Features
Heat pump water heaters and car air conditioners, are also used as refrigerant in the binary refrigeration cycle of refrigerated showcases. When used as a hot water heater, it is characterized by being extremely high pressure and exceeding the supercritical zone and becoming a transcritical cycle. The reason why the use of CO2 , which needs to be reduced, as a refrigerant, is because it is a natural refrigerant with a LOWER GWP than the other refrigerant overwhelmingly.
| Refrigerant number | R744 |
| Name | Carbon dioxide |
| Category | Natural refrigerant |
| Molecular structure |  |
| ODP | 0 |
| GWP | 1 (carbon dioxide is the benchmark) |
| Safety classification | Nonflammable, non-toxic (A1) |