Method of forming a refrigerant system

Abstract

A method for forming an improved refrigeration system, the method comprising: (a) providing an existing refrigeration circuit, an existing refrigeration circuit including an existing refrigerant having a GWP greater than 1200, a plurality of evaporators in a refrigeration space containing consumer accessible product, a compressor rack, and at least one condenser positioned remotely from a consumer accessible area; (b) disconnecting a fluid connection between the existing liquid refrigerant from the condenser and the evaporator; (c) disconnecting the fluid connection between the existing refrigerant vapor from the evaporator in step (b) and the suction inlet of the compressor or compressor rack; and (d) establishing a new first refrigeration circuit comprising a compressor rack and the condenser; (e) establishing a new second refrigeration circuit comprising at least one of the evaporators by steps comprising: removing the existing refrigerant from the evaporator, and replacing the removed existing refrigerant with a second refrigerant.

Description

Technical Field

[0001] This 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 an existing vapor pressure refrigeration system, such as, but not limited to, large centralized supermarket refrigeration systems using high-global-warming refrigerants, such as R404A, R448, R449, R407, dichlorofluoromethane (R-22), etc. Background Technology

[0002] Distributed refrigeration systems (such as those used to cool supermarket display cases) typically employ air-cooled or water-cooled condensers supplied by compressor racks. In common practice, the compressors are connected in parallel so that they can be turned on and off in stages to adjust the system's cooling capacity according to load requirements, and the condensers are located externally, usually on the roof or in a machine room adjacent to the shopping area where the refrigerated display cases are located.

[0003] Inside each refrigerated cabinet is an evaporator supplied by piping from a condenser, through which expanding refrigerant circulates to cool the cabinet. Because the cabinets are located on the retail floor of the supermarket and the condenser is positioned away from the roof or machine room, which is inaccessible to consumers, long piping connected by joints, valves, and control systems is a fundamental characteristic of such existing systems.

[0004] Supermarket practice typically involves using separate systems to provide different individual cooling temperature ranges to various retail displays. For example, low-temperature displays contain frozen foods, ice cream, etc., and are generally operated to maintain their contents in a temperature range of approximately -30°C to approximately -10°C, while medium-temperature displays for meat, dairy products, etc., are typically designed to maintain their contents from approximately -10°C to approximately 5°C below. These separate low-temperature and medium-temperature systems usually constitute their own centralized refrigeration systems and each typically employs its own compressor or compressor rack and its own set of refrigerant conduits leading to and from the compressor and condenser.

[0005] As mentioned above, centralized refrigeration systems have this conventional arrangement and are very expensive to construct and maintain. A significant component of this high cost is the long refrigerant conduits. Long conduits are not only expensive in terms of hardware and installation costs, but the amount of refrigerant required to fill them is also a major factor. The longer the conduits, the more refrigerant is required. Environmental factors further increase the cost of such systems. In these systems, refrigerants that perform well in terms of heat transfer performance and safety (low toxicity or non-toxicity and low flammability or non-flammability) but are highly unfavorable from an environmental perspective due to their high global warming potential are often used. For example, the following refrigerants (with GWP values ​​according to IPCC AR4) have been frequently used in such systems: R404A (GWP = 3922), R22 (GWP = 1760), R407F (GWP = 1824), R448A (GWP = 1387), and R449A (GWP = 1397). Because components in such systems are likely to leak over time, these environmentally harmful refrigerants could escape into the atmosphere. Furthermore, long conduit runs involve more potentially leaky pipe joints, valves, etc., and therefore, the longer the conduit runs, the greater the amount of high-growth-potential refrigerant lost into the atmosphere in the event of a leak.

[0006] Efforts to address the environmental drawbacks of refrigeration systems, particularly but not limited to centralized refrigeration systems, present considerable engineering challenges, partly due to the substantial costs associated with large-scale replacements of such expensive and potentially very large systems. Furthermore, conventional roof-mounted or room-mounted condenser / compressor systems offer high levels of efficiency and capacity, and any effort to modify these systems to be more environmentally attractive should ideally maintain this efficiency and capacity. This important but challenging task of achieving environmental improvements is reflected, for example, in recently implemented EU regulations, particularly those applicable to large systems with refrigerant charges of 3 kg or more.

[0007] Several thermodynamic and fluid flow challenges have arisen in efforts to convert conventional centralized refrigeration systems to more environmentally friendly ones while maintaining efficiency and capacity. For example, the applicant has recognized that it is difficult, if not impossible, to identify environmentally friendly refrigerants (e.g., with a GWP of approximately 150 or less (as measured by AR45)) that can be easily used in existing refrigeration systems to replace existing high-GWP refrigerants. Previously disclosed alternatives to R-22 have been studied and shown to result in reduced cooling capacity and increased power requirements, thus leading to a significant overall reduction in performance (see WO2020 / 223196A1). This demonstrates the difficulty in developing a viable solution to this problem.

[0008] Furthermore, in many applications, particularly in many centralized refrigeration systems, the use of non-flammable compositions is often considered important or necessary. As used herein, the term "non-flammable" refers to a compound or composition that has been determined to be non-flammable, as described in ASHRAE Standard 34-2016, "Designation and Safety Classification of Refrigerants," and Annex B1 of ASHRAE Standard 34-2016, under the conditions described therein (incorporated herein by reference). Unfortunately, many HFCs that might have been expected to be used to retrofit existing centralized refrigeration systems are not non-flammable, as this term is used herein. For example, the fluoroalkane difluoroethane (HFC-152a) and the fluoroolefin 1,1,1-trifluoropropylene (HFO-1243zf) are each flammable and therefore impractical for use in many applications.

[0009] Regarding efficiency, it is important to note that the loss of refrigerant thermodynamic properties or energy efficiency can have secondary environmental impacts due to increased fossil fuel use resulting from increased demand for electricity.

[0010] Therefore, the applicant has recognized that significant advantages can be achieved by creating a more environmentally friendly centralized refrigeration system that is comparable to the old system in terms of thermodynamic performance, refrigerant safety (toxicity and flammability), and only requires relatively low capital costs in terms of system infrastructure. Summary of the Invention

[0011] The applicant has discovered that the above-mentioned and other requirements can be met by a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0012] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0013] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0014] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0015] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0016] (e) Establishing a new second refrigeration circuit comprising at least one evaporator, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected 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, provided that the sum of components (1) to (4) accounts for at least 95% by weight of the second refrigerant, and wherein the second refrigerant:

[0017] (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Category A1 according to ASHRAE Standard 34; and (iii) has a gross potential cost (GWP) of approximately 150 or less; and

[0018] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0019] For convenience, the composition according to this paragraph is referred to herein as system formation method 1A.

[0020] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0021] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0022] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0023] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0024] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0025] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 59 wt% to about 69.5 wt% of CF3I; (2) about 9 wt% to about 19.5 wt% of HFO-1234yf; and (3) 16.5 wt% to about 21.5 wt% of HFC-32, provided that the sum of components (1) to (3) constitutes at least 95 wt% of the second refrigerant, and wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0026] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0027] For convenience, the composition according to this paragraph is referred to herein as system formation method 1B.

