Briton Refrigerant R744 (Carbon dioxide)
Briton Refrigerant R744, 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 even less global warming potential than hydrocarbons. It also has excellent thermodynamic properties and low energy usage making it suitable for a range of applications such as industrial heat extraction, chilled warehousing, shipping vessels, commercial refrigeration, and mobile air conditioning. One major difference between R744 and other refrigerants is its pressure/temperature characteristic: because of its high pressure and low critical temperature, refrigeration systems require special equipment designs.
Briton Refrigerant R744 – CO2 – Use and Applications
Briton Refrigerant R744 (Carbon dioxide) has many applications: in gas form, for example, it is used in the food industry for cooling, storage and pH management purposes. 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 alongside ammonia.
As a refrigerant, it does not function exactly the same as hydrocarbons and the operating pressures may also be elevated as a result. For this reason, the efforts to develop improved equipment are ongoing to enable wider use of carbon dioxide. An asset of carbon dioxide plants is that the pipe size is significantly smaller than with other refrigerants.
Various plants that utilise carbon dioxide have been in test operation for many years. C02 is suited to refrigeration plants with either direct evaporation or pump circulation. It is an excellent refrigerant for freezing plants, in which it can provide evaporation temperatures of up to -50°C.
Physical Properties of Briton Refrigerant R744 (Carbon dioxide)
|Molecular Weight (lb/mol)||44.01|
|Critical Temp. (°F)||87.9|
|Critical Pressure (psia)||1071.0|
|Boiling Point (°F)||-109.2|
|Melting Point (°F)||-69.9|
|Psat @ 70°F (psia)||852.8|
|Liquid Density @ 70°F (lb/ft3)||47.64|
|Gas Density @ 70°F 1 atm (lb/ft3)||0.1144|
|Specific Volume @ 70°F 1 atm (ft3/lb)||8.74|
|Specific Heat @ 70°F (Btu/lbmol-°F)||8.92|