Compressor Analysis — validation & limitations
What this calculator checks and the method behind each result, the independent reference cases its engine is tested against, and what it does not check. Use it to decide how far you can rely on a result.
Open the Compressor AnalysisWhat it calculates
Standard / method: Ideal-gas thermodynamics (ASME PTC 10 / ISO 1217 terminology)
Textbook ideal-gas compression thermodynamics with an isentropic efficiency (not polytropic) · terminology per ASME PTC 10 / ISO 1217 — not a test-code evaluation (no polytropic head, Schultz factor or real-gas properties)
- Shaft power and drive power sizing (ideal-gas thermodynamics, isentropic efficiency)
- Actual discharge temperature checked against a machine-type limit, for air, nitrogen, CO₂, methane, hydrogen or a custom γ and R
- Multi-stage compression with an intercooler approach (outlet above suction; 0 K = perfect intercooling) — per-stage P, T and work breakdown
- P-V and T-s thermodynamic diagrams showing isentropic vs. actual path
- Reciprocating compressor P-V indicator loop — volumetric efficiency, indicated work per cycle and indicated power
- Centrifugal compressor surge margin and choke margin with operating-point map
- Standard motor frame size selection from the nearest IEC/NEMA duty rating
Related standards — reference only, not implemented
- ASME PTC 10reference only — Ideal-gas isentropic specific work (PTC 10 terminology, not a test evaluation), shaft power, discharge temperature, multi-stage intercooling, P-V indicator loop and centrifugal surge/choke map.
Validation evidence — independent reference cases (1)
Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.
Specific compression work and discharge temperature
AgreesSource: Cengel & Boles, Thermodynamics: An Engineering Approach, 7th/8th ed., ch. 7, worked example 'Work Input for Various Compression Processes'; hand derivation
Inputs: Air 100 to 900 kPa, T1 300 K, R 0.287 kJ/kg·K, k 1.4; 1 or 2 stages; isentropic efficiency 100 % or 80 %
Quantity Reference value Tolerance Isentropic work 263.21 kJ/kg (published 263.2) 1e-6 vs hand; 0.05 % vs printed Isothermal work 189.18 kJ/kg (published 189.2) 1e-6 vs hand; 0.05 % vs printed Two-stage isentropic work 222.24 kJ/kg 1e-6 relative Discharge T2 at 80 % efficiency 627.54 K (FAIL) 1e-6 relative tests/golden/REF-compressor-compression-work.golden.test.ts
Limitations
Not checked by this tool
- Reciprocating compressor rod load, valve and frame ratings (API 618) — Thermodynamic sizing only; check rod-load reversal and frame ratings with the compressor maker
- Pulsation and piping vibration — Not assessed; run a pulsation study for reciprocating machines (API 618)
- Leakage, clearance volume and volumetric efficiency — Not modelled; use the maker's capacity data for the delivered flow
- Moisture condensation in intercoolers and aftercoolers — Dry gas assumed; size condensate drains and separators and check the dew point
- Intercooler and aftercooler heat-exchanger sizing — Only the duty is reported; size the cooler area with /heatex
- Real-gas validity for a custom gas — The real-gas screen needs critical constants; for a custom gas use an equation of state
Results are engineering calculations for qualified users — see the disclaimer. Other tools: all validation pages · standards reference · symbols glossary.