Method for forming a refrigerant system

Abstract

A method of forming an improved refrigeration system is disclosed that includes: (a) providing an existing refrigeration circuit that includes an existing refrigerant having a GWP greater than 1200, a plurality of evaporators in a refrigerated space that includes a consumer-accessible product, a compressor rack, and at least one condenser located away from the consumer-accessible area; (b) severing a fluid connection between the existing liquid refrigerant from the condenser and the evaporator; (c) severing a fluid connection between the existing refrigerant vapor from the evaporator in step (b) and the suction port of the compressor or compressor rack; (d) establishing a new first refrigeration circuit that includes the compressor rack and the condenser; and (e) removing the existing refrigerant from the evaporator and replacing the removed existing refrigerant with a second refrigerant.

Description

[Technical Field]

[0001] The present invention relates to vapor compression refrigeration systems, and more particularly to a method for forming an improved vapor compression refrigeration system based on a series of steps for modifying existing vapor pressure refrigeration systems, such as, but not limited to, large-scale centralized supermarket refrigeration systems that use high global warming potential refrigerants, such as R404A, R448, R449, R407, chlorodifluoromethane (R-22), etc. [Background technology]

[0002] Distributed refrigeration systems, such as those for refrigerated supermarket display cases, have typically employed air- or water-cooled condensers fed by racks of compressors. Typically, the compressors are coupled in parallel so that they can be switched on and off in stages to adjust the cooling capacity of the system to match the load demands, and the condensers are located outdoors, typically on the roof or in a machine room adjacent to the shopping area where the refrigerated cases are located.

[0003] Within each refrigerated case is an evaporator fed by a line from a condenser through which expanded refrigerant circulates to cool the case. Because the cases are located on the supermarket's retail floor and the condensers are remotely located on the roof or in machine shops inaccessible to consumers, long lengths of piping connected by fittings, valves, and control systems are an essential feature of such existing systems.

[0004] Within supermarkets, it is common to use separate systems to provide different individual refrigeration temperature ranges to various retail cases. For example, low temperature cases contain frozen foods, ice cream, and the like, and are typically operated to maintain the contents at a temperature ranging from about −30° C. to about −10° C., while medium temperature refrigeration is for display cases of meat, dairy, and the like, and has a typical goal of maintaining the contents at about −10° C. to less than about 5° C. These separate low temperature and medium temperature systems typically each constitute their own centralized refrigeration system, and each usually employs its own compressor or rack of compressors, and its own set of refrigerant conduits between the compressor and the condenser.

[0005] Centralized refrigeration systems, with their traditional configurations as generally described above, are expensive to build and maintain. One major component of this high cost is the long length of refrigerant lines. Long lines are not only expensive in terms of hardware and installation costs, but the amount of refrigerant required to fill the lines is also a major factor. The longer the line length, the more refrigerant is required. Environmental factors add to the cost of such systems. It has been common for such systems to use refrigerants that perform well in terms of heat transfer performance and safety (low or non-toxic and low or non-flammable), but are highly disadvantageous from an environmental perspective because they have high global warming potentials. For example, the following refrigerants (with GWP values ​​listed according to IPCC AR4): R404A (GWP=3922), R22 (GWP=1760), R407F (GWP=1824), R448A (GWP=1387), and R449A (GWP=1397) are frequently used in such systems. The fittings in such systems are likely to eventually leak, allowing these environmentally harmful refrigerants to escape into the atmosphere. Furthermore, longer pipe runs contain more plumbing fittings, valves, etc. that can potentially leak, so in the event of a leak, the longer the pipe run, the greater the amount of high-GWP refrigerant that will be lost to the atmosphere.

[0006] Efforts to address the environmental deficiencies of refrigeration systems, particularly but not exclusively centralized refrigeration systems, present considerable engineering challenges due to the significant costs associated with large-scale replacement of such expensive and sometimes very large systems. Moreover, conventional roof-mounted or machine-room condenser / compressor systems provide high levels of efficiency and capacity, and any efforts to modify these systems to make them more environmentally attractive should desirably maintain this efficiency and capacity. The significant yet difficult challenge of achieving environmental improvements, particularly in such large systems, is reflected, for example, in recently implemented regulations in the European Union that apply to large systems having a refrigerant charge of 3 kilograms or more.

[0007] Several thermodynamic and fluid flow challenges arise in connection with efforts to convert conventional centralized refrigeration systems to be more environmentally friendly while maintaining efficiency and capacity. For example, applicants have come to realize that it is extremely difficult, if not impossible, to identify an environmentally friendly refrigerant (e.g., a GWP of about 150 or less (as measured by AR45)) that can be simply used in existing refrigeration systems in place of existing high-GWP refrigerants. Previously disclosed alternatives to R-22 have been investigated and shown to result in reduced cooling capacity and increased power requirements, thus resulting in an overall significant decrease in performance. (See WO 2020 / 223196(A1)). This presents a challenge in developing a viable solution to this problem.

[0008] Additionally, the use of compositions that are non-flammable is generally considered either important or essential in many applications, particularly in many centralized refrigeration systems. As used herein, the term "non-flammable" refers to a compound or composition that is determined to be non-flammable when measured in accordance with ASTM Standard E-681-2009 Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases) under the conditions set forth in Appendix B1 of ASHRAE Standard 34-2016, which is incorporated herein by reference. Unfortunately, many HFCs that may be desirable as retrofits for existing centralized refrigeration systems are not non-flammable as used herein. For example, the fluoroalkane difluoroethane (HFC-152a) and the fluoroalkene 1,1,1-trifluoropropene (HFO-1243zf) are each flammable and therefore ineffective for use in many applications.

[0009] With regard to efficiency of use, it is important to note that loss of thermodynamic performance or energy efficiency of a refrigerant can have secondary environmental impacts due to increased demand for electrical energy resulting in increased use of fossil fuels.

[0010] Applicants have therefore come to realise that significant advantages can be achieved in creating a centralised refrigeration system that is comparable to older systems in terms of thermodynamic performance, refrigerant safety (toxicity and flammability) and is much more environmentally friendly, and with only a relatively low capital cost outlay in terms of system infrastructure. Summary of the Invention

[0011] Applicants have discovered that the above needs, and others, can be met by a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 30% to about 70% by weight of CF3I; (2) about 9% to about 58% by weight of HFO-1234yf; (3) 1% to about 21.5% by weight of HFC-32; and optionally (4) 0.5% to 4% by weight of HFC-125, CO2, or a combination of HFC-125 and CO2, wherein the sum of components (1) through (4) comprises at least 95% by weight of the second refrigerant, and the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 by ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0012] For convenience, compositions according to this paragraph will be referred to herein as System Formation Method 1A.