[0028] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0029] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0030] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0031] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0032] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0033] (e) Establishing a new second refrigeration circuit comprising at least one evaporator, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 32.8 wt% to about 53.8 wt% of CF3I; (2) about 29 wt% to about 58 wt% of HFO-1234yf; (3) 2 wt% ± 0.2 wt%

[0034] (1) to about 16.5% by weight of HFC-32; and (4) 1% by weight ± 0.2% by weight to 3.2% by weight ± 0.2% by weight of HFC-125, provided that the sum of components (1) to (4) accounts for at least 95% by weight of the second refrigerant, and wherein the second refrigerant is:

[0035] (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Category A1 according to ASHRAE Standard 34; and (iii) has a gross potential cost (GWP) of approximately 150 or less; and

[0036] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0037] For convenience, the composition according to this paragraph is referred to herein as system formation method 1C.

[0038] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0039] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0040] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0041] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0042] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0043] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected 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% by weight of CF3I. (1) about 44 wt% of HFO-1234yf; (2) about 11 wt% to about 15 wt% of HFC-32; and (3) 1 wt% ± 0.2 wt% to 3.5 wt% ± 0.2 wt% of CO2, provided that the sum of components (1) to (4) accounts for at least 95 wt% of the second refrigerant, and wherein said second refrigerant: (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0044] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0045] For convenience, the composition according to this paragraph is referred to herein as System Formation Method 1D.

[0046] The present invention also includes a method for forming an improved large-capacity centralized refrigeration system, the method comprising:

[0047] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0048] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0049] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0050] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0051] (e) Establishing a new second refrigeration circuit comprising at least one, and preferably all, of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 32.8 wt% to about 53.8 wt% of CF3I; (2) about 29 wt% to about 58 wt% of HFO-1234yf; (3) 2 wt% + / - 0.2 wt% to about 16.5 wt% of HFC-32; and (4) 0.5 wt% to 4 wt% of HFC-125, CO2, or a combination of HFC-125 and CO2, provided that component (1)

[0052] The total of components (4) constitutes at least 95% by weight of the second refrigerant, and wherein said second refrigerant: (i) has an occupational exposure limit (OEL) greater than 400; (ii)

[0053] Classified as A1 according to ASHRAE Standard 34; and (iii) having a GWP of about 150 or less; and

[0054] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0055] For convenience, the composition according to this paragraph is referred to herein as system formation method 1E.

[0056] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0057] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0058] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0059] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0060] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0061] (e) Establishing a new second refrigeration circuit comprising at least one, and preferably all, of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed 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)

[0062] Classified as A1 according to ASHRAE Standard 34; and (iii) having a GWP of less than approximately 150; and

[0063] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0064] For convenience, the composition according to this paragraph is referred to herein as system formation method 2A.

[0065] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0066] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0067] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0068] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0069] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0070] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 69.5% by weight of CF3I; (2) about 9% by weight of HFO-1234yf; and (3) about 21.5% by weight of HFC-32, wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0071] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0072] For convenience, the composition according to this paragraph is referred to herein as system formation method 2B.

[0073] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0074] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0075] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0076] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0077] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0078] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators that have been disconnected in steps (b) and (c), and preferably all of the evaporators, by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) about 59 wt% CF3I; (2) about 19.5 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;

[0079] (ii) Classified as A1 according to ASHRAE Standard 34; and (iii) has a GWP of less than approximately 150; and

[0080] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0081] For convenience, the composition according to this paragraph is referred to herein as system formation method 3A.

[0082] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0083] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0084] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0085] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0086] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0087] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 59 wt% CF3I; (2) about 19.5 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 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0088] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0089] For convenience, the composition according to this paragraph is referred to herein as system formation method 3B.

[0090] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0091] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0092] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0093] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0094] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0095] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) about 38 wt% CF3I; (2) about 54 wt% HFO-1234yf; and (3) about 5 wt% HFC-32; and (4) about

[0096] 3% + 1% / - 0.2% of HFC-125, wherein the second refrigerant: (i) has a greater than

[0097] (ii) has an occupational exposure limit (OEL) of 400; (iii) is classified as a Class A1 according to ASHRAE Standard 34; and (iii) has a gross potential cost (GWP) of less than approximately 150; and

[0098] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0099] For convenience, the composition according to this paragraph is referred to herein as system formation method 4A.

[0100] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0101] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0102] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0103] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0104] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0105] (e) Establishing a new second refrigeration circuit comprising at least one, and preferably all, of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 38 wt% CF3I; (2) about 54 wt% HFO-1234yf; and (3) about 5 wt% HFC-32; and (4) about 3% + 1% / -0.2% HFC-125, wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii)

[0106] With a GWP of less than approximately 150; and

[0107] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0108] For convenience, the composition according to this paragraph is referred to herein as system formation method 4B.

[0109] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0110] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0111] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0112] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0113] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0114] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 45 wt% CF3I; (2) about 40 wt% HFO-1234yf; and (3) about 13 wt% HFC-32; and (4) 2 wt% + 1 wt% / -0.2 wt% CO2, wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0115] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0116] For convenience, the composition according to this paragraph is referred to herein as system formation method 5A.

[0117] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0118] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0119] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0120] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0121] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0122] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) about 45 wt% CF3I; (2) about 40 wt% HFO-1234yf; and (3) about 13 wt% 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 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0123] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0124] For convenience, the composition according to this paragraph is referred to herein as system formation method 5B.

[0125] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0126] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0127] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0128] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0129] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0130] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 45% by weight of CF3I; (2) about 40% by weight of HFO-1234yf; and (3) about 13% by weight of HFC-32; and (4) about 2 + 1% / - 0.2% of CO2, wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0131] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0132] For convenience, the composition according to this paragraph is referred to herein as system formation method 5C.

[0133] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0134] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0135] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0136] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0137] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0138] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 32.8 wt% to 42.8 wt% of CF3I; (2) 48 wt% to 58 wt% of HFO-1234yf; (3) 2 wt% to 6 wt% of HFC-32; and (4) 1 wt% ± 0.2 wt% to 3.2 wt% ± 0.2 wt% of HFC-125, wherein the second refrigerant: (i) has an Occupational Exposure Limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0139] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0140] For convenience, the composition according to this paragraph is referred to herein as system formation method 6.

[0141] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0142] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0143] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0144] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0145] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0146] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (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 wt% ± 0.2 wt% to 3.2 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 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0147] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0148] For convenience, the composition according to this paragraph is referred to herein as system formation method 7.

[0149] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0150] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0151] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0152] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0153] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0154] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators that have been disconnected in steps (b) and (c), and preferably all of the evaporators, by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) about 45 wt% CF3I; (2) about 54 wt% HFO-1234yf; (3) 5 wt% ± 0.5 wt% HFC-32; and (4) 1 wt% ± 0.2 wt% to 3.2 wt% ± 0.2 wt% HFC-125, wherein the second refrigerant: (i) has an occupational exposure limit (OEL) greater than 400;

[0155] (ii) Classified as A1 according to ASHRAE Standard 34; and (iii) has a GWP of less than approximately 150; and

[0156] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0157] For convenience, the composition according to this paragraph is referred to herein as system formation method 8.

