As we indicated in the previous post, in this one we will talk about the positioning of the extractor and details to be taken into account for the system to work properly.
It is possible to extract moisture directly by placing an opening to the outside in the lowest part and placing the fan directly (the coldest and most humid air tends to be in the lower part of the room), but in my case, being a ground floor in contact with the mountainside, I had to bring the humid air from below to the top, so I used 90 mm diameter PVC pipe, with a fan connected to it in the lower part.
Another advantage of using a tube is that, by extracting the air away from the outlet, we can leave the gap between the hole and the tube open and the outside air will enter through it, without the need to open another hole. It should be borne in mind that the gap should not be too narrow, or the flow rate will be reduced as the air will have a lot of resistance in its movement.
If we do not have a ventilation holeas was my case, we will have to do it. We have two options; either call a professional who will make the hole with a glass crown in a moment, or with a cheap electric hammer, after delimiting where we wanted it to appear on the inside, we measure with reference to something visible on the outside (a column, wall, etc.), we mark the area and drill. It is very important not to perforate any of the main columns of the house..
Materials for pipe laying
Depending on your needs, this can vary a lot; for example, we can replace the PVC pipe with any other durable material that is somewhat resistant to the passage of air. In my case I have needed:
- An exhaust fan/exhaust fan or fume extractorWe can use one recycled from an old kitchen extractor fan, or one from a large computer. Keep in mind that the greater the distance and the larger the room, the more power and size must be in accordance. In this case we are dealing with a room of 30 m3 so a 10W is sufficient. Noise is also very important; the less dB it emits when operating, the better. Ideally, it should be placed outside, out of the rain.
- 3 m of PVC pipe, 90 mm diameter. Available in construction warehouses.
- 2 elbows or bends PVC 87º diameter 90 mm. for the breaks.
- An eccentric reduction from 110 to 90 mm. to position the fan connected to the pipe.
- Galvanised perforated Apollo tape to fix the tube.
- Screw anchors and plugs of the size required for the size of the holes in the Arduino grid and box.
- And the necessary tools; electric hammer; cable, adhesive tape, crosshead screwdriver, etc.
Let's get to work
The first thing to do is to open up the passage for the pipe at the bottom of the wall, but where we have no water problems that it can enter (by placing it a few centimetres higher), or with the humid air when leaving, and that it cannot be blocked in the future.
It is important to check that there are no electrical, water, gas or any other type of conduits in the area. to drill the hole. Metal detectors are available to check this, but it is best to examine adjacent areas to see if anything could pass through the site. And if in doubt... probe very carefully.
After a couple of hours of effort (it was 50 cm of concrete), drilling inside and outside, we chopped the area until we had a hole free enough to place the pipe. A tip: These hammers are not very strong; to advance more quickly it is convenient to use the flat pointer and not to sink it, but to go removing small pieces; it will help us to begin with the widest to be able to work loosely.
The next step is to lay the tube. I have used recycled pieces I had in the warehouse to assemble it; in total 3 mts. of pipe. The one we put towards the outlet is important that it protrudes a little to cut it just flush with the lid or grille, so that it is connected directly to the outside.
Normally the parts are so tight that no need to use glue to fix them to each other (a small gap of a few tenths of a millimetre will not affect performance), making it easier to fit it and to release it in the future if necessary.The tube placed on presentation still unmoored
Perforated galvanised tape is usually used to fix it, it is well fixed and allows flexibility of placement. You can also use a wire, or whatever you can think of.
Once the pipe is in place, which will extract the humid air from the lower part of the "storeroom", We proceed to attach the box with the Arduino controller to the wall. where it is visible so that its status can be verified:
The fan has a power cord with a plug, and to activate it with the relay, I had to connect another wire to one of the poles, so that when I connected it (closing the circuit) the fan would start up.. We can connect it by accessing its junction box, as I did, or we can do it directly by cutting the power cable.
Attention: It is important to take safety precautions when working with voltages above 50V.Make sure that the cables are unplugged from the mains when carrying out any manipulation.
If several devices are to be connected, we will need a power strip with several socketsI screwed one to the wall for the occasion.
To conclude, it is important to place a filter or mosquito net. to prevent small insects from entering the room through the ventilation hole (being at a low height, they can enter too easily); I have stuck a piece of mosquito netting with silicone.
On the outside we cut the tube flush with the hole. In the photo you can see where I originally placed the external sensor, which I changed to another position later as it was partially in contact with the indoor environment and the values were not quite correct.
To give you an idea of the effectiveness of the extractor fan, on the first day it was running for several hours at a time, and the stones on the floor that were hit by the air became damp:
To get the most accurate values possible from the external sensor, I made a small opening in the wall.I placed the sensor base glued with the hot-melt glue, and it will be covered, as we have seen in the picture at the beginning, by a smaller grid.
I hope you found some of these ideas useful, I look forward to your next visit my dear readers!