[0013] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 59% to about 69.5% by weight of CF3I; (2) 9% to about 19.5% by weight of HFO-1234yf; and (3) 16.5% to 21.5% by weight of HFC-32, wherein the sum of components (1)-(3) comprises at least 95% by weight of the second refrigerant, the second refrigerant (i) having an occupational exposure limit (OEL) greater than 400; (ii) being classified as Class A1 by ASHRAE Standard 34; and (iii) having a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0014] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 1B.

[0015] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 32.8% to about 53.8% by weight of CF3I; (2) about 29% to about 58% by weight of HFO-1234yf; (3) 2% ± 0.2% to about 16.5% by weight of HFC-32; and (4) 1 ± 0.2 to 3.2 ± 0.2% by weight of HFC-125, wherein the sum of components (1) through (4) comprises at least 95% by weight of the second refrigerant, the second refrigerant (i) having an occupational exposure limit (OEL) greater than 400; (ii) being classified as Class A1 by ASHRAE Standard 34; and (iii) having a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0016] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 1C.

[0017] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 41.5% to about 49.5% by weight of CF3I; (2) about 36% to about 44% by weight of HFO-1234yf; (3) 11% to about 15% by weight of HFC-32; and (4) 1±0.2 to 3.5±0.2% by weight of CO2, wherein the sum of components (1) through (4) comprises at least 95% by weight of the second refrigerant, and the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 by ASHRAE Standard 34; and (iii) has a GWP of about 150 or less. establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0018] For convenience, compositions according to this paragraph are referred to herein as System Formation Method 1D.

[0019] The present invention also includes a method for forming an improved large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 32.8% to about 53.8% by weight of CF3I; (2) about 29% to about 58% by weight of HFO-1234yf; (3) 2% ±0.2% to about 16.5% by weight of HFC-32; and (4) 0.5% to 4% by weight of HFC-125, CO2, or a combination of HFC-125 and CO2, wherein the sum of components (1) through (4) comprises at least 95% by weight of the second refrigerant, the second refrigerant having: (i) an Occupational Exposure Limit (OEL) greater than 400; and (ii) an Occupational Exposure Limit (OEL) greater than 400, as defined by ASHRAE (iii) classified as Class A1 by Standard 34, and (iv) having a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0020] For convenience, compositions according to this paragraph are referred to herein as System Formation Method 1E.

[0021] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 69.5 wt. % CF3I, (2) about 9 wt. % HFO-1234yf, and (3) about 21.5 wt. % HFC-32, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0022] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 2A.

[0023] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) about 69.5 wt. % CF3I, (2) about 9 wt. % HFO-1234yf, and (3) about 21.5 wt. % HFC-32, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0024] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 2B.

[0025] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and the conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 59% by weight CF3I, (2) about 19.5% by weight HFO-1234yf, and (3) about 21.5% by weight HFC-32, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0026] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 3A.

[0027] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) about 59% by weight CF3I, (2) about 19.5% by weight HFO-1234yf, and (3) about 21.5% by weight HFC-32, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0028] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 3B.

[0029] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 38% by weight CF3I, (2) about 54% by weight HFO-1234yf, (3) about 5% by weight HFC-32, and (4) about 3% + / - 0.2% HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0030] For convenience, compositions according to this paragraph will be referred to herein as System Formation Method 4A.

[0031] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) about 38% by weight CF3I, (2) about 54% by weight HFO-1234yf, (3) about 5% by weight HFC-32, and (4) about 3% + / - 0.2% HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0032] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 4B.

[0033] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising (1) about 45% by weight CF3I, (2) about 40% by weight HFO-1234yf, (3) about 13% by weight HFC-32, and (4) 2% by weight -1 / -0.2% by weight CO2, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0034] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 5A.

[0035] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 45% by weight CF3I, (2) about 40% by weight HFO-1234yf, (3) about 13% by weight HFC-32, and (4) about 2 + 1 / - 0.2% CO2, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0036] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 5B.

[0037] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) about 45% by weight CF3I, (2) about 40% by weight HFO-1234yf, (3) about 13% by weight HFC-32, and (4) about 2 + 1 / - 0.2% CO2, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0038] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 5C.

[0039] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) 32.8% to 42.8% by weight of CF3I, (2) 48% to 58% by weight of HFO-1234yf, (3) 2% to 6% by weight of HFC-32, and (4) 1±0.2% to 3.2±0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0040] For convenience, compositions according to this paragraph will be referred to herein as System Formation Method 6.

[0041] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 38 wt. % CF3I; (2) about 54 wt. % HFO-1234yf; (3) 5 wt. % ±0.5 wt. % HFC-32; and (4) 1 ±0.2 to 3.2 ±0.2 wt. % HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 by ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0042] For convenience, compositions according to this paragraph will be referred to herein as System Formation Method 7.

[0043] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 38 wt. % CF3I, (2) about 54 wt. % HFO-1234yf, (3) 5 wt. % ± 0.5 wt. % HFC-32, and (4) 1 ± 0.2 to 3.2 ± 0.2 wt. % HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0044] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 8.

[0045] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising (1) 38% ± 1% by weight of CF3I, (2) about 54% ± 1% by weight of HFO-1234yf, (3) 5% ± 1% by weight of HFC-32, and (4) 3 ± 0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0046] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 9A.

[0047] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) 38% ± 1% by weight of CF3I, (2) about 54% ± 1% by weight of HFO-1234yf, (3) 5% ± 1% by weight of HFC-32, and (4) 3 ± 0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0048] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 9B.

[0049] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) 38% ± 1% by weight of CF3I, (2) about 54% ± 1% by weight of HFO-1234yf, (3) 5% ± 1% by weight of HFC-32, and (4) 3 ± 0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 40, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0050] For convenience, compositions according to this paragraph are referred to herein as System Formulation Method 9C.

[0051] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) 45% to 55% by weight of CF3I, (2) 30% to 40% by weight of HFO-1234yf, (3) 10% to 20% by weight of HFC-32, and (4) 1 to 2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 40, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0052] For convenience, compositions according to this paragraph will be referred to herein as system forming method 10.

[0053] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 50 wt. % CF3I; (2) about 34.5 wt. % HFO-1234yf; (3) 5 wt. % ±0.5 wt. % HFC-32; and (4) 1.5 wt. % ±0.2 wt. % HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 by ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0054] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 11A.

