Tales from a Ventilation Lunatic

[sternwake]

About time weirdo overlord took the hint 

I should get a new gooseneck for my 92mm delta fan, mine tries to return to straight.  Its just worn out but I can still aim it most everywhere by moving the spring clamp around.  This fan is also powerful at higher voltage that it can push itself backwards against the gooseneck's position


I forget what kind of threaded fastener those professional microphone goosenecks take, I think the diameter is 5/8, not sure on thread count.  Mine is in my workshop holding the screaming banshee aloft but I do not know how much longer I will have workshop as the termites might decide to stop holding hands on it soon and the property owner wants to rip it down.


A long while back I used to simply place a fan in my screened conversion van slider window, much like blanch's bathroom fan.  I found that a significant portion of fan's flow was  making a loop, and being recycled through the fan time and again, so while the fan could move say 100 CFM, perhaps it was only forcing 50% of this flow into the van.  I wanted 100% air displacement or as close as possible to this.

At first I made a thin plywood shroud with  two 120mm cutouts and one 180mm cutout for three fans.  While I painted it black, the plywood, even though a marine plywood, did not like the moisture cycling. and the outer black painted veneer peeled off on the exterior after 2 years or so and took on a damp plywood smell that would assault me when I opened the door

I replaced it with 1/4 inch acrylic/plexiglass shroud,  and painted that flat black.

The 180MM fan, currently, is the silverstone fm181, rated at ~165CFM, it has its own speed control built in.  I mounted the speed control potentiometer on the fan itself.  The following pic shows a spiral grate/grille on the 180MM fan.  This is from the silverstone AP182, a  higher RPM fan, whose airflow rating was suprisingly not much higher despite its 1.3 amp draw at max speed(2000 rpm), vs the 0.29 amp draw of the fm181 at max speed (1300 rpm). 

 Anyway the AP182 did not like battery charging voltages at max speed, the hub would get stinky plastic hot.  I put a voltage bucker inline on it to limit it to 11 volts after the stinky plactic hub was noticed.  That one overheating, and  salt laden moisture caused corrosion on the circuit board killed the fan in about a year and a half.  They'd doubled the price of the AP182 fan in the interim, so I got the fm181 instead for ~25$.  I cut off the spiral grille of the failed ap182fan and installed it on the FM181 as a fingerguard.

The two  silverstone fans mentioned above, are unfortunately, white. I removed the impeller and painted them black so they could not be easily noticed from outside.  This requires a special tool to release the hub, and the paint if done sloppily can throw the impeller out of balance and cause vibration and more noise.
  Thankfully the new industrial Noctua's are black body and impeller.

Anyway here is the 3 fan shroud in my driver's side rear conversion van window. I have my mattress lifted for this photo, and my black out window panels in place.  The bungee cords are usually employed in how weather to hold my pillows during the day and keep the sun's heat from radiating to the interior.

With these 3 fans on medium high, I can turn off my ceiling fans, and the uppermost fan will keep spinning from the flow of these 3 other fans pushing air into the van. This could never happen without the shroud on the intake fans.   That is with the side door cracked  one vent open up front, and it is not as if my door seals are in good condition so I think this is a testament to the efficacy of the intake fans in the shroud in terms of air displacement.

I am really liking the industrial Noctua fans.  Yesterday, I kept going into the van in midday and lowering the speed of all three intake fans until i stepped in the van and it was noticeably hotter inside than out.  the crossing point was just below 1/3 of max speed on all three fans with ceiling fan combo at ~75% speed.  It was 85F ambients parked in direct sun. I did not take amp measurements, but the 5 fans together were likely around 0.65 amps to keep the interior at ambinet temps with all window shades in place.

So  A fan in a window/opening is good, but a shroud around the fan so that the air pushed out from it cannot do a quick 180 degree Loop and go through fan again, means it is near 100% air displacement and much more effective at exchanging air and thus keeping the interior cooler and with speed controlled fans can be done for less noise and amperage consumed to do so.



All three of these fans are individually switched, the Two Noctuas are controlled by the same speed controller.  I can slide the window open  enough for 0, 1, 2, or all three fans depending on required/desired airflow.  Even when cool at night I still like fresh air exchange and using more blankets and will leave the window open enough for just a portion of the 180Mm fan, but might not have the fan on.  The ceiling fans can pull fresh air through the intake fan shroud.


My ceiling exhaust fan/mushroom vent combo will be a future post in this thread, although improvements can and likely will be made to it at some point.  Unfortunately the Noctua industrial fan did not like a counterrotating feeder fan like the silverstone fm121 fan does.  The Noctua has the same airflow rating as the SS fm121, but more than  twice the static pressure rating.  It might on its own be as effective as the fan combo I now use, but i have no easy way to actually test that, and for now further improvement is not required.

What is neat is the Noctua industrial fan  nf-f12 3000 rpm fan only draws 0.3 amps at max speed, the silverstone at max speed  and airflow in an unrestricted environment, draws 0.4 amps.  But the Noctua in a restricted environment in front of fan should be able to move 2x as much, for 25% less amperage consumed.

Those wanting to add a very simple speed control to a computer fan can use a PWM motor speed controller or LED light dimmer. The issue is the frequency of the controller needs to be 21Khz or higher or it is likely the fan will make a whining sound at reduced speeds.

Here is a 21 Khz motor speed controller capable of handling 15 amps I had previously bookmarked

https://www.amazon.com/Controller-Adjust...35&sr=8-35

There are other cheaper smaller versions capable of about 8 amps, but do  keep in mind the 21Khz factor.

