Real-gas polytropic head and efficiency from plant readings, an energy-balance check on your measurements, and the yearly energy cost of running away from the best operating point.
USD 49 one-time purchase
Download the sample report (PDF)
Need it once? Use it online: check your data free, unlock results from USD 9 for 3 runs.
What it does
Any gas or mixture
Pure chemicals or mixtures of up to 12 components, including hydrogen-rich, CO₂-rich and wet gas.
Three methods side by side
Real-gas polytropic (Schultz), ideal-gas n-exponent and isentropic. Flow as actual inlet, standard or mass.
Real-gas states
Z, density, enthalpy and entropy at suction, discharge and the isentropic point (Peng-Robinson).
Checks on your data
Energy balance with a warning above 5 % difference, and an expected-versus-measured discharge temperature check.
What-if energy cost
Power and yearly cost of a lower suction temperature or a different pressure ratio.
Print-ready report
Ranked findings, performance charts and a report on A4.
Built for engineers
- Visible formulas — nothing hidden, so you can check every step.
- Fully referenced — methods from the standard references, checked against their published worked examples.
- Safe to share — sheets are protected against accidental edits, with an open password so you can still customise.
- Built-in input checks — clear warnings for impossible inputs and values outside typical ranges.
For engineering estimates; verify against site data. Code-based methods are aligned with the publicly documented procedure; they are not a licensed reproduction or a certification.
Preview the workbook
Real pages from the workbook with its built-in example loaded (example data, not a measured plant). Choose a page below, or select the large image to enlarge it.
Specification and checks
| Format | Excel workbook (.xlsx), no macros |
| Version | v1.0 |
| Works in | Excel 2010 or later, Windows and Mac |
| Units | SI, US and British, mixed freely |
| Includes | Guide tab with method and references, calculator, print-ready report |
| Checked against | 13 operating points against an independent converged calculation of the same equation of state (agreement to 5E-13), and against CoolProp reference equations within 0.3 percentage points for five of six gases. For gases close to their critical point the workbook tells you to use your simulator or vendor data. |
| Free version | Try a free gas calculator |
Online tool or Excel workbook?
| Online tool | Excel workbook (this page) | |
|---|---|---|
| What it does | The same sheet as the Excel workbook, run in your browser | Real-gas polytropic head and efficiency from plant readings, an energy-balance check on your measurements, and the yearly energy cost of running away from the best operating point. |
| Cost | Check your inputs free. Results: 3 runs for USD 9, or every online tool for USD 15 a month (USD 99 a year) | USD 49 once, yours to keep |
| Input checks and findings | Every input checked; findings with the unlocked results | Every input checked, with findings and recommendations |
| Report for your calculation file | Printable results sheet | Print-ready report with your plant, tag, document number, revision and sign-off |
| Formulas | Method described in the guide | Every formula visible in its cell |
| Save, edit and rerun your cases | Each run separately | Yes: keep and edit your own file |
| Works offline, on a plant PC | No, needs the internet | Yes: Excel 2010 or later, Windows and Mac |
Online access and the Excel workbook are separate licences: one does not include the other.
Compatibility, licence and support
| File | Excel workbook (.xlsx), no macros, version v1.0; works in Excel 2010 or later on Windows and Mac. Sheets are protected against accidental edits, with an open password so you can customise. |
| Licence | Single user. A team licence (up to 5 named users) is 3 × the shop price; site licences on request — licence terms. |
| Updates | Updates to this major version are included; download them again from the link in your receipt. |
| Support | Email [email protected] with your order number — questions on the method, your inputs or your results are welcome. |
| Refunds | If the tool does not work as described, or has an error we cannot fix, email [email protected] with your order number within 14 days of purchase and we will refund you in full. Refunds are not offered for a change of mind once a file has been downloaded. Read the full refund policy. |