# philipn / Corsi-Rosenthal Cube testing results

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This is a "scratch" page used to record various measurements and test results obtained for the Corsi-Rosenthal Cube.

## Room sizing / CADR figure

CFM measurements of a 4-sized cube configuration were taken here:

As per conversation with David Elfstrom, these figures were using a Lasko Power Plus fan, which puts out ~20% more flow than typical fan.

In David Elfstrom's own CADR predictions, he uses a figure of $$\sim62\%$$ efficacy of the MERV-13 filters (confirmed with him). So this is a figure based on $$0.3um$$ particles expected lower bound performance with the MERV-13 filters.

COVID-carrying particles are likely larger than 0.3um (most penetrating particle size), so this is a lower bound figure. I am not sure if the exact size distribution of COVID-carrying particles is known. We know $$80\%$$ of them are are "less than $$5um$$."

Using John Semmelhack's CFM measurements, we can make a guess at the difference between the cube with 1" filters and the cube with 2" filters. His cube was constructed with 2" MERV-13 filters.

We assume a conservative figure here. Want to give a lower bound. So this scale multiple looks like $$(349/455)$$.

$$(349/455)*871*0.62*0.80 = 331 \text{ CFM CADR}$$.

As per David Elfstrom's measurements, an optimally-sized fan shroud increases the fan flow by $$47\%$$. We should assume that not everyone gets the exact optimal fan shroud sizing (due to differences in fan models), so let's lower this by $$20\%$$ to $$37.6\%$$:
$$331 * 1.376 = 455 \text{ CFM CADR}$$