast to relative humidity).
To do this, we lower the vertical line from this point to the intersection with the d axis (moisture content).
... It turned out about 14 grams of moisture in a kilogram of dry air.
In each particular case, this parameter will be different, but having a thermometer and a hygrometer, you can apply the corresponding point yourself and find out the absolute moisture content.
The formation of condensate in the exhaust ventilation system usually occurs in rooms with humid conditions and high temperatures: kitchen, bathroom, laundry room, etc.
Waste moist, but relatively warm air, passing through the air ducts towards the street, where the air temperature is lower than in the room, gradually cools.
Since the moisture content of the air remains unchanged, the cooling process will occur along a vertical downward movement in the diagram.
If the air was heated, then we would lead the line up.
But we lower the vertical line from point 1 to the intersection with the 100% relative humidity curve (maximum), put point 2 there and see that this humidity parameter occurs at about +19°C.
According to the formulas, you can calculate more accurately, but that's not the point.
This means that when the air from our bathroom is cooled to this temperature or below, the air can no longer hold moisture.
This point 2 on the diagram is the “Dew Point”, and it is relevant for certain humid air with a specific moisture content.
Imagine, only six degrees (from +25°С to +19°С) will cool the air with these parameters and condensation in the ventilation duct is inevitable.
Do you think this situation is real in winter?
More than sure.
And if the parameters of the air in the room have an even higher temperature and moisture content, then the situation will worsen even more.
The air is cooled down to its dew point temperature and the moisture automatically and inevitably condenses.
... And now tell me, which of you observed condensation in the exhaust ventilation system in an apartment in a multi-storey building, and not in the private sector?
Let's clarify the situation.
• Firstly, all ventilation ducts and chimneys pass only through internal warm walls.
Installation of these along the outer walls is prohibited by law!
Therefore, the exhaust air does not cool as quickly and the “dew point” in such conditions comes a little later.
• Secondly, a multi-storey building implies the presence of a vertical ventilation duct, and the higher it is, the greater the draft in the mine.
The minimum speed is regulated, therefore, the air is quickly removed from the system and also does not have time to cool to the critical temperature at which condensate forms.
But even if it does, the condensate will form closer to the outlet and it will be much less formed in the duct.
• And thirdly, the ventilation ducts are made of porous brick or concrete.
Naturally, during wet procedures, condensate may form in the ventilation, but it is immediately absorbed into the porous structure of the surface of the channels, and does not flow into the room so quickly.
And since the hood with natural circulation works continuously, that small part of the moisture that has been absorbed into the ventilation duct safely evaporates by the time of the next shower.
... But if we have a ready-made private one-story house, then the arrangement of a new insulated ventilation duct passing through the whole house and attic can become too costly and absolutely irrational.
It is much easier to put up with the presence of water in the ventilation duct and remove it through a steam trap, for example, immediately into the sewer.
Just keep in mind that drainage should be drained into the sewer system through a water trap to prevent unpleasant odors from the exhaust grille.
And you also need to take into account that if condensate does not form in the air duct in summer, then the water seal will dry out and smells from the pit will definitely appear.
In winter, there are usually no such problems, but in summer you need:
• or add water to the water seal;
• or use a water trap with a dry valve;
• or connect a steam trap to the sewerage system above the already existing, non-drying due to frequent use, water seal, as in my case.
For example, you can use a siphon for a shower tray bought a siphon for a bathtub.
It has a pipe for overflow, where I will remove the condensate from the exhaust ventilation.
Thank you for attention!
#condensation #StopCondensation #VentCondensation