Heat transfer compositions and methods
Compositions, methods and systems which comprise or utilize a multi-component mixture comprising: (a) from about 10% to about 35% by weight of HFC-32; (b) from about 10% to about 35% by weight of HFC-125; (c) from about 20% to about 50% by weight of HFO-1234ze, HFO-1234yf and combinations of these; (d) from about 15% to about 35% by weight of HFC-134a; and optionally (e) up to about 10% by weight of CF3I and up to about 5% by weight of HFCO-1233ze, with the weight percent being based on the total of the components (a)-(e) in the composition.
1. A refrigerant consisting essentially of: (a) about 13.0% by weight of HFC-32; (b) about 13.0% by weight of HFC-125; (c) about 30% by weight of HFC-134a; and (d) about 44% by weight HFO-1234yf with the weight percent being based on the total of the components (a)-(d) in the composition, wherein said refrigerant has a GWP of not greater than 1000.
2. A heat transfer composition comprising the refrigerant of claim 1 and further comprising at least one polyol ester lubricant.
3. The refrigerant of claim 1 having a coefficient of performance, based upon HFC-404A, of about 100% or greater.
4. A method of replacing an existing refrigerant fluid contained in heat transfer system comprising removing at least a portion of said existing refrigerant fluid from said system, said existing refrigerant fluid being HFC-404A and replacing at least a portion of said existing refrigerant fluid by introducing into said system a refrigerant comprising: (a) about 13.0.% by weight of HFC-32; (b) about 13.0% by weight of HFC-125; (c) about 30% by weight of HFC-134a; and (d) about 44% by weight HFO-1234yf, with the weight percent being based on the total of the components (a)-(d) in the composition.
5. The method of claim 4 wherein said existing heat transfer system further comprises in said system at least one polyol ester lubricant.
6. The method of claim 4 wherein said heat transfer system comprises a low temperature refrigeration system, a medium temperature refrigeration system, or an air conditioning system.
7. A low temperature refrigeration, medium temperature refrigeration or air conditioning heat transfer system comprising a compressor, a condenser and an evaporator in fluid communication, and a heat transfer composition in said system, said heat transfer composition comprising a refrigerant consisting essentially of: (a) about 13.0% by weight of HFC-32; (b) about 13.0% by weight of HFC-125; (c) about 30% by weight of HFC-134a; and (d) about 44% by weight HFO-1234yf, with the weight percent being based on the total of the components (a)-(d) in the composition, said condenser having an operating temperature of from about 35° C. to about 45° C.
8. The heat transfer system of claim 7 wherein said heat transfer composition further comprises at least one polyol ester lubricant.
9. The heat transfer system of claim 7 wherein said evaporator has an operating temperature of from about −40° C. up to less than about −15° C.
10. The heat transfer system of claim 7 wherein said evaporator has an operating temperature of from about −35° C. to about −25° C.