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Big Ass Fan’s Clean Air System

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Re: Big Ass Fan’s Clean Air System

#71

Post by bluGill »

danans wrote: post #66
jessaustin wrote: post #65

Earlier quoted context omitted.

HRVs have been designed to exchange heat, and ERVs to exchange heat and moisture, but have either specifically been designed not to exchange virus particles? One wouldn't want to make any assumptions...

At least with heat recovery ventilators, the air streams do not mix at all. Unless the virus finds a way to penetrate the metal fins of the heat exchanger, it should be completely fine.

There are several different designs, some there is a mix of streams.

Most are sadly not particularly efficient overall, but still much better than leaving a window open.

Re: Big Ass Fan’s Clean Air System

#72

Post by Barrin92 »

craftinator wrote: post #68
Barrin92 wrote: post #32

Earlier quoted context omitted.

Those 3rd party studies seem like a pretty big joke >"The test unit was installed in the center of the test chamber with a blade height of 93” from the floor. The test chamber measured 10' x 10' x 10' (3m x 3m x 3m) and a microbial suspension was aspirated into the chamber. Air samples were taken from the test chamber once the unit was turned on, and then at client specified intervals (0, 5, 10, 15, 20, 30, 45, 60, 9…

> Test that thing in a restaurant or a hair salon with a dozen people continuously interacting in it and then test the quality of the air That's not how scientific studies work.

Of course not, scientific studies create artificial conditions so we can claim that overpriced fans are a magic cure for a virus. They should hire these people at Volkswagen, they'd make great emission testers and splendid scientists

Re: Big Ass Fan’s Clean Air System

#73

Post by theptip »

danans wrote: post #53
Tepix wrote: post #36

A german Max Planck institute is working on a DIY system for schools that will get rid of 90% of aerosols. It costs less than 200€ to build out of easily available parts. German link: https://www.mpic.de/4770837/eine-lueftungsanlage-fuer-schule...

The question with that system is: where is the replacement air coming from? To be effective for disease particle controls, it needs to come from outside, otherwise you'd just be sucking dirty air from the rest of the building into the classroom - or even worse: backdrafting CO2 and CO from any combustion appliances within the building envelope. You can achieve a clean air supply by opening another window in the class…

Is there a reason you can’t just recirculate through a HEPA filter? They capture viruses AFAIK. Seems easier than recovering exhaust heat and refilling from outside.

Re: Big Ass Fan’s Clean Air System

#74

Post by [deleted] »

irowe wrote: post #24
mplanchard wrote: post #15

We’ve got a beautiful newish library in downtown Austin, and they use Big Ass Fans in a number of the outdoor spaces, balconies, patios, etc., including the enclosed balcony in the children’s wing, with the brand name clearly legible on the fans. While it’s not something that bothers me, I do always wonder whether and how often they get complaints from parents about the word “ass” being there for children to potentia…

Big Ass is based in my hometown, and I've had a few friends who've worked there. They absolutely get a lot of complaints about the name and actively taunt people who are offended by it [1] Apparently they do have models without the logo that can get used in churches and schools, though. [1] https://www.kentucky.com/news/business/article44375274.html

[deleted]

Re: Big Ass Fan’s Clean Air System

#75

Post by Mengkudulangsat »

Slightly off topic; I've been reading about putting dispersal disinfectants like Tea Tree Oil [1] into ventilation shafts so they spread around the building.

Works similar to O3, but is safe around people. I'm wondering what sort of concentrations these dispersals need to be to actually make a difference.

[1] https://www.pathology.uwa.edu.au/research/microbiology/tea-t...

Re: Big Ass Fan’s Clean Air System

#76

Post by [deleted] »

irowe wrote: post #24
mplanchard wrote: post #15

We’ve got a beautiful newish library in downtown Austin, and they use Big Ass Fans in a number of the outdoor spaces, balconies, patios, etc., including the enclosed balcony in the children’s wing, with the brand name clearly legible on the fans. While it’s not something that bothers me, I do always wonder whether and how often they get complaints from parents about the word “ass” being there for children to potentia…

Big Ass is based in my hometown, and I've had a few friends who've worked there. They absolutely get a lot of complaints about the name and actively taunt people who are offended by it [1] Apparently they do have models without the logo that can get used in churches and schools, though. [1] https://www.kentucky.com/news/business/article44375274.html

[deleted]

Re: Big Ass Fan’s Clean Air System

#77

Post by mdorazio »

I genuinely don't understand how this is supposed to work in a real-world environment. Let's say someone near a fan is infected with Covid and sneezes. The airflow from the fan would then immediately push covid-containing particles around the space and closer to other people than if there were no airflow at all. Is it really possible that their magic "ion" particles would counteract this negative aspect? I'm extremely skeptical.

It seems like a much better solution would be to point the fan outside and have actual air filtration systems at inlets to the space.

Re: Big Ass Fan’s Clean Air System

#79

Post by anessaiver »

deegles wrote: post #55

Can someone please point me to actual studies validating the "ion" generation stuff? My dad insists that a wearable ion generator he bought works "because it's made by NASA" (it's not) but I can't find studies that validate the technology. Thanks in advance!

Ionizers work through two mechanisms: 1. Charged particles stick together, forming larger clumps that eventually drop out of the air. 2. Charged particles can build up on the surface of airborne pathogens, sometimes directly disrupting membranes or lipid layers, and if there is enough of a buildup they can induce an electric current through the organism that can kill / inactivate it. One study on bipolar ionization showed antiviral efficiencies were 64.3, 89.1, and 97.4% with exposure times of 15, 30, and 45 min, respectively (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7094352/).

The advantage to ion generation based air purification systems is that they are able to actively operate in occupied spaces, not relying on air to get pumped out of a return duct and through a filter or UV system.

It's not possible for them to achieve an instantaneous elimination of airborne pathogens, but any significant percentage reduction can help to lower the total viral load that people in the room are being exposed to.

That being said, it's unlikely that what he's wearing around his neck will generate a sufficient quantity of ions to make much of a difference. It wouldn't be enough to fill the room, and the amount of time any such ions would have to act on a particle that comes close to him really isn't enough to have a large impact.

Re: Big Ass Fan’s Clean Air System

#80

Post by kylebenzle »

mdorazio wrote: post #77

I genuinely don't understand how this is supposed to work in a real-world environment. Let's say someone near a fan is infected with Covid and sneezes. The airflow from the fan would then immediately push covid-containing particles around the space and closer to other people than if there were no airflow at all. Is it really possible that their magic "ion" particles would counteract this negative aspect? I'm extremel…

It doesn't "work". The fact that it made it to the front page of HN bodes badly for this community that has been going down hill for a long time. It just one step above a text based Reddit at this point.
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