[0055] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) about 50 wt. % CF3I, (2) about 34.5 wt. % HFO-1234yf, (3) 5 wt. % ±0.5 wt. % HFC-32, and (4) 1.5 wt. % ±0.2 wt. % HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0056] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 11B.

[0057] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) about 50 wt. % CF3I, (2) about 34.5 wt. % HFO-1234yf, (3) 5 wt. % ± 0.5 wt. % HFC-32, and (4) 1.5 wt. % ± 0.2 wt. % HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 40, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0058] For convenience, compositions according to this paragraph are referred to herein as System Formation Method 11C.

[0059] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising (1) 50% by weight ±1% by weight of CF3I, (2) about 34.5% by weight ±1% by weight of HFO-1234yf, (3) 14% by weight ±1% by weight of HFC-32, and (4) 1.5% by weight ±0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of about 150 or less; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

[0060] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 12A.

[0061] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting essentially of (1) at least 50% by weight ±1% by weight of CF3I, (2) about 34.5% by weight ±1% by weight of HFO-1234yf, (3) 14% by weight ±1% by weight of HFC-32, and (4) 1.5% by weight ±0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 400, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0062] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 12B.

[0063] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (iii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) 50% by weight ±1% by weight of CF3I, (2) about 34.5% by weight ±1% by weight of HFO-1234yf, (3) 14% by weight ±1% by weight of HFC-32, and (4) 1.5% by weight ±0.2% by weight of HFC-125, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 40, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0064] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 12C.

[0065] The present invention also includes a method of forming an improved refrigeration system, preferably a large capacity centralized refrigeration system, the method comprising: (a) providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (ii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; (b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; (c) severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; (d) establishing a new first refrigeration circuit including the compressor or compressor rack and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant; (e)(i) removing the existing refrigerant from at least a portion of the evaporator and conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant consisting of (1) 40% to 50% by weight CF3I, (2) 35% to 45% by weight HFO-1234yf, (3) 10% to 16% by weight HFC-32, and (4) 1.5% to 2.5% by weight CO2, wherein the second refrigerant (i) has an occupational exposure limit (OEL) greater than 40, (ii) is classified as Class A1 by ASHRAE Standard 34, and (iii) has a GWP of less than about 150; establishing a new second refrigeration circuit comprising at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: (f) thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with a new inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to a liquid in the first circuit.

[0066] For convenience, compositions according to this paragraph will be referred to herein as System Formulation Method 13. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a semi-schematic process flow diagram illustrating a prior art centralized refrigeration system. [Figure 2] 1 is a semi-schematic view of an exemplary start-up centralized refrigeration system for use in the heat transfer system formation method of the present invention. [Figure 3A] FIG. 1 is a schematic diagram of an exemplary start-up centralized refrigeration system illustrating the cut points in the process of forming the heat transfer system of the present invention. [Figure 3B] 1 is a schematic diagram of an exemplary completed centralized refrigeration system constructed in accordance with the heat transfer system formation method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0068] definition For purposes of this invention, the term "about" in relation to amounts expressed as weight percent for amounts greater than 2% means that the amount of the ingredient may vary by an amount of + / - 2% by weight.

[0069] For purposes of the present invention, the term "about" in reference to temperatures in degrees Celsius (°C) means that the stated temperature can vary by an amount of + / - 5°C.

[0070] For purposes of this invention, the term "about" in relation to percentages of power usage means that the stated percentage may vary by up to 1%.

[0071] For purposes of this invention, the term "substantial portion" with respect to removing existing refrigerant from a heat transfer system means removing at least about 50% of the existing refrigerant contained in the system.

[0072] The term "capacity" refers to the amount of cooling (BTU / hr or kW) provided by a refrigerant in a refrigeration system. It is determined experimentally by multiplying the change in enthalpy in BTU / lb or kJ / kg of the refrigerant as it passes through the evaporator by the mass flow rate of the refrigerant. Enthalpy can be determined from measurements of the refrigerant's pressure and temperature. The capacity of a refrigeration system is related to its ability to maintain a refrigerated area at a specific temperature. Refrigerant capacity represents the amount of cooling or heating the refrigerant provides and provides a measure of the compressor's ability to pump that amount of heat for a given volumetric flow rate of refrigerant. In other words, given a particular compressor, a refrigerant with a higher capacity will provide more cooling or heating power.

[0073] The phrase "coefficient of performance" (hereinafter "COP") is a widely accepted measure of refrigerant performance that is particularly useful for expressing the relative thermodynamic efficiency of a refrigerant in a specific heating or cooling cycle involving evaporation or condensation of the refrigerant. In refrigeration, this term represents the ratio of useful refrigeration or cooling capacity to the energy applied by the compressor during vapor compression, and thus represents the ability of a given compressor to pump a quantity of heat for a given volumetric flow rate of a heat transfer fluid, such as a refrigerant. In other words, given a particular compressor, a refrigerant with a higher COP will deliver more cooling or heating power. One means for estimating the COP of a refrigerant at specific operating conditions is from the refrigerant's thermodynamic properties using standard refrigeration cycle analysis techniques (see, for example, R.C. Downing, FLUOROCARBON REFRIGERANTS HANDBOOK, Chapter 3, Prentice-Hall, 1988, incorporated herein by reference in its entirety).

[0074] The phrase "discharge temperature" refers to the temperature of the refrigerant at the outlet of the compressor. The advantage of a low discharge temperature is that it allows the use of existing equipment without activating the thermal protection aspects of the system, which are preferably designed to protect compressor components and avoid the use of expensive control devices such as liquid injection to reduce the discharge temperature.

[0075] As used herein, the term "centralized refrigeration system" means a refrigeration system that includes one or more centrally located compressors or racks of compressors, one or more centrally located condensers, and a plurality of evaporators located remotely from the centralized compressors or racks of compressors and that receive liquid refrigerant from the centrally located condensers.

[0076] As used herein, "direct expansion" refers to a heat transfer system utilizing an evaporator in which liquid refrigerant enters the evaporator, flows through a coil (preferably a tubular coil), and evaporates as heat is absorbed from the air circulating within the display case, using a thermostatic expansion valve at the inlet of the evaporator, and controlled to provide enough refrigerant to evaporate substantially all of the refrigerant at the evaporator outlet, and optionally have a predetermined amount of superheat at the outlet.

