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Refrigerant Properties Calculator

Saturation tables for R290 (Propane), R744 (CO2), R32, R410A, and R134a. Look up pressure, density, enthalpy, latent heat, and specific heat at any temperature.

Select a refrigerant and temperature below. Properties are interpolated from ASHRAE reference data. Natural refrigerants R290 and CO2 are highlighted — the future of sustainable heating and cooling.

Saturation Property Lookup

Saturated liquid-vapour equilibrium
Range: -40°C to +80°C
-40°C 80°C
GWP 3 ✓ Natural Refrigerant
Saturation Pressure
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bar
Liquid Density
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kg/m³
Vapour Density
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kg/m³
Liquid Enthalpy hf
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kJ/kg
Vapour Enthalpy hg
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kJ/kg
Latent Heat hfg
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kJ/kg
Cp Liquid
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kJ/kg·K

Full Saturation Table — R290 (Propane)

T (°C) P (bar) ρL (kg/m³) ρV (kg/m³) hf (kJ/kg) hg (kJ/kg) hfg (kJ/kg) Cp,L (kJ/kg·K)

Key Thermodynamic Relationships

Clausius-Clapeyron Equation

Pressure-Temperature Slope Along Saturation Curve
Relates the slope of the saturation pressure curve to latent heat and the specific volume change between phases. Fundamental to understanding how saturation pressure varies with temperature for every refrigerant.

Antoine Equation (P-T Approximation)

Log-Linear Pressure-Temperature Relationship
An empirical correlation widely used to approximate saturation pressure as a function of temperature. Constants A, B, C are specific to each refrigerant and are fitted to ASHRAE or NIST reference data.

Latent Heat of Vaporisation

Energy Required for Phase Change
The latent heat is the difference between vapour and liquid enthalpies at saturation. It determines how much energy a refrigerant can absorb in the evaporator per unit mass — critical for heat pump and refrigeration cycle design.

Need help selecting the right refrigerant?

Karnot builds high-efficiency heat pumps using R290 and CO2 — natural refrigerants with near-zero GWP. Talk to our engineering team about the best solution for your application.

Contact Karnot Engineering

Frequently Asked Questions

What are natural refrigerants and why do they matter?

Natural refrigerants are substances that occur in nature and have negligible environmental impact. R290 (propane, GWP 3) and R744 (CO2, GWP 1) are the two most common natural refrigerants used in heat pumps and refrigeration. They are not subject to the Kigali Amendment phase-down schedule that applies to high-GWP HFC refrigerants like R410A (GWP 2,088) and R134a (GWP 1,430). Karnot Heat Pumps use R290 and R744 exclusively.

What is the Kigali Amendment HFC phase-down?

The Kigali Amendment to the Montreal Protocol is an international agreement to phase down the production and consumption of hydrofluorocarbons (HFCs). Developed countries must reduce HFC consumption by 85% by 2036, while developing countries follow staggered schedules. High-GWP refrigerants like R410A and R134a are being replaced by lower-GWP alternatives including R32, R290, and R744 (CO2).

How do I read a refrigerant saturation table?

A saturation table lists thermodynamic properties at the point where liquid and vapour coexist in equilibrium. For a given saturation temperature, you can read the corresponding saturation pressure, liquid density, vapour density, liquid enthalpy (hf), vapour enthalpy (hg), and latent heat (hfg = hg − hf). The latent heat is the energy absorbed or released during phase change and is critical for sizing evaporators and condensers.

Why does latent heat decrease as temperature increases?

As temperature rises toward the critical point, the difference between liquid and vapour phases diminishes. Liquid density decreases while vapour density increases, and their enthalpies converge. At the critical point, the distinction between liquid and vapour disappears entirely, and latent heat drops to zero. This is why refrigeration systems become less effective as condensing temperatures rise — there is less latent heat available per kilogram of refrigerant.