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Energy calculation

VSD pump
energy savings

Compare an entered fixed-speed operating profile with an indicative variable-speed case, then evaluate annual savings, payback and present value.

Registration required for results

Enter your project values.No operating or financial assumptions are preselected. Fixed-speed power should come from measurement, motor data or an accepted pump calculation.

01 / Project inputs

Define the operating profile

Your details

Required so Metsiworx can retain the calculation record and contact you if an engineering concern is identified.

Project

Pumping system basis

Indicative variable-speed power modelPower ratio = flow ratio × [static-head share + dynamic-head share × flow ratio²] ÷ VSD efficiency

Enter design-flow pump-and-motor electrical input before VSD losses. The model treats dynamic system head as proportional to flow squared and holds combined pump and motor efficiency constant. Final savings require verified pump curves, control philosophy, minimum speed and efficiency across the operating range.

Annual operating profile

Band 1 is required. Bands 2 and 3 are optional; either complete every field in an optional band or leave the entire band blank. Combined hours may not exceed 8,760 per year.

Band 1 · Required
Band 2 · Optional
Band 3 · Optional
Financial assumptions Required for payback and present value

Enter 0 where no additional annual VSD maintenance is included; it is treated as a constant annual nominal amount. Demand charges, reactive-energy charges, replacement costs and downtime benefits are excluded unless reflected in the entered data.

Calculation basis

A transparent screening
of potential savings

01

Entered baseline

Existing fixed-speed input power and annual hours are entered for each operating band rather than assumed from a control method.

02

Variable-speed estimate

Dynamic head varies with flow squared, while the entered static-head share remains. VSD losses are applied separately.

03

Commercial result

First-year net savings, simple payback and discounted present value use the entered tariff, escalation, maintenance and project cost.