WALRUS: Refrigerant Match

WALRUS is a field screening tool for qualified HVAC/R technicians. Enter a stabilized recovery-cylinder temperature and pressure, and WALRUS ranks the bundled refrigerants by how closely their modeled pressure-temperature behavior agrees with your reading -- nothing more, nothing less. HOW IT WORKS Enter a stabilized temperature and pressure from a recovery cylinder that holds both liquid and vapor. Choose gauge or absolute pressure, select your units (F/C, psi/bar/kPa), and add elevation if you're working with a gauge reading -- WALRUS corrects for the local atmospheric baseline. For zeotropic blends, both the bubble and dew pressures are used so glide is accounted for, not ignored. WALRUS then ranks every supported refrigerant by pressure-temperature agreement and groups the results into Close, Possible, and Weak agreement bands, so you can see at a glance which candidates are worth pursuing and which are noise. WHAT'S IN THE DATASET WALRUS ships a versioned dataset of 50 refrigerants -- pure fluids, HFCs, HFOs, azeotropic and zeotropic blends, hydrocarbons, ammonia, and CO2 -- spanning the ASHRAE safety classes you already work with (A1, A2, A2L, A3, B1, B2L). Every shipped saturation curve was generated from pinned CoolProp 8.0.0 and passed a complete public-source pressure-temperature grid: three separated saturation checkpoints for a pure fluid, or three bubble plus three dew checkpoints for a blend. This is a nominal-curve cross-check, not field validation or specialist approval. The dataset version ships with the app so you always know exactly what data produced a given result. WHAT WALRUS IS NOT A single temperature and pressure reading can narrow the field, but it cannot establish identity, composition, or purity. Contaminated, mixed, fractionated, or non-condensable-laden cylinders can all produce a reading that looks like a clean match. Contamination, moisture, oil, air, and non-condensable gases are invisible to a pressure-temperature reading -- WALRUS has no way to see them, and it never connects to gauges, probes, or Bluetooth sensors -- you type in what your own instruments read. When a reading matters -- reclaim, resale, or anything safety-critical -- the only way to confirm what's actually in a cylinder is laboratory analysis by gas chromatography, per AHRI Standard 700. WALRUS is built to point you toward that step when a reading is ambiguous, not to replace it. WALRUS also does not offer handling, charging, recovery, venting, or retrofit guidance. It answers one question -- how well does this reading agree with each candidate refrigerant -- and stops there. BUILT FOR THE TRUCK, NOT THE CLOUD - Works fully offline. Every comparison, the whole refrigerant dataset, and your saved history run on your device with no connection -- airplane mode, a basement, a roof with no signal, all fine. - Your readings never leave your phone. No measurement, result, or history entry is ever transmitted anywhere. - No account, no sign-in, no cloud sync. - No ads, no analytics, no tracking, no location access. - One optional exception: if you choose to write in the Send Feedback form, that message is sent to us for review. Nothing else goes with it, and the app shows you exactly what is attached before you send. Skip the form and WALRUS never makes a network connection at all. - The last 100 comparisons are stored locally on your device so you can revisit past readings. - One-time purchase of $19.99. No subscription, no in-app purchases. WALRUS is a screening tool for experienced technicians who already know how to read a manifold and a thermometer. It narrows the field fast in the field -- the lab confirms the rest.