Non-flammable refrigerants with low GWP and secondary refrigerant systems containing such refrigerants

Abstract

A non-flammable refrigerant having a low GWP and a secondary refrigeration system containing such a refrigerant are provided. The refrigeration system may include a high-temperature refrigeration circuit having a first refrigerant and a low-temperature refrigeration circuit having a second refrigerant, the second refrigerant including a blend of R1234ze(Z), R1234ze(E), R1336mzz(E), and optionally R227ea, or a blend of R1234ze(Z), R1234ze(E), R1224yd(Z), and optionally R(227ea). The refrigerant fluid may have one of the following characteristics: (i) a global warming potential (GWP) of less than 150, (ii) an evaporator glide of less than 5.5°C, (iii) non-flammability in accordance with ASHRAE Standard 34, and / or (iv) a boiling point of less than 6°C.

Description

[Technical Field]

[0001] (Cross-Reference to Related Applications) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 534,526 filed on August 24, 2023 and U.S. Provisional Application No. 63 / 536,848 filed on September 6, 2023, each of which is incorporated herein by reference as if fully set forth below.

[0002] (Field of the Invention) The present disclosure relates to safe and effective non-flammable low-global warming potential ("low GWP") refrigerant fluids, and secondary refrigeration systems and methods. [Background Art]

[0003] In typical air conditioning and refrigeration systems, a compressor is used to compress heat transfer vapor from low pressure to high pressure, thereby adding heat to the vapor. This added heat is typically released in a heat exchanger, commonly referred to as a condenser. In the condenser, the vapor is condensed, at least largely, to produce a liquid heat transfer fluid at relatively high pressure. Typically, the condenser uses a fluid readily available in the surrounding environment, such as ambient air, as a heat sink. Upon condensation, the high-pressure heat transfer fluid undergoes substantially isenthalpic expansion, such as by passing through an expansion device or valve, where it expands to a low pressure, resulting in a decrease in the fluid's temperature. The low-pressure, low-temperature heat transfer fluid from the expansion operation is then typically sent to an evaporator, where it absorbs heat and thus evaporates. This evaporation process then results in the cooling of the fluid or object being cooled. In typical air conditioning applications, the cooled fluid is the indoor air of the conditioned dwelling. In refrigeration systems, cooling may involve cooling the air inside a cold box or storage unit. The heat transfer fluid evaporates at low pressure in the evaporator and is then returned to the compressor, where the cycle restarts. The complex and interrelated combination of factors and requirements is related to forming an efficient, effective, and safe air conditioning and refrigeration system, which is also environmentally friendly, i.e., has low GWP and low ozone depletion (ODP) impacts. In terms of efficiency and effectiveness, it is important that the heat transfer fluid operates with high levels of efficiency and capacity in the air conditioning and refrigeration systems. At the same time, since the heat transfer fluid can leak into the atmosphere over time, it is important that the fluid has low values ​​for both GWP and ODP.

[0004] While certain fluids can achieve both high levels of efficiency and effectiveness, and simultaneously low levels of both GWP and ODP, the applicant has come to recognize that many fluids that meet this combination of requirements still suffer from safety-related deficiencies. For example, fluids that may otherwise be acceptable may not be recommended for use due to flammability and / or toxicity concerns. The applicant has come to recognize that the use of fluids with such properties is particularly undesirable in typical air conditioning systems and some refrigeration systems, as such flammable and / or toxic fluids could be inadvertently released into a cooled (or heated in the case of heat pump applications) dwelling or into a space where people live (such as on the floor of a supermarket), thus potentially exposing the occupants to danger. [Overview of the project]

[0005] The present invention provides a fluid refrigerant composition having a low GWP, and a multi-stage refrigeration system using such a refrigerant composition. Advantageously, a preferred refrigerant composition has one or more, preferably all, of the following: a global warming potential (GWP) of 150 or less, an evaporator glide of 5.6°C or less, non-flammability in accordance with ASHRAE Standard 34 2022, and / or a standard boiling point of 6.3°C or less.

[0006] The present invention includes a refrigeration system comprising a high-temperature refrigeration circuit containing a first refrigerant and a low-temperature refrigeration circuit containing a second refrigerant, wherein the second refrigerant comprises (a) a first component comprising one or more of cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), and (b) trans-1,1,1,4,4,4-hexafluoro The secondary refrigerant comprises (c) a second component comprising one or more of -2-butene (R1336mzz(E)), R1224yd(Z), and R1233zd(E), and (c) optionally a third component comprising at least one of R134a, R245fa, and R227ea, wherein the secondary refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) a complete evaporator glide of about 5.5°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34 2022, and (iv) a standard boiling point of about 6°C or less. The refrigerant system described in this paragraph may also be referred to herein as refrigerant system 1A for convenience.

[0007] The present invention includes a refrigeration system comprising a high-temperature refrigeration circuit containing a first refrigerant and a low-temperature refrigeration circuit containing a second refrigerant, wherein the second refrigerant comprises (a) a first component containing cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), a second component containing R1233zd(E), and (c) a third component containing R245fa, wherein the second refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less. The refrigerant system according to this paragraph may, for convenience, be referred to herein as refrigerant system 1B.

[0008] The present invention includes a refrigeration system comprising a high-temperature refrigeration circuit containing a first refrigerant and a low-temperature refrigeration circuit containing a second refrigerant, wherein the second refrigerant comprises (a) a first component containing cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), and (b) a second component containing R1336mzz(E), wherein the second refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less. The refrigerant system according to this paragraph may, for convenience, be referred to herein as refrigerant system 1C.

[0009] The present invention includes a refrigeration system comprising a high-temperature refrigeration circuit containing a first refrigerant and a low-temperature refrigeration circuit containing a second refrigerant, wherein the second refrigerant comprises (a) a first component comprising cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) and (b) a second component comprising cis-1-chloro-2,3,3,3-tetrafluoropropene (R1224yd(Z)), wherein the second refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less. The refrigerant system according to this paragraph may, for convenience, be referred to herein as refrigerant system 1D.

[0010] The present invention also, (a) cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)), (b) Trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), (c)R1233zd(E), and (d) A refrigerant composition comprising R245fa, The refrigerant composition has (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less. The refrigerant composition described in this paragraph may be referred to as refrigerant A for convenience in this specification.

[0011] The present invention also, (a) R1234ze(Z) in an amount of approximately 20% to 70% by weight, (b) R1234ze(E) of approximately 7% to 15% by weight, (c) R1233zd(E) in an amount of approximately 9% to 52% by weight, and (d) A refrigerant composition comprising approximately 3% to 5% by weight of R245fa, The components (a) to (d) together are, It comprises at least about 95% by weight of the composition. The refrigerant composition according to this paragraph may also be referred to herein as refrigerant B for convenience.

[0012] The present invention also, (a) R1234ze(Z) in an amount of approximately 20% to 70% by weight, (b) R1234ze(E) of approximately 7% to 15% by weight, (c) R1233zd(E) in an amount of approximately 9% to 52% by weight, and (d) A refrigerant composition comprising approximately 3% to 5% by weight of R245fa, Components (a) to (d) together constitute at least about 95% by weight of the composition, and the refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less. The refrigerant composition according to this paragraph may be referred to herein as refrigerant C for convenience. [Brief explanation of the drawing]

[0013] [Figure 1] This is a generalized process flow diagram of the air conditioning system disclosed herein. [Figure 2] This is a generalized process flow diagram of the air conditioning system disclosed herein. [Figure 3] This is a generalized process flow diagram of the air conditioning system disclosed herein. [Figure 4] This is a schematic diagram of the heat exchanger according to this disclosure. [Figure 5] This is a generalized process flow diagram of a reversible heat pump system that can operate in both cooling and heating modes in accordance with this disclosure. [Figure 6] This is a generalized process flow diagram for the R410A air conditioning system. [Modes for carrying out the invention]

[0014] This disclosure includes refrigerant compositions and refrigerant systems and methods. Particularly preferred, the refrigerant is used in air conditioning methods and systems, and for cooling articles located in dwellings inhabited by humans or other animals, and the systems and methods include air conditioning methods and systems, and for cooling articles located in dwellings inhabited by humans or other animals.

