Property bases

A revision's component_set.record_source selects one property basis; every stream and unit of the revision evaluates on it, and streams of different bases never mix. Any value that is not a registered key selects the synthetic SYN-001 basis, whose components are then the only ones accepted.

Basis	record_source	Components	Domain	Units that bind
IAPWS-95 water (iapws95-v1)	benchmarks/s05/components.yaml	H2O	273.16–1273.15 K, 10²–10⁸ Pa	thermal.*, routing models
CoolProp HEOS (coolprop-heos-v1)	benchmarks/s07/components.yaml	exactly one of 123 fluids	per fluid	thermal.*, routing models
Wilson γ–φ (wilson-ig-v2)	benchmarks/s10/records.yaml	CH3OH, C2H5OH, H2O	300–400 K, 30–200 kPa	the column, five mixture units, the compressor and turbine, routing models
Peng–Robinson C1 (pr-c1-v1)	benchmarks/m01/components.yaml	H2, N2, NH3, Ar, CH4	200–1000 K, 10⁴–3 × 10⁷ Pa	c1.*
SYN-001 (syn001)	any other value	A, B, C (synthetic)	280–440 K, 50–200 kPa	syn001.*

The unit catalogue lists, for every model, the bases it binds on. A model on a basis it does not support is refused at binding, with the reason (model_unsupported(thermal.pump): the Wilson basis has no liquid volume, which a pump needs).

IAPWS-95 water (iapws95-v1)

The IAPWS-95 formulation for ordinary water, implemented from the release's coefficients (IAPWS's attribution is in Licence and attributions). Its reference state is the formulation's own — internal energy and entropy zero for the saturated liquid at the triple point — which is not a formation datum, so no reacting unit can be built on it. Stream regimes are declared (liquid, vapor, or vapor_liquid for saturated states); saturated streams are produced only by thermal.* units, and there is no phase-regime discovery. Close to the critical point the near-critical rules of the provider apply.

CoolProp pure fluids (coolprop-heos-v1)

CoolProp's Helmholtz-energy equations of state, one fluid per revision, named as the revision's one component (for example R134a, CO2, Nitrogen). Needs the coolprop extra; the provider imports CoolProp only when a revision selects it. Each fluid keeps its own domain and the qualification tier it was admitted under. The thermal.* units' rules are those of IAPWS-95 above.

Wilson activity model (wilson-ig-v2)

The Wilson activity-coefficient model for the liquid with an ideal-gas vapour (γ–φ), for methanol, ethanol and water, with TP and PH flashes and molar entropy. Its records hold fitted binary parameters and the measured points they were fitted to. Compared with measured vapour–liquid equilibrium, it is within its pre-registered bands for methanol–ethanol–water (the ternary at 101.3 kPa; the binaries with water at 323–333 K); methanol's liquid enthalpy and heat capacity are not within band against CoolProp. That comparison is the validation report. On this basis the column takes reflux, rate and duty end specifications only, and the compressor and turbine are single-phase vapour machines. The records ship with the package.

Peng–Robinson for the ammonia loop (pr-c1-v1)

The Peng–Robinson route of the ammonia-synthesis loop: hydrogen, nitrogen, ammonia, argon and methane, vapour only, with binary interaction parameters zero. It is validated for pure-component behaviour only, with no mixture VLE validation; a liquid regime is reported unsupported. It binds the c1.* models, including the PyMRM reactor, which runs out of process in its own pinned environment.

SYN-001 (syn001)

A synthetic three-component system (ideal vapour, incompressible ideal liquid, vapour–liquid equilibrium) with closed-form references, used to verify the numerics. Its results are verified, never validated: the components have no real chemical identity.