TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: In the composition, the first component comprises R-1234ze(E). The composition comprises at least 15% by weight R-1234ze(E); up to 35%, preferably 30% by weight R-744; and up to about 60% by weight of the third component, preferably up to about 50% by weight, where the third component is selected from R-32, R-152a, R-161, 1R-134a, R-1234yf, R-1243zf, R1270, R-290 and mixtures. The composition comprises 10-95% R-1234ze(E) by weight, 2-30% by weight R-744, and 3-60% by weight of the third component. The composition has a critical temperature of greater than 65 degrees C, preferably greater than about 70 degrees C. The third component comprises R-134a, preferably 2-50% R-134a. The composition comprises 20-94% by weight R-1234ze(E), 2-30% by weight R-744 and 4-50% by weight R-134a. The third component comprises R-32, preferably 2-30% by weight R-32. The composition comprises 60-91% by weight R-1234ze(E), 4-30% by weight R-744 and 5-30% by weight R-32, preferably comprising 58-85% R1234ze(E), 10-28% by weight R-744 and 5-30% by weight R-32. The third component comprises R-152a, preferably 2-50% by weight R-152a. The composition comprises 30-94% R1234ze(E), 4-30% by weight R-744 and 2-40% by weight R-152a. The third component comprises R-161, preferably 2-30% by weight R-161. Also, the third component comprises propylene and/or propane, optionally where the compositions contain 1-20% by weight of the third component, preferably 1-12% of the third component. The third component comprises R-1234y1, preferably 4-60% by weight R-1234yf; R-1243zf, preferably 4-60% by weight R-1243zf; R-263fb, preferably in an amount up to about 50% by weight; R-245eb, preferably in an amount up to 30% by weight; n-butane, preferably in an amount up to 20% by weight; isobutane, preferably in an amount up to 20% by weight; ammonia, preferably in an amount up to 30% by weight. The composition further comprises R-134a, preferably 5-50% by weight R-1 34a; and pentafluoroethane (R-125). Alternatively, the composition comprises essentially of 4-34% by weight carbon dioxide (R-744) and 66-96% by weight trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)). The composition has a critical temperature of greater than 70 degrees C. The composition has a GWP of less than 1000, preferably less than 150. The composition has a volumetric refrigeration capacity within 15%, preferably within 10% of the existing refrigerant that it is intended to replace. The composition is less flammable than R-32 alone, R-152a alone, R-1234yf alone or R-161 alone. The composition has: (a) a higher flammable limit; (b) a higher ignition energy; and/or (c) a lower flame velocity compared to R-32 alone, R-152a alone, R-1234yf alone or R-161 alone. The composition has a fluorine ratio (F/(F+H)) of 0.42-0.7, preferably 0.44-0.67. The composition is non-flammable. The composition has cycle efficiency within about 5% of the existing refrigerant that it is intended to replace. The composition has a compressor discharge temperature within about 15K, preferably within about 10K, of the existing refrigerant that it is intended to replace. In a second alternative case, the composition comprises a lubricant and the composition above. The lubricant is selected from mineral oil, silicone oil, polyalkyl benzenes (PABs), polyol esters (POEs), polyalkylene glycols (PAGs), polyalkylene glycol esters (PAG esters), polyvinyl ethers (PVEs), poly (alpha-olefins) and combinations. The composition further comprises a stabilizer, where the stabilizer is selected from diene-based compounds, phosphates, phenol compounds and epoxides, and mixtures. In a third alternative case, the composition comprises a flame retardant and the composition. The flame retardant is selected from tri-(2-chloroethyl)-phosphate, (chloropropyl) phosphate, tri-(2,3-dibromopropyl)-phosphate, tri-(1,3-dichloropropyl)-phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, a fluorinated iodocarbon, a fluorinated bromocarbon, trifluoro iodomethane, perfluoroalkyl amines, bromo-fluoroalkyl amines and mixtures. The composition is a refrigerant composition. Preferred Device: The transfer device is a refrigeration device. The heat transfer device is selected from automotive air conditioning systems, residential air conditioning systems, commercial air conditioning systems, residential refrigerator systems, residential freezer systems, commercial refrigerator systems, commercial freezer systems, chiller air conditioning systems, chiller refrigeration systems, and commercial or residential heat pump systems, preferably where the heat transfer device is an automobile air- conditioning system. The heat transfer device contains a compressor. The mechanical power generating device is adapted to use a Rankine Cycle or modification to generate work from heat. Preferred Method: In retrofitting the heat transfer device, the heat transfer device is a refrigeration device or an air conditioning system. In reducing the environmental impact arising from the operation of the product comprising the existing compound or composition, Preparing the composition, and/or the heat transfer device comprises removing at least some of the existing R-134a from the heat transfer device before introducing the R-1243ze(E), R744, any additional third component, and optionally the R-125, the lubricant, the stabilizer and/or the flame retardant. Generating greenhouse gas emission credit is carried out on a product from the fields of air-conditioning, refrigeration, heat transfer, blowing agents, aerosols or sprayable propellants, gaseous dielectrics, cryosurgery, veterinary procedures, dental procedures, fire extinguishing, flame suppression, solvents, cleaners, air horns, pellet guns, topical anesthetics, and expansion applications. The product is selected from a heat transfer device, a blowing agent, a foamable composition, a sprayable composition, a solvent or a mechanical power generation device. The product is the heat transfer device. The existing compound or composition is a heat transfer composition. EXAMPLE - No suitable example given.