Hello, I am kind of at a loss with a project I am working on
I am working on an energy savings project to decrease airflow in an existing system. The current design has a very high airflow that is no longer required.
Where I am confused is
1) one motor attached to the exhaust system is distributed to two seperate areas. One area is not used anymore, so dampers will close off that ductwork, leaving only the one area operating. This changes the fan curve -static pressure and rpm- while maintaining the existing airflow for that area.
Total current CFM= 23024
CFM for area that will remain operational= 11032
Static pressure at the one area=5
Total static pressure= 12.33
I found the Constant of the total system= 5.491E-8
and then plugged in the CFM of the area I am using(11032) and found my new static pressure= 6.68
I plotted this on my fan curve( shifted the curve) and the HP dropped to approx 18BHP
One area running specs
** I dont know how to get an accurate NEW RPM from this information??
2) Now for the energy savings part!
once I know what the calcuated line is running only the one area, I will be decreasing that CFM (11032) to 4600
Using the constant(5.491E-8) I found my new static pressure= 1.16
**the reason I want to be able to get the RPM at the energy savings point is so that I can ensure, when I add a VFD to the motor, it will run a no less than 20HZ
This is the information I have to work with.
Also- air quality testing will be preformed post install. I just want to be able to get the math right