[0015] This disclosure includes refrigeration systems for regulating air and / or cooling articles located within a dwelling where humans or other animals reside. A preferred embodiment of such a system includes at least a first heat transfer circuit, which preferably includes a first heat transfer fluid in a vapor / compression circulation loop located substantially outside the dwelling or other habitable structure. This first circuit may also be referred to herein as an “outdoor loop” for convenience. The outdoor loop preferably comprises a compressor, a heat exchanger which preferably functions to condense the heat transfer fluid in the outdoor loop by heat exchange with the outdoor ambient air, and an expansion device. A preferred system also includes at least a second heat transfer circuit, which includes a second heat transfer fluid different from the first heat transfer fluid, and is located substantially inside the dwelling or other habitable structure. This second circuit may also be referred to herein as an “indoor loop” for convenience.

[0016] Preferably, the indoor loop comprises an evaporator heat exchanger that functions to evaporate the second heat transfer fluid in the indoor loop by heat exchange with indoor air. In a preferred embodiment, the second heat transfer circuit does not comprise a vapor compressor, but comprises a liquid pump for the second heat transfer fluid when it is in a liquid phase.

[0017] A preferred system comprises at least one intermediate heat exchanger that enables heat exchange between a first heat transfer fluid and a second heat transfer fluid, such that heat is transferred to the first heat transfer fluid, preferably thereby evaporating the first heat transfer fluid, and heat is transferred from the second heat transfer fluid, thereby condensing the second heat transfer fluid. Preferably, the intermediate heat exchanger is located outside a residence or other occupied structure, or outside an area where air is being conditioned.

[0018] I. Definitions The phrase "global warming potential" (hereinafter "GWP") was developed to allow comparison of the impacts of different gases on global warming. It compares the amount of heat trapped by a given mass of a gas to the amount of heat trapped by the same mass of carbon dioxide over a specific period of time. Carbon dioxide was selected as the reference gas by the Intergovernmental Panel on Climate Change (IPCC), and its GWP is set to 1. The higher the GWP, the more a given gas warms the Earth compared to CO₂ over that time period. As used herein, the term GWP refers to the IPCC Fifth Assessment Report, 2014 1 means the GWP value measured in accordance with, referred to and abbreviated herein as AR5. 1 Myhre, G., D. Shindell, F.-M. Breon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. Included in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change[Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. https: / / www.ipcc.ch / pdf / assessmentreport / ar5 / wg1 / WG1AR5_Chapter08_FINAL.pdf (pp. 73-79)

[0019] The term "non-flammable" refers to a compound or composition that is determined to be non-flammable when determined according to ASTM Standard E-681-2009 Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapor and Gas) under the conditions described in ASHRAE Standard 34-2022 Designation and Safety Classification of Refrigerants and Appendix B1 of ASHRAE Standard 34-2022 (each standard exists as of the filing date of this application), and these are the "non-flammability tests" which are incorporated herein by reference in their entirety. Flammability is defined as the ability of a composition to ignite and / or propagate a flame. This test determines flammability by measuring the flame angle. Non-flammable materials are classified as Class "1" by ASHRAE Standard 34-2022 Designation and Safety Classification of Refrigerants (each standard exists as of the filing date of this application).

[0020] As used herein, the term “complete evaporator glide” means the difference between the boiling point and the dew point of the refrigerant at the mean pressure of the evaporator, assuming that the pressure at the evaporator outlet is the same as the pressure at the inlet.

[0021] As used herein, the phrase “non-toxic or low-toxicity” means that the composition is classified as Class “A” by ASHRAE Standard 34-2022 Designation and Safety Classification of Refrigerants and is listed in Appendix B1 of ASHRAE Standard 34-2022 (each standard exists as of the filing date of this application). Non-flammable and low-toxicity substances are classified as “A1” by ASHRAE Standard 34-2022 Designation and Safety Classification of Refrigerants and are listed in Appendix B1 of ASHRAE Standard 34-2022 (each standard exists as of the filing date of this application).

[0022] Where used herein, the term “about” with respect to quantities expressed as weight percentages means that the amount of a specified component may vary by + / - 10% in relative weight percentages. For example, if a quantity is specified as about 10%, it covers 10% plus 1% (i.e., 11%) and 10% minus 1% (i.e., 9%), and if a quantity is specified as about 20%, it covers 20% plus 2% (i.e., 22%) and 20% minus 2% (i.e., 18%). Unless otherwise specified or understood from the context, references to quantities in “percent” or “%” refer to weight percentages.

[0023] For the purposes of the present invention, the term "approximately" in relation to temperatures below 10°C in degrees Celsius (°C) means that the stated temperature may vary by an amount of + / - 1°C. In preferred embodiments, the temperature identified as approximately is preferably + / - 0.5°C from the specified temperature.

[0024] As used herein, the term "cis-1,3,3,3-tetrafluoropropene" refers to the cis isomer of HFO-1234ze and is abbreviated as HFO-1234ze(Z) or R1234ze(Z).

[0025] As used herein, the term "trans-1,3,3,3-tetrafluoropropene" refers to the trans isomer of HFO-1234ze and is abbreviated as HFO-1234ze(E) or R1234ze(E).

[0026] As used herein, the term "trans-1,1,1,4,4,4-hexafluoro-2-butene" refers to the trans isomer of HFO-1336mzz and is abbreviated as HFO-1336mzz(E) or R1336mzz(E).

[0027] As used herein, the term "1,1,1,2,3,3,3-heptafluoropropane" refers to HFC-227ea, abbreviated as R-227ea.

[0028] As used herein, the term "cis-1-chloro-2,3,3,3-tetrafluoropropene" refers to the cis isomer of HCFO-1224yd and is abbreviated as R1224yd(Z).

[0029] As used herein, the term “trans-1-chloro-3,3,3-tetrafluoropropene” refers to the trans isomer of HCFO-1233zd and is abbreviated as R1233zd(E).

[0030] As used herein, the term "1,1,1,2-tetrafluoroethane" refers to HFC-134a, abbreviated as R-134a.

[0031] As used herein, the term "1,1,1,3,3-pentafluoropropane" refers to HFC-245fa, abbreviated as R-245fa.

[0032] As used herein, the term "fluoroethane" refers to HFC-161, abbreviated as R-161.

[0033] As used herein, the term "2,3,3,3-tetrafluoropropene" refers to HFO-1234yf, abbreviated as R-1234yf.

[0034] As used herein, the term “difluoromethane” refers to HFC-32, abbreviated as R-32.

[0035] As used herein, the term "propane" refers to HC-290, abbreviated as R-290.

[0036] As used herein, the term "R471A" means a refrigerant designated as 471A by ASHRAE, consisting of 78.7% + 0.4 / -1.5% HFC-1234ze(E), 17% + 1.5 / -0.4% HFC-1336mzz(E), and 4.3% + 1.5 / -0.4% HFC-227ea.

[0037] As used herein, the term "R476A" means a refrigerant designated as 476A by ASHRAE, consisting of 78.7% ± 0.5% ± 2% HFC-1234ze(E), 12% ± 2% ± 0.5% HFC-1336mzz(E), and 10% ± 2% ± 0.51% HFC-134a.

[0038] As used herein, the term "R482A" means a refrigerant designated as 482A by ASHRAE, consisting of approximately 10% HFC-134a, approximately 83.5% HFC-1234ze(E), and approximately 6.5% HFO-1224yd(Z).

[0039] As used herein, the term “residential air conditioning” refers to a refrigeration system that operates with a heat exchanger that absorbs heat from or adds heat to indoor air within a structure in which humans reside.

[0040] As used herein, the term “split direct expansion air conditioning system” refers to an air conditioning system that operates with an indoor unit located inside a dwelling and including a heat exchanger that absorbs heat from or adds heat to indoor air within a human-inhabited structure, and an outdoor unit located outside the dwelling and including a heat exchanger that releases heat to or absorbs heat from outdoor air.

[0041] As used herein, the term “secondary loop air conditioning system” refers to an air conditioning system having an internal refrigeration circuit that uses an indoor (or secondary) refrigerant to heat and / or cool indoor air, and an external refrigeration circuit that uses an outdoor (or primary) refrigerant different from the indoor refrigerant and releases heat to the outside air or absorbs heat from the outside air.