[0077] The phrase "Global Warming Potential" (hereinafter "GWP") was developed to allow for comparison of the global warming impact of different gases, and as used herein, refers to the GWP determined by AR5 as described above. Specifically, it is a measure of how much energy emitting one ton of a gas absorbs over a given period of time relative to emitting one ton of carbon dioxide. The higher the GWP, the more a given gas will warm the Earth over that period compared to CO2. A commonly used time period for GWP is 100 years. GWP provides a common measure that allows analysts to add together emission estimates for different gases. See http: / / www.protocolodemontreal.org.br / site / images / publicacoes / setor_manufatura_equipamentos_refrigeracao_arcondicionado / Como_calcular_el_Potencial_de_Calentamiento_Atmosferico_en_las_mezclas_de_refrigerantes.pdf.

[0078] The term "Occupational Exposure Limit (OEL)" is determined in accordance with ASHRAE Standard 34-2016 Designation and Safety Classification of Refrigerants.

[0079] As used herein, the phrase "acceptable toxicity" means that the composition is classified as Class "A" by ASHRAE Standard 34-2016 Designation and Safety Classification of Refrigerants and as described in Appendix B1 of ASHRAE Standard 34-2016, as each standard exists as of the filing date of this application. A material that is non-flammable and has low toxicity is classified as "A1" by ASHRAE Standard 34-2016 Designation and Safety Classification of Refrigerants and as described in Appendix B1 of ASHRAE Standard 34-2016, as each standard exists as of the filing date of this application.

[0080] The term "mass flow rate" is the mass of refrigerant passing through a conduit per unit time.

[0081] As used herein, the term "replacement" refers to the use of the compositions of the present invention in a heat transfer system designed for or suitable for use with another refrigerant. For example, when a refrigerant or heat transfer composition of the present invention is used in a heat transfer system designed for use with R-410A, the refrigerant or heat transfer composition of the present invention is a replacement for R-410A in that system. Thus, the term "replacement" will be understood to include the use of the refrigerant and heat transfer compositions of the present invention in both new and existing systems designed for, commonly used with, or suitable for use with R-410A.

[0082] The term "glide" applies to non-azeotropic refrigerant mixtures that have different temperatures during the phase change process in an evaporator or condenser at constant pressure, and is quantified herein as the difference between the saturated vapor temperature and the saturated liquid temperature at a pressure of 100 kPa.

[0083] The term "low temperature refrigeration system" refers to a heat transfer system that operates at a condensing temperature of about 40°C to about 70°C and an evaporating temperature of about -45°C to -12°C (inclusive).

[0084] The term "medium temperature refrigeration system" refers to a heat transfer system that operates at a condensing temperature of about 40°C to about 70°C and an evaporating temperature of -12°C to about 0°C.

[0085] As used herein, the term "supermarket refrigeration" refers to commercial refrigeration systems used to keep food cool or frozen in both product display cases and storage refrigerators.

[0086] The term "normal boiling point" refers to the boiling point of a single component measured at 1 atmosphere and refers to the initial boiling point of a blend of components at 1 atmosphere.

[0087] The term "R-22" means chlorodifluoromethane.

[0088] As used herein, the terms "HFC-32" and "R-32" each mean difluoromethane.

[0089] The term "R-125" means pentafluoroethane.

[0090] The term "R-134a" means 1,1,1,2-tetrafluoroethane.

[0091] The term "R-143a" means 1,1,1-trifluoroethane.

[0092] The term "R-404A" refers to a combination of about 44% by weight R-125, about 52% by weight R-143a, and about 4% by weight R-134a.

[0093] The term "R-407A" refers to a combination of about 20% by weight R-32, about 40% by weight R-125, and about 40% by weight R-134a.

[0094] The term "R-407F" refers to a combination of about 23% by weight R-32, about 25% by weight R-125, and about 52% by weight R-134a.

[0095] The term "R-407H" refers to a combination of 32.5% ± 1% by weight R-32, 15% ± 1% by weight R-125, and about 52.5% ± 2% by weight R-134a.

[0096] The term "R-448A" refers to a combination of about 26% by weight R-32, about 26% by weight R-125, and about 21% by weight R-134a.

[0097] The term "R-449A" refers to a combination of about 24.3% by weight R-32, about 24.7% by weight R-125, and about 25.7% by weight R-134a.

[0098] As used herein, the terms "HFO-1234yf" and "R-1234yf" each mean 2,3,3,3-tetrafluoropropene.

[0099] As used herein, the terms "HFO-1234ze(E)", "R-1234ze(E)", and "1234ze(E)" each mean trans-1,3,3,3-tetrafluoropropene.

[0100] Reference herein to a group of defined terms includes all such defined terms and includes all such terms with a suffix designation.

[0101] Systems and methods The method of the present invention generally involves a first step of refrigerating an existing centralized refrigeration system. A schematic example of such a centralized refrigeration system is shown in FIG. 1, which illustrates a system including a rack of compressors 30, condensers 32, accumulators 38, and a series of display cases 34, each housing an evaporator 42. A high-GWP refrigerant, such as R-404a, circulates through such a system through a piping network 46 that carries the liquid refrigerant and a piping network 48 that carries the refrigerant vapor. While shown schematically in FIG. 1, in reality, each of these piping networks typically represents a wide, long series of conduits for transporting liquid refrigerant from the accumulators 38, which, along with the compressor racks 30 and condensers 32, are typically located remotely from the display cases. Thus, the piping network 46 is large, covering distances from, for example, the supermarket roof or machine room to the supermarket floor to reach the numerous display cases located therein. 1 shows only two display cases, those skilled in the art will recognize that in many situations there will be from one to about 150 display cases per circuit distributed over a large consumer retail area that need to be reached by liquid piping network 46, and an equally large vapor return piping network 48 required to return refrigerant vapor to the roof or mechanical room in each of these cases. In many applications, the length of piping required for the liquid supply from the compressor and the vapor return to the compressor is at least about 20 meters (65 feet).

[0102] 1 is shown as having four compressors 30, those skilled in the art will also recognize that in practice, a compressor rack may include from one to about five compressors, depending on the particular application. Stated another way, an existing refrigeration system provided in accordance with the present invention may exhibit a compressor work capacity of from about 3 kW to about 500 kW. With regard to compressor type, while it is contemplated that all types of compressors may be present in such systems, in many such systems, the compressors used are selected from screw compressors, scroll compressors, reciprocating compressors, centrifugal compressors, twin-screw compressors, and combinations thereof.