[0158] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0159] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0160] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0161] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0162] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0163] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 38 wt% ± 1 wt% CF3I; (2) about 54 wt% ± 1 wt% HFO-1234yf; (3) 5 wt% ± 1 wt% HFC-32; and (4) 3 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 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0164] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0165] For convenience, the composition according to this paragraph is referred to herein as system formation method 9A.

[0166] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0167] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0168] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0169] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0170] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0171] (e) Establishing a new second refrigeration circuit comprising at least one, and preferably all, of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) 38 wt% ± 1 wt% CF3I; (2)

[0172] (2) approximately 54 wt% ± 1 wt% HFO-1234yf; (3) 5 wt% ± 1 wt% HFC-32; and (4) 3 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 according to ASHRAE Standard 34; and (iii) has a GWP less than approximately 150; and

[0173] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0174] For convenience, the composition according to this paragraph is referred to herein as system formation method 9B.

[0175] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0176] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0177] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0178] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0179] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0180] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 38 wt% ± 1 wt% CF3I; (2) about 54 wt% ± 1 wt% HFO-1234yf; (3) 5 wt% ± 1 wt% HFC-32; and (4) 3 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 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0181] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0182] For convenience, the composition according to this paragraph is referred to herein as system formation method 9C.

[0183] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0184] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0185] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0186] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0187] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0188] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 45% to 55% by weight of CF3I; (2) 30% by weight of CF3I.

[0189] (3) 10% to 20% HFC-32; and (4) 1% to 2% HFC-125, wherein the second refrigerant: (i) has an occupational exposure limit (OEL) greater than 40; (ii) is classified as A1 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0190] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0191] For convenience, the composition according to this paragraph is referred to herein as system formation method 10.

[0192] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0193] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0194] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0195] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0196] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0197] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected 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% ±

[0198] 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 Group A1 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0199] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0200] For convenience, the composition according to this paragraph is referred to herein as system formation method 11A.

[0201] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0202] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0203] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0204] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0205] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0206] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) about 50 wt% CF3I; (2) about 34.5 wt% HFO-1234yf; (3) 5 wt% ± 0.5 wt% HFC-32; and

[0207] (4) 1.5 wt% ± 0.2 wt% of HFC-125, wherein the second refrigerant is: (i)

[0208] (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Category A1 according to ASHRAE Standard 34; and (iii) has a gross potential cost (GWP) of less than approximately 150; and

[0209] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0210] For convenience, the composition according to this paragraph is referred to herein as system formation method 11B.

[0211] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0212] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0213] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0214] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0215] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0216] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected 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 40; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0217] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0218] For convenience, the composition according to this paragraph is referred to herein as system formation method 11C.

[0219] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0220] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0221] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0222] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0223] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced;

[0224] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) about 50 wt% ± 1 wt% CF3I; (2) about 34.5 wt% ± 1 wt% HFO-1234yf; (3) 14 wt% ± 1 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 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and

[0225] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

[0226] For convenience, the composition according to this paragraph is referred to herein as system formation method 12A.

[0227] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0228] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0229] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0230] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0231] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0232] (e) Establishing a new second refrigeration circuit comprising at least one, and preferably all, of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant substantially composed of: (1) 38 wt% ± 1 wt% CF3I; (2)

[0233] (2) approximately 34.5 wt% ± 1 wt% of HFO-1234yf; (3) 14 wt% ± 1 wt% of HFC-32; and (4) 1.5 wt% ± 0.2 wt% of HFC-125, wherein the second refrigerant: (i) has an occupational exposure limit (OEL) greater than 400; (ii)

[0234] Classified as A1 according to ASHRAE Standard 34; and (iii) having a GWP of less than approximately 150; and

[0235] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0236] For convenience, the composition according to this paragraph is referred to herein as system formation method 12B.

[0237] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0238] (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 a consumer-accessible product, and (iii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned via a conduit to the suction side of the compressor or compressor rack;

[0239] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0240] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0241] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0242] (e) Establishing a new second refrigeration circuit comprising at least one of the evaporators, and preferably all of the evaporators, which have been disconnected in steps (b) and (c), by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); and (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 50 wt% ± 1 wt% CF3I; (2) about 34.5 wt% ± 1 wt% HFO-1234yf; (3) 14 wt% ± 1 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 according to ASHRAE Standard 34; and (iii) has a GWP less than about 150; and

[0243] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0244] For convenience, the composition according to this paragraph is referred to herein as system formation method 12C.

[0245] The present invention also includes a method for forming an improved refrigeration system, preferably a large-capacity centralized refrigeration system, the method comprising:

[0246] (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 a consumer-accessible product, and (ii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit;

[0247] (b) Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators;

[0248] (c) Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and

[0249] (d) Establishing a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is removed and replaced with a new first refrigerant different from the existing refrigerant;

[0250] (e) Establishing a new second refrigeration circuit comprising at least one and preferably all of the evaporators that have been disconnected in steps (b) and (c) by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (ii) replacing the removed existing refrigerant with a second refrigerant comprising: (1) 40% to 50% by weight of CF3I; (2) 35% by weight of CF3I.

[0251] (3) 10% to 16% HFC-32; and (4) 1.5% to 2.5% CO2, wherein the second refrigerant is:

[0252] (i) has an occupational exposure limit (OEL) greater than 40; (ii) is classified as Category A1 according to ASHRAE Standard 34; and (iii) has a gross potential cost (GWP) of less than approximately 150; and

[0253] (f) Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the liquid in the first circuit.

[0254] For convenience, the composition according to this paragraph is referred to herein as system formation method 13. Attached Figure Description

[0255] Figure 1 This is a semi-schematic process flow diagram illustrating a centralized refrigeration system according to existing technology.

[0256] Figure 2 This is a half-schematic diagram of an exemplary initial centralized refrigeration system used in the heat transfer system formation method of the present invention.

[0257] Figure 3AThis is a schematic diagram of an exemplary starting centralized refrigeration system showing the breakpoint in the process of forming the heat transfer system of the present invention.

[0258] Figure 3B This is a schematic diagram of a completed exemplary centralized refrigeration system manufactured according to the heat transfer system forming method of the present invention. Detailed Implementation

[0259] definition

[0260] For the purposes of this invention, for amounts greater than 2%, the term "about" in relation to amounts expressed as a weight percentage means that the amount of the component may vary by + / - 2% by weight.

[0261] For the purposes of this invention, the term "about" in relation to temperature in degrees Celsius (°C) means that the temperature can vary by + / - 5°C.

[0262] For the purposes of this invention, the term “about” in relation to the percentage of power usage means that the percentage may vary by a maximum of 1%.

[0263] For the purposes of this invention, the term "major" in relation to the removal of existing refrigerant from a heat transfer system means the removal of at least about 50% of the existing refrigerant contained in the system.