[0042] As used herein, the term “suction line” as used in relation to a secondary loop air conditioning system refers to the refrigerant flow path from the outlet of the intermediate heat exchanger to the inlet of the compressor.

[0043] As used herein, the term “liquid line” as used in relation to a secondary loop air conditioning system refers to the refrigerant flow path from the condenser outlet to the inlet of the intermediate heat exchanger.

[0044] As used herein, the term “refrigerant” is used to describe a special fluid that may be used in a system to facilitate a heating or cooling process.

[0045] As used herein, the term “heat transfer composition” refers to a special fluid comprising a refrigerant and, optionally, a lubricant and / or other additive components.

[0046] II. Refrigerants and Heat Transfer Compositions The present invention includes, but is not limited to, refrigerants A, B, and C, and refrigerants that are generally useful in heat transfer applications. In addition, the following table defines a set of refrigerants according to the present invention, including the components and amounts shown, each of which is defined as a refrigerant and abbreviated in the table by the letter R followed by a number in column 1 of the table below, and all values ​​are understood to be preceded by the word “approximately” unless otherwise indicated in the table. In the following table R, it is also understood that a refrigerant includes the refrigerant components shown unless “refrigerant components” are specifically indicated in column 2 of the table (below the heading of the transitional clause) as “including” (using the abbreviation “COMP”), “essentially consisting of” (using the abbreviation “CEO”), or “consisting of” (using the abbreviation “CO”). The notation “NR” is understood to mean that the component is not required (but may be present within the scope of the transitional clause).

[0047] [Table 1-1]

[0048] [Table 1-2]

[0049] [Table 1-3]

[0050] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have a global warming potential (GWP) of 150 or less.

[0051] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have an evaporator glide of 5.6°C or lower.

[0052] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, are preferably non-flammable in accordance with ASHRAE Standard 34.

[0053] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have a standard boiling point of 6.3°C or lower.

[0054] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have two or more of the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less.

[0055] The refrigerants of the present invention, which include refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have three or more of the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less.

[0056] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less.

[0057] The refrigerants of the present invention, including refrigerants A, B, and C as defined in the table above, and refrigerants R1 to R14, preferably have the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.5°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6°C or less.

[0058] The present invention also includes a cascade system and method utilizing a first heat transfer composition comprising a first refrigerant and optionally a lubricant for a compressor in a primary refrigeration circuit, and a second heat transfer composition comprising a second refrigerant in a secondary refrigeration circuit connected to the first circuit for heat transfer.

[0059] Primary refrigerant composition and heat transfer composition In a preferred embodiment, the first refrigerant (sometimes referred to herein as the “primary refrigerant”) may comprise one or more components that make the refrigerant substantially less desirable than the second refrigerant in terms of toxicity and / or flammability, and all such first refrigerants are included within the broad scope of this disclosure.

[0060] For example, the first refrigerant may include one or more blends containing one or more of the following: difluoromethane (HFC-32 or R32), 2,3,3,3-tetrafluoropropene (HFO-1234yf or R1234yf), fluoroethane (R161), carbon dioxide (CO2), and propane. In contrast to the first heat transfer composition, the second heat transfer composition of the present disclosure generally does not contain lubricants in preferred embodiments, as the second heat transfer composition or fluid passes through the compressor.

[0061] The following table defines a set of primary refrigerants of this disclosure, including the components and quantities shown, each of which is defined as a primary refrigerant and abbreviated in the table by its PR number in column 1 of the table below, and all values ​​are understood to be preceded by the word “approximately” unless otherwise indicated in the table. In the following table, unless “refrigerant component” is specifically indicated in column 2 of the table (below the heading of the transitional clause) as “contains” (using the abbreviation COMP), “essentially consists of” (using the abbreviation CEO), or “consists of” (using the abbreviation CO), the notation “NR” is understood to mean that the component is not required (but may be present).

[0062] [Table 2]

[0063] The Disclosure also provides a first (or "primary") heat transfer composition comprising a broad range of primary refrigerants, including the specific primary refrigerant compositions described in Section A and Table 1 above.

[0064] The first heat transfer composition generally comprises a primary refrigerant and a lubricant. In preferred embodiments, the heat transfer composition contains the lubricant in amounts as low as 0.1% by weight, 0.5% by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, and 30% by weight, or in amounts within any range encompassed by any two of the aforementioned values ​​as endpoints.

[0065] Other optional components that may be included in the heat transfer composition include compatibilizers such as propane, for the purpose of assisting the compatibility and / or solubility of the lubricant. Such compatibilizers, including propane, butane, and pentane, if present, are preferably present in an amount of about 0.5 to about 5% by weight of the composition. As disclosed in U.S. Patent No. 6,516,837 (the disclosure of which is incorporated by reference), combinations of surfactants and solubilizers may also be added to the composition to assist in oil solubility. Commonly used refrigerant lubricants used in refrigerators with hydrofluorocarbon (HFC) refrigerants, such as polyol esters (POE), polyvinyl ethers (PVE), and polyalkylene glycols (PAG), silicone oils, mineral oils, alkylbenzenes (AB), and poly(alpha-olefins) (PAO), may be used with the refrigerant compositions of this disclosure. A preferred lubricant is POE.

[0066] The following table defines a series of primary heat transfer compositions of the present disclosure, each such heat transfer composition being defined as a heat transfer composition and including a primary refrigerant and lubricant as defined by the PF number in the table above, abbreviated in the table by the HTC number in column 1 of the table below, and all values ​​are understood to be preceded by the word "approximately" unless otherwise indicated in the table.

[0067] [Table 3]

[0068] B. Secondary refrigerant composition Since the secondary refrigerant compositions of this system and method will come into heat transfer contact with the room air, it is generally considered particularly important that such fluids possess not only excellent properties related to heat transfer performance, but also properties related to safety, such as acceptable toxicity and non-flammability. Low GWP of the secondary refrigerant is also an important characteristic of secondary refrigerants. The applicants have found that the refrigerant of the present invention can unexpectedly provide a second refrigerant that offers this desirable combination of properties, including non-flammability. In addition, for optimal performance, the secondary fluid should have a positive operating pressure under various conditions of system operation. Positive pressure is required to ensure that the system is always at positive pressure and to avoid any contamination by moist air in the event of leakage. This also ensures that materials such as PVC can be used in the connection lines. To avoid the system becoming sub-atmospheric pressure, the secondary fluid should have a boiling point range of 0-6°C. Secondly, in order to maintain a reasonable approach temperature (the difference between the refrigerant temperature at the condenser (high-pressure cycle) outlet and the average evaporator (low-pressure secondary cycle) temperature), the complete evaporator glide of the secondary refrigerant should be less than 5.5°C in a preferred embodiment and less than 3.5°C in a most preferred embodiment.

[0069] It is desirable that the secondary fluid provides high heat transfer and low pressure drop within the system under all operating conditions. The applicant has defined a merit number, which is the ratio of the heat transfer coefficient to the frictional pressure drop. The proposed secondary fluid should have a higher merit number than conventionally used glycols, which suggests that the proposed secondary fluid will provide superior performance in actual systems.

[0070] Those skilled in the art will understand, in consideration of the disclosures contained herein, the advantage of using only relatively safe (low toxicity and low flammability) low-GWP refrigerants, which would be highly preferable for use in locations close to human or other animal dwellings, as commonly encountered in air conditioning applications.

[0071] Accordingly, this disclosure provides second refrigerant compositions (sometimes referred to herein as “secondary refrigerant compositions”) comprising each of refrigerants A, B, and C, which can be used in multistage air conditioning systems with primary refrigerants such as the primary refrigerants listed in Table 1 above and / or primary heat transfer compositions listed in Table 2 above. Preferred embodiments of the present invention can unexpectedly provide a second refrigerant or heat transfer composition that is non-flammable in accordance with ASHRAE Standard 34 (which measures the flammability of initial vapors from a portion of a mixture, such as in the case of refrigerant leakage) and generates a pressure of about 1 bar or more within the indoor loop of a refrigeration system. In addition, preferred embodiments have a relatively high boiling point compared to other refrigerant fluids to avoid overpressurizing PVC piping used indoors in air conditioning and refrigeration systems. The evaporator glide of the secondary refrigerant in preferred embodiments is also relatively low compared to other refrigerant fluids, which prevents deterioration of the refrigeration system.

