Fan Heat Question

[leeave96]

How does one calculate fan heat added to a system when:

1. Only the fan is in the air stream.

2. Fan and motor are in the air stream.

Thanks!
Bill

 

[MintJulep]

http://www.hpac.com/Issue/Article/24839/Fan_Heat_and_Pump_Heat_Sources_and_Significance

and

http://www.hpac.com/Issue/Article/24835/Fan_Heat_and_PumpHeat_Sources_and_Significance

 

[marcoh]

As per the articles above heat is added to the system at the fan.

If the fan motor is in the airstream then all motor losses would be added as well (heat transferred from the motor to the air).

If the fan motor is out of the airstream then only the energy imparted to the airstream by the fan blade would heat the air.

EG: 30kW motor and 90% efficiency = 33.3kW electrical energy.

If the motor is in the airstream, 33.3 kW of heat is added

If the motor is out of the airstream, 30.0 kW is added to the airstream.