[0264] The term "capacity" refers to the amount of cooling (in BTU / hour or kW) provided by a refrigerant in a refrigeration system. This is determined experimentally by multiplying the enthalpy change of the refrigerant as it passes through the evaporator (in BTU / lb or kJ / kg) by the refrigerant's mass flow rate. Enthalpy can be determined by measurements of the refrigerant's pressure and temperature. The capacity of a refrigeration system relates to its ability to maintain a region cooled at a specific temperature. The capacity of a refrigerant indicates the amount of cooling or heating it provides and provides some measure of the compressor's ability to pump heat for a given volumetric flow rate of refrigerant. In other words, given a particular compressor, a higher capacity refrigerant will deliver more cooling or heating power.

[0265] The phrase “coefficient of performance” (hereinafter referred to as “COP”) is a generally accepted measure of refrigerant performance, particularly used to indicate the relative thermodynamic efficiency of a refrigerant in a specific heating or cooling cycle involving refrigerant evaporation or condensation. In refrigeration engineering, the term represents the ratio of available cooling or refrigeration capacity to the energy exerted by the compressor when compressing the vapor, and thus the ability of a given compressor to pump 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 method for estimating the COP of a refrigerant under specific operating conditions is to estimate it from the thermodynamic properties of the refrigerant using standard refrigeration cycle analysis techniques (see, for example, RCDowning, *FLUOROCARBON REFRIGERANTS HANDBOOK*, Chapter 3, Prentice-Hall, 1988, the full text of which is incorporated herein by reference).

[0266] The phrase "discharge temperature" refers to the temperature of the refrigerant at the compressor outlet. The advantage of a low discharge temperature is that it allows the use of existing equipment without activating the system's thermal protection features, which are preferably designed to protect compressor components, and avoids the use of costly control measures (such as liquid injection) to lower the discharge temperature.

[0267] As used herein, the term "centralized refrigeration system" means a refrigeration system comprising one or more centrally located compressors or compressor racks and one or more centrally located condensers and multiple evaporators located remotely from the centralized compressors or compressor racks and receiving liquid refrigerant from the centrally located condensers.

[0268] As used herein, “direct expansion” means utilizing a heat transfer system of an evaporator in which liquid refrigerant enters the evaporator and flows through a coil (preferably a tubular coil) and evaporates as it absorbs heat from the air circulating in the display case. The heat transfer system uses a thermostatic expansion valve at the inlet of the evaporator and is controlled to supply sufficient refrigerant so that substantially all of the refrigerant evaporates at the outlet of the evaporator and optionally has a predetermined amount of superheat at the outlet.

[0269] The phrase “Global Warming Potential” (hereinafter referred to as “GWP”) has evolved to allow comparisons of the global warming effects 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 a ton of gas emitted over a given time period will absorb relative to a ton of carbon dioxide emitted. The larger the GWP, the warmer the Earth will be over that time period compared to CO2. A 100-year time period is typically used for GWP. GWP provides a universal metric—allowing analysts to aggregate 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

[0270] The term “Occupational Exposure Limit (OEL)” is determined according to ASHRAE Standard 34-2016 Nomenclature and Safety Classification of Refrigerants.

[0271] As used herein, the phrase "acceptable toxicity" means that the composition is classified as "Class A" according to ASHRAE Standard 34-2016 Nomenclature and Safety Classification of Refrigerants and is described in Annex B1 of ASHRAE Standard 34-2016 (if any standards existed prior to the filing date of this application). Non-flammable and low-toxicity substances are classified as "Class A1" according to ASHRAE Standard 34-2016 Nomenclature and Safety Classification of Refrigerants and are described in Annex B1 of ASHRAE Standard 34-2016 (if any standards existed prior to the filing date of this application).

[0272] The term "mass flow rate" refers to the mass of refrigerant that passes through a conduit per unit time.

[0273] As used herein, the term "substitute" means the use of the composition of the present invention in a heat transfer system that has been designed for use with, or is suitable for use with, another refrigerant. By way of example, when the refrigerant or heat transfer composition of the present invention is used in a heat transfer system designed for use with R-410A, then the refrigerant or heat transfer composition of the present invention is a substitute for R-410A in said system. Therefore, it should be understood that the term "substitute" includes the use of the refrigerant and heat transfer composition of the present invention in both novel and existing systems that have been designed for use with, are typically used with, or are suitable for use with R-410A.

[0274] The term “slip” applies to non-azeotropic refrigerant mixtures with different temperatures during a 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 100 kPa pressure.

[0275] The term "cryogenic refrigeration system" refers to a heat transfer system that operates at a condensation temperature of about 40°C to about 70°C and an evaporation temperature of about -45°C to at most and including -12°C.

[0276] The term "intermediate 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.

[0277] As used in this article, the term "supermarket refrigeration" refers to a commercial refrigeration system used to keep refrigerated or frozen foods in both product display cases and storage refrigerators.

[0278] The term "standard boiling point" refers to the boiling point of a single component measured at 1 atmosphere, and also to the initial boiling point of a blend of the components at 1 atmosphere.

[0279] The term "R-22" refers to difluorochloromethane.

[0280] As used in this article, the terms “HFC-32” and “R-32” each refer to difluoromethane.

[0281] The term "R-125" refers to pentafluoroethane.

[0282] The term "R-134a" refers to 1,1,1,2-tetrafluoroethane.

[0283] The term "R-143a" refers to 1,1,1-trifluoroethane.

[0284] The term “R-404A” refers to a combination of approximately 44% by weight of R-125, approximately 52% by weight of R-143a and approximately 4% by weight of R-134a.

[0285] The term “R-407A” refers to a combination of approximately 20% by weight of R-32, approximately 40% by weight of R-125 and approximately 40% by weight of R-134a.

[0286] The term “R-407F” refers to a combination of approximately 23% by weight of R-32, approximately 25% by weight of R-125 and approximately 52% by weight of R-134a.

[0287] The term “R-407H” refers to a combination of 32.5 wt% + / - 1 wt% R-32, 15 wt% + / - 1 wt% R-125, and approximately 52.5 wt% + / - 2 wt% R-134a.

[0288] The term “R-448A” refers to a combination of about 26% by weight of R-32, about 26% by weight of R-125 and about 21% by weight of R-134a.

[0289] The term “R-449A” refers to a combination of approximately 24.3% by weight of R-32, approximately 24.7% by weight of R-125 and approximately 25.7% by weight of R-134a.

[0290] As used herein, the terms “HFO-1234yf” and “R-1234yf” each refer to 2,3,3,3-tetrafluoropropylene.

[0291] As used herein, the terms “HFO-1234ze(E)”, “R-1234ze(E)” and “1234ze(E)” each refer to trans-1,3,3,3-tetrafluoropropylene.

[0292] References to a set of defined items in this article include all such defined items, including all such items with a suffix in their names.