[0072] Therefore, the applicant was unexpectedly able to identify a second refrigerant having certain properties that are highly advantageous for use inside multi-stage air conditioning and refrigeration systems. For example, the second refrigerant may have a low global warming potential, low evaporator glide, a low boiling point, and / or non-flammability, preferably all of these characteristics.

[0073] The second refrigerant preferably has a low global warming potential (GWP), such as less than 500, less than 450, less than 400, less than 350, less than 300, less than 250, less than 200, less than 150, less than 100, or less than 50.

[0074] The second refrigerant also preferably has a low evaporator glide such as less than 6°C, less than 5.5°C, less than 5°C, less than 4.5°C, less than 4°C, less than 3.5°C, less than 3°C, less than 2.5°C, less than 2°C, less than 1.5°C, less than 1°C, or less than 0.5°C. In some embodiments, the second refrigerant includes R1336mzz(E) and has a complete evaporator glide of less than 3.5°C. In some embodiments, the second refrigerant includes R1224yd(Z) and has a complete evaporator glide of less than 5.5°C.

[0075] The second refrigerant also preferably has low flammability and low toxicity, and preferably has Class A toxicity and Class 1, Class 2, or Class 2L flammability according to ASHRAE Standard 34-2022. In a particularly preferred embodiment, the secondary refrigerant fluid has non-flammability according to ASTM standard E-681-2001, under the conditions described in ASHRAE Standard 34-2013 and Appendix B1 of ASHRAE Standard 32-2013.

[0076] The second refrigerant also preferably has a boiling point of less than 15°C, less than 14°C, less than 13°C, less than 12°C, less than 11°C, less than 10°C, less than 9°C, less than 8°C, less than 7°C, less than 6°C, less than 5°C, less than 4°C, less than 3°C, less than 2°C, less than 1°C, or less than 0.5°C.

[0077] In preferred embodiments, the secondary refrigerant may include a blend of two or more different low-GWP fluids, including cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)), trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), trans-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzz(E)), R1233zd(E), 1,1,1,2-tetrafluoroethane (R134a), and 1,1,1,2,3,3,3-heptafluoropropane (R227ea), R134a, R245fa, and R227ea, provided that 1234ze(E) is present in all blends. Any of the aforementioned fluids may be mixed in different proportions to form a three-component or four-component blend. For example, the secondary refrigerant may include a four-component blend of R1234ze(Z), R1234ze(E), R1233zd(E), and R245fa. In another example, the secondary refrigerant may include a three-component blend of R1234ze(Z), R1234ze(E), and R1336mzz(E). The secondary refrigerant may also include a four-component blend of R1234ze(Z), R1234ze(E), R1336mzz(E), and R227ea. The ranges in the following table for each component correspond to the amounts that may be present in any fluid blend of the second refrigerant.

[0078] The following table defines a set of secondary refrigerants of this disclosure, including the components and quantities shown, each of which is defined as a secondary refrigerant and abbreviated in the table by its SR number in column 1 of the table below, and all values ​​are understood to be preceded by the word “approximately” unless otherwise indicated in the table. In the following table, unless “refrigerant component” is specifically indicated in column 2 of the table (below the heading of the transitional clause) as “essentially consisting of” (using the abbreviation CEO) or “consisting of” (using the abbreviation CO), the refrigerant also contains the refrigerant component shown. The notation “NR” is understood to mean that the component is not required (but may be present).

[0079] Table 3 Secondary refrigerant composition The following table defines a set of secondary refrigerants of this disclosure, including the components and quantities shown, each of which is defined as a secondary refrigerant and abbreviated in the table by its SR number in column 1 of the table below, and all values ​​are understood to be preceded by the word “approximately” unless otherwise indicated in the table. In the following table, unless “refrigerant component” is specifically indicated in column 2 of the table (below the heading of the transitional clause) as “contains” (using the abbreviation “COMP”), “essentially consists of” (using the abbreviation “CEO”), or “consists of” (using the abbreviation “CO”), a refrigerant also contains the refrigerant component shown. The notation “NR” is understood to mean that the component is not required (but may be present within the scope of the transitional clause).

[0080] [Table 4-1]

[0081] [Table 4-2]

[0082] [Table 4-3]

[0083] [Table 4-4]

[0084] The secondary refrigerants of the present invention, which include refrigerants A, B, and C as defined in Table 3 above, and refrigerants SR1 to SR14, preferably have a global warming potential (GWP) of 150 or less.

[0085] The refrigerants of the present invention, including refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have an evaporator glide of 5.6°C or lower.

[0086] The refrigerants of the present invention, including refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, are preferably non-flammable in accordance with ASHRAE Standard 34.

[0087] The refrigerants of the present invention, including refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have a standard boiling point of 6.3°C or lower.

[0088] The refrigerants of the present invention, including refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have two or more of the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less.

[0089] The refrigerants of the present invention, which include refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have three or more of the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6.3°C or less.

[0090] The refrigerants of the present invention, which include refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.6°C or less, (iii) It is non-flammable in accordance with ASHRAE Standard 34, and (iv) has a standard boiling point of 6.3°C or lower.

[0091] The refrigerants of the present invention, including refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, preferably have the following characteristics: (i) a global warming potential (GWP) of 150 or less, (ii) an evaporator glide of 5.5°C or less, (iii) non-flammability in accordance with ASHRAE Standard 34, and (iv) a standard boiling point of 6°C or less.

[0092] The present invention also includes a cascade system and method utilizing a first heat transfer composition in a primary refrigeration circuit comprising a first refrigerant and optionally a lubricant for the compressor, and a second heat transfer composition in a secondary refrigeration circuit connected to the first circuit for heat transfer comprising a second refrigerant comprising refrigerants A, B, and C as defined in Table 3, and refrigerants SR1 to SR14, respectively.

[0093] III. Secondary Systems The following tables define a set of secondary systems of the present disclosure, which may use the secondary conditions and components of Table 3 above, and may also include elements or limitations as defined in Table 4 below, each such system being defined as a Secondary System (SS) of the present disclosure by the SS number / letter in column 1 of Table 4 below, and all values ​​are understood to be preceded by the word "approximately" unless otherwise indicated in the tables. The notation "NR" is understood to mean that the component or characteristic is not required (but may be present), while the notation "NP" means that the component is not present in the system. The abbreviations in the following tables are as follows: "Ref." represents refrigerant, "Lub." represents lubricant, and "Comp." represents compressor.

[0094] [Table 5-1]

[0095] [Table 5-2]

[0096] [Table 5-3]

[0097] [Table 5-4]

[0098] Table 5-5

[0099] Table 5-6

[0100] Table 5-7

[0101] Table 5-8

[0102] Table 5-9

[0103] Table 5-10

[0104] Table 5-11

[0105] Table 5-12

[0106] Table 5-13

[0107] Table 5-14

[0108] Table 5-15

[0109] Table 5-16

[0110] Table 5-17

[0111] Table 5-18

[0112] Table 5-19

[0113] Table 5-20

[0114] Table 5-21

[0115] Table 5-22

[0116] Table 5-23

[0117] Table 5-24

[0118] Table 5-25

[0119] [Table 5-26]

[0120] [Table 5-27]

[0121] [Table 5-28]

[0122] [Table 5-29]

[0123] [Table 5-30]

[0124] [Table 5-31]

[0125] [Table 5-32]

[0126] [Table 5-33]

[0127] III. Secondary circuit system shown in Figure 1 In the following description, components or elements of a system that are generally the same or similar, or may be so, in different embodiments are indicated by the same number or symbol.

[0128] Figure 1 illustrates one preferred air conditioning system, shown as 10 in its entirety, with a dotted line representing the approximate boundary between the indoor loop and the outdoor loop, where the compressor 11, condenser 12, intermediate heat exchanger 13, and expansion valve 14 are located outdoors, along with any associated conduits 15 and 16 and other connections and associated equipment (not shown). The outdoor loop, sometimes referred to herein as the “high-temperature circuit,” preferably comprises a first heat transfer composition comprising a first refrigerant and a lubricant for the compressor, preferably one or more of the heat transfer compositions listed in Table 2 above, with at least the first refrigerant circulating within the circuit by conduits 15 and 16 and other associated conduits and equipment. The first refrigerant may be any of the refrigerant compositions listed in Table 1 above.

