Granted, I used a blower fan as instead of the box fan the canonical design uses.
Due to a series of unfortunate events, we've found ourselves with a reasonably clean basement. One of my wife's biggest complaints about the basement had always been dust. Dust from my very infrequently used wood-shop. Dust from the litter box. Dust from... well, dust.
The new basement seemed like a good excuse to take a crack at the dust situation and this design sprung into mind.
I built it with four 16x25 MERV 11 filters, some plywood, some 1x4s, some plumber's tape to hold the fan in place, and the aforementioned blower fan. I could have gone for a higher MERV rating, but I didn't feel the need to go super overboard. I can also crank the fan for multiple consecutive passes. That's the whole idea of the design after all.
The box itself is only held together with tape and the weight of the fan. Now that the basement is more together I might model and print some brackets to make the box more solid.
One cheap motion sensor plug later and the air down there is honestly pretty fresh
im curious why its so complicated. would taping a filter to both sides of a fan and turning it on be to much stress on the fan?
Having 4 filters in a box setup reduces the strain on the fan and allows for more airflow versus just a single filter. The larger surface area also means everything can run longer before the filters get too clogged.
feels like something that is perfect for 3d printing where all the filters could slide in with a nice cradle on top to fit a standard fan (how standard are box fans?)
The most common box fan size seems to be 20" which is also a super common air filter size so it works out pretty nicely. There's actually a handful of 3D printable frames on printables if you search for Cori Rosenthal
thanks.
You could absolutely print this, but going straight plastic seems wasteful. Theres also the size angle - this thing is big. Mixed material for stuff like this is where it's at IMO. Wood's cheap, won't be here for forever after I'm dead, and is pretty sustainable.
Speaking of which, I intend to design and print some brackets to hold the wooden uprights in place better. Right now it's just the tape holding things together.
But yes, you can more or less slap a single filter on the back of a fan though.
Sure, no one's stopping you from doing that, but it's gonna be less efficient and will put more wear and strain on your fan.
The principle behind the CR design is tipping the scale towards high flow, because when doing the CADR calculation between a low flow HEPA compared to a high flow design with "lower quality" filters often the high flow design wins out. Because of the probabilistic nature of particle capture (Brownian motion and electrostatic capture), you don't need a filter with super small holes to catch super small particles. So using a filter with bigger holes it turns out nets you so much flow, that the extra air changes results in cleaner air than the more restrictive filter.
So I would guess that a single filter would be too restrictive to be as effective.
More surface area = more air flow for a given fan.
which is why wood shops have done this 40 years before 2020.