[0293] Systems and Methods

[0294] The method of the present invention typically includes the first step of providing an existing centralized refrigeration system. Illustrative examples of such centralized refrigeration systems are provided in... Figure 1 The figure illustrates a system comprising a compressor rack 30, a condenser 32, an accumulator 38, and a series of display cases 34, each containing an evaporator 42. High-GWP refrigerants (such as R-404a) circulate in such systems through a network of pipes 46 carrying liquid refrigerant and a network of pipes 48 carrying refrigerant vapor. Although in Figure 1The diagram is schematic, but in practice, each of these piping networks typically represents a large and long series of conduits for conveying liquid refrigerant from the accumulator 38, which is usually located away from the display cases along with the compressor rack 30 and condenser 32. Therefore, the piping network 46 is large, covering a distance from, for example, the roof or machine room of a supermarket to the floor, reaching multiple display cases located there. Although Figure 1 Only two (2) display cases are shown, but those skilled in the art will understand that in many cases, in large consumer retail areas that require access via the liquid piping network 46, each loop may have one or more of about 150 display cases, and an equally large vapor return piping network 48 will be required to return refrigerant vapor from each of these cases to the roof or machine room. In many applications, the piping length required to supply liquid from the compressor and return vapor to the compressor is at least about 20 meters (65 feet).

[0295] Those skilled in the art should also understand that, although Figure 1 The compressor rack is depicted as having four compressors 30, but in practice, the compressor rack may include one (1) compressor or up to about five compressors, depending on the application. In other words, the existing refrigerant system provided according to the invention can exhibit a compressor operating capacity of about 3 kW to about 500 kW. Regarding the type of compressor, all types of compressors are expected to be present in such systems, but in many such systems, the compressors used are selected from screw compressors, scroll compressors, reciprocating compressors, centrifugal compressors, twin-screw compressors, and combinations thereof.

[0296] Existing refrigerants used in the conventional centralized refrigeration systems of this invention typically have a GWP of 1200 or greater (as determined according to AR5) and include R404A, R22, and R407 (including each of R407A, R407B, R407C, R407D, and R407F), R448 (all-letter designation, including R448A), and R449 (all-letter designation, including R449A). In this application, referring to a refrigerant by its letter designation without a suffix (such as R448) is intended to individually refer to each refrigerant having that designation, including all refrigerants with suffixes. Thus, for example, referring to “R448” is intended to individually refer to each of R448A and R448B.

[0297] This invention relates to improved Figure 1 The system of the type disclosed herein aims to improve the environmental friendliness of the system. A preferred method includes the steps of: disconnecting the liquid connection between the condenser and at least one (preferably all) of the evaporators, and also disconnecting the vapor connection between the evaporators and the compressor suction inlet. For example, see reference... Figure 2 A, Figure 2 B and Figure 2 C. Liquid line 14 is disconnected, preferably just downstream of accumulator 13, to separate the liquid side of the evaporator from the liquid from condenser 12, and vapor line 15 is disconnected, preferably just upstream of compressor, to separate the vapor side of the evaporator from compressor. This disconnection step thus makes it possible to convert an existing single refrigeration circuit into a new first refrigeration circuit and a new second refrigeration circuit (see, for example, 10A and 10B in Figure 3C). As used herein, the term “new” should be understood to mean only that the circuit defined by the present invention did not previously exist, but it should be understood that one object of the present invention is to utilize most of the “old” piping network and the “old” evaporator as part of the new second refrigeration circuit. In some preferred embodiments, another object is to use the “old” compressor, condenser, and accumulator, as well as the piping and valves between them, to form the second new refrigeration circuit.

[0298] Before, during, or after the disconnection step, the existing refrigerant is removed from the network of liquid and vapor piping connected to the evaporator, as well as from the evaporator itself and all other piping, valves, etc., used to form a new second refrigeration loop (such as loop 10B in Figure 3C). A preferred second loop (an example of which is shown in Figure 3C) is formed by including a liquid pump 21, which, in a preferred embodiment, supplies cooled liquid refrigerant via an accumulator 22. The pump provides kinetic energy to deliver the second refrigerant to each of the evaporators that have been disconnected from the compressor. The liquid refrigerant in the second loop 10B cools the display case as it evaporates in the evaporator by absorbing heat from the air and / or products in the display case.

[0299] An important aspect of this invention is that, unlike the original system where vapor from the evaporator returns to the compressor, the invention relates to the step of thermally interconnecting a new first refrigeration circuit 10A and a 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 the liquid refrigerant leaving the condenser in the new first circuit, thereby evaporating the first refrigerant and producing refrigerant supplied to the compressor 11 of the first circuit. In this arrangement, the inter-circuit heat exchanger acts as an evaporator in the first circuit and a condenser in the second circuit.

[0300] Importantly, the method of the present invention relates to the use of a low-GWP refrigerant in the new second circuit, the low-GWP refrigerant having a GWP of 150 or less, and preferably having an OEL greater than 400 and conforming to the standard Class 1A refrigerant. Table A below identifies three refrigerant blends A1, A2, and A3 that meet these criteria and provide substantially unexpected advantages according to the invention. It should be understood that the quantities in this table are considered to be preceded by "about":

[0301] Table A

[0302]

[0303] Existing refrigerant contained in the piping and equipment associated with the condenser and compressor (i.e., the new first refrigeration loop) is expected to be retained and used as the refrigerant in the new first loop. However, it is generally preferred to remove the existing refrigerant from the compressor / condenser loop and replace it with a new, preferably lower GWP refrigerant. In those embodiments in which the existing refrigerant is retained in the new first loop, it is expected that the existing equipment (including the compressor, condenser, accumulator, connecting piping, etc.) will also not need to be replaced. Such embodiments have the advantage of minimizing increased capital equipment costs but will result in the use of a high GWP refrigerant in the new second refrigeration loop. While such arrangements have significant environmental advantages because the amount of high GWP refrigerant used in the conversion system is greatly 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, it may be necessary to replace and / or modify one or more of those components of the system, which again increases capital expenditure. However, from an environmental perspective, the most desirable results are achieved according to the embodiment in which high-GWP refrigerant is removed from the first loop, because it provides a conversion system in which only low-GWP refrigerant is used. Typically, for such embodiments, the novel refrigerant used in the first loop will have a GWP of less than 150, more preferably less than 100, and even more preferably less than about 25.

[0304] For existing refrigerants such as R404A, R407, R507, or R22, whose GWP is greater than 1500, the refrigerant used to replace these refrigerants is preferably selected according to Case 1 in the table below:

[0305] Case 1

[0306]

[0307]

[0308] In other cases, the existing refrigerant is R448 (with a GWP of less than about 1200) or R449 (with a GWP of less than about 1500), and in such cases, the existing refrigerant is not replaced, preferably as case 2 according to the table below.

[0309] Case 2

[0310]

[0311] In embodiments where the existing refrigerant has a GWP greater than 1500, other examples of low-GWP refrigerants (such as R404A, R407, R507 or R22) to be used in the new first refrigerant loop include 1234ze(E)1234yf and blends containing these.

[0312] As those skilled in the art will understand, the present invention includes the method of combining a wide range of existing systems having existing refrigerants and a variety of specific refrigerants that can be used in a new second circuit, and optionally as a replacement for existing refrigerants in a new first circuit.

