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What is the expected maximum efficiency of end suction centrifugal pump?

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moideen

moideen

Mechanical
May 9, 2006
359
What is the expected maximum efficiency of an end-suction centrifugal pump? This question coming from a selection for a new project and I got a proposal from XYLEM, it meets only 76.5% for a 50meter head 56 l/s flow rate. As we know, when increasing efficiency then decreasing the absorbed electrical Power. I encountered with team XYLEM for getting above 80% efficiency and saying they don’t have selection above 80%.

The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-
 
 https://files.engineering.com/getfile.aspx?folder=691554e7-269a-47fc-8d17-63821ee8e141&file=xylem-1.pdf
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That's about standard efficiency for small pumps

A black swan to a turkey is a white swan to the butcher ... and to Boeing.
 
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For many small pumps 50-60% is fairly standard.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
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That's actually very good for a 200 m3/hr low head pump.

But it's what the efficiency is at your duty point which matters.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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As others have already said, the efficiency for a pump of the flow / head is the norm. You maybe able to increase the efficiency slightly by hand finishing the internal surfaces of the impeller. An alternate is to look a a larger unit running at 6 pole (960 rpm) the pump and driver price will increase that needs to be balanced against the running costs of each pump selection.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
 
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Thanks for all the comments. I had purchased and installed a condenser pump, same XYLEM, one year before. It was 86.7% with a 34-meter head and flow of 97l/s. this high-efficiency figure was my before when I send the inquiry to xylem. A noted thing is the efficient model is from the e-1510 family, but the new one is e-1610. xylem competitors in Dubai slurring it is coming from China and e-1510 coming from the US. The local xylem team says, e-1510 is not making above 40-meter head…..thank you

The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-
 
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@Artisi:Can you elaborate on this statement “hand finishing the internal surfaces of the impeller”? is it by factory or ..? what is the expected efficiency difference from 4 poles? Nowadays, all are thinking to decrease the operational cost irrespective of capital costs.

The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-
 
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moideen, the impellers on small mass produced pumps wouldn't have much attention paid to the as cast internal surface of the impellers, therefore cleaning any rough surface finish in the impeller eye and passage-ways that can be reached will /could bump the efficiency by a point or 2.

Depending of the duty point, a larger pump running at a lower speed could increase the efficiency by a considerable amount - ask your pump supplier for a selection at 6 pole speed - without being advised normally a selection is based on initial cost not overall running costs.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
 
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86.7% is about the highest figure I've ever seen for such a pump. But lower head is a bit easier.

But I think you're right in that OPEX and life time cost is becoming more important as it is increasing faster than the capital cost. So a bigger efficiency AT YOUR DUTY POINT but a bit more CAPEX is starting to become thought about a bit more.

Tends to depend on whether its the operator buying it or an EPC contractor....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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Simple solution is to contact your favourite pump supplier, advise the pump duty and simply tell them you want highest efficiency not lowest price.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
 
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LittleInch: I attached that curve for a reference as 86.7% efficiency @duty point

The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-
 
 https://files.engineering.com/getfile.aspx?folder=b038102e-ea78-4a43-b542-32a4f8522afd&file=86.7%_efficiency.jpg
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Interesting.

They do seem to highlight it as a "Premium Efficiency Product".

Hence it is the upper bound level and not what you would "normally" expect from such a sized of unit.

As you get bigger, efficiency becomes more important for people as the cost of power starts to exceed the cost of the unit.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
 
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Price of power is going up.


Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
 
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If this pump is in variable flow application in actual operation, you most likely may save more money on life cycle cost over the long term with a VSD with this pump, than with a fixed speed pump with optimum eff at 80% that burns off excess power at low flow-low eff.
 
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