[0103] Existing refrigerants used in the existing centralized refrigeration systems of the present invention generally have a GWP (determined in accordance with AR5) of 1200 or greater and include R404A, R22, and R407 (including each of R407A, R407B, R407C, R407D, and R407F), R448 (all letter designations, including R448A), and R449 (all letter designations, including R449A). In this application, a reference to a refrigerant by a letter designation without a suffix (such as R448) is intended to refer individually to each refrigerant having that designation and includes all suffixed refrigerants. Thus, for example, a reference to "R448" is intended to refer individually to each of R448A and R448B.

[0104] The present invention involves improving a system of the type disclosed in FIG. 1 to improve the system's environmental friendliness. A preferred method involves disconnecting the liquid connection between the condenser and at least one of the evaporators, preferably all of the evaporators, and also disconnecting the vapor connection between the evaporator and the compressor suction. For example, referring to FIGS. 2A, 2B, and 2C, liquid line 14 is preferably disconnected immediately downstream of accumulator 13 to separate the liquid side of the evaporator from the liquid from condenser 12, and vapor line 15 is preferably disconnected immediately upstream of the compressor to separate the vapor side of the evaporator from the compressor. This disconnection step thus allows for the conversion of an existing single refrigeration circuit into a new first refrigeration circuit and a new second refrigeration circuit (see, for example, 10A and 10B, respectively, in FIG. 3C). As used herein in this context, the term "new" will be understood to mean only that a circuit as defined by this invention did not previously exist, but it will be understood that one objective of the present invention is to utilize much of the "old" piping network and "old" evaporator as part of a new, second refrigeration circuit. In some preferred embodiments, it is also an objective to use the "old" compressor, condenser, and accumulator, and the piping and valves between them, to form a second, new refrigeration circuit.

[0105] Either before, simultaneously with, or after the disconnection step, existing refrigerant is removed from the liquid and vapor piping network remaining connected to the evaporators, as well as from the evaporators themselves and all other piping, valves, etc. used to form a new second refrigeration circuit, such as circuit 10B in FIG. 3C. A preferred second circuit, one example of which is shown in FIG. 3C, is formed by including a liquid pump 21, which, in a preferred embodiment, is supplied with cold liquid refrigerant by an accumulator 22. The pump provides motive power for transporting the second refrigerant from the compressor to each of the disconnected evaporators. The liquid refrigerant in second circuit 10B provides cooling to the display cases as it evaporates in the evaporators by absorbing heat from the air and / or products in the display cases.

[0106] An important aspect of the present invention is that vapor from the evaporator is not returned to the compressor as in the original system, but instead the present invention includes thermally interconnecting the new first refrigeration circuit 10A and the new second refrigeration circuit 10B with a new inter-circuit heat exchanger 20. Vapor from the evaporator travels to this inter-circuit heat exchanger where at least a portion of the second refrigerant is condensed by transferring heat to liquid refrigerant exiting a condenser in the new first circuit, thereby evaporating the first refrigerant and producing refrigerant for supplying the first circuit compressor 11. In this configuration, the inter-circuit heat exchanger functions as an evaporator in the first circuit and as a condenser in the second circuit.

[0107] Importantly, the method involves using in the new second circuit a low-GWP refrigerant having a GWP of 150 or less, and preferably a normal, Class 1A refrigerant having an OEL greater than 400. Table A below identifies three refrigerant blends A1, A2, and A3 that meet these criteria and provide substantial unexpected advantages in accordance with the present invention, with it being understood that all amounts in the table are considered to be preceded by "about."

[0108] [Table 1]

[0109] While it is contemplated that the existing refrigerant contained in the piping and equipment associated with the condenser and compressor (i.e., the new first refrigeration circuit) can be retained and used as the refrigerant for the new first circuit, it is generally preferred, however, that the existing refrigerant can be removed from the compressor / condenser circuit and replaced with a new, preferably lower-GWP, refrigerant. In those embodiments in which the existing refrigerant in the new first circuit remains, it is contemplated that the existing equipment, including the compressor, condenser, accumulator, connecting piping, etc., also need not be replaced. Such an embodiment has the advantage of minimizing increases in capital equipment costs, but results in a high-GWP refrigerant being utilized in the new second circuit. While such a configuration has significant environmental benefits, as the amount of high-GWP refrigerant used in the converted system is significantly reduced compared to the original system, in another generally preferred embodiment, the existing refrigerant is removed from the compressor, condenser, accumulator, connecting piping, etc., and a new, low-GWP refrigerant is used to replace all or substantially all of the existing refrigerant. In such embodiments, one or more, or all, of those components of the system will likely need to be replaced and / or modified, which in turn increases capital expenditures. However, proceeding according to an embodiment in which high-GWP refrigerants are removed from the first circuit provides the most desirable results from an environmental standpoint, as it provides a conversion system in which only low-GWP refrigerants are used. Generally, in such embodiments, the new refrigerant for the first circuit has a GWP of less than 150, more preferably less than 100, and even more preferably less than about 25.

[0110] If the existing refrigerant is R404A, R407, R507 or R22, all of which have a GWP greater than 1500, the refrigerant used to replace such refrigerant is preferably selected according to the following table, labeled Case 1:

[0111] [Table 2]

[0112] In other cases, the existing refrigerant is R448 (which has a GWP of less than about 1200) or R449 (which has a GWP of less than about 1500), and in such cases the existing refrigerant is preferably not replaced according to the table below, designated Case 2.

[0113] [Table 3]

[0114] Other examples of low GWP refrigerants for use in the first refrigerant circuit in the new embodiments where the existing refrigerant has a GWP greater than 1500, such as R404A, R407, R507 or R22, include 1234ze(E) 1234yf and blends containing these.

[0115] As will be appreciated by those skilled in the art, the present invention includes methods for combining a wide range of existing systems with existing refrigerants with a variety of specific refrigerants that may be used in the new second circuit and, optionally, as a replacement for the existing refrigerant in the new first circuit. [Example]

[0116] The following examples are offered for the purpose of illustrating the present invention, but not limiting its scope.

[0117] For the evaluation of possible ways to improve existing centralized refrigeration systems to make them more environmentally friendly, it is important to consider performance parameters, including, for comparative purposes, essentially removing the entire charge of the existing high-GWP refrigerant and replacing it with a refrigerant with a lower GWP.

[0118] Comparative Example C1 - Refrigeration System Using R-404A as the Refrigerant in Medium Temperature Applications A direct expansion refrigeration system of the type disclosed in Figure 1, having a capacity of approximately 100 kW, has R-404A as the existing refrigerant. The system operating conditions using R-404A as the refrigerant in the system of Figure 1 are as follows: Cooling capacity: 100kW Isentropic efficiency: 65% Volumetric efficiency: 100% Condensation temperature: 45℃ Subcooling: 0°C (system with receiver) Evaporator superheat: 5.5℃ Temperature rise in intake line: 10°C Evaporation temperature: -8℃

[0119] While this system works well from a thermodynamic and heat transfer performance standpoint, it is highly undesirable from an environmental impact standpoint, as the entire system involves the high GWP refrigerant R404A circulating throughout a large and complex piping network.

