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Ammonia (NH3) Properties Calculator

Ammonia refrigerant property lookup for industrial refrigeration: saturated and superheated tables with two-property state determination

Reviewed by Christopher FloiedUpdated

This free online ammonia (nh3) properties calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Supports both metric (SI) and imperial units with built-in unit selection dropdowns on every input field, so you can work in whatever units your problem provides. Designed for engineering students and professionals working through coursework, design projects, or quick reference calculations.

Ammonia (NH3) Properties Calculator

Enter any two properties to find the complete thermodynamic state of ammonia. Saturated data from -60 to 132°C (critical point). Common in industrial refrigeration systems.

State: Saturated Mixture (Two-Phase)

Complete Thermodynamic State

Temperature T-10.00 °C
Pressure P291.60 kPa
Specific Volume v0.210007 m³/kg
Enthalpy h787.00 kJ/kg
Entropy s2.8247 kJ/(kg·K)
Internal Energy u728.00 kJ/kg
Quality x0.5000

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Ammonia (NH3) Properties Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.

3

Read the results

The Ammonia (NH3) Properties Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.

4

Explore parameter sensitivity

Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.

Formula Reference

Ammonia (NH3) Properties Calculator Formula

See calculator inputs for the governing equation

Variables: All variables and their units are labeled in the calculator interface above. Input fields accept values in multiple unit systems — select your preferred unit from the dropdown next to each field.

When to Use This Calculator

  • Use the Ammonia (NH3) Properties Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations — instant feedback 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.

About This Calculator

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: saturated and superheated tables with two-property state determination All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Inputs support both metric (SI) and imperial unit systems, with unit conversion handled automatically — simply select your preferred unit from the dropdown next to each field. Results are computed instantly in the browser without sending data to a server, ensuring both speed and privacy. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

The Theory Behind It

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 −33.34°C (good for low-temperature refrigeration down to about −60°C), critical temperature 132.25°C, critical pressure 11.33 MPa (higher than most refrigerants), molecular weight 17.03 g/mol (low, giving high volumetric cooling capacity), and very high latent heat of vaporization 1371 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 = 71.8 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 supports saturated and superheated ammonia property lookup over the industrial refrigeration range.

Real-World Applications

  • 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.

Frequently Asked Questions

Why is ammonia used in industrial refrigeration?

Four main reasons: (1) high latent heat of vaporization (1371 kJ/kg at 0°C) gives high cooling capacity per unit mass flow; (2) zero GWP and zero ODP make it environmentally excellent; (3) low cost compared to HFCs and HFOs; (4) natural refrigerant with no synthetic chemistry required. The main barriers to wider use are toxicity (irritant at low concentrations, lethal at high) and incompatibility with copper, which makes it unsuitable for residential and most commercial HVAC applications that rely on copper tubing.

Is ammonia dangerous?

Yes, ammonia is toxic. OSHA sets permissible exposure limit (PEL) at 50 ppm time-weighted average for 8 hours. Immediate danger to life and health (IDLH) is 300 ppm. Short-term (15 min) exposure limit is 35 ppm. Ammonia's pungent smell is detectable at about 5 ppm, giving early warning of leaks well below harmful concentrations. Industrial systems have leak detection, ventilation, and emergency response procedures to manage the risk. Despite toxicity, the safety record of properly-designed and maintained ammonia systems is excellent — hundreds of thousands of systems operate worldwide.

Why can't ammonia be used with copper?

Ammonia corrodes copper and copper alloys aggressively, especially in the presence of moisture. This chemical incompatibility means all ammonia refrigeration equipment must use steel piping, steel condenser tubes, and steel fittings. Copper-free design adds cost and limits available component selection, making ammonia systems more expensive than equivalent HFC systems in small sizes. At industrial scale, the cost difference is offset by the lower refrigerant cost and better efficiency.

What's the environmental advantage of ammonia?

Ammonia has zero ozone depletion potential (unlike CFCs and HCFCs), zero global warming potential (unlike HFCs), and zero smog formation. It is a 'natural refrigerant' — the ammonia atmospheric lifetime is short (days, not centuries like HFCs) and breaks down into N₂ and H₂O. From a climate perspective, ammonia is the best available refrigerant. The toxicity and flammability trade-offs restrict its application to industrial settings with proper engineering controls.

How does ammonia's latent heat compare to other refrigerants?

Ammonia has exceptionally high latent heat of vaporization at refrigeration temperatures: 1371 kJ/kg at 0°C, about 6× higher than R-134a (217 kJ/kg). This means that for the same cooling duty, an ammonia system needs 1/6 the refrigerant mass flow, which translates to smaller compressor displacements and smaller pipe sizes. The high latent heat is primarily due to ammonia's small molecular weight (17 g/mol) and strong hydrogen bonding in the liquid phase.

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References & Further Reading