I have received one vendor pump quote stating 11.9% efficiency. So I have clarification, Are there any limitations / minimum criteria for the Centrifugal pump?
An efficiency that low implies to me that you're looking at a 'low flow' pump. Some centrifugal pumps have straight radial vanes, like 24 of them, and are capable of very low flow rates, like 1 gpm. Although the efficiency is low, the hp is also low, so the actual amount of power lost to inefficiency is fairly low. These tend to be a bit niche applications, to allow a single stage pump to be used instead of a multistage pump.
For example, look at the Goulds LF3196 series; I've sold those many times for specific applications where the client wanted a single stage pump capable of a low flow rate.
Medium : HC Condensate, Flow: 6.83m3/h, Head: 54m, Efficiency: 11.6%, MCSF: 1.57m3/h, BEP: 7m3/h, Power: 8.6kW. API 610 Pump. Please let me know if any information required.
As the pump curve isn't attached it will be assumed that the pump is operating very far to the left on the operating curve which explains the efficiency of 11.6%.
If this is the only pump that is capable of the flow and head - that's it.
All you can do is look for an alternate pump / supplier but don't think you will find anything with a higher efficiency.