[0129] The indoor loop, sometimes referred to herein as the “low-temperature circuit,” preferably comprises at least a second heat transfer composition containing a second refrigerant, and preferably both are selected from the compositions listed in Table 3 above. Preferably, the second refrigerant has at least one safety property, such as flammability and toxicity, which is superior to the corresponding safety property of the first refrigerant. In a very preferred embodiment, the second refrigerant is preferably sufficiently toxic to be designated as Class A in accordance with ASHRAE Standard 34 2022, and preferably sufficiently flammable to have a flammability rating of Class 1 or 2L. In a preferred embodiment, the second refrigerant or heat transfer composition comprises R1234ze(E) and R1234ze(Z), and in some embodiments also comprises one or more of R227ea, R1336mzz(E), and R1224yd(Z). Those skilled in the art will understand, in consideration of the disclosures contained herein, that such embodiments of the disclosure offer the advantage of utilizing only relatively safe (low toxicity and low flammability) low-GWP refrigerants, such as those described in Section II above, from a first refrigerant, while being separated from humans or animals that are in or may be in a dwelling or air-conditioned space, in a location in close proximity to humans or other animals that reside in or enter an air-conditioned space. Therefore, preferred refrigerant configurations and selections enable the provision of systems that benefit from the use of refrigerants that have many desirable properties such as capacity, efficiency, low GWP, and low ODP, but at the same time have one or more properties that would otherwise be highly disadvantageous and / or prevent their use in close proximity to humans or other animals in limited and / or enclosed locations. Such combinations offer very good advantages with respect to all of the above desirable properties of such refrigerant systems.

[0130] During operation, the second refrigerant according to this disclosure circulates through the circuit by flowing through the intermediate heat exchanger 13, transferring heat to the first refrigerant, thereby condensing at least a portion, preferably substantially all, of the second refrigerant into a liquid form, and exiting the intermediate heat exchanger through the conduit 17. In a preferred embodiment, the second refrigerant exiting the intermediate heat exchanger enters a receiver 18, which is provided with a liquid reservoir for the second refrigerant. In the figure, the receiver 18 is shown to be located indoors, but this container may be located outdoors, and if a pump 20 is present, the pump 20 may preferably be located outdoors. The liquid refrigerant from the separation container is led to an evaporator via the conduit 21. In the example shown in Figure 1, the liquid pump 20 is shown as assisting in the transport of the liquid refrigerant to the evaporator 24 through the conduits 21, 22 and valve 23. However, in other embodiments, the liquid second refrigerant can be transported from the receiver by other means or techniques that can be used either alone or in combination with the liquid pump. For example, in some embodiments, the transport of the liquid refrigerant can be achieved by using gravity supply of the liquid to the evaporator, while in other embodiments, a thermal siphon arrangement can be used to transport the second liquid refrigerant to the evaporator 24 and from the evaporator to the intermediate heat exchanger 13.

[0131] In a preferred embodiment, the operating conditions in cooling mode correspond to the values ​​listed in the table below:

[0132] [Table 6]

[0133] [Table 7]

[0134] In a preferred embodiment, the operating conditions in heating mode correspond to the values ​​listed in the table below:

[0135] [Table 8]

[0136] [Table 9]

[0137] IV. Secondary circuit system with suction / liquid line heat exchanger shown in Figure 2 Another preferred embodiment of the present invention is illustrated in Figure 2, in which a compressor 11, a condenser 12, an intermediate heat exchanger 13, an expansion valve 14, and a suction line heat exchanger 30 are located outdoors, together with any of the associated conduits 15A, 15B, 16A, 16B, and other connections and associated equipment (not shown). The outdoor loop, sometimes referred to herein as the “high-temperature refrigerant circuit,” preferably comprises a first heat transfer composition comprising a first refrigerant and a lubricant for the compressor, with at least the refrigerant circulating within the circuit by conduits 15A, 15B, 16A, and 16B and other associated conduits and equipment. The first refrigerant may be any of the primary refrigerant compositions listed in Table 1 above, and the heat transfer composition may be any of the heat transfer compositions listed in Table 2.

[0138] The indoor loop is configured substantially the same as described above in relation to the indoor loop in Figure 1, and the first and second heat transfer compositions are also preferably as shown separately herein. Preferred secondary refrigerant compositions are provided in Table 3 above.

[0139] During operation, the first refrigerant according to this disclosure is discharged from the compressor 11 as a relatively high-pressure refrigerant vapor, which may contain a lubricant additive, and then enters the condenser 12, where it preferably transfers heat to the ambient air and at least partially condenses. The refrigerant effluent from the condenser 12 is transported via conduit 15A to the suction line heat exchanger 30, where it loses further heat compared to the effluent from the intermediate heat exchanger 13. The effluent from the suction / liquid line heat exchanger 30 is then transported via conduit 15B to the expansion valve 14, where the refrigerant pressure decreases, thereby lowering the refrigerant temperature. The relatively low-temperature liquid refrigerant from the expansion valve then enters the intermediate heat exchanger 13, where it gains heat from the second refrigerant vapor exiting the evaporator 24 in the chamber loop. The first refrigerant effluent vapor from the intermediate heat exchanger is then transported via conduit 16A to the suction / liquid line heat exchanger 30, where it receives heat from the condenser effluent from conduit 15A to produce a higher temperature second refrigerant vapor, which is then transported via conduit 16B to the inlet of the compressor 11.

[0140] The evaporator effluent is transported from the receiver conduit 19 to the intermediate heat exchanger 13, where heat is lost relative to the effluent from the suction line heat exchanger. This is then transported to the intermediate heat exchanger via conduit 15B, generating a relatively low-temperature flow of the second refrigerant. This low-temperature flow of the second refrigerant exiting the intermediate heat exchanger 13 is transported to a receiver tank 18, which provides a reservoir of low-temperature liquid refrigerant. The low-temperature liquid refrigerant is transported from the tank via conduit 21 and then supplied to the evaporator 24 by a control valve 23. In some embodiments, a pump 20 is provided to supply the liquid flow to the control valve 23. The cooled ambient air loses heat relative to the low-temperature liquid refrigerant in the evaporator 24, causing the liquid refrigerant to evaporate and produce refrigerant vapor with little to no superheating, which then flows back into the intermediate heat exchanger 13.

[0141] In a preferred embodiment, the operating conditions in cooling mode correspond to the values ​​listed in the table below:

[0142] [Table 10]

[0143] [Table 11]

[0144] In a preferred embodiment, the operating conditions in heating mode correspond to the values ​​listed in the table below:

[0145] [Table 12]

[0146] [Table 13]

[0147] V. Secondary circuit system with steam injection heat exchanger shown in Figure 3 Another preferred embodiment of the present disclosure is illustrated in Figure 3, in which a steam injection heat exchanger 40, including a two-stage compressor 11, a condenser 12, an intermediate heat exchanger 13, an expansion valve 14, and an associated intermediate expansion valve 41, is located outdoors, together with any associated conduits 15A-15C and other connections and associated equipment (not shown and / or unreferenced). The outdoor loop, sometimes referred to herein as the “high-temperature refrigerant circuit,” preferably comprises a first heat transfer composition comprising a first refrigerant and a lubricant for the compressor, with at least the refrigerant circulating within the circuit by conduits 15 and 16, and other associated conduits and equipment. The first refrigerant composition may be any of the refrigerant compositions listed in Table 1 above. The first heat transfer composition may be any of the heat transfer compositions in Table 2.

[0148] The indoor loop is configured substantially the same as described above in relation to the indoor loop in Figure 1, and the first and second heat transfer compositions are also preferably as otherwise shown herein.

[0149] During operation, the first refrigerant according to this disclosure, which may contain a lubricant, is discharged from the compressor 11 as a relatively high-pressure refrigerant vapor, which may also contain a lubricant, and then enters the condenser 12, where it preferably transfers heat to the ambient air and at least partially condenses. The outflow from the condenser 12 contains at least partially, preferably substantially completely condensed, refrigerant. The refrigerant outflow from the condenser 12 is transported through conduit 15A, a portion of which is sent to the intermediate expansion unit 41 via conduit 15B, and another portion of which, preferably the remainder, is transported to the steam injection heat exchanger 40.

