Fan power and flow rate

[saeedplc]

‌Dear Experts,

Is it possible to get actual air flow (m3/h) of an AHU by refering to it's fan curve in a specific frequency by having actual kw of the fan?
It is a backward centrifuge fan with exact curvd in different frequency and power.
Actual power kw and actual RPM is displayed on VFD drive.

Regards,

 

[saeedplc]

Dear Experts

Your reply will be highly appriciated

 

[MintJulep]

https://www.engineeringtoolbox.com/fan-affinity-laws-d_196.html

 

[LittleInch]

Most people take the weekend off....

not sure what a "backward centrifugal fan" is??

Fan curve at the right frequency will give you some of the data and then depends on the pressure differential to get flow.

Power might get you to within about 25% of the actual airflow., but depends on how sensitive the fan curve is.

Also electrical power to the motor is not the same (more) as shaft power from the motor to the fan... So you will overestimate airflow just using electrical power.

Easier to buy a small air flow meter.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[HVAC-Novice]

I assume OP means backwards-curved fan....

And no, you can't. At least not with any type of accuracy. Look at the fan curve go flat it. you need rpm, actual shaft power, pressure gain and so on.

 

[LittleInch]

I'm thinking the fan is going the wrong way around....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.