ABSTRACT
Proper pumping system design is the most important single element in minimizing Life Cycle Costs (“LCC”). Guaranteed or rated pump efficiency is only one component among many, and not necessarily the most important. However, when it comes to improving the operating efficiency of a pumping system, users often look for the pumps with the higher efficiencies, and favor the one which might exceed others by as little as 1/2 or 1 percent. All things being equal, there is some logic to this approach. But all things are seldom equal! To begin with, small differences in guaranteed efficiency may have been obtained at the expense of reliability, either by providing smaller running clearances or using lighter shafts, a point to note when comparing specifications and proposals. Moreover, the savings in power consumption obtained from a small difference in efficiency are rarely significant.
