The refrigerant R744 gas, i.e. carbon dioxide (CO2), is an environmentally friendly refrigerant. Its ODP is zero and its GWP is as low as 1, which means that it has an even lower global warming potential than hydrocarbons.
R744 gas applications and use
Carbon dioxide has many applications: in gaseous form, for example, it is used in the food industry for cooling, preservation and pH control. Carbon dioxide prevents microbial growth, which means that it is used as a packaging gas for many food products. Carbon dioxide is often used as a secondary refrigerant together with ammonia.
As a refrigerant, R744 gas does not work in exactly the same way as hydrocarbons, and as a result operating pressures can also be high. For this reason, efforts are under way to develop improved equipment to enable wider use of carbon dioxide. One advantage of carbon dioxide systems is that pipe sizes are significantly smaller than with other refrigerants.
Various systems using carbon dioxide have been in operation for many years. CO2 is suitable for refrigeration systems with direct expansion or pump circulation. It is an excellent refrigerant for freezing systems, where it can provide evaporating temperatures down to -50 °C.
Many carbon dioxide systems are already in use in Europe, and this experience will be useful in developing and building new systems.
Alternative refrigerants to R744 refrigerant gas
Replacement or alternative R134a, R404A, R22