[0150] The intermediate expansion valve 41 reduces the pressure of the outflow flow, preferably substantially isenthalpic, to near the pressure of the second stage suction of the compressor 11, or to a sufficiently higher pressure considering the pressure drop through the heat exchanger 41 and associated conduits, fixtures, etc. As a result of the pressure drop across the expansion valve 41, the pressure of the refrigerant flowing into the heat exchanger 40 is reduced relative to the temperature of the high-pressure refrigerant flowing into the heat exchanger 40. In the heat exchanger 40, heat is transferred from the high-pressure flow to the flow that has passed through the expansion valve 41. As a result, the temperature of the intermediate pressure flow leaving the heat exchanger 40 is higher than the temperature of the inlet flow, thereby generating a superheated steam flow that is transported to the second stage of the compressor 11 via the conduit 19C.

[0151] As the high-pressure flow transported by conduit 15A moves through the heat exchanger 40, heat is lost to the low-pressure flow exiting the expansion device 41, which then exits the heat exchanger through conduit 15C, flows to the expansion device 14 where it receives heat, and is then sent to the intermediate heat exchanger where it receives heat and is transported to the first stage of the compressor suction.

[0152] In a preferred embodiment, the operating conditions correspond to the values ​​listed in the table below:

[0153] [Table 14]

[0154] [Table 15]

[0155] In a preferred embodiment, the operating conditions in heating mode correspond to the values ​​listed in the table below:

[0156] [Table 16]

[0157] [Table 17]

[0158] VI. Secondary circuit system with a reversible valve as shown in Figure 5 In the following description, components or elements of a system that are generally the same or similar, or may be so, in different embodiments are indicated by the same number or symbol.

[0159] The embodiment disclosed in Figure 5 is similar to the embodiment in Figure 1, except that the system is equipped with a reversible valve and can operate in heating mode, as described below.

[0160] One preferred air conditioning system capable of operating in both cooling and heating modes is shown as 10 in whole and illustrated in Figure 1, where the indicated line represents the approximate boundary between the indoor loop and the outdoor loop, and the compressor 11, outdoor coil 12, intermediate heat exchanger 13, expansion valve 14, and switching valve 500 are located outdoors, along with any associated conduits 15 and 16 and other connections and associated equipment (not shown). The outdoor loop preferably includes a first heat transfer composition, preferably one or more of the preferred embodiments described above, which includes a first refrigerant and a lubricant for the compressor, and at least the first refrigerant circulates within the circuit by conduits 15 and 16 and other associated conduits and equipment. The first refrigerant composition may be any of the refrigerant compositions listed in Table 1 above. The first heat transfer composition may be any of the heat transfer compositions in Table 2.

[0161] The indoor loop preferably comprises at least a second heat transfer composition containing a second refrigerant, the second refrigerant having at least one safety property, such as flammability and toxicity, that is superior to the corresponding safety properties of the first refrigerant. In a very preferred embodiment, the second refrigerant is preferably sufficiently toxic to be designated as Class A in accordance with ASHRAE Standard 34, and preferably sufficiently flammable to have a flammability rating of Class 1 or 2L. The secondary refrigerant may be any of the refrigerants listed in Table 3 above.

[0162] In preferred embodiments, the second refrigerant or heat transfer composition includes R1234ze(E) and R123ze(Z), and in some embodiments also includes R227ea, R1226mzz(E), and / or R1224yd(Z). Those skilled in the art will understand, in consideration of the disclosures contained herein, that such embodiments of the disclosure offer the advantage of utilizing only relatively safe (low toxicity and low flammability) low-GWP refrigerants, such as those described in Section II above, from the first refrigerant, while being separated from humans or animals that are in or may be in a dwelling or air-conditioned space, in a location in close proximity to humans or other animals that reside in or enter an air-conditioned space. Thus, preferred configurations and selections of refrigerants enable the provision of systems that benefit from the use of refrigerants that have many desirable properties such as capacity, efficiency, low GWP, and low ODP, but at the same time have one or more properties that would otherwise be highly disadvantageous and / or prevent their use in close proximity to humans or other animals in limited and / or enclosed locations. Such a combination offers significant advantages in terms of all desirable characteristics of such a refrigerant system.

[0163] The second heat transfer composition generally comprises the second refrigerant and lubricant of the present invention. Preferred heat transfer compositions are provided in Table 2 above. In preferred embodiments, the heat transfer composition contains the lubricant in amounts as low as 0.1% by weight, 0.5% by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 15% by weight, 20% by weight, 25% by weight, and 30% by weight, or in amounts within any range encompassed by any two of the aforementioned values ​​as endpoints.

[0164] Other optional components that may be included in the heat transfer composition include compatibilizers such as propane, for the purpose of assisting the compatibility and / or solubility of the lubricant. Such compatibilizers, including propane, butane, and pentane, if present, are preferably present in an amount of about 0.5 to about 5% by weight of the composition. As disclosed in U.S. Patent No. 6,516,837 (the disclosure of which is incorporated by reference), combinations of surfactants and solubilizers may also be added to the composition to assist in oil solubility. Commonly used refrigerant lubricants used in refrigerators with hydrofluorocarbon (HFC) refrigerants, such as polyol esters (POE), polyvinyl ethers (PVE), and polyalkylene glycols (PAG), silicone oil, mineral oil, alkylbenzene (AB), and poly(alpha-olefin) (PAO), may be used with the refrigerant composition of this disclosure. A preferred lubricant is POE.

[0165] During operation, the second refrigerant, according to the heating mode embodiment of Figure 5 of this disclosure, circulates through the circuit by flowing through the intermediate heat exchanger 13, removing heat from the first refrigerant, thereby evaporating at least a portion, preferably substantially all, of the second refrigerant into vapor form, which exits the intermediate heat exchanger through the conduit 17. The vaporized refrigerant is led through the conduit 21 to the condenser, where it condenses and releases heat into the dwelling. In the example shown in Figure 1, a liquid pump 20 is shown as assisting in the transport of liquid refrigerant to the condenser 24 through conduits 21, 22 and valve 23. In addition, this indoor loop also includes a reversible valve 501 that allows the system to operate in both heating and cooling modes. [Examples]

[0166] In the following examples, a series of primary and secondary fluids were evaluated based on several criteria. The compositions of the primary fluids H1-H4 and secondary fluids L1-L5 are shown in Table 9 below.

[0167] For each fluid blend, the following criteria were evaluated: Boiling point: The preferred boiling point range is 0 to 6°C, more preferably 3.9 to 6°C.

[0168] Complete evaporator glide: A preferred complete evaporator glide is less than 5.5°C (to avoid performance degradation), more preferably less than 4.0°C, and most preferably less than 2.5°C.

[0169] Flammability: Non-flammable fluids are preferred (low-temperature fluids).

[0170] Performance index: Capacity and pumping force.

[0171] [Table 18-1]

[0172] [Table 18-2]

[0173] The following table provides suitable applications for combinations of primary and secondary refrigerants (each column in Table 10 below refers to a refrigerant as defined in Table 9 above).

[0174] [Table 19-1]

[0175] [Table 19-2]

[0176] [Table 19-3]

[0177] [Table 19-4]

[0178] [Table 19-5]

[0179] Example 1A: Thermodynamic performance of a small secondary cycle-basic cycle The following embodiments highlight the unique advantages and features of the compact secondary system according to this disclosure.

[0180] Small secondary systems allow for the use of ultra-low GWP non-flammable refrigerants in homes while adapting the system design to accommodate the efficiency of R410A. These small secondary systems exhibit higher efficiency than R410A under high ambient conditions.