[0120] Example 1A - Modifying the original system using R-404A, replacing the R404A in the new primary loop with R448A, and replacing the R404A in the new secondary loop with refrigerants A1-A5 to form centralized refrigeration. The heat transfer system of Comparative Example C1 (including the existing refrigerant R404A therein) is used as a starting point for creating an improved heat transfer system. The system modifications are first described in connection with Figure 3A. The portions of the system including the condenser 12A (and optional free-cooling condenser 12 shown in Figure 3B), compressor rack 11, and accumulator 13, each located outdoors or in the machine room (above dotted line 100A in Figure 3B), are disconnected from the display case, preferably near where the compressor rack and accumulator are located, for example, by disconnecting the liquid line 14 leading from the accumulator and the vapor riser 15 leading to the compressor rack, respectively. Although the present invention includes embodiments in which the existing refrigerant R404A located in this portion of the system is not removed, in a preferred embodiment of this example, the existing refrigerant R404A is removed from this portion of the system (above dotted line 100A, i.e., indicating the outdoor or mechanical room location) and replaced with R448A, and the R404A located in the remainder of the system (below the dotted line, indicating the outdoor or mechanical room location) is removed from all of the remaining refrigerant conduits and all evaporators and replaced with the refrigerant of the present invention.

[0121] As shown in Figure 3B, the system is then reconfigured as a first heat transfer system 10A using R448A and a second heat transfer circuit 10B including evaporators 1-5, each using a new low-GWP refrigerant A1-A5 according to the present invention. Fresh heat exchanger 20 thermally interconnects first heat transfer circuit 10A to second heat transfer circuit 10B by transporting liquid R448A refrigerant from the accumulator, preferably over a relatively short distance in conduit 14A, to intercircuit heat exchanger 20, which absorbs heat from the fresh refrigerant in the second circuit to evaporate it. The evaporated R-448A is then returned to the suction side of the compressor rack via conduit 15A, which also preferably extends a relatively short distance.

[0122] A liquid pump 21 is added to the second circuit system to provide the motive force for delivering the low-GWP refrigerant (A1-A5) to each of the evaporators via their respective conduits and valves. In each evaporator, the refrigerant vapor of the present invention evaporates upon thermal contact with the relatively warm air within the display case, thereby cooling its respective display case. The refrigerant vapor of the present invention exiting evaporators 1-5 is then manifolded to riser 15B, where it is transported to inter-circuit heat exchanger 20, where it rejects heat to liquid R-448A from the first circuit (or optionally to a partial free-cooling condenser (note that appropriate valves are provided to achieve this optional operation, but are not shown)), thereby condensing back into a liquid. The liquid refrigerant of the present invention from heat exchanger 20 travels via conduit 14B to accumulator 22, which provides a source of liquid of the present invention to pump 21.

[0123] In accordance with the present invention, the refrigerant vaporizes (partially or completely) within each evaporator, and the return flow of refrigerant vapor through riser 15B is saturated or superheated.

[0124] Table E1A below demonstrates that superior performance is achieved according to the systems and methods of the present invention as exemplified in this Example 1A, with results reported for the base system of Comparative Example C1 having R404A as the only refrigerant in the centralized refrigeration system described.

[0125] [Table 4]

[0126] Example 1B - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-404A, replacing the R404A in the new primary loop with R449A, and replacing the R404A in the new secondary loop with refrigerants A1-A5 Example 1A is repeated, except that the new primary loop contains R449A. Table E1B below demonstrates that superior performance is achieved in accordance with the system and method of the present invention as illustrated in this Example 1B, with results reported for the base system of Comparative Example C1, which has R404A as the only refrigerant in the centralized refrigeration system described.

[0127] [Table 5]

[0128] Example 2A - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407A, replacing the R407A in the new primary loop with R448A, and replacing the R407A in the new secondary loop with refrigerants A1-A5. Example 1A is repeated, except that the existing refrigerant is R407A. Table E2A below demonstrates the superior performance achieved in accordance with the system and method of the present invention as illustrated in this Example 2A, with results reported for the base system of Comparative Example C1, which has R407A as the only refrigerant in the centralized refrigeration system described.

[0129] [Table 6]

[0130] Example 2B - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407A, replacing the R407A in the new primary loop with R449A, and replacing the R407A in the new secondary loop with refrigerants A1-A5 Example 1B is repeated, except that the existing refrigerant is R407A. Table E2B below demonstrates the superior performance achieved in accordance with the systems and methods of the present invention as illustrated in this Example 2B, with results reported for the base system of Comparative Example C1, which has R407A as the only refrigerant in the centralized refrigeration system described.

[0131] [Table 7]

[0132] Example 3A - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407C, replacing the R407C in the new primary loop with R448A, and replacing the R407C in the new secondary loop with refrigerants A1-A5 Example 1A is repeated, except that the existing refrigerant is R407C. Table E3A below demonstrates the superior performance achieved in accordance with the systems and methods of the present invention as illustrated in this Example 3A, with results reported for the base system of Comparative Example C1, which has R407C as the only refrigerant in the centralized refrigeration system described.

[0133] [Table 8]

[0134] Example 3B - Forming centralized refrigeration by modifying the original system using the existing refrigerant R-407C, replacing the R407C in the new primary loop with R449A, and replacing the R407C in the new secondary loop with refrigerants A1-A5 Example 1B is repeated, except that the existing refrigerant is R407C. Table E3B below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as illustrated in this Example 3B, with results reported for the base system of Comparative Example C1, which has R407C as the only refrigerant in the centralized refrigeration system described.

[0135] [Table 9]

[0136] Comparative Example C2 - Centralized Refrigeration System Using R-404A as the Refrigerant in Low Temperature Applications A centralized direct expansion refrigeration system of the type disclosed in Figure 1 having a cooling capacity of approximately 35 kW is equipped with R-404A as the existing refrigerant. The low temperature system operating conditions using R-404A as the refrigerant in the system of Figure 1 are as follows: Cooling capacity: 35kW Isentropic efficiency: 55% Volumetric efficiency: 100% Condensation temperature: 45℃ Subcooling: 0°C (system with receiver) Evaporator superheat: 5.5℃ Temperature rise in intake line: 10°C Evaporation temperature: -35℃

[0137] While this system works well from a thermodynamic and heat transfer performance standpoint, it is highly undesirable from an environmental impact standpoint, as the entire system involves the high GWP refrigerant R404A circulating throughout a large and complex piping network.

