Pump/Motor Heat Dissipation

[Zac H]

I have three raw water pumps each driven by 620kW TEWAC induction motors in a pump room that I am trying to determine the heat load for. I know the efficiency of the motors at full load=96%, 75% load=95.9% and 50% load=95.3% but I'm unsure what the actual heat dissipated would be when taking into account the effect of the water-air cooling.

Additionally, I am unsure of how to determine what heat would be generated by the pump itself (not the motor) from friction in the bearings or otherwise.

Can someone offer any advise on this topic?

Thanks

 

[itsmoked]

Are the pipes uninsulated and carrying cold water? If so they can often cover the entire heat removal problem. If there's water running thru the pump all the heat generated in the pump itself is carted away in the fluid.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LittleInch]

What sort of water air cooling are you thinking of? Heat within the pump should be small compared to the losses from the motor. How many pumps and load are you talking about?

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

 

[MintJulep]

The motor manufacturer should be able to provide charts of frame heat load vs motor load vs cooling water temperature.

To a degree you get to choose if you have control of the cooling water temp, flow or both.

For the pump the temperature of the fluid will likely be far more important than the friction losses.

 

[lilliput1]

Page 18.6 to 18.7 of ASHRAE 2017 Fundamentals I-P Edition tabulates typical efficiencies of different types and sizes of motors. Also equation of heat gain to space for each of the 3 cases below are given:
Equation (2) is for motor and driven equipment and driven fluid within the conditiones space
Equation (3) is for when te motor is outside but the driven equipment and fluid are in the conditioned space
Equation (4) is when the motor is inside the conditioned space and the driven equipment is outside. It also applies to fan or pump in the conditioned space tat exaust air or pumps fluid outside the conditioned space.