[0181] The operating conditions for the R410A basic cycle shown in the schematic diagram in Figure 6 are provided below: 1. Condensation temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensation temperature - ambient temperature = 10°C 3. Expansion device supercooling = 5.0℃ 4. Evaporation temperature = 7°C, corresponding room temperature = 27°C 5. Evaporator overheating = 5.0℃ 6. Isentropic efficiency = 72% 7. Volumetric efficiency = 98%

[0182] The operating conditions for the small secondary cycle shown in the schematic diagram of Figure 1 are provided below: 1. Condensation temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensation temperature - ambient temperature = 10°C 3. Expansion device supercooling = 5.0℃ 4. Evaporation temperature = 7°C, corresponding room temperature = 27°C 5. Evaporator overheating = 0.0℃ (full liquid type) 6. Intermediate heat exchanger superheat = 5.0℃ 7. Isentropic efficiency = 72% 8. Volumetric efficiency = 98% 9. Saturation temperature difference of the intermediate heat exchanger = 5°C

[0183] The operating conditions for each air conditioning system yielded the performance data shown in the table below.

[0184] [Table 20-1]

[0185] [Table 20-2]

[0186] Table 11 shows the thermodynamic performance of a small secondary system with different primary refrigerants and using five secondary refrigerants: R471A, R476A, R482A, L1, L2, L3, and L4. The capacity of the small secondary system was compatible with the R410A system in all cases.

[0187] Table 12 shows the condensation temperatures required to adjust efficiency using different refrigerants.

[0188] [Table 21-1]

[0189] [Table 21-2]

[0190] To match the efficiency, the condensation temperature can be lowered, and a heat transfer area that improves efficiency can thereby be added to the condenser. The size of the condenser is inversely proportional to the condensation temperature required to match the efficiency, and therefore a higher condensation temperature is desirable.

[0191] Table 13 shows the performance of compact secondary systems using different refrigerants under high ambient conditions.

[0192] [Table 22-1]

[0193] [Table 22-2]

[0194] All refrigerants exhibited superior efficiency compared to R410A as the ambient temperature increased from 35°C to 55°C.

[0195] Example 1B: Thermodynamic performance of the compact secondary cycle - basic cycle In Example 1B, the performance of a compact secondary cycle using each of the primary fluids shown in Table 1 of the present specification and each of the secondary fluids shown in Table 3 is evaluated.

[0196] The same system and operating conditions as those in Example 1A are maintained. All refrigerants exhibit superior efficiency compared to R410A as the ambient temperature increases from 35°C to 55°C.

[0197] Example 2A: Thermodynamic performance of a compact secondary cycle having a suction line / liquid line heat exchanger A compact secondary system having a suction line / liquid line heat exchanger exhibits improved efficiency. Furthermore, it exhibits superior efficiency compared to R410A under high ambient conditions.

[0198] The operating conditions for the R410A basic cycle shown in the schematic diagram of Figure 6 are provided below: 1. Condensing temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensing temperature - Ambient temperature = 10°C 3. Supercooling at expansion device = 5.0°C 4. Evaporation temperature = 7°C, corresponding indoor temperature = 27°C 5. Evaporator superheat = 5.0°C 6. Isentropic efficiency = 72% 7. Volumetric efficiency = 98%

[0199] The operating conditions for the compact secondary cycle having a suction line / liquid heat line (SL / LL) heat exchanger, schematically shown in Figure 2, are provided below: 1. Condensing temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensing temperature - Ambient temperature = 10°C 3. Supercooling at expansion device = 5.0°C 4. Evaporation temperature = 7°C, corresponding indoor temperature = 27°C 5. Evaporator superheat = 0.0°C (flooded type) 6. Intermediate heat exchanger superheat = 5.0°C 7. Isentropic efficiency = 72% 8. Volumetric efficiency = 98% 9. Saturation temperature difference of the intermediate heat exchanger = 5°C 10. Suction line / liquid line effectiveness = 35%, 55%, 75%, 85%

[0200] Table 14 shows the thermodynamic performance of the compact secondary system having a suction line liquid line heat exchanger.

[0201] [Table 23-1]

[0202] [Table 23-2]

[0203] Table 14 shows that the capacity for all refrigerants was matched to that of R410A. Performance improvements were observed in the suction / liquid line heat exchanger. Table 15 shows the condensation temperatures required to adjust efficiency using different refrigerants.

[0204] [Table 24-1]

[0205] [Table 24-2]

[0206] To improve efficiency, the condensation temperature can be lowered, and a heat transfer area that improves efficiency can be added to the condenser.

[0207] The size of the condenser is inversely proportional to the condensation temperature required to optimize efficiency. Therefore, a higher condensation temperature is desirable.

[0208] Table 16 shows the performance of small secondary systems using different refrigerants under high ambient conditions.

[0209] [Table 25-1]

[0210] [Table 25-2]

[0211] The effectiveness of SL / LL HX is assumed to be 75% in this example, but the results are similar for any value of effectiveness.

[0212] All refrigerants offered exhibit superior efficiency compared to R410A as ambient temperatures rise from 35°C to 55°C.

[0213] Example 2B: Thermodynamic performance of a small secondary cycle - suction line / liquid line heat exchanger cycle In Example 2B, the performance of a small secondary cycle using each of the primary fluids in Table 1 and each of the secondary fluids in Table 3 of this specification is evaluated.

[0214] The same system and operating conditions as in Example 2A were maintained. All refrigerants showed superior efficiency compared to R410A as the ambient temperature rose from 35°C to 55°C.

[0215] Example 3A: Thermodynamic performance of a small secondary cycle with steam injection Small secondary systems with steam injection exhibit improved efficiency. Furthermore, they demonstrate superior efficiency compared to R410A under high ambient conditions.

[0216] The operating conditions for the R410A basic cycle shown in the schematic diagram in Figure 6 are provided below: 1. Condensation temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensation temperature - ambient temperature = 10°C 3. Expansion device supercooling = 5.0℃ 4. Evaporation temperature = 7°C, corresponding room temperature = 27°C 5. Evaporator overheating = 5.0℃ 6. Isentropic efficiency = 72% 7. Volumetric efficiency = 98%

[0217] The operating conditions for a small secondary cycle with two-stage compression, as shown in the schematic diagram in Figure 3, are provided below. 1. Condensation temperature = 45°C, corresponding outdoor ambient temperature = 35°C 2. Condensation temperature - ambient temperature = 10°C 3. Expansion device supercooling = 5.0℃ 4. Evaporation temperature = 7°C, corresponding room temperature = 27°C 5. Evaporator overheating = 0.0℃ (full liquid type) 6. Intermediate heat exchanger superheat = 5.0℃ 7. Equal enentropy efficiency of both stages = 72% 8. Volumetric efficiency = 98% 9. Saturation temperature difference of the intermediate heat exchanger = 5°C 10. Effectiveness of steam injection heat exchangers = 35%, 55%, 75%, 85%

[0218] Figure 3 shows a schematic diagram of an R410A air conditioning system and a small secondary system with two-stage compression.

[0219] Table 17 shows the thermodynamic performance of two-stage steam injection miniature secondary systems with different primary refrigerants and using R471A, R476A, R482A, L1, L2, L3, and L4 as secondary refrigerants.

[0220] [Table 26-1]

[0221] [Table 26-2]

[0222] The capacity of the small secondary system was compatible with the R410A system in all cases.

[0223] Table 18 shows the condensation temperatures required to adjust efficiency using different refrigerants.

[0224] [Table 27-1]

[0225] [Table 27-2]

[0226] To adjust efficiency, the condensation temperature can be lowered, and a heat transfer area that improves efficiency can be added to the condenser. For refrigerants with the same or higher efficiency as R410A, the condensation temperature should be kept the same as that of R410A.

[0227] [Table 28-1]

[0228] [Table 28-2]

[0229] Table 19 shows the performance of small secondary systems using different refrigerants under high ambient conditions.

[0230] In this embodiment, a heat exchanger with 75% efficiency is assumed, but the results are similar for any value of efficiency.

[0231] All refrigerants exhibit superior efficiency compared to R410A as the ambient temperature rises from 35°C to 55°C.

[0232] Example 3B: Thermodynamic performance of a small secondary cycle with a steam injection cycle Example 3B evaluates the performance of a small secondary cycle using each of the primary fluids in Table 1 and each of the secondary fluids in Table 3 of this specification.

[0233] The same system and operating conditions as in Example 3A were maintained. All refrigerants showed superior efficiency compared to R410A as the ambient temperature rose from 35°C to 55°C.

[0234] Example 4: System with aluminum heat exchanger and liquid-filled evaporator Due to the low pressures of the secondary fluids R471A, R476A, R482A, L1, L2, L3, and L4, the evaporator can be made of aluminum, resulting in lower costs and a lighter overall system. Furthermore, the evaporator can be used in a full-liquid configuration to improve heat transfer and make the heat exchanger more compact.

