by Joe Evans
January 29, 2013

The “Results” columns show the calculated results for the two alternatives. These include annual flow, brake horsepower required, wire-to-water efficiency and total energy costs. The “Payback” portion computes the overall cost increase and energy savings and uses them to compute the payback period. In this example, the two-line, two-pump alternative will pay for itself in a little more than two years. The potential for increased maintenance costs is not included in this analysis but could be entered in the “Additional System Costs” in columns 2 and 3.

The calculator is not limited to single-point branches as shown in this example. The “A to B” column could also be a branch zone that feeds multiple branches within the zone. If more than three branches or zones are required, more columns can be added to the spreadsheet.

Next month, we will look at another alternative to the single-line, single-pump, open-branch design.