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Power Lost on Restriction in Ductwork

  1. May 5, 2010 #1
    Hello,

    I need a formula to calculate how much power is wasted on different types of air filters. A typical application is a residential central air ductwork. A typical pressure drop is 0.1-0.2 inch wg. Typical volume passing through filters is 700-2000 cfm. A typical filter size is 2-3 sq. ft.

    Your help is much appreciated in advance.

    gm

    This is not a homework. :smile:
     
    Last edited: May 5, 2010
  2. jcsd
  3. May 5, 2010 #2

    russ_watters

    User Avatar

    Staff: Mentor

    Welcome to PF. The equation is:

    CFM*dP/6356/eff=hp

    That's flow in CFM, dP in inches w.g. and efficiency of the fan. A typical good HVAC fan is about 65% efficient, so for example, 2000 CFM at 0.2" is 2000*.2/6356/.65=0.097hp
     
  4. May 5, 2010 #3
    russ,

    Awesome. Thanks a lot.
     
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