[0235] A typical schematic diagram is provided in Figure 1. The intermediate heat exchanger (tube-in-tube) can be constructed from PVC (outer tube) and metal (inner tube) to reduce costs and system weight.

[0236] The evaporator operates in a full-fluid configuration to minimize pressure drop due to secondary fluids (R471A, R476A, R482A, L1-L4). This configuration provides excellent heat transfer performance and results in a more compact heat exchanger.

[0237] Since the pressures of R471A, R476A, R482A, and L1-L4 are very low, circular tube fin thermal evaporators can be made of aluminum instead of copper.

[0238] Similarly, in the case of a tube-in-tube intermediate heat exchanger, the outer tube through which the secondary fluid (R471A, R476A, R482A, L1~L5) flows can be made of plastic, while the inner tube containing the primary refrigerant is made of metal (aluminum, copper).

[0239] Figure 4 provides an intermediate heat exchanger structure that exhibits a tube-in-tube configuration.

[0240] Example 5: Glide and standard boiling point performance Due to specific characteristics of the air conditioning system, in certain embodiments, it is important that such a system can exhibit reliable system operating parameters using a secondary refrigerant. Such operating parameters include: Low-Pressure Side Pressure: If the system is not to be sub-atmospheric over the expected range of evaporator temperatures, low pressure is permitted in the secondary loop. This is necessary to ensure that the system always has positive pressure and that any outside air enters the system in case of leakage. To assess this requirement, a property called the "Normal Boiling Temperature" (NBT: boiling point at atmospheric pressure) of the fluid in question is used. This NBT is in the range of 0°C to 6°C and must be at least lower than the lowest evaporation temperature found in a typical air conditioning system. Within this NBT range, the pressure of the secondary fluid also allows for the use of alternative, low-cost materials for connecting lines, such as PVC.

[0241] Secondary fluid glide: The complete evaporator glide of the secondary refrigerant should be less than 5.5°C in a preferred embodiment and less than 3.5°C in a most preferred embodiment. This is necessary to maintain a reasonable approach temperature in the intermediate heat exchanger, which is the difference between the refrigerant temperature at the evaporator outlet in the high-pressure cycle and the average condensation temperature of the low-pressure cycle in the cooling mode.

[0242] The above and other operating parameters are determined for compositions L1 to L4 specified in the table above in accordance with the present invention, and these operating parameters are reported in the table below.

[0243] [Table 29]

[0244] Example 6: Figure of Merit Heat Transfer Coefficient / Friction Pressure Drop In the following examples, various secondary fluids are evaluated to estimate their performance in actual systems. The heat transfer and pressure drop characteristics of different fluids are evaluated for flow through an 8.8 mm fixed-diameter pipe, and the results are compared to glycol based on the example in Appendix D of AHRI Standard 441(SI)-2019. The mass fluxes of glycol and the various secondary fluids were maintained as expected in actual applications. The thermodynamic and transport properties of the secondary fluids are determined at a typical evaporator temperature of 45°F. To determine the properties, the mixing parameters of each binary pair were regressiond to experimentally obtained data, and the parameters were also incorporated into the National Institute of Science and Technology (NIST) Reference Fluid Thermodynamics and Transport Properties Database (Refprop9.1 NIST Std Database, 2013). Standard mixing parameters already available in Refprop9.1 were used for other binary pairs. The heat transfer coefficient of glycol was estimated using the Dittus-Boelter correlation for turbulent single-phase flow (as seen in "Heat and Mass Transfer" by Frank P. Incropera and David P. DeWitt, 5th edition, p. 491). The heat transfer coefficient of the secondary fluid was estimated by the Shah (1982) correlation (ASHRAE Fundamentals 2021 - Chapter 5 "Two Phase Flow"). The friction pressure gradient of the two-phase fluid was calculated based on the Friedel correlation (Friedel, L., "Improved friction pressure drop correlation for horizontal and vertical two-phase pipe flow", European Two-phase Flow Group Meeting Paper E2, Ispra, Italy, (1979)).

[0245] Secondary fluids are desirable to provide a high heat transfer coefficient and have a low pressure drop within the system. Therefore, the merit number is defined as the ratio of the heat transfer coefficient to the frictional pressure drop. Secondary fluids with higher merit numbers are expected to provide better performance in actual systems. The merit numbers of the various secondary fluids evaluated were 200% to 350% higher than glycol (30% propylene glycol + 50% water), suggesting that secondary fluids (L1, L1, L2, and L3) provide superior performance in actual systems.

[0246] [Table 30]

[0247] While the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various modifications may be made, and elements may be replaced with equivalents, without departing from the scope of the invention. In addition, many modifications can be made to the teachings of the invention to suit specific circumstances or materials, without departing from the essential scope of the invention. Accordingly, the present invention is not limited to the specific embodiments disclosed, and is intended to include all embodiments that fall within the scope of the appended claims or any subsequently added claims.

Claims

1. It is a freezing system, A first refrigerant circuit containing a first refrigerant, The system comprises a second refrigerant circuit which includes a second refrigerant that exchanges heat with the first refrigerant in the first refrigeration circuit, wherein the second refrigerant includes cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)), trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), and 1233ZD(e), and (i) Global warming potential (GWP) of 150 or less, (ii) Complete evaporator glide below 5.6°C, (iii) Non-combustible in accordance with ASHRAE Standard 34 2022, and (iv) A refrigeration system having a standard boiling point of 6.3°C or lower.

2. (i) The first refrigerant circuit further comprises a condenser, an expansion device, a compressor, and an intermediate heat exchanger, and (ii) The second refrigerant circuit further comprises a receiver, an evaporator, and the intermediate heat exchanger, according to claim 1.

3. The refrigeration system according to claim 2, wherein the higher temperature refrigerant circuit and the lower temperature refrigerant circuit further comprise connection lines containing polyvinyl chloride (PVC), the connection lines operate under positive pressure, and the first refrigerant and the second refrigerant are "A1" in accordance with ASHRAE Standard 34-2022 Design and Safety Classification of Refrigerants and are described in Appendix B1 of ASHRAE Standard 34-2022.

21.

4. The refrigeration system according to claim 1, wherein the first refrigerant comprises 10% to 30% by weight of difluoromethane (R32) and 70% to 90% by weight of 2,3,3,3-tetrafluoropropene (R-1234yf).

5. The refrigeration system according to claim 1, wherein the second refrigerant further comprises R245fa.

6. The refrigeration system according to claim 5, wherein the second refrigerant essentially consists of cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)), trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), 1233ZD(e), and R245fa.

7. A refrigerant comprising: (a) a first component comprising one or more of cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)); (b) a second component comprising one or more of trans-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzz(E)), R1224yd(Z), and R1233zd(E); and (c) an optional third component comprising at least one of R134a, R245fa, and R227ea, wherein the secondary refrigerant has (i) a global warming potential (GWP) of 150 or less, (ii) a complete evaporator glide of about 5.5°C or less, and (iii) ASHRAE Standard 34 A refrigerant that is non-flammable in accordance with 2022 and has a standard boiling point of approximately 6°C or lower (iv).

8. The refrigerant according to claim 7, wherein (a) the first component comprises cis-1,3,3,3-tetrafluoropropene (R1234ze(Z)) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)), (b) the second component comprises R1233zd(E), and (c) the third component is present and comprises R245fa.

9. (a) R1234ze(Z) in an amount of approximately 20% to 70% by weight, (b) R1234ze(E) in an amount of approximately 7% to 15% by weight. (c) R1233zd(E) in an amount of approximately 9% to 52% by weight, and (d) Contains approximately 3% to 5% by weight of R245fa, The refrigerant according to claim 8, wherein the components (a) to (d) together constitute at least about 95% by weight of the composition.

10. Essentially, (a) R1234ze(Z) in an amount of approximately 20% to 70% by weight, (b) R1234ze(E) in an amount of approximately 7% to 15% by weight. (c) R1233zd(E) in an amount of approximately 9% to 52% by weight, and (d) The refrigerant according to claim 9, comprising approximately 3% to 5% by weight of R245fa.

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