Static Efficiency in Fan
Static Efficiency in Fan
(OP)
Hi all,
I am about to write a new program for HVAC units design. I am using Nicotra's datas on it but there is a problem the datas Nicotra provided me. They gave me Total Efficiency of fan data but not Static Efficiency. I think I have to calculate it by myself. Is there anyone knows what the formula of Static Efficiency is?
Thanks all
I am about to write a new program for HVAC units design. I am using Nicotra's datas on it but there is a problem the datas Nicotra provided me. They gave me Total Efficiency of fan data but not Static Efficiency. I think I have to calculate it by myself. Is there anyone knows what the formula of Static Efficiency is?
Thanks all





RE: Static Efficiency in Fan
If you use the term in a manner I consider it, total efficiency is ratio of total fan airflow power (effective power exerted to air) to power input from prime mover's connection. I did not hear for such term as static efficiency, please try to explain.
RE: Static Efficiency in Fan
Thanks
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RE: Static Efficiency in Fan
Nt = (Volume flow * total pressure loss)/(3600 * etat) in kW
Volume - volume flow in m3/h
Total pressure loss in Pa
etat - (toatal) fan efficiency, dimensionless or in %
Effiecency (call it total) should be etat = Nt/Noutp
Noutp - power output from electric motor in kW (not installed motor power input!)
So, fan power for static pressure would be:
Ns = (Volume flow * static pressure loss)/(3600 * etas) in kW
and static efficiency sould be etas = Ns/ Noutp,
but looking in a data at selection pages of your program, this data doesn't give adequate results.
(Total efficiency in percent should equal "fan power" divided by "motor power"). I presume "motor power" is given as motor power input, so you need to know motor efficiency, to calculate motor power output, and than you should be able to use formulas above.
RE: Static Efficiency in Fan
They assumed etat = etas, that is fan efficiency doesn't change with minor changes in working point (which is a bit illogical, that way they don't need term "total" and "static" efficency).
In that case
Total efficiency/Static efficiency = Total pressure/ Static pressure.
So Static efficiency = Total efficinecy * (Static pressure / total pressure)
There could be discussion are these terms they choose fully correct, but I beleive this formula can fulfill your needs.
RE: Static Efficiency in Fan