Why are some hydrofluoroolefin HFO refrigerant classified as A2L?
HFO refrigerants generally fall in the category of A2L refrigerants because they contain fluorine. Fluorine makes HFO refrigerants less flammable than hydrocarbon refrigerants, which are highly flammable.
R-1234ze is an HFO and is classified as A2L, but, as previously noted, it is actually non-flammable at temperatures below 300C. R-1234yf is a closer match to the performance of R-134a, which makes it suitable for use in chillers where the system is designed to use a lower flammability refrigerant.
The notable difference between A2 and A2L refrigerants is the burning velocity, which is < 10 cm/s for A2L while it is > 10 cm/s for A2. This difference allows a higher charge of A2L refrigerants because the risks are considerably reduced (10 cm/s).
The A2L subgroup, as categorized by ASHRAE Standard 34, are a class of refrigerants that have lower toxicity and flammability (flame propagation speed is less than 10 cm/s) compared to other classifications — A = non-toxic, 2 = flammable, L = low burning velocity — making it the second-safest refrigerant category.
While A2Ls are mildly flammable, they are less flammable than Class 3 refrigerants and are safe when handled properly. Like all refrigerants, specific codes and standards apply to A2Ls. A2L refrigerants, or A2Ls, are used in refrigeration systems around the world, making sure that cold items stay cold.
In summary, A2L refrigerants are not toxic but mildly flammable refrigerants, and most HFOs as well as R-32 belong to this category. The definition alone suggests a pro and a con of this class of refrigerant: they are less flammable than A2 and A3 refrigerants but more flammable than A1 refrigerants.
HFO refrigerants are categorised as having zero ODP (Ozone Depletion Potential) and low GWP and so offer a more environmentally friendly alternative to CFCs, HCFCs and HFCs.
Many refrigerants in the HFO class are inherently stable chemically and inert, non toxic, and non-flammable or mildly flammable. Many HFOs have the proper freezing and boiling points to be useful for refrigeration at common temperatures.
The hydrofluoroolefins are the synthetic refrigerants having zero ODP, low GWP and extremely short atmospheric lifetime. The fluorinated isomers also can be identified as for example HFO-1234ye, HFO-1234yf. When a carbon-carbon double bond exist is stereoisomers may exist.
In this case, A2L has lower flammability and toxicity compared to other classifications—making it the second safest refrigerant category.
What states allow A2L refrigerants?
What's in Your State? Connecticut, Florida, North Carolina, Ohio, Oregon, South Carolina, Utah, Washington, and West Virginia have already updated their state building codes to allow for the use of A2L refrigerants in air conditioners.
This is the substantial difference between a refrigerant in class A3 and a refrigerant in class A2L: the sufficient refrigerant quantity in air to generate a combustion is ≤ a 3% in case of an A3 and higher than this value in case of A2L.
A1 vs A2 Materials
A1 materials are completely non-combustible while A2 materials have very limited combustibility. While A1 materials have no contribution to fire, A2 materials have limited contribution to fire. Stringent tests must be passed in order for construction products to reach a Class A rating.
They are divided into two groups: HC refrigerants and inorganic refrigerants. The following are natural refrigerants: 1) various hydrocarbons (HC), 2) carbon dioxide (R744), 3) ammonia (R717), 4) water (R718) and 5) air.
There are four main groups of refrigerants and they are determined by their chemical constituents but are generally classified as Chlorofluorocarbons (CFCs), Hydro chlorofluorocarbons (HCFCs), Hydro fluorocarbons (HFCs) and Natural Refrigerants [7]. ...
Refrigerants are divided into groups according to their chemical composition. Following the discovery that some of these chemical compounds may be harmful to the environment, they are being replaced with more environmentally friendly alternatives (see Figure 5.2).
Please remember that using the wrong type of refrigerant for your system can create a hazard or cause serious damage so it is very important to get it right.
R-134a is one of the world's most used refrigerants, widely embedded in automotive, commercial and residential air conditioning systems, across the world. R-32 is another commonly used, as an attractive lower GWP solution for air conditioning.
HFOs are miscible in Polyolester (POE)-type lubricating oils.
Propane has excellent thermodynamic properties, leading to high energy efficiency. For instance, the latent heat of vaporisation of propane is almost two times higher than that of the most common HFC refrigerants: this means a higher cooling/heating effect for the same refrigerant mass flow.
What are the benefits of HFO refrigerant?
- Energy Efficient. HFO refrigerants reduce emissions over the equipment lifecycle for key applications, like air conditioning and refrigeration. ...
- Lower Cost. Greater efficiency means lower running costs for use in supermarkets, heat pumps, cold transport and much more. ...
- Safe and Reliable.
HFO may have a composition of 88 wt% C, 10 wt% H, 1 wt% S, 0.5 wt% H2O, 0.1 wt% ash, and may contain dispersed solid or semisolid particles (asphaltenes, minerals and other leftovers from the oil source, metallic particles from the refinery equipment, and some dumped chemical wastes), plus some 0.5% water.
HFO-1234yf can be described as being “mildly flammable” as measured by standard methodology.
R-1234yf is an HFO refrigerant.
The ideal refrigerant is nontoxic, noncorrosive, has PVT and physical properties compatible with the system needs, and has a high latent heat of vaporization.
This colorless gas is being used as a replacement for R-134a as a refrigerant in automobile air conditioners. As of 2022, 90% of new U.S. vehicles from original equipment manufacturers (OEMs) are estimated to use HFO-1234yf.
