How do I estimate a pressure/flow curve for a filter of specified area, efficiency rating, MERV and MPR?(Duct work is negligible)
I am trying to pick an appropriately rated fan/fans to maintain a target cfm:
I'm trying to add a filter to a wall-mounted AC unit. If I can't do this I will need to replace the whole system. I'm trying to calculate the resulting static pressure assuming I can boost flow to maintain cfm. I have chosen a filter and I know my target cfm; How do I find static pressure so I can choose the right fan to boost the unit.
constraints are as follows:
- the unit is rated for approx. 400 c.f.m. on a 240V circuit
- inbuilt blower motor: 8P DC280-340V 30W
- filter area is ~$3ft^2$
- filter efficiency is 93%
- filter MERV rating 12
- filter MPR rating 1900
- I don't have any more information
How do I figure this out? I've looked at the Affinity laws:
$ \frac{Q_{1}}{Q_{2}} = \frac{N_{1}}{N_{2}} $
$ \frac{H_{1}}{H_{2}} = (\frac{N_{1}}{N_{2}})^2 = (\frac{Q_{1}}{Q_{2}})^2 $
$ \frac{P_{1}}{P_{2}} = (\frac{N_{1}}{N_{2}})^3 = (\frac{Q_{1}}{Q_{2}})^3 = (\frac{H_{1}}{H_{2}})^\frac{3}{2} $
Also perhaps important:
Flow coefficient: $ C_{v} = Q \sqrt{\frac{SG}{\Delta P}} $ (can i estimate $C_{v}$ of my filter?)
I don't really have any test equipment. I was hoping to estimate all necessary values based on product specs and labels. I'd like to know how to calculate my estimated pressure and flow, although perhaps I might up-vote a ballpark answer if it helps me pick a fan:
I have ~2.5" gap space behind my baffle to install my boost fan/fans. I was thinking of installing some 120mm, 110V, 100cfm muffin fans in this space. What total CFM should I aim for? Are muffin fans the right choice?