[0313] Example

[0314] The following embodiments are provided to illustrate the present invention, but do not limit the scope of the invention.

[0315] To evaluate possible ways to improve existing centralized refrigeration systems to be more environmentally friendly, including for comparative purposes, by essentially removing the full charge of the existing high-GWP refrigerant and replacing it with a lower-GWP refrigerant, it is important to consider performance parameters.

[0316] Comparative Example C1 - Refrigeration system using R-404A as refrigerant in medium-temperature applications

[0317] Figure 1 The disclosed type of direct expansion refrigeration system with a capacity of approximately 100kW uses R-404A as an existing refrigerant. Figure 1 The operating conditions for systems using R-404A as the refrigerant are:

[0318] Cooling capacity: 100kW

[0319] Isoentropy efficiency: 65%

[0320] Volumetric efficiency: 100%

[0321] Condensation temperature: 45℃

[0322] Supercooling: 0°C (for systems with receivers)

[0323] Evaporator overheating: 5.5℃

[0324] Temperature rise in the suction line: 10°C

[0325] Evaporation temperature: -8℃

[0326] Although the system operates well from a thermodynamic and heat transfer performance point of view, it is highly undesirable from an environmental impact point of view because the entire system contains high-GWP refrigerant R404A circulating throughout a large and complex piping network.

[0327] Example 1A - Modify the original system by using R-404A and replace R404A with R448A in the new main loop. Furthermore, in the new secondary loop, refrigerant A1 to refrigerant A5 are used to replace R404A to form a centralized refrigeration system.

[0328] The heat transfer system of Comparative Example C1, which contains the existing refrigerant R404A, is used as the starting point for forming an improved heat transfer system. Firstly, combining... Figure 3A Describe the modifications to the system. This includes condenser 12A (and...). Figure 3B The optional natural cooling condenser 12), compressor frame 11, and accumulator 13 shown (each of these components is located outdoors or in a machine room) Figure 3B The portions of the system above the dashed line 100A are each disconnected from the display case, preferably near the location of the compressor rack and accumulator, for example by cutting off the liquid line 14 leading from the accumulator and by cutting off the vapor riser 15 leading to the compressor rack. While the invention includes embodiments in which the existing refrigerant R404A 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 the dashed line 100A, i.e., indicating the outdoor or machine room location) and replaced with R448A, and the R404A in the remaining portions of the system (below the dashed line, indicating the outdoor or machine room location) is removed from all remaining refrigerant conduits and all evaporators and replaced with the refrigerant of the present invention.

[0329] like Figure 3BAs shown, the system is then reconfigured to use a first heat transfer system 10A with R448A and a second heat transfer loop 10B, which includes evaporators 1 to 5 and uses each of the new low-GWP refrigerants A1 to A5 according to the invention. A new heat exchanger 20 thermally interconnects the first heat transfer loop 10A to the second heat transfer loop 10B by conveying liquid R448A refrigerant from the accumulator, preferably via conduit 14A, over a relatively short distance to the inter-loop heat exchanger 20, where heat is absorbed from the new refrigerant in the second loop and evaporates. The evaporated R448A then returns to the suction side of the compressor frame via conduit 15A, which also preferably extends a relatively short distance.

[0330] A liquid pump 21 is added to the second loop system to provide motive power for delivering low-GWP refrigerant (A1 to A5) to each evaporator via corresponding conduits and valves. In each evaporator, the refrigerant according to the invention provides cooling to its corresponding display case as it evaporates upon thermal contact with the relatively warm air in the display case. The refrigerant vapor exiting from evaporator 1 to evaporator 5 according to the invention is then manifolded to riser 15B, in which the refrigerant vapor is conveyed to the inter-loop heat exchanger 20, and in which the refrigerant vapor dissipates heat from the first loop to liquid R-448A (or optionally partially dissipates it to a free-cooling condenser (note that suitable valve arrangements for achieving this optional operation are provided, but not shown)), and condenses back into liquid in doing so. The liquid refrigerant according to the invention from the heat exchanger 20 travels via conduit 14B to accumulator 22, which in turn provides a source of liquid according to the invention to pump 21.

[0331] According to the invention, the refrigerant evaporates (partially or completely) in each evaporator, and the refrigerant vapor is in a saturated or superheated state through the reflux of the riser 15B.

[0332] Table E1A below shows that the system and method of the present invention, as illustrated in Example 1A, achieves excellent performance, with results reported relative to the base system of Comparative Example C1, which uses R404A as the sole refrigerant in the described centralized refrigeration system:

[0333] Table E1A - Intermediate Temperature Performance - Cases 1A to 1E

[0334]

[0335] Example 1B - Modifying the original system using existing refrigerant R-404A and using it in the new main loop To form a centralized system, R449A replaces R404A, and refrigerants A1 to A5 replace R404A in the new secondary loop. cold

[0336] Example 1A is repeated, except that the new main loop contains R449A. Table E1B below shows that the system and method of the present invention illustrated in Example 1B achieves excellent performance, with results reported relative to the base system of Comparative Example C1, which uses R404A as the sole refrigerant in the described centralized refrigeration system:

[0337] Table E1B - Intermediate Temperature Performance - Cases 1F to 1J

[0338]

[0339] Example 2A - Modifying the original system using existing refrigerant R-407A and using it in the new main loop To form a centralized system, R448A replaces R407A, and refrigerants A1 to A5 replace R407C in the new secondary loop. cold

[0340] Example 1A is repeated, except that the existing refrigerant is R407A. Table E2A below shows that the system and method of the present invention illustrated in Example 2A achieves excellent performance, with results reported relative to the basic system of Comparative Example C1, which uses R407A as the sole refrigerant in the described centralized refrigeration system:

[0341] Table E2A - Intermediate Temperature Performance - Condition 1K to Condition 1O

[0342]

[0343] Example 2B - Modifying the original system using existing refrigerant R-407A and using it in the new main loop To form a centralized system, R449A replaces R407A, and refrigerants A1 to A5 replace R407A in the new secondary loop. cold

[0344] Example 1B is repeated, except that the existing refrigerant is R407A. Table E2B below shows that the system and method of the present invention illustrated in Example 2B achieves excellent performance, with results reported relative to the basic system of Comparative Example C1, which uses R407A as the sole refrigerant in the described centralized refrigeration system:

[0345] Table E2B - Intermediate Temperature Performance - Case 1P to Case 1T

[0346]

[0347] Example 3A - Modifying the original system using existing refrigerant R-407C and using it in the new main loop To form a centralized system, R448A replaces R407C, and refrigerants A1 to A5 replace R407C in the new secondary loop. cold

[0348] Example 1A is repeated, except that the existing refrigerant is R407C. Table E3A below shows that the system and method of the present invention illustrated in Example 3A achieves excellent performance, with results reported relative to the basic system of Comparative Example C1, which uses R407C as the sole refrigerant in the described centralized refrigeration system:

[0349] Table E3A - Intermediate Temperature Performance - Condition 1T to Condition 1X

[0350]