HFOs Are Replacing HFCs (For the Better!)
HFO stands for hydrofluoroolefin. The chemical is also made of hydrogen, fluorine, and carbon. However, unlike HFCs, HFOs have zero ODP (Ozone Depletion Potential) and low GWP, making them a more environmentally-friendly option than HFCs.
Hydrofluoroolefin (HFO) refrigerants are unsaturated organic compounds composed of carbon, hydrogen and fluorine.
Toxicity. The refrigerant toxicity classification has 400 ppm Occupational Exposure Limit (OEL) as the divide between higher and lower toxicity refrigerants. All widely used HFCs (except HFC-245fa), HFOs and HCFOs are classed as low toxicity, with OELs in the range 400 to 1000 ppm.
Which of the following must be recorded on the label of A2L equipment upon the completion of a system installation? Date that the pressure test and evacuation was completed.
Which refrigerant classification would indicate least toxicity?
Refrigerant Toxicity
There are two classes for toxicity: lower toxicity (Class A) and higher toxicity (Class B).
A1 classified refrigerants such as HFC R-407C and HFC R-410A have no flame propagation and low toxicity1. B1 classified refrigerants such as R-10, R-21 and the rather obscure R-764 sulfur dioxide2 have no flame propagation but higher toxicity.
Some HFOs, which have very low global warming potential, are mildly flammable and are classified as A2L. This indicates that they are of lower toxicity and have low burning velocity.
Question #1: Which of the following refrigerants is not used in Type II systems? R-245fa is not a high-pressure refrigerant and is not used in Type II systems.
The Occupational Safety and Health Administration (OSHA) requires that if flammable refrigerant cylinders are to be stored in an enclosure, the enclosure be secure and ventilated. They cannot be enclosed in confined spaces, containers, or lockers.
An A2 certified product has a higher combustibility and can sustain flame for no more than 20 seconds. In contrast, A1 has a lower combustibility and no sustained flaming when tested. Crucially, a product can be certified as A2 even if it gives off an unlimited amount of smoke and unlimited flaming particles/droplets.
The first letter gives a classification based on the combustibility and contribution to fire: A1 and A2 is non-combustible, B till D go from very limited to medium contribution to fire and E and F go to high contribution to easily flammable.
“Class II” ozone-depleting substances ( ODS. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform.
Refrigeration & Equipment Engineering (1+1)
The primary refrigerant which directly take part in the refrigeration system. Where as the refrigerant which are first cooled by primary refrigerants and then used for cooling purpose is called secondary refrigerants.
Class I includes the fully halogenated CFCs, halons, and the ODSs that are the most threatening to the ozone layer. Class II compounds are those substances that are known or reasonably anticipated to have harmful effects on the stratospheric ozone layer. Class II substances are all hydrochlorofluorocarbons (HCFC).
What is a2 refrigerant classification?
The A2L subgroup, as categorized by ASHRAE Standard 34, are a class of refrigerants that have lower toxicity and flammability (flame propagation speed is less than 10 cm/s) compared to other classifications — A = non-toxic, 2 = flammable, L = low burning velocity — making it the second-safest refrigerant category.
For example, Standard 34 defines two safety classifications for toxicity. Class A denotes refrigerants of lower toxicity, and class B denotes refrigerants of higher toxicity.
Hydrochlorofluorocarbons, or HCFCs, are chemicals that are mainly used as refrigerants. Unfortunately, releases of HCFCs deplete the Earth's protective ozone layer and contribute to climate change. R-22 is an HCFC refrigerant that is often used in air-conditioning equipment.
This is the substantial difference between a refrigerant in class A3 and a refrigerant in class A2L: the sufficient refrigerant quantity in air to generate a combustion is ≤ a 3% in case of an A3 and higher than this value in case of A2L.
exactly are HFOs? Hydrofluoroolefins (HFO's) are a family of unique compounds compared to the compounds previously developed for commercial use for heat transfer, blowing agent, solvent and propellant applications.
Classified as mildly flammable (A2L), R454B allows for a much higher charge size than other flammable refrigerants and can be safely used by following the applicable codes and standards.
HFO stands for hydrofluoroolefin. The chemical is also made of hydrogen, fluorine, and carbon. However, unlike HFCs, HFOs have zero ODP (Ozone Depletion Potential) and low GWP, making them a more environmentally-friendly option than HFCs. HFOs don't trap heat in our atmosphere and don't contribute to global warming.
The hydrofluoroolefins are the synthetic refrigerants having zero ODP, low GWP and extremely short atmospheric lifetime. The fluorinated isomers also can be identified as for example HFO-1234ye, HFO-1234yf. When a carbon-carbon double bond exist is stereoisomers may exist.
R454b refrigerant has been used in the HVAC industry for many years, but it has recently been phased out due to its negative impact on the environment.
R454B is a “mildly flammable” A2L refrigerant blend of 68.9% R32 and 31.1% 1234yf. It has a GWP of 466. Chemours claims it offers improved energy efficiency, similar capacity, and excellent design compatibility. R513A is a non-toxic, non-flammable A1 refrigerant with a GWP of 631.
Can R-454B be used in a R410A system?
In general, these results show that R452B and R454B are good replacement candidates for R410A for heat pump using tube-fin heat exchangers and microchannel heat exchangers.