Ammonia (NH3) Properties Calculator

• •Use the Ammonia (NH3) Properties Calculator to check your hand calculations on homework or exam problems — comparing its result with your own working helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The Ammonia (NH3) Properties Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Ammonia refrigerant property lookup for industrial refrigeration: two-property state determination from the Gao et al. (2023) reference equation of state All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Follow the units printed beside each field. Where a unit selector is provided, the selected unit is converted internally. Results are computed in your browser without sending data to a server, which keeps your inputs private. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

Ammonia (NH₃, also called R-717 in refrigeration nomenclature) has been used as a refrigerant since the late 1800s and remains the dominant refrigerant for industrial refrigeration — ice rinks, cold-storage warehouses, food processing, fish storage, petrochemical cooling — due to excellent thermodynamic properties and zero ozone/global warming impact. Key properties: normal boiling point −33.32°C (good for low-temperature refrigeration down to about −60°C), critical temperature 132.41°C, critical pressure 11.36 MPa (higher than most refrigerants), molecular weight 17.03 g/mol (low, giving high volumetric cooling capacity), and very high latent heat of vaporization 1262 kJ/kg at 0°C (about 6× higher than R-134a). This high latent heat means ammonia systems need very low refrigerant mass flow for a given cooling duty, resulting in smaller compressors and less piping mass. Zero ozone depletion potential, zero global warming potential, and zero smog formation make ammonia an environmental favorite. The main drawbacks are toxicity (ammonia vapor is an irritant at 25 ppm and lethal at 500 ppm sustained exposure), mild flammability (15-28% in air with high ignition energy — unlikely to ignite without a strong spark), and chemical incompatibility with copper (which mandates steel piping). The last limitation is why ammonia is not used in residential or commercial HVAC where copper tubing is standard. Operating pressures at typical industrial conditions: −40°C evaporator = 71.6 kPa (vacuum), 40°C condenser = 1555 kPa. The very low evaporator pressure requires special sealing to prevent air ingress, which creates non-condensable gas problems in the condenser. The calculator evaluates the Gao et al. (2023) reference equation of state for any two known properties within the equation's stated range, from the triple point (−77.65°C) to 451.85°C and up to 1000 MPa; for a few pairs it reports that the state is ambiguous or cannot be resolved, for example close to the critical point.

• •Industrial cold storage: ammonia is the dominant refrigerant for large cold-storage warehouses (100,000 ft² or more). Low-temperature storage (−18°C to −30°C) for meat, seafood, and frozen foods uses ammonia extensively.
• •Ice rinks and hockey arenas: the ice surface beneath most hockey rinks is cooled by ammonia in buried tubing. System size typically 150-400 kW for a regulation rink.
• •Food processing plants: fish processing, beer brewing, wine storage, meat packing, dairy, and bakery all use ammonia refrigeration for both storage and process cooling.
• •Petrochemical and natural gas processing: LNG trains use ammonia in cascade with propane and ethane for progressive cooling toward liquefaction temperatures.
• •Pharmaceutical cold storage: vaccines, biologics, and temperature-sensitive drugs are stored in ammonia-refrigerated warehouses or freezer farms.