Pump Recirculation - Your Opinion

[macmet]

Hello Everyone,

I would like to get your advice on whether or not I should have a pump recirculation loop installed on a cooling loop we're providing.

It is pumping water at 200F at a rate of 150 usgpm @ 35-45 ft of head.

I'm not all that familar with pumps but from what I've read on this site it seems like we should have one. I know there is a guy on the current site I'm on who believes all pumps of this site should have one despite it's lower pressure requirement.

Please let me know if any other information would be helpful.

Appreciate the help,

Cheers.

 

[MikeHalloran]

Don't make changes based on advice from 'a guy', even me.

YOU need to map your system's operating point(s) onto your pump's curve, and see how efficiently your pump is running.
That will tell you what to do next.




Mike Halloran
Pembroke Pines, FL, USA

 

[macmet]

I guess I should also say that this pump will run continuously once it's set up. The pressure changes will be minimal and it pumps within a closed loop.

 

[Artisi]

Follow Mike's advise and plot the operating conditions onto the pump curve, only this will tell you if you need a recirc. line.

 

[raronen]

Ditto the other comments--plot the point on the curve.

Also, calculate the suction specific speed of the pump and follow typical guidelines for minimum flow as % of BEP based on the suction specific speed.

Basically, the higher the suction specific speed, the closer your pump needs to run to BEP and more likely you need a minimum flow bypass.

 

[mtngreen]

If its a closed loop with minimal pressure changes AND you select the appropriate pump I don't see the need for a re-circ loop.

 

[GPRnD]

I agree. If your pump will run continuously above about 20% of BEP, no recirc loop is required.

Its a pretty low power pump in any case.