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R-134a Properties Calculator

Comprehensive R-134a refrigerant property lookup: enter any two properties to get T, P, v, h, s, u, quality, and state (saturated/superheated)

Reviewed by Christopher FloiedUpdated

This free online r-134a 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.

R-134a (Tetrafluoroethane) Properties Calculator

Enter any two properties to find the complete thermodynamic state of R-134a refrigerant. Saturated data from -40 to 101°C (critical point). Superheated data at key pressures.

State: Saturated (showing sat. liquid)

Complete Thermodynamic State

Temperature T20.00 °C
Pressure P570.00 kPa
Specific Volume v8.10000e-4 m³/kg
Enthalpy h84.80 kJ/kg
Entropy s0.3364 kJ/(kg·K)
Internal Energy u84.70 kJ/kg
Quality x0.0000

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the R-134a 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 R-134a 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

R-134a 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 R-134a 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 R-134a Properties Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Comprehensive R-134a refrigerant property lookup: enter any two properties to get T, P, v, h, s, u, quality, and state (saturated/superheated) 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

R-134a (1,1,1,2-Tetrafluoroethane, CH₂FCF₃) is a hydrofluorocarbon (HFC) refrigerant that replaced R-12 (CFC) in automotive air conditioning and medium-temperature refrigeration applications following the Montreal Protocol's CFC phaseout. R-134a has zero ozone depletion potential (unlike CFCs) but has a global warming potential (GWP) of 1430, making it a target for replacement under the Kigali Amendment to the Montreal Protocol. Its thermodynamic properties are well-characterized in ASHRAE and NIST databases, with the most accurate formulation being the Tillner-Roth and Baehr (1994) equation of state, adopted by NIST REFPROP. Key properties at standard conditions: normal boiling point −26.1°C (just below the freezing point of water, making it unsuitable for low-temperature refrigeration), critical temperature 101.06°C, critical pressure 4.059 MPa, molecular weight 102.03 g/mol. The vapor pressure curve sets the relationship between evaporator temperature and pressure: at 0°C, P_sat ≈ 293 kPa; at 40°C, P_sat ≈ 1017 kPa. For a vapor-compression refrigeration cycle, these pressures define the low and high pressure sides of the system. The latent heat of vaporization is 217 kJ/kg at 0°C, relatively high for an HFC and giving good cooling capacity per unit mass flow. Specific heat of liquid is about 1.45 kJ/(kg·K) and of vapor 0.91 kJ/(kg·K) at 0°C. The saturation dome is wide, allowing substantial superheat and subcooling without crossing saturation. The calculator provides look-up and interpolation of saturation properties (T, P, v_f, v_g, h_f, h_fg, h_g, s_f, s_g) and two-phase quality calculations for R-134a-based refrigeration and heat pump analysis.

Real-World Applications

  • Automotive air conditioning: R-134a is the standard refrigerant for mobile AC in most vehicles built after 1994, replacing the ozone-depleting R-12. System designers use the property tables to size components and predict cycle performance.
  • Domestic refrigerators and freezers: medium-temperature refrigeration (0°C evaporator) uses R-134a for refrigerator applications. Freezers typically use R-404A or other low-temperature refrigerants.
  • Commercial chillers and heat pumps: water-cooled chillers in commercial HVAC historically used R-134a. Current-generation units often use R-1234yf or other low-GWP alternatives due to climate regulations.
  • Cascade refrigeration systems: R-134a is the high-temperature stage in cascade systems for ultra-low temperature applications, paired with R-23 or CO₂ for the low temperature stage.
  • Training and education: R-134a is the most common refrigerant used in university HVAC/refrigeration courses, with extensive published property tables and cycle analysis examples.

Frequently Asked Questions

What is R-134a?

R-134a is 1,1,1,2-tetrafluoroethane (CH₂FCF₃), an HFC refrigerant introduced in the 1990s to replace R-12 (CFC-12) after CFCs were banned due to ozone depletion. R-134a has zero ozone depletion but GWP of 1430, making it a greenhouse gas. It is the standard automotive AC refrigerant and has been widely used in residential refrigeration and medium-temperature commercial systems.

What's the boiling point of R-134a?

The normal (atmospheric) boiling point is −26.1°C at 101.325 kPa. In refrigeration systems, R-134a operates at higher pressures: an evaporator at 0°C runs at about 293 kPa, and a condenser at 40°C runs at about 1017 kPa. The pressure ratio (about 3.5) is typical for mobile AC systems. At atmospheric pressure, R-134a is a gas that rapidly evaporates if released.

Why was R-134a chosen to replace R-12?

R-134a has similar thermodynamic properties to R-12 (boiling point, vapor pressures, cooling capacity), making retrofit of existing systems feasible with minimal hardware changes (new oils, slightly larger evaporators). It has zero ozone depletion potential (R-12 had 1.0) and is non-toxic, non-flammable, and chemically stable. The main drawback is its GWP of 1430, which has led to the current transition to lower-GWP refrigerants like R-1234yf (GWP 4).

What's replacing R-134a?

R-1234yf (2,3,3,3-tetrafluoropropene) is the main replacement for automotive AC, with GWP of about 4 (500x lower than R-134a). R-513A, R-450A, and R-515A are blends used in chillers and commercial refrigeration. Each has trade-offs: R-1234yf is mildly flammable (A2L), R-513A has similar flammability characteristics, and performance varies slightly from R-134a in existing systems.

How do I compute cycle performance with R-134a?

Look up saturated properties at the evaporator and condenser pressures, then compute the vapor-compression cycle states: (1) saturated vapor at evaporator pressure (state 1, compressor inlet); (2) superheated vapor at condenser pressure (state 2, compressor outlet, from isentropic compression or with isentropic efficiency); (3) saturated liquid at condenser pressure (state 3, condenser outlet); (4) two-phase at evaporator pressure (state 4, throttle outlet, constant enthalpy from state 3). Compute COP = (h₁ − h₄)/(h₂ − h₁) from these enthalpies.

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References & Further Reading