Reference cooling water and seawater

Read docs/process/equipment/reference_cooling_water.md before constructing the model. Verify the source/JAR version and APIs; a newly published source API may not exist in the installed release. Use @process-model for the two-stream flowsheet and @utility-design for plant supply/pumping. Coordinate with @thermo-fluid when composition or property validity is uncertain.

Select the model

Keep the process-side EOS and transport models. A WATER physical-property enum on an SRK/PR/CPA system does not select reference-water enthalpy. Reference-system constructors already add one nominal component; set total flow, without adding salts or setting an EOS mixing rule. Use the tested Java guide through the verified Java/JPype interface; do not invent a curated MCP execution route.

Define and execute the case

1. Record process composition, model/mixing rule, flow, T/P and duty or outlet target. Record utility supply T/P, return-temperature limit, mass flow or unknown demand, salinity basis and seasonal range. Keep bara separate from barg and hydraulic pressure drop.
2. Use IAPWS-IF97 for fresh water. For seawater, set Reference-Composition Salinity in g/kg solution. Practical salinity 35 corresponds to 35.16504 g/kg for Reference Composition. Do not substitute g/kg solvent or an arbitrary NaCl concentration. Treat missing salinity as a stated assumption.
3. For two streams, create independent fluids and named supply/return streams; preserve them in the canonical ProcessSystem. The fixed-salinity model carries bulk-solution mass using nominal water moles; use mass-based results.
4. For WaterCooler, use setOutletTemperature, setWaterInletTemperature, setWaterOutletTemperature, setWaterPressure and setCoolingWaterSalinity. Do not force the water property package on the process gas. Require return temperature above supply temperature. Utility demand alone does not prove a specified UA can reach the process target.
5. For CoolingWaterSystem, use setCoolingWaterPressure in bara separately from setSystemPressureDrop in bar. Set setCoolingWaterSalinity; supply and return temperature setters use Celsius. Remove tower fan demand for a once-through seawater system by setting its power fraction to zero.
6. Establish equilibrium and call initProperties() before transport getters or geometry-based rating. Liquid water uses IAPWS viscosity/conductivity; seawater uses the G10-15 conductivity increment and a published salinity viscosity multiplier. Do not replace these with unexplained constants.

Validate and report

• Close total mass and enthalpy on each side; check utility demand against the independent reference enthalpy rise and actual inlet volume. Duty is W in HeatExchanger/WaterCooler; CoolingWaterSystem requirements are kW.
• Check terminal approaches, positive flow and capacity ordering. Retain the existing secant heat-capacity/NTU approximation; a terminal approach check does not qualify internal pinch behavior or boiling.
• Inspect neqsim.thermo.util.steam.SeawaterProperties validity before using results. The implemented bulk cooling envelope is 273.15–353 K, 1–120 bara, 0–120 g/kg. Above 313 K or 42 g/kg, saline pressure derivatives are extrapolations. Report this and the high-pressure extension of the seawater viscosity multiplier. Reject actual states outside the implemented envelope.
• Test nearby seasonal T/S/flow, repeated runs, changed salinity and fouling cases. Preserve rejected or nonconverged points. The seawater capacity probe may be bounded below the hot-feed temperature; this does not permit an actual utility outlet outside its model range.
• Change salinity on the live stream fluid after a run, then rerun dependent equipment. Stream.run() clones fluid state; the original fluid passed to its constructor need not remain the live object.
• Cite IAPWS AN5-13(2016), R13-08, R12-08, R15-11, G10-15 and the viscosity source. Record version, units, salinity basis, model, assumptions and balance residuals. Use CoolingWaterReferenceTest, ReferenceCoolingWaterTest and ReferenceWaterHeatExchangerTest as executable evidence, not a claim of field qualification or material/corrosion suitability.
• Escalate freeze/boiling margin, fouling allowances, discharge limits, chlorination, corrosion, material selection and mechanical design to their engineering workflows using actual design evidence. Do not infer those results from thermophysical properties alone.