How can I fix problematic ventilation in the basement of the garage?
Hello! I have a question about reorganizing the ventilation of the basement garage. The size of the basement is 6x4x4 m around the perimeter of the entire garage, i.e. basement “exactly” under the garage. The point is this: Inlet and exhaust openings are located on one short wall. An extract through the knee through the FBS to the street, a length of about 3 m. With a manufactured and installed Khanzhenkov deflector (TsAGI) in the upper corner of the basement.
The inflow is also through the knee through the FBS and lowered by the ventilation duct in another corner to the floor, ~ 25-30 cm from the basement floor. This scheme is incorrect, because a “jumper” is formed and a stagnation area at the far corners of the basement. If you transfer, lengthening the inflow or outflow by the ventilation channel, you can get a diagonal pattern, but what is preferable to transfer, the inflow or outflow?
Assuming combined ventilation, extend the outlet and install an axial fan, although the deflector works fine, I checked it with smoke and a strip of paper, but on the extension duct, which is 6 meters, the ventilation will not work without coercion due to the local resistance of the channel.
If the inflow is lengthened in the same way, leaving the outlet as it is (natural), then there will be almost no inflow again, due to local resistance of the ventilation duct, or to install a fan on the inflow. The inlet and outlet diameters of 125 mm, there is no possibility to redo, as well as to transfer the outlet or influx in a building way.
Natural ventilation at such diameters and the calculation device does not work, but practically it is, probably due to the deflector, but there are stagnation zones in far corners.
When lengthening the influx according to the natural ventilation scheme, the ventilation duct will obviously have to be tilted “down”? although all-one will work extremely badly due to losses in the resistance of the channel itself. How to proceed?
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Good afternoon, Alexander.
The inflow depends on the maximum throughput of the channel and the traction force of the outflow. In your case, it is preferable to transfer the inflow, because the outlet is working and is already creating some kind of air movement. I would not advise touching it again. Inflow throughput with a pipe diameter of 125 mm. It is enough for a room with a cubic capacity of 48 m3.
To understand how the ventilation system as a whole will work, it is necessary to measure the air flow rate of the exhaust duct. You can act empirically, because the problem must be solved anyway. Transfer the inflow and see what is the outflow traction force.
If newsprint is noticeably sucked in, air circulates. If it slightly sticks to the hole, install an exhaust fan on the outflow, thereby increasing the flow of fresh air and the air exchange as a whole.
I recommend buying a fan with a humidity sensor right away. By setting it to a specific indicator, it will independently turn on / off without your participation.
I advise you to additionally read the articles:
1. Basement ventilation - here is the general information.
2. Plastic ducts - varieties with recommendations for choice. Useful at the stage of transfer of the inflow.
3. Instead of a fan with a humidity sensor, ducts are often installed, this solution is also suitable for you. Operating parameters and views are detailed in this article.
Good day, Alexey! Thanks for the answer! Actually, while I was waiting for an answer, I didn’t sit idle and through my speculative conclusions, intuition and technical education, it was the influx нил that lengthened the ventilation channel
Of course, a duct (axial) fan had to be installed in the inflow, as well as in experiments and also in the outflow. An influx of slightly lower performance. The deflector works when there is wind, and if not, the hood is without a fan, but then almost complete mechanized ventilation is obtained получается In general, I go through the options, there are not many of them 🙂
Regarding the device, I already thought that in order to at least evaluate in figures the difference between inflow and outflow, the question is in the solution.
As for the humidity sensor. In fact, you need to compare the air humidity “overboard” and inside, recalculate the absolute humidity here and there, and only then decide whether to ventilate this air or not. Electronics will be able to do this, otherwise you can “bring” more moisture than it is, and the basement walls have not yet been insulated, i.e. cold and dew point has not been canceled ...
1. Everything is clear here, but I can’t change anything in the construction way, or it will be very expensive.
2. I use plastic F125 mm “VENTS” fans also from this manufacturer VKO
As I understand it, I already need a mechanized inflow on a regular basis, therefore the ventilation duct of the inflow can be mounted “exactly”. In winter, the inflow fan must be switched on sporadically, except that I have an electric shutter for the inflow. With the hood (outflow) you will need to think.