[0351] Example 3B - Modifying the original system using existing refrigerant R-407C and using it in the new main loop To form a centralized system, R449A replaces R407C, and refrigerants A1 to A5 replace R404A in the new secondary loop. cold

[0352] Example 1B is repeated, except that the existing refrigerant is R407C. Table E3B below shows that the system and method of the present invention illustrated in Example 3B achieves excellent performance, with results reported relative to the basic system of Comparative Example C1, which uses R407C as the sole refrigerant in the described centralized refrigeration system:

[0353] Table E3B - Intermediate Temperature Performance - Case 1P to Case 1T

[0354]

[0355] Comparative Example C2 - Centralized refrigeration system using R-404A as refrigerant in low-temperature applications

[0356] Figure 1 The disclosed type is a centralized direct expansion refrigeration system with a capacity of approximately 35 kW, equipped with R-404A as an existing refrigerant. Figure 1 The operating conditions for cryogenic systems using R-404A as the refrigerant are:

[0357] Cooling capacity: 35kW

[0358] Isoentropy efficiency: 55%

[0359] Volumetric efficiency: 100%

[0360] Condensation temperature: 45℃

[0361] Supercooling: 0°C (for systems with receivers)

[0362] Evaporator overheating: 5.5℃

[0363] Temperature rise in the suction line: 10°C

[0364] Evaporation temperature: -35℃

[0365] Although the system operates well from a thermodynamic and heat transfer performance point of view, it is highly undesirable from an environmental impact point of view because the entire system contains high-GWP refrigerant R404A circulating throughout a large and complex piping network.

[0366] Example 4A - Modify the original system by using R-404A and replace R404A with R448A in the new main loop. Furthermore, in the new secondary loop, refrigerant A1 to refrigerant A5 are used to replace R404A to form a centralized refrigeration system.

[0367] The cryogenic refrigeration system of Comparative Example C2, which contains the existing refrigerant R404A, was used as the starting point for forming an improved heat transfer system. This is in conjunction with Comparative Example 1. Figure 3A and Figure 3B Generally described, the system is modified to produce the system of the present invention.

[0368] Table E4A below shows that the system and method of the present invention, as illustrated in Example 4A, achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R404A as the sole refrigerant in the described centralized refrigeration system:

[0369] Table E4A - Low Temperature Performance - Cases 1A to 1E

[0370]

[0371] Example 4B - Modifying the original system using existing refrigerant R-404A and using it in the new main loop Replacing R404A with R449A and replacing R404A with refrigerant A1 to refrigerant A5 in the new secondary loop to form a centralized system. cold

[0372] Example 4A is repeated, except that the new main loop contains R449A. Table E4B below shows that the system and method of the present invention illustrated in Example 4B achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R404A as the sole refrigerant in the described centralized refrigeration system:

[0373] Table E4B - Low Temperature Performance - Cases 1F to 1J

[0374]

[0375] Example 5A - Modifying the original system using existing refrigerant R-407A and using it in the new main loop To form a centralized system, R448A replaces R407A, and refrigerants A1 to A5 replace R407C in the new secondary loop. cold

[0376] Example 4A is repeated, except that the existing refrigerant is R407A. Table E5A below shows that the system and method of the present invention illustrated in Example 5A achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R407A as the sole refrigerant in the described centralized refrigeration system:

[0377] Table E5A - Low Temperature Performance - Condition 1K to Condition 1O

[0378]

[0379] Example 5B - Modifying the original system using existing refrigerant R-407A and using it in the new main loop To form a centralized system, R449A replaces R407A, and refrigerants A1 to A5 replace R404A in the new secondary loop. cold

[0380] Example 4A is repeated, except that the existing refrigerant is R407A. Table E5B below shows that the system and method of the present invention illustrated in Example 5B achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R407A as the sole refrigerant in the described centralized refrigeration system:

[0381] Table E5B - Low Temperature Performance - Condition 1P to Condition 1T

[0382]

[0383] Example 6A - Modifying the original system using existing refrigerant R-407C and using it in the new main loop To form a centralized system, R448A replaces R407C, and refrigerants A1 to A5 replace R407C in the new secondary loop. cold

[0384] Example 4A is repeated, except that the existing refrigerant is R407C. Table E6A below shows that the system and method of the present invention illustrated in Example 6A achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R407C as the sole refrigerant in the described centralized refrigeration system:

[0385] Table E6A - Low Temperature Performance - Case 1U to Case 1Y

[0386]

[0387] Example 6B - Modifying the original system using existing refrigerant R-407C and using it in the new main loop To form a centralized system, R449A replaces R407C, and refrigerants A1 to A5 replace R404A in the new secondary loop. cold

[0388] Example 4B is repeated, except that the existing refrigerant is R407C. Table E6B below shows that the system and method of the present invention illustrated in Example 6B achieves excellent performance, with results reported relative to the base system of Comparative Example C2, which uses R407A as the sole refrigerant in the described centralized refrigeration system:

[0389] Table E6B - Low Temperature Performance - Cases 1Z to 1AC

[0390]

[0391] Comparative Example C3A - Refrigeration system using R-448A as refrigerant in medium-temperature applications.

[0392] Figure 1 The disclosed type of direct expansion refrigeration system with a capacity of approximately 100kW is equipped with R-448A as an existing refrigerant. Figure 1 The operating conditions for systems using R-448A as the refrigerant are:

[0393] Cooling capacity: 100kW

[0394] Isoentropy efficiency: 65%

[0395] Volumetric efficiency: 100%

[0396] Condensation temperature: 45℃

[0397] Supercooling: 0°C (for systems with receivers)

[0398] Evaporator overheating: 5.5℃

[0399] Temperature rise in the suction line: 10°C

[0400] Evaporation temperature: -8℃

[0401] Although the system operates well from a thermodynamic and heat transfer performance point of view, it is highly undesirable from an environmental impact point of view because the entire system contains high-GWP refrigerant R448A circulating throughout a large and complex piping network.

[0402] Example 7A - Modify the original system by using R-448A and leave R448A in the new main loop and in the new Refrigerants A1 to A5 are used in the secondary loop to form centralized refrigeration.

[0403] The medium-temperature refrigeration system of Comparative Example 3A, which contains the existing refrigerant R448A, was used as the starting point for forming an improved heat transfer system. This is in conjunction with Comparative Example 1. Figure 3A and Figure 3B Generally described, the system is modified to produce the system of the present invention, the difference being that the existing refrigerant R448A in the main loop equipment is not replaced.

[0404] Table E7A below shows that the system and method of the present invention, as illustrated in Example 7A, achieves excellent performance, with results reported relative to the base system of Comparative Example C3, which uses R448A as the sole refrigerant in the described centralized refrigeration system:

[0405] Table E7A - Intermediate Temperature Performance - Cases 2A to 2E

[0406]

[0407] Comparative Example C3B - Centralized refrigeration system using R-449A as refrigerant in medium-temperature applications.

[0408] Comparative example C3A was repeated, except that the existing refrigerant was R-449A.

