Estimating Heat Gain from Recirc Pumps

[Ajax001]

This question might be more appropriate to thermodynamics but that Forum category doesn't exist. But it does relate to heat loss / gain which I suspect energy engineers need to know alot about.

Can anyone provide the formula that can be used to determine the amount of heat lost to a process fluid due to pump inefficiency? Note that I am not concerned about heat loss from the motor since the majority of that loss will go to atmosphere.

In this case, the process fluid is freshwater or saltwater. Normal operating temperatures would be between about 5 - 20C.

To provide some additional background, I am trying to estimate the amount of heat gain that an aquaculture system would observe from the recirculation pumps in any particular application.

Thanks for the help.....

 

[MikeHalloran]

I remember a circulating temperature bath system that used a relatively viscous silicone fluid and canned pumps. It needed a refrigerator to maintain 'ambient' temperature, because _all_ of the electrical energy going into the motor showed up as heat in the fluid.

To a first approximation, that provides an upper limit that should be valid for any circulating system, and using it would be conservative for design purposes.





Mike Halloran
Pembroke Pines, FL, USA

 

[EdStainless]

The low limit is the pump inefficiency, the high limit is all of the pumping power. Somewhere between you will have your real value.

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Plymouth Tube

 

[Ajax001]

Actually, I found the answer buried on this site. See the following thread:

http://www.eng-tips.com/viewthread.cfm?qid=102433

Using this calculation, it seems in our applications, heat gain from the recirc pumps is pretty small.