I recently stayed in an apartment that didnt have central air so I created a corsi-rosenthal box since the smoke from the Canadian wildfires were so bad.
After 30 days of continuous use, with very minimal periods of it being turned off, this is what the filters look like!
It’s disgusting yet also so satisfying to see the filters get darker from debris, dust, and dirt.
Edit: typos
TIL about the Corsi-Rosenthal Box
It is by far the best air purifier you can get for the money.
I got MERV 13 filters to help with my kids allergies. Inside the house, perfectly fine, but once outside it’s sneezing and runny noses. It’s amazing.
Do you know how much power it uses?
the PC fan version uses 10W max
Techingredients just did a video on ceiling fan designs and realized that DC motors are vastly more efficient.
They also figured the cost savings to pay for the motor change, and it didn’t take long to pay off.
Hi, electrical systems engineer with an offgrid solar system powering fans I tested with meters signing in.
The typical fans you can buy in consumer stores are about 100W on average a little less on low aroubd 80w a little more on high like 110-120w.
They make more energy efficient fans, particularly brushless motor DC powered fans meant for marine boating power systems are incredibly energy efficient and quiet but they’re also incredibly expensive.
Also keep in mind consumer fans kind of suck compared to a true industrial fan which can take a lot more power for serious wind speed output which the Wikipedia for this device says improves efficiency of purification. You can get power tool industrial fans that run off dewalt tool type batteries that are low DC voltage but high amperage, they’ll be more powerful than typical consumer fans too but run out of juice battery wise within hours.
I personally like the 10-15watt DC fans with pass through USBC charging for personal cooling but thats not what were talking about.
I looked up a 20 inch box fan on Amazon and it was rated for 67 watts. I ran it almost 24 hrs a day(kids loved to mess with it) and didn’t notice it on my bill.
67 watts is 1.608 kilowatt hours per day. In California (one of the more expensive states for electricity), electricity costs $0.31/kwh. That would come to just under $0.50/day or $15/month.
Watts per hour isn’t a thing. Watts is already a measurement of rate. 67 watts, running for 24 hours, is 1.608 kilowatt-hours.
The rest of your math checks out, assuming no hidden “distribution” or “transmission” fees (like I have).
Thanks for the clarification. Fixed.
Been aware of the general idea for a long time, but had no idea that strapping HEPA filters to a fan has a fancy name.
You have to cut some cardboard and use tape too. After when your solution beat every commercial solution you are allowed to name it, just to be able to shame corpo easily.
from huppakke:
Someone posted a link to Wikipedia in the comments, came across their names:
Richard Corsi, an environmental engineer and the incoming Dean of Engineering at the University of California, Davis
Jim Rosenthal, the CEO of filter manufacturer Tex-Air Filters
take what you will from this, but it’s definitely not a stick-it-to-the-corp kinda thing
Yeah I was trying a joke. It still beat commercial alternatives which I fell is a Second good reason to give it a name.
“Corsi-Rosenthal Box” sounds like it’s some theoretical physics thought experiment, but no it’s some filters and a box fan.
Be tempted to build one of those for my shop.
I’m going to start talking in vague terms about my own designs for a “Corsi-Rosenthal Box” when I want to sound smart.
It’ll be great if anyone bothers to look it up.
I mean, it sounds like an Einstein-Rosen bridge.
“My Corsi-Rosenthal Box is designed to efficiently accelerate particles inwards. The particles are then ‘captured’ using a special filtering technique, and separated from the air molecules which are allowed through.”
It’s removing particulates though.
So you could call it and “anti-particulate vertical fluid acceleration device” maybe.
I thought it was for filtering weed smoke, designed by the famous grower and strain creator Ed Rosenthal.
Think it was a covid thing.
No word on ed being the rosenthal in question.
Someone posted a link to Wikipedia in the comments, came across their names:
Richard Corsi, an environmental engineer and the incoming Dean of Engineering at the University of California, Davis
Jim Rosenthal, the CEO of filter manufacturer Tex-Air Filters
Oh, that’s disappointing.
could be his brother
These have been around for a long time as DIY filters for folks, I remember seeing one of these on Reddit before comments were a thing.
Once upon a time Reddit drove you to interact with other websites instead of shitposting your best hot take about the title of the post someone else didn’t even visit.
Comments truly ruined Reddit
Long time ago I made my own activated carbon filter from plans I found online out of chicken wire, some duct parts, of course activated carbon, and pantyhose. got some funny looks when buying that last one, but it worked like a freaking charm.
custom filters are common in the aquarium hobby, lots of fun pipe fittings to play with
That a good idea ! Didn’t think about it.
well…
A 2022 study found the clean air delivery rate on the five-filter design was between 600 and 850 cubic feet (17–24 m3) per minute (depending on fan speed), costing roughly a tenth of commercial air filters.
hope you can keep up!
Yeah may be a little overkill
Now imagine that, but in your lungs. Yikes.
lungs are self cleaning, dirt just dosent stay in there it gets pushed out again by tiny moving hairs
… mostly into your stomach.
I have great news for you about what happens to the contents of the stomach!
dont worry they mix with the microplastics down there
I mean, yes.
But like, they have to, without the filter.
