Heat pump refrigerant

Abstract

a) a non-flammable, high-volatility component consisting of carbon dioxide; and b) a non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoroprop-1-ene, and mixtures thereof; c) a medium-volatility component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf, and mixtures thereof; and d) optionally a refrigerant consisting essentially of a component selected from the group consisting of HFC227ea, HFC152a, HFC32, and mixtures thereof.

Description

Technical Field

[0001] The present invention relates to heat pumps having a wide intrinsic glide and refrigerant compositions having a very wide glide, and more particularly, but not limited to, refrigerants for compositions having a GWP of less than 400, preferably less than 150, more preferably less than 10. The refrigerant can be used in various applications including refrigeration, air conditioning and heat pump processes. These applications are collectively known as heat pumps.

Background Art

[0002] Embodiments of the present invention operate in a Reverse Rankine Cycle (RRC).

[0003] RRC equipment is well known to those skilled in the art. In its simplest form, an RRC device consists of an evaporator where a two-phase liquid / vapor refrigerant evaporates at a lower pressure and temperature to absorb heat from an adjacent heat sink. The vapor from the evaporator is drawn into a compressor and compressed to a higher pressure and higher temperature. The vapor then enters a condenser and condenses into a liquid by being discharged to an adjacent heat sink. The liquid at a higher pressure and higher temperature passes through an expansion device that reduces its pressure to the pressure of the evaporator, and a portion of the liquid evaporates to lower its temperature. The two-phase mixture of liquid and vapor enters the evaporator to continue the cycle.

[0004] Another name for RRC is the "Vapor Recompression Compression" (VRC) cycle.

[0005] Non-azeotropic refrigerant compositions evaporate and condense over a certain temperature range under constant pressure. This range is called the “thermal glide” or simply the “glide.” Confusingly, however, different definitions of the term “glide” are found in the prior art. For example, the term “glide” is defined as the temperature difference between the bubble point and the dew point at a specific constant pressure. In such a definition, the “glide” is purely a thermodynamic property of the refrigerant and independent of the equipment and operating conditions. Hereinafter, the difference between the bubble point and the dew point at an absolute pressure of 1 atmosphere is referred to as the “thermodynamic glide” of a blend.

[0006] Alternatively, the “glide” in an evaporator can refer to the difference between the entry temperature and the dew point, which is necessarily smaller than the thermodynamic glide and depends on the operating conditions, equipment design, and blend composition. In a condenser, the glide is the difference between the dew point and the foaming point, which also depends on the operating conditions, equipment design, and blend composition. In this specification, the term “intrinsic temperature glide” refers to the temperature difference between the beginning and end of a two-phase heat transfer region in an evaporator or condenser, assuming no pressure drop. If the evaporator or condenser is “immersed,” both the liquid and vapor phases are present simultaneously along the entire length of the DX heat exchanger coil, and therefore the glide is the temperature difference between the ends of the heat exchanger. This value will be smaller than the value given by the previous definition.

[0007] In some thermal heat pumps, refrigerant glide is used to improve performance using the RRC / VRC development known as the Lorentz cycle. In this specification, the term RRC / VRC also encompasses the Lorentz cycle.

[0008] In this specification, thermodynamic temperature glides are classified as follows: 1. Negligible glide - less than 0.5K 2. Small glide - 0.5K~2.0K 3. Moderate glide - over 2.0K to 5.0K 4. Wide glide - over 5K to 10.0K 5. Extremely wide glide - over 10.0K

[0009] The compositions of the present invention may have a broad or very broad thermodynamic temperature glide.

[0010] In real heat exchangers, there is inevitably a pressure drop to maintain the flow of the refrigerant. This results in a “pressure-induced thermal glide.” The intrinsic and pressure-induced glide combine to produce the actual glide. In the evaporator, the intrinsic and pressure-induced glide act in opposite directions, and therefore in the two-phase evaporation region, the actual thermal glide is smaller than the intrinsic thermal glide. However, in the two-phase condensation flow region, the intrinsic and pressure-induced glide act in the same direction. Therefore, they are additive, and the actual thermal glide is larger than the intrinsic thermal glide. For convenience, in this