The most enjoyable part of being a part of this “movement” to create DIY air cleaners is seeing the energy, creativity, knowledge and spirit to provide better and safer indoor air. As Thomas Thalhelm said several years ago, “an air cleaner is just a fan and a filter.” So true. But who could have imagined the iterations?
One of the most interesting is the use of PC fans. These fans provide significant air flow with very low energy usage and noise. Several very creative and knowledgeable people have done a great deal of research as well as trial and error testing on different PC fans and PC fan configurations to optimize this approach. (They are also supporters of the Corsi-Rosenthal Foundation.) Their website is here: Corsi Rosenthal Box | Clean Air Kits
A few weeks ago I purchased PC fan air cleaner components from them so that I could create several versions of the Corsi-Rosenthal Box. (But these components are also available from other sources.) One was the Mini – as shown above. It is super simple. 4 – 12X12X2 MERV 13 filters. Two Arctic P-14 fans. Connections to plug into a standard outlet. Fan covers and fasteners. A pre-cut “base.” And, of course, duct tape. It took about 30 minutes to build.
But how does it perform?
To test it we built a 1’X6′ tunnel. The idea was to reduce the “swirl” associated with fans. This swirl has raised questions about our use of anemometers to measure air flow. While I believe all of our measurements using anemometers are within the acceptable margin of error for the applications involved, there is no harm in providing a more precise estimate.
We measured the air flow with an anemometer at 6 different locations on the air exit side of the tunnel. There was some variation – 198 fpm and 224 fpm. The average was 210 fpm.
The unit is very quiet. Noise level at 1 meter was 42-43 decibels. Power usage – 4 watts.
These results are pretty impressive – especially for a bedroom, hotel room, office or conference room. The Mini Corsi-Rosenthal Box – Version 2 – is definitely a step in the right direction.