Some dirt gets pushed out and sum just stays
This is a great reminder to clean my computer fans.
I totally did not realize how much real science was behind these things. I mean this design is so simple and obvious, it seems like something I would throw together because it just looks like it “should” work. And according to the research I just read they are very efficient and effective. Super cool!!!
I think the science comes in showing that it does actually work. Like, this is so simple of an idea that I would be skeptical of if it would work if I had had the idea by myself. I’m glad that I live in a world where, if I had thought of this and wondered “is this a good idea, or am I just being dumb for thinking something so simple could work?”, I am able to go online and find information and guides on this and other diy filters
make sure you get merv 13 or higher for smoke. the filters get gross fast even with 8 but you can tell the difference when you breathe.
I have 2 to 4 of these going at all times and the 8s are full time and 13+ are periodic unless fire season.
correct me if I’m wrong but anything higher than MERV 13 has diminishing returns because of increased resistance. instead of going for increased MERV I recommend getting thicker MERV 13 because of their bigger surface area.
CR boxes rely on raw total air volume and increased ACH vs HEPA which relies on filtering as much air as possible on the first pass.
If you go for the 2” thick filters they breathe better and have more surface area.
Christ i wish we could get these filters in au at non-arserapey prices
I read that as “our-SER-uh-pee” at first. I now have a new adjective.
Say it in a pirate accent
Is that a portmanteau made from “arse” and “therapy”? Because I might be interested.
have you heard of the Ikea Starkvind filters? they’re a bit smaller but you can tape together as many as you want
Theres a way i bet. You just need the filter dimensions to match the fan on one axis.
Can you order from Alibaba?
You can make them yourself using felt, wire and glue. Might not be exactly as effective but better than nothing.
Post a new one for comparison.
You can eference the outer edges for a satisfying before/after.
Those start out white?? I think it’s time to replace mine.
Ya, they were brand new filters from the store. I bought them along with the box fan and duct tape.
This apartment doesnt have a HVAC system (just wall mounted AC unit) so it’s doing all the air filtration.
This is why I buy my HVAC filters in bulk 4 or 8 at a time and replace them every 3-4 months (less if there is smoke). The difference it makes in keeping the house clean is very noticable. I get very little dust accumulation except in my teens rooms because they leave their doors closed.
Hey, I have that same rug
It really ties the room together
Yeah, well, you know, that’s just, like, your opinion, man.
I have the same box fan
i have the same duct tape
Will all of you get out of my house?!?!
Nope, the air is good here. Have any beer?
I saw a couple left in the fridge. Will you grab more chips while you’re up, please?
Link? Used to have one like that but now I can’t find another one
Do you have the link for it? So we can all have one.
You’re not a true lemmy unless you own The Rug
Lemmy’s ‘Upvote Soup’?
I got it from my parents after they didn’t want it anymore, but I think they got it from IKEA
I really need to make one of these.
Good job, Captain Lovell. That’s some Apollo 13-level engineering right there.
Just doing my part ground control 🫡
Ok. I’ve been looking into this a lil and there are better options than a cr box.
Housefresh has been looking into this and they recommend the nukit tempest or luggable XL or another one - think it was a Canadian brand - as the cheapest total costs over time and lowest sound and most efficient purification. All of those use regular HVAC filters which cuts down on operating cost and are quite big which cuts down electricity and sound.
So recommend getting one of those for long term use, if you have the space for it.
There’s also an open source tempest that you can use a CNC for and customize to your liking with a script. https://github.com/opennukit/Nukit-Open-Air-Purifier/tree/main/Nukit Open Air Purifier-W(all) v1.0
I have an unfinished project to make a nukit with a power knob.
I got a cardboard proof of concept working but need to make my mark 1 out of plywood or something else.
Duct tape an electrical knob device to the front and call it a day?
Now it matches the rug & walls, though
Funny enough I cleaned that rug after first moving in (apartment was pre-furnished) and it looked clean for a whole day.
I feel ya. My house was miles away from the evacuation zone of the PacNW fires a little ways back, and the filters didn’t last the month. We wore masks with filters rated for smoke whenever we had to go outside, and sealed every external seam, hoping the firefighters could get it under control in time. Thankfully, they’re the public servants that actually know what that phrase means, and to the enth degree. I trust every one of them right alongside our Nat’l Park service members (rangers, et al), sight unseen.
When this nation’s collapse comes to your town, remember this simple rule, fellow US peeps:
Firefighters & National Park Service? Heroes of the people, through & through.
Cops, etc.? Shoot on sight (if that’s your chosen theme for the apoc, ofc.) 😅
Can you put a bag of ice in this for simple ac?
You would have to go out and buy ice, if you use your own fridge to make the ice you will have a net negative energy also just buy a cheap AC, it would save so, so much energy.
Oh, leaving the house? Yeah sorry i don’t put pants on anymore. Good call.
Just get the ice delivered from the local grocery store.
Oh, that’s an interesting idea, not too much different from a swamp cooler actually so ya I think it would work.
My question is, where would be the optimal spot for the ice/icepacks:
- Inside, at the bottom
- Inside, suspended in the middle
- Inside, at the top near the fan
