Low GWP. R744 has an extremely low GWP of just 1 – meaning it won't play a part in accelerating climate change. Zero ozone depletion potential (ODP). With zero ODP, R744 refrigerant won't contribute to the depletion of the ozone layer.
Carbon dioxide operates at a far higher pressure than typical HFC refrigerants, therefore the leak potential increases and the component cost becomes higher.
R-22 is a refrigerant that is often used in air- conditioning equipment. Because R-22 depletes the ozone layer, production and import was further limited in 2010. In 2020, R-22 will no longer be produced or imported.
Chlorofluorocarbons (CFCs) were widely used as refrigerants until the 1980s when it was confirmed that they were the main source of harm to the ozone layer. They are also considered greenhouse gases that cause climate change.
Compared with other refrigerants CO2 operates at higher pressures which means component costs are higher and there is leak potential. Also, it is not preferable for very hot climates since it mostly operates in supercritical phase, which is not efficient for refrigeration.
Although R-744 is non-flammable, its high pressures, toxicity in high concentrations and potential for dry ice formation must be considered when applying and handling it.
R744 (CO2) is refrigerant grade CO2, used as a replacement for R134a and R404A in ultra-low, low and medium-temperature refrigeration applications.
These compounds contribute to ozone depletion, and are called ozone-depleting substances ( ODS. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform.
When it comes to the ozone hole, chlorine is the enemy. The chlorine comes from chlorofluorocarbons (CFCs, for short), which were widely used in early refrigeration and cooling systems.
Solution. Nitrogen oxide (NO) and chlorofluorocarbons are two gases that deplete the ozone layer (freons).
The plan's final stage is scheduled to be implemented on Jan. 1, 2030, at which time the government will officially ban the remaining production and import of all HCFCs. The goal is to eventually eliminate not just the production but also the use of R-22 and other HCFCs altogether.
R-410A is a hydro-fluorocarbon (HFC) which does not contribute to ozone depletion. R-410A can also absorb and release more heat than R-22.
It lined out a timeline to change the industry standard to a non-HFC refrigerant by January 1st, 2025. The American Innovation and Manufacturing Act (AIM) of 2020, which was signed by President Trump, cemented r410a's fate by mandating the EPA to reduce the production of HFCs by 85% over the next 15 years.
R744 is pure carbon dioxide.
CO2 (R744)
Exempt from the Section 608 venting prohibition, meaning it is legal to knowingly release this refrigerant to the environment; however, CO2 is not exempt from the Section 609 requirements such as use of certified refrigerant handling equipment.
HFC = HydroFluoroCarbons
The hydrofluorocarbons are refrigerants that contain no chlorine and are not harmful to the ozone layer (ODP = 0, see section 5.3). However, their impact on global warming is very large compared with traditional refrigerants.
Chlorofluorocarbon gas is the most harmful to the ozone layer. There are three most harmful gases which may destroy ozone layer namely - Chlorofluorocarbons, Hydrochlorofluorocarbons and Halons.
Stratospheric ozone is destroyed by reactions involving reactive halogen gases, which are produced in the chem- ical conversion of halogen source gases (see Figure Q8-1). The most reactive of these gases are chlorine monoxide (ClO), bromine monoxide (BrO), and chlorine and bromine atoms (Cl and Br).
Freons are colorless, odorless fluorinated chemicals used as cooling agents in refrigerators. These gases move through carefully regulated symptoms of coils and compressors converting hot air to cold air. But leakage of this coolant is harmful to humans as well as responsible for ozone depletion.
However, while HFCs have helped the ozone layer recover, they still cause some harm, resulting in the area reforming more slowly than once thought. Ozone holes still form regularly in Antarctica. While scientists expect the ozone hole to recover over time, there are still many natural forces affecting its progress.
A collection of human-made greenhouse gases known as ozone-depleting substances (ODSs), including chlorofluorocarbons that can be found in everyday products such as air conditioners, refrigerators, and aerosol cans, have been destroying the ozone layer.
Ozone is an odorless, colorless gas made up of three oxygen atoms (O3) and is a natural part of the environment. It occurs both in the Earth's upper atmosphere, or stratosphere, and at ground level in the lower atmosphere, or troposphere.
R744 is a high purity carbon dioxide (CO2) based refrigerant gas with a typical moisture content of less than 10 parts per million. The low moisture content enables the refrigerant to work more effectively and, more importantly, have less corrosive impact on your refrigeration systems. CO2 4.0 (99,99%).
However, R-744 is unlikely to be used as a refrigerant in some applications because of its high working pressure. This creates challenges in the design and operation of refrigeration systems and can increase costs.
R744 (CO2) was first adopted by Mercedes in the S-Class in 2017, although it has since dropped this approach. VW's ID EVs on the MEB platform use R744 in models that have a heat pump. R744, by definition, has a GWP of 1.