Result
Formula
Calculation logicAbout this calculator
What this calculator does
Polytropic head and shaft power. This is a screening calculator: fast enough for optioneering, transparent enough to check. Preliminary pump screening. Confirm with manufacturer curves and NPSH tests.
When to use / when not to use
Preliminary pump screening. Confirm with manufacturer curves and NPSH tests.
Input and output variables
- W
- Mass flow
- T1
- Suction abs temperature
- PR
- Pressure ratio
- Power
- Polytropic head x flow/eff
Worked example
Doubling PR at fixed suction temperature roughly doubles polytropic head — check discharge temperature limits before accepting the duty.
Standards: HI 9.6.3 (NPSH margin) · Affinity laws
Frequently asked questions
How do I use the Compressor Polytropic Power?
Enter nameplate inputs with units as labeled, read each output with its substituted formula, then verify against datasheets and field readings before acting.
Is this result final?
Preliminary pump screening. Confirm with manufacturer curves and NPSH tests.
Learn
How to interpret the result
Estimate compressor head and driver size.
Checklist before you rely on it
- Confirm units match the input labels before trusting the result.
- Recompute at minimum and maximum operating cases, not just the design point.
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Save this calculation to your workspace
Save this calculation to your private workspace: keep inputs + result, compare scenarios side by side, and export a report with substituted formulas.
- Save projects — return to inputs, result, and report.
- Compare scenarios — see which option holds margin.
- Export report — PDF/CSV with formulas shown.
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