[0138] Example 4A - Modifying the original system using R-404A to form centralized refrigeration by replacing R404A in a new primary loop with R448A and replacing R404A in a new secondary loop with refrigerants A1-A5. The low temperature refrigeration system of Comparative Example C2 (including the existing refrigerant R404A therein) is used as a starting point for creating an improved heat transfer system. This system is modified to produce the system of the present invention, as generally described in connection with Figures 3A and 3B of Comparative Example 1.

[0139] Table E4A below demonstrates that superior performance can be achieved in accordance with the systems and methods of the present invention as exemplified in this Example 4A, with results reported for the base system of Comparative Example C2 having R404A as the only refrigerant in the centralized refrigeration system described.

[0140] [Table 10]

[0141] Example 4B - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-404A, replacing the R404A in the new primary loop with R449A, and replacing the R404A in the new secondary loop with refrigerants A1-A5 Example 4A is repeated, except that the new primary loop contains R449A. Table E4B below demonstrates that superior performance is achieved in accordance with the system and method of the present invention as illustrated in this Example 4B, with results reported for the base system of Comparative Example C2, which has R404A as the only refrigerant in the centralized refrigeration system described.

[0142] [Table 11]

[0143] Example 5A - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407A, replacing the R407A in the new primary loop with R448A, and replacing the R407A in the new secondary loop with refrigerants A1-A5. Example 4A is repeated, except that the existing refrigerant is R407A. Table E5A below demonstrates the superior performance achieved in accordance with the systems and methods of the present invention as illustrated in this Example 5A, with results reported for the base system of Comparative Example C2, which has R407A as the only refrigerant in the centralized refrigeration system described.

[0144] [Table 12]

[0145] Example 5B - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407A, replacing the R407A in the new primary loop with R449A, and replacing the R407A in the new secondary loop with refrigerants A1-A5 Example 4A is repeated, except that the existing refrigerant is R407A. Table E5B below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as illustrated in this Example 5B, with results reported for the base system of Comparative Example C2 having R407A as the only refrigerant in the centralized refrigeration system described.

[0146] [Table 13]

[0147] Example 6A - Formation of centralized refrigeration by modifying the original system using the existing refrigerant R-407C, replacing the R407C in the new primary loop with R448A, and replacing the R407C in the new secondary loop with refrigerants A1-A5 Example 4A is repeated, except that the existing refrigerant is R407C. Table E6A below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as illustrated in this Example 6A, with results reported for the base system of Comparative Example C2, which has R407C as the only refrigerant in the centralized refrigeration system described.

[0148] [Table 14]

[0149] Example 6B - Forming centralized refrigeration by modifying the original system using the existing refrigerant R-407C, replacing the R407C in the new primary loop with R449A, and replacing the R407C in the new secondary loop with refrigerants A1-A5 Example 4B is repeated, except that the existing refrigerant is R407C. Table E6B below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as illustrated in this Example 6B, with results reported for the base system of Comparative Example C2, which has R407A as the only refrigerant in the centralized refrigeration system described.

[0150] [Table 15]

[0151] Comparative Example C3A - Refrigeration System Using R-448A as a Refrigerant in Medium Temperature Applications A direct expansion refrigeration system of the type disclosed in Figure 1, having a capacity of approximately 100 kW, has R-448A as the existing refrigerant. The system operating conditions using R-448A as the refrigerant in the system of Figure 1 are as follows: Cooling capacity: 100kW Isentropic efficiency: 65% Volumetric efficiency: 100% Condensation temperature: 45℃ Subcooling: 0°C (system with receiver) Evaporator superheat: 5.5℃ Temperature rise in intake line: 10°C Evaporation temperature: -8℃

[0152] While this system works well from a thermodynamic and heat transfer performance standpoint, it is highly undesirable from an environmental impact standpoint, as the entire system involves the high GWP refrigerant R448A circulating throughout a large and complex piping network.

[0153] Example 7A - Formation of centralized refrigeration by modifying the original system using R-448A, leaving R448A in the new primary loop, and using refrigerants A1-A5 in the new secondary loop. The medium temperature refrigeration system of Comparative Example 3A (including the existing refrigerant R448A therein) is used as a starting point for forming an improved heat transfer system. This system is modified to produce the inventive system generally described in connection with Figures 3A and 3B of Comparative Example 1, except that the existing refrigerant R448A in the primary loop equipment is not replaced.

[0154] Table E7A below demonstrates that superior performance can be achieved in accordance with the systems and methods of the present invention as exemplified in this Example 7A, with results reported for the base system of Comparative Example C3 having R448A as the only refrigerant in the centralized refrigeration system described.

[0155] [Table 16]

[0156] Comparative Example C3B - Centralized Refrigeration System Using R-449A as the Refrigerant in Medium Temperature Applications Comparative Example C3A is repeated except that the existing refrigerant is R-449A.

[0157] Example 7A - Formation of centralized refrigeration by modifying the original system using R-449A, leaving R449A in the new primary loop, and using refrigerants A1-A5 in the new secondary loop. The medium temperature refrigeration system of Comparative Example 3B (including the existing refrigerant R449A therein) is used as a starting point for forming an improved heat transfer system. This system is modified to produce the inventive system generally described in connection with Figures 3A and 3B of Comparative Example 1, except that the existing refrigerant R449A in the primary loop equipment is not replaced.

[0158] Table E7B below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as exemplified in this Example 7B, with results reported relative to the base system of Comparative Example C3B having R449A as the only refrigerant in the centralized refrigeration system described.

[0159] [Table 17]

[0160] Comparative Example C4A - Centralized Refrigeration System Using R-448A as the Refrigerant in Low Temperature Applications A centralized direct expansion refrigeration system of the type disclosed in Figure 1 having a cooling capacity of approximately 35 kW has R-448A as the existing refrigerant. The low temperature system operating conditions using R-448A as the refrigerant in the system of Figure 1 are as follows: Cooling capacity: 35kW Isentropic efficiency: 55% Volumetric efficiency: 100% Condensation temperature: 45℃ Subcooling: 0°C (system with receiver) Evaporator superheat: 5.5℃ Temperature rise in intake line: 10°C Evaporation temperature: -35℃

[0161] While this system works well from a thermodynamic and heat transfer performance standpoint, it is highly undesirable from an environmental impact standpoint, as the entire system involves the high GWP refrigerant R448A circulating throughout a large and complex piping network.