[0409] Example 7B - Modify the original system by using R-449A and leave R449A in the new main loop and in the new Refrigerants A1 to A5 are used in the secondary loop to form centralized refrigeration.

[0410] The medium-temperature refrigeration system of Comparative Example 3B, which contains the existing refrigerant R449A, was used as the starting point for forming an improved heat transfer system. This is in conjunction with Comparative Example 1. Figure 3A and Figure 3BGenerally described, the system is modified to produce the system of the present invention, the difference being that the existing refrigerant R449A in the main loop equipment is not replaced.

[0411] Table E7B below shows that the system and method of the present invention, as illustrated in Example 7B, achieves excellent performance, with results reported relative to the basic system of Comparative Example C3B, which uses R449A as the sole refrigerant in the described centralized refrigeration system:

[0412] Table E7B - Intermediate Temperature Performance - Cases 2F to 2J

[0413]

[0414] Comparative Example C4A - Centralized refrigeration systems using R-448A as refrigerant in low-temperature applications.

[0415] Figure 1 The disclosed type is a centralized direct expansion refrigeration system with a capacity of approximately 35 kW, equipped with R-448A as an existing refrigerant. Figure 1 The operating conditions for cryogenic systems using R-448A as the refrigerant are:

[0416] Cooling capacity: 35kW

[0417] Isoentropy efficiency: 55%

[0418] Volumetric efficiency: 100%

[0419] Condensation temperature: 45℃

[0420] Supercooling: 0°C (for systems with receivers)

[0421] Evaporator overheating: 5.5℃

[0422] Temperature rise in the suction line: 10°C

[0423] Evaporation temperature: -35℃

[0424] Although the system operates well from a thermodynamic and heat transfer performance point of view, it is highly undesirable from an environmental impact point of view because the entire system contains high-GWP refrigerant R448A circulating throughout a large and complex piping network.

[0425] Example 8A - Modify the original system by using R-448A and leave R448A in the new main loop and in the new The secondary loop uses refrigerants A1 to A5 to form a centralized cryogenic refrigeration system.

[0426] The cryogenic refrigeration system of Comparative Example 4, which includes the existing refrigerant R448A, was used as the starting point for forming an improved heat transfer system. This is in conjunction with Comparative Example 1. Figure 3A and Figure 3BGenerally described, the system is modified to produce the system of the present invention, the difference being that the existing refrigerant R448A in the main loop equipment is not replaced.

[0427] Table E8A below shows that the system and method of the present invention, as illustrated in Example 8A, achieves excellent performance, with results reported relative to the base system of Comparative Example C4, which uses R448A as the sole refrigerant in the described centralized refrigeration system:

[0428] Table E8A - Low Temperature Performance - Cases 2A to 2E

[0429]

[0430] Comparative Example C4B - Centralized refrigeration system using R-449A as refrigerant in low-temperature applications.

[0431] Comparative example C4A was repeated, except that the existing refrigerant was R-449A.

[0432] Example 8B - Modify the original system by using R-449A and leave R449A in the new main loop and in the new The secondary loop uses refrigerants A1 to A5 to form a centralized cryogenic refrigeration system.

[0433] The cryogenic refrigeration system of Comparative Example 4B, which contains the existing refrigerant R449A, was used as the starting point for forming an improved heat transfer system. This is in conjunction with Comparative Example 1. Figure 3A and Figure 3B Generally described, the system is modified to produce the system of the present invention, the difference being that the existing refrigerant R449A in the main loop equipment is not replaced.

[0434] Table E8B below shows that the system and method of the present invention, as illustrated in Example 8B, achieves excellent performance, with results reported relative to the base system of Comparative Example C4B, which uses R449A as the sole refrigerant in the described centralized refrigeration system:

[0435] Table E8B - Low Temperature Performance - Cases 2F to 2J

[0436]

Claims

1. A method for forming an improved refrigeration system, the method comprising: a. Provide 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 a consumer-accessible product, and (ii) at least one compressor or compressor rack 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 wherein the existing refrigerant vapor from the evaporator is returned to the suction side of the compressor or compressor rack via a conduit; b. Disconnect the existing liquid refrigerant from the condenser from at least one of the evaporators, preferably substantially all of the evaporators; c. Disconnect the fluid connection between the existing refrigerant vapor from at least one of the evaporators in step (b) and the suction inlet of the compressor or compressor frame; and d. Establish a new first refrigeration circuit including the compressor or compressor frame and the condenser, wherein the existing refrigerant is retained in the first refrigeration circuit or is removed and replaced; e. Establishing a new second refrigeration circuit comprising at least one of the evaporators that have been disconnected in steps (b) and (c), and preferably all of the evaporators, by the following steps: (i) removing the existing refrigerant from the evaporator and at least a portion of the conduit that has been disconnected in steps (b) and (c); (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, provided that the sum of components (1) to (4) accounts for at least 95% by weight of the second refrigerant, and wherein the second refrigerant: (i) has an occupational exposure limit (OEL) greater than 400; (ii) is classified as Class A1 according to ASHRAE Standard 34; and (iii) has a GWP of about 150 or less; and f. Thermally interconnect 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 evaporates by absorbing heat from the refrigerant vapor in the second circuit, and wherein at least a portion of the second refrigerant vapor condenses by transferring heat to the refrigerant liquid in the first circuit.

2. The method of claim 1, wherein the second refrigerant comprises: (1) about 59 wt% to about 69.5 wt% of CF3I; (2) about 9 wt% to about 19.5 wt% of HFO-1234yf; and (3) 16.5 wt% to about 21.5 wt% of HFC-32, provided that the sum of components (1) to (3) accounts for at least 95 wt% of the second refrigerant.

3. The method of claim 1, wherein the second refrigerant comprises: (1) about 32.8 wt% to about 53.8 wt% of CF3I; (2) about 29 wt% to about 58 wt% of HFO-1234yf; (3) 2 wt% ± 0.2 wt% to about 16.5 wt% of HFC-32; and (4) 1 wt% ± 0.2 wt% to 3.2 wt% ± 0.2 wt% of HFC-125, provided that the sum of components (1) to (4) accounts for at least 95 wt% of the second refrigerant.

4. The method of claim 1, wherein the second refrigerant comprises: (1) about 41.5 wt% to about 49.5 wt% of CF3I; (2) about 36 wt% to about 44 wt% of HFO-1234yf; (3) about 11 wt% to about 15 wt% of HFC-32; and (4) 1 wt% ± 0.2 wt% to 3.5 wt% ± 0.2 wt% of CO2, provided that the sum of components (1) to (4) accounts for at least 95 wt% of the second refrigerant.

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

6. The method of claim 1, wherein the second refrigerant comprises substantially the following: (1) Approximately 69.5% by weight of CF3I; (2) Approximately 9% by weight of HFO-1234yf; (3) Approximately 21.5% by weight of HFC-32.

7. The method of claim 1, wherein the second refrigerant comprises substantially the following: (1) Approximately 59% by weight of CF3I; (2) Approximately 19.5% by weight of HFO-1234yf; and (3) Approximately 21.5% by weight of HFC-32.

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

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

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