Controlling the speed via voltage instead is what i have done to the 92mm delta fan, but wasy speed changes require one desolder the provided potentiometer which requires a precision screwdriver to adjust and solder in wires to reach a fingerturn potentiometer, and one loses 1.2 volts on the top end and thus the fan will not run at as high a speed when desired, while the PWM motor speed controller will still allow that top end rpm and requres no soldering.  My voltage controller is good for only 3 amps max and that is likely with extra heatsinking.

[sternwake]

My 92MM interior circulation fan's blades got their second cleaning today. I noticed that since Fiona the furball moved in, that dust has been building up quicker.

Unwilling to committ to a permanent location, I used some Velcro and remounted the soeed control potentiometer on the fan hub. I used some more velcro and lined the perimeter of the 92MM fan on the intake side.

I removed the fingerguard grille and used 3.5 inch deck screws, tightened by hand into the screw holes on the corners, then I wrapped these screws with a filter sock i made from charcoal filter material. i used a paper stapler to size it and close the ends. This filter is not so restrictive that it noticeably restricts airflow.

I have had it running for less than 12 hours and I can swear i can already see it loading with dust/lint/and Fiona fur/dander. When she shakes, I reach over and crank the speed upto high. 150 CFM and ~450 Cubic feet in the whole van, if it were empty it should oin theory clean the air inside of dust and lint pretty quickly..

I set up a similar filter a while back but quit using it. I had used rubber bands insead of velcro to hold the filter material to the fan. but the velcro is way better, and cleaning it should be pretty easy.

The filter sticks about 8 inches behind the fan blade, but I really wanted the filter back. I can tell there is less dust floating around. Probably a lot healthier not to be inhaling all that dust/lint/dander.

Pics to come.

[Matlock]

Great to see this post. I assembled the Silverstone 180mm version and really like the included speed control and low amp draw. I have need of a smaller assembly and purchased the 3000 RPM Noctua about a year ago and components to build a diy controller (been in a box for awhile). Now that I see your link for the PWM controller I'll go that route.

Nothing beats a good DIY fan assembly, and for me, volume, amp draw and noise are priorities. I just clicked the checkout button and wanted to say thank you.

Richard

[MN C Van]

Did you try one of the DIY heat exchangers?

Similar to 4" PVC w/ 3" alumafoil vent inside-

[sternwake]

Here is my internal circulation 92MM delta fan on the gooseneck, clamped to my cabinet.



The Filter is a recent addition. I vaccuumed it today and is got several shades darker having collected a disgusting amount of dust in the short time it has been employed.

The Speed control potentiometer is now velcroed to the hub and is much better than having it ziptied to the gooseneck. Dialing in the lower speeds requires a really fine touch. A 10 turn potentiometer might be overkill, but a 3/4 turn potentiometer really requires a lot of finesse to dial in the low speeds. as OFF to minimum speed represents about a 10 degree turn on the dial, out of 360 degrees.

Very much digging the filter, as this furball has added a huge dust load to my living quarters:


I forget which product I ordered for the carbon filter. I mostly got it for the black color. When new it will discharge black dust when brushed. Not sure mine is doing any charcoal style filtering/neutralizing anymore.

It sticks well to velcro, i use a portion on my intake fans in my conversion van sliding window. It blocks 95% of light from entering or exiting. It is exposed to the elements outside and hangs on at highway speeds without issue.

https://www.amazon.com/s/ref=nb_sb_noss_...r+material
When new it changed the smell of a passing skunk. I remove it when max airflow is required. Supposed to reach 98f here tomorrow. It is removed.

[Cammalu]

Clean and happy dog!


Sent from my iPhone using Tapatalk

[Putts]

I imagine a tour of Sternwake's van as answers to a fairly long series of "What the fuck is that thing?" by the tourist.

[Ballenxj]

Here is my internal circulation 92MM delta fan on the gooseneck, clamped to my cabinet.

Very much digging the filter, as this furball has added a huge dust load to my living quarters:

Fiona looks very at ease and comfortable. Happy Dog.  
Your filtration setup looks very simple, a fan blowing through a filter? Even I can understand that principle.  
Thanks for posting this and that in a fashion that even us Dummies can understand.  
Question, do you simply turn the filter sock inside out and rinse with water when it needs cleaning?
Edit, since this is a charcoal filter you probably just replace. I'm still working on my first cup of coffee this morning.

[sternwake]

The fan is actually pulling dust into the filter, not pushing it into the filter.  It is important to not present too much restriction to the fan, and my filter being about 8 inches long behind the fan does not seem to affect airflow at all, nor does it widen the column of air sent from the business end of the fan.


I have used my buckethead shopvac to clean it in place, but could detach it and run some water or compressed air through it.

It is rather impressive how quickly it is loading up with dust.

[sternwake]

One of my Noctua industrial fans failed today. II was sitting nearby and smelled the burnt electronics smell and than saw the fan spin down and cursed.

Looks like the microprocessor overheated.

Only been in operation since mid september last year, about 7 months, and certainly not turned on the whole time.

While I voided the warranty by cutting the wires adding an inline switch, I still sent Noctua an Email with a photo showing what I believe is the failed component. Perhaps they will make it right.

I returned an older fairly powerful fan to Duty, but it has no speed control.

Rare that I need to run all three intake fans anyway.