The world is looking for an alternative to R22 refrigerant, but there has been little real progress. Each on the so-called “environmentally friendly” refrigerant, either toxic, or is explosive, or is low efficiency and expensive. Related manufacturers and supporting compressor tech is also relatively lagging behind, the introduction of R32, R290 refrigerant more or less hidden dangers, we hope this article on R32, R290 refrigerant characteristics will help you.

Characteristics of R32 refrigerant

  • Full name: Difluoromethane
  • Molecular formula: CH2F2
  • Physical properties: Colorless, odorless, slightly combustible (A2 level).

R32 has similar thermodynamic properties to R410A.

R32 refrigerant

Characteristics of R290 refrigerant

  • Full name: Propane
  • Molecular formula: C3H8
  • Appearance and properties: colorless gas, odorless in pure form.
  • Solubility: slightly soluble in water, soluble in ether, ethanol.
  • Flash point (°C): -104.
  • Upper explosion limit % (V/V): 9.5.
  • Lower explosion limit % (V/V): 2.1.

NOTE: Flash point: the temperature at which the first flash of a mixture of vapour and air on the surface of a combustible liquid occurs in contact with fire.

R290 refrigerant

Comparison of Refrigerant Physical Properties

R22 R410A R290 R32
ODP 0.05 0 0 0
GWP 1700 2100 <20 675
Toxicity No No No No
Combustibility A1 A1 A3 A2
Filling volume (relative to R22) 1 0.8 0.45 0.7

Advantages and disadvantages relative to HFC

Refrigerant Molecular GWP ODP
R290 C3H8 3 0
R32 CH2F2 580 0
R410A R32/R125 1900 0
R22 CHF2Cl 1700 0.055

Classification of commonly used refrigerants by safety level

R290 R32 R22 R410A R134a
Lower flammable limit vol% 2.1 13.5 NA NA NA
kg/m3 0.038 0.306 NA NA NA
Automatic ignition temperature 470 648 635 N.D. 743
Minimum ignition energy mJ 0.31 30-100 NA NA NA
Burning velocity cm/s 46 6.7 NA NA NA
Heat of combustion MJ/kg 50.3 9.4 2.2 -4.4 4.2
Occupational exposure limit PPMv 1000 1000 1000 1000 1000
Safety class(ASHRAE34) A3 A2 A1 A1 A1

R32 Summary

R32 refrigerant’s global warming factor is 1/3 of R410A, and is more environmentally friendly than traditional R410A and R22 refrigerants, but R32 has some flammability.

Compared with R410A refrigerant, R32 saturation pressure is about 3% higher, exhaust temperature is about 8-15℃ higher, power is about 3-5% higher and energy efficiency ratio is about 5% higher.

Under the same working condition and the same operating frequency of the compressor, the refrigeration capacity and energy efficiency of R32 system is about 5% higher than that of R410A refrigerant.

R290 Summary

  • Health hazard: simple asphyxiation and anesthesia. Brief human exposure to 1 % propane causes no symptoms, concentrations below 10 % cause only mild dizziness, exposure to high concentrations may result in anesthesia and loss of consciousness, very high concentrations may cause asphyxiation.
  • Hazardous characteristics: flammable gas, mixed with air can form explosive mixtures, the risk of combustion and explosion when exposed to heat sources and open flames.

The amount of R290 refrigerant is only 40%~55% of R22 and R410a, which is less and more economical.

The low freezing point and greater latent heat of evaporation make the cooling speed faster per unit time, the isentropic compression ratio does less work, which makes the compressor work easier and extends the service life of the compressor; the small molecular weight and good fluidity make the delivery pressure lower and reduce the load of the compressor. Using R290 refrigerant, the energy saving rate can reach 15~35%.

Precautions for use of R32, R290 refrigerants

When welding in the user’s home, combustible materials are strictly prohibited within 2 meters of the working site. In case of accidental large leakage of refrigerant, prompt ventilation is required, taking care not to introduce ignition sources.

When the refrigeration system needs to replace parts in maintenance, the machine must be vacuumed before burning welding operation.

10 thoughts on “What are the Operating Precautions for Combustible Refrigerants R32 and R290 ?

    • szscyzl says:

      there are several options, including:
      R290 (Propane): This is a natural hydrocarbon refrigerant with zero ozone depletion potential (ODP) and low global warming potential (GWP). It is a suitable alternative for some small to medium-sized refrigeration and air conditioning systems.
      R450A and R513A: These are HFO/HFC blends with lower GWP than R32. They are suitable for use in new equipment and as retrofit options for existing systems using R32 or other HFC refrigerants.
      R454B and R466A: These are additional HFO/HFC blends with lower GWP than R32. They are also suitable for use in new equipment and as retrofit options for existing systems using R32 or other HFC refrigerants.

      • Gino says:

        Si può aggiungere a una pompa di calore di una asciugatrice che utilizza r290 con r32? Grazie.

        • Leo says:

          No, non si dovrebbe mescolare R290 con R32 in una pompa di calore per asciugatrici. Questi due refrigeranti hanno caratteristiche diverse e mescolarli può causare problemi di sicurezza e ridurre l’efficienza dell’apparecchio. È importante seguire le indicazioni del produttore e usare solo il tipo di refrigerante raccomandato.

    • Sandro says:

      Assolutamente no, il GPL è una miscela di propano e butano odorizzata, R290 è propano per refrigerazione, ad elevato livello di purezza e PRIVO DI ODORIZZANTE

  1. Dario says:

    E’ sicuro mettere un’asciugatrice con pompa di calore con R290 nella stessa stanza della caldaia a gas?

    • Leo says:

      In generale, non è consigliabile posizionare un’asciugatrice con pompa di calore che utilizza il refrigerante R290 nella stessa stanza di una caldaia a gas. R290 è un refrigerante idrocarburo, noto anche come propano, ed è infiammabile. Avere un’asciugatrice con R290 vicino a una caldaia a gas aumenta il rischio di incendio o esplosione in caso di perdite e presenza di una fonte di innesco. È essenziale assicurarsi di avere una buona ventilazione e seguire i codici e le normative di sicurezza. È meglio consultare un professionista per valutare il rischio e garantire che l’installazione rispetti tutti gli standard di sicurezza.

Leave a Reply

Your email address will not be published. Required fields are marked *