R-32 pressure–temperature table and P–h diagram
Difluoromethane — a single-component HFC. Saturation pressure from −70 to 76 °C, every 2 K, and a pressure–enthalpy diagram to read any state from, computed with CoolProp. Also written R32.
Safety class A2LGWP 675 (AR4), 771 (AR6)ODP 0Sources
Pressure–enthalpy diagram
Point anywhere on the diagram to read the state there
- Pressure
- —
- Temperature
- —
- Specific enthalpy
- —
- Specific entropy
- —
- Density
- —
- Specific volume
- —
- Saturation
- —
- Superheat or subcooling
- —
Values come from a CoolProp 7.2.1dev tabulation of R-32 (91 pressures, each with states across its liquid, two-phase and vapour spans), interpolated between the points of that grid, and must be verified by a qualified professional before they're relied on.
Enthalpy and entropy are on the IIR datum: h = 200 kJ/kg and s = 1 kJ/(kg·K) for saturated liquid at 0 °C.
Where CoolProp gives no state — outside its equation's range of −136.8 to 161.9 °C, for one — the diagram is shaded, the readout says "Not solved here" and nothing is filled in.
Points
| Reading | Value |
|---|---|
| Critical temperatureCoolProp, from its equation of state | 78.11°C |
| Critical pressureCoolProp, from its equation of state | 5,782.7kPa |
| Normal boiling pointAt 101.325 kPa, solved by CoolProp | −51.65°C |
Saturation pressure
| T (°C) | P (kPa abs) | P (bar g) |
|---|---|---|
| −70 | 36.1 | −0.65 |
| −68 | 40.8 | −0.61 |
| −66 | 46.0 | −0.55 |
| −64 | 51.7 | −0.50 |
| −62 | 58.0 | −0.43 |
| −60 | 65.0 | −0.36 |
| −58 | 72.5 | −0.29 |
| −56 | 80.8 | −0.21 |
| −54 | 89.8 | −0.12 |
| −52 | 99.5 | −0.02 |
| −50 | 110.1 | 0.09 |
| −48 | 121.6 | 0.20 |
| −46 | 134.0 | 0.33 |
| −44 | 147.4 | 0.46 |
| −42 | 161.9 | 0.61 |
| −40 | 177.4 | 0.76 |
| −38 | 194.1 | 0.93 |
| −36 | 212.0 | 1.11 |
| −34 | 231.1 | 1.30 |
| −32 | 251.6 | 1.50 |
| −30 | 273.4 | 1.72 |
| −28 | 296.7 | 1.95 |
| −26 | 321.6 | 2.20 |
| −24 | 348.0 | 2.47 |
| −22 | 376.0 | 2.75 |
| −20 | 405.8 | 3.04 |
| −18 | 437.3 | 3.36 |
| −16 | 470.7 | 3.69 |
| −14 | 506.0 | 4.05 |
| −12 | 543.3 | 4.42 |
| −10 | 582.6 | 4.81 |
| −8 | 624.1 | 5.23 |
| −6 | 667.9 | 5.67 |
| −4 | 713.9 | 6.13 |
| −2 | 762.3 | 6.61 |
| 0 | 813.1 | 7.12 |
| 2 | 866.5 | 7.65 |
| 4 | 922.5 | 8.21 |
| 6 | 981.1 | 8.80 |
| 8 | 1,042.6 | 9.41 |
| 10 | 1,106.9 | 10.06 |
| 12 | 1,174.2 | 10.73 |
| 14 | 1,244.5 | 11.43 |
| 16 | 1,317.9 | 12.17 |
| 18 | 1,394.6 | 12.93 |
| 20 | 1,474.6 | 13.73 |
| 22 | 1,558.0 | 14.57 |
| 24 | 1,644.8 | 15.44 |
| 26 | 1,735.3 | 16.34 |
| 28 | 1,829.5 | 17.28 |
| 30 | 1,927.5 | 18.26 |
| 32 | 2,029.4 | 19.28 |
| 34 | 2,135.3 | 20.34 |
| 36 | 2,245.4 | 21.44 |
| 38 | 2,359.7 | 22.58 |
| 40 | 2,478.3 | 23.77 |
| 42 | 2,601.4 | 25.00 |
| 44 | 2,729.2 | 26.28 |
| 46 | 2,861.6 | 27.60 |
| 48 | 2,998.9 | 28.98 |
| 50 | 3,141.2 | 30.40 |
| 52 | 3,288.7 | 31.87 |
| 54 | 3,441.5 | 33.40 |
| 56 | 3,599.7 | 34.98 |
| 58 | 3,763.6 | 36.62 |
| 60 | 3,933.2 | 38.32 |
| 62 | 4,108.9 | 40.08 |
| 64 | 4,290.9 | 41.90 |
| 66 | 4,479.3 | 43.78 |
| 68 | 4,674.5 | 45.73 |
| 70 | 4,876.8 | 47.75 |
| 72 | 5,086.7 | 49.85 |
| 74 | 5,304.6 | 52.03 |
| 76 | 5,531.5 | 54.30 |
Gauge pressure is absolute pressure less a standard atmosphere, 101.325 kPa; below it, gauge pressure is negative.
Identity
- Designation
- R-32 (also written R32)
- Name
- Difluoromethane
- Formula
- CH₂F₂
- Kind
- single-component HFC
Environment and safety
- Safety class
- A2LLower toxicity, lower flammability. The class assigned in ISO 817 or ANSI/ASHRAE 34, as tabled in UNEP RTOC 2018; the Australian Government lists A2L (AS/NZS ISO 817).
- GWP, 100-year (AR4)
- 675IPCC AR4 (2007).
- GWP, 100-year (AR6)
- 771IPCC AR6 (2021).
- ODP
- 0Not an ozone-depleting substance in the Montreal Protocol's annexes.
Two GWPs, both for a 100-year horizon. AR4 is the assessment that Australia's Ozone Protection and Synthetic Greenhouse Gas Management Act 1989 and the Montreal Protocol count HFCs in, so it is the figure behind Australia's HFC import phase-down (DCCEEW). The Montreal Protocol's Annexes A, C and F list the same AR4 figures for the CFCs, HCFCs and HFCs they control. AR6 is the IPCC's most recent assessment. The GHG Protocol's table of IPCC GWPs (version 2.0, August 2024) recommends using these latest values.
Sources
- UNEP RTOC 2018: Annex I to Chapter 2, Tables 2.I-1 to 2.I-3: safety classes as assigned in ISO 817:2014 or ANSI/ASHRAE Standard 34-2016.
- DCCEEW (Australian Government): Hydrofluorocarbon refrigerants – global warming potential values and safety classifications (last updated 13 December 2024): AR4 GWPs as used under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989, safety classes from AS/NZS ISO 817:2016.
- IPCC AR4 (2007): Working Group I, Chapter 2, Table 2.14, 100-year GWP (as corrected in the Working Group I errata).
- IPCC AR6 (2021): Working Group I, Chapter 7 Supplementary Material, Table 7.SM.7, GWP-100.
- Montreal Protocol: Annex A, Group I (CFCs), and Annex C, Group I (HCFCs): ozone-depleting potentials.
- GHG Protocol (2024): IPCC Global Warming Potential Values, version 2.0 (7 August 2024): the recommendation to use AR6.
Source
- Computed with
- CoolProp 7.2.1dev, HEOS backend — open-source software under the MIT licence
- Fluid
- R32, CoolProp's pure-fluid model
- Equation of state
- TillnerRoth-JPCRD-1997 (CoolProp’s reference key)
- Cite
- Bell, I.H., Wronski, J., Quoilin, S., Lemort, V. (2014). Pure and pseudo-pure fluid thermophysical property evaluation and the open-source thermophysical property library CoolProp. Ind. Eng. Chem. Res. 53(6), 2498-2508.
Related
Use R-32 in Kelvin
Kelvin’s Free plan includes the refrigerant library, P–h diagrams, single-stage cycles and draft reports. Paid plans carry a system on through pipework, equipment, charge, energy and cost to issued reports.
Verify before relying on these figures
The property figures are computed with CoolProp from published equations of state. The GWP, ODP and safety class are the named sources’ figures, a blend’s GWP and ODP summed from its composition. They must be verified by a qualified professional before they’re relied on.