Heat transfer compositions, methods, and systems

A method of cooling in a low or medium temperature heat transfer system comprising an evaporator, a condenser and a compressor, the process comprising the steps of

• i) condensing a refrigerant comprising at least about 97% by weight of the following four compounds, with each compound being present in the following relative percentages:
• about 41 to about 49% by weight trifluoroiodomethane (CF3I);
• about 36 to about 44% by weight 1,1,1,2-tetrafluoropropene (HFO-1234yf);
• about 12 to about 15% by weight difluoromethane (HFC-32);
• and
• 1 to 3.5±0.2% by weight carbon dioxide (CO2)and ii) evaporating the composition in the vicinity of body or article to be cooled, wherein the evaporating temperature of the refrigerant in the heat transfer system is in the range of from about −40° C. to about 0° C.

A heat transfer system comprising:

• a compressor, a condenser, an evaporator, a sequestration material, and a heat transfer composition , wherein:
• (a) said heat transfer composition comprises a POE lubricant and a refrigerant comprising at least about 97% by weight of the following four compounds , with each compound being present in the following relative percentages:
• about 43 to about 47% by weight trifluoroiodomethane (CF31);
• about 38 to about 42% by weight 1,1,1,2-tetrafluoropropene (HFO-1234yf);
• about 12 to about 15% by weight difluoromethane (HFC-32);
• and
• 1 to 3.5±0.2% by weight carbon dioxide (CO2);
• and
• (b) said sequestration material is comprises:
• i. activated alumina, or
• ii. a zeolite molecular sieve comprising copper, silver, lead or a combination thereof, or
• iii. an anion exchange resin, or
• iv. a moisture-removing material, or
• v. a combination of two or more of the above.