[0162] Example 8A - Formation of a centralized low-temperature refrigeration system by modifying the original system using R-448A, leaving R448A in the new primary loop, and using refrigerants A1-A5 in the new secondary loop. The low temperature refrigeration system of Comparative Example 4 (including the existing refrigerant R448A therein) is used as a starting point for creating an improved heat transfer system. This system is modified to produce the inventive system generally described in connection with Figures 3A and 3B of Comparative Example 1, except that the existing refrigerant R448A in the primary loop equipment is not replaced.

[0163] Table E8A below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as exemplified in this Example 8A, with results reported for the base system of Comparative Example C4 having R448A as the only refrigerant in the centralized refrigeration system described.

[0164] [Table 18]

[0165] Comparative Example C4B - Centralized Refrigeration System Using R-449A as the Refrigerant in Low Temperature Applications Comparative Example C4A is repeated except that the existing refrigerant is R-449A.

[0166] Example 8B - Formation of a centralized low-temperature refrigeration system by modifying the original system using R-449A, leaving R449A in the new primary loop, and using refrigerants A1-A5 in the new secondary loop. The low temperature refrigeration system of Comparative Example 4B (including the existing refrigerant R449A therein) is used as a starting point for forming an improved heat transfer system. This system is modified to produce the inventive system generally described in connection with Figures 3A and 3B of Comparative Example 1, except that the existing refrigerant R449A in the primary loop equipment is not replaced.

[0167] Table E8B below demonstrates that superior performance is achieved in accordance with the systems and methods of the present invention as exemplified in this Example 8B, with results reported relative to the base system of Comparative Example C4B having R449A as the only refrigerant in the centralized refrigeration system described.

[0168] Table 19

Claims

1. 1. A method of forming an improved refrigeration system, comprising: a. providing an existing refrigeration circuit comprising: (i) an existing refrigerant having a GWP greater than 1200; (ii) a plurality of evaporators located in or near a refrigerated space containing consumer accessible products; and (ii) at least one compressor or rack of compressors and at least one condenser located away from the consumer accessible area, wherein the existing refrigerant liquid from the condenser is fluidly connected to the evaporator via a conduit and the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; b) severing the fluid connection between the existing liquid refrigerant from the condenser and at least one of the evaporators, preferably substantially all of the evaporators; c. severing the fluid connection between the existing refrigerant vapor from the at least one of the evaporators in step (b) and the suction of the compressor or compressor rack; d. establishing a new first refrigeration circuit comprising the compressor or compressor rack and the condenser, wherein the existing refrigerant either remains in the first refrigeration circuit or is removed and replaced; e. (i) removing the existing refrigerant from at least a portion of the evaporator and the conduit severed in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 30% to about 70% by weight of CF3I; (2) about 9% to about 58% by weight of HFO-1234yf; (3) 1% to about 21.5% by weight of HFC-32; and optionally (4) 0.5% to 4% by weight of HFC-125, CO2, or a combination of HFC-125 and CO2, wherein the sum of components (1) through (4) comprises at least 95% by weight of the second refrigerant, and wherein the second refrigerant (i) has an Occupational Exposure Limit (OEL) greater than 400; and (ii) is ASHRAE compliant. (iii) classified as Class A1 by Standard 34, and having a GWP of about 150 or less; establishing a new second refrigeration circuit comprising said at least one of the evaporators disconnected in steps (b) and (c), preferably all of the evaporators disconnected in steps (b) and (c), by steps comprising: f. thermally interconnecting the new first refrigeration circuit and the new second refrigeration circuit with an inter-circuit heat exchanger, wherein at least a portion of the refrigerant in the first circuit is evaporated by absorbing heat from the second circuit refrigerant vapor and at least a portion of the second refrigerant vapor is condensed by transferring heat to the first circuit refrigerant liquid.

2. 10. The method of claim 1, wherein the second refrigerant comprises: (1) about 59% to about 69.5% by weight of CF3I; (2) about 9% to about 19.5% by weight of HFO-1234yf; and (3) 16.5% to about 21.5% by weight of HFC-32, the total of components (1)-(3) comprising at least 95% by weight of the second refrigerant.

3. 10. The method of claim 1, wherein the second refrigerant comprises: (1) about 32.8% to about 53.8% by weight of CF3I; (2) about 29% to about 58% by weight of HFO-1234yf; (3) 2%±0.2% to about 16.5% by weight of HFC-32; and (4) 1±0.2 to 3.2±0.2% by weight of HFC-125, the total of components (1) through (4) comprising at least 95% by weight of the second refrigerant.

4. 10. The method of claim 1, wherein the second refrigerant comprises: (1) about 41.5% to about 49.5% by weight of CF3I; (2) about 36% to about 44% by weight of HFO-1234yf; (3) about 11% to about 15% by weight of HFC-32; and (4) 1±0.2 to 3.5±0.2% by weight of CO2, the total of components (1) through (4) comprising at least 95% by weight of the second refrigerant.

5. 10. The method of claim 1, wherein the second refrigerant comprises: (1) about 32.8% to about 53.8% by weight of CF3I; (2) about 29% to about 58% by weight of HFO-1234yf; (3) 2% ±0.2% to about 16.5% by weight of HFC-32; and (4) 0.5% to 4% by weight of HFC-125, CO2, or a combination of HFC-125 and CO2, the total of components (1) through (4) comprising at least 95% by weight of the second refrigerant.

6. 10. The method of claim 1, wherein the second refrigerant consists essentially of: (1) about 69.5 wt. % CF3I; (2) about 9 wt. % HFO-1234yf; and (3) about 21.5 wt. % HFC-32.

7. 10. The method of claim 1, wherein the second refrigerant consists essentially of: (1) about 59 wt. % CF3I; (2) about 19.5 wt. % HFO-1234yf; and (3) about 21.5 wt. % HFC-32.

8. 10. The method of claim 1, wherein the second refrigerant consists essentially of: (1) about 38% by weight CF3I; (2) about 54% by weight HFO-1234yf; (3) about 5% by weight HFC-32; and (4) about 3% + 1 / - 0.2% HFC-125.

9. 10. The method of claim 1, wherein the second refrigerant consists essentially of: (1) about 45% by weight CF3I; (2) about 40% by weight HFO-1234yf; (3) about 13% by weight HFC-32; and (4) about 2+1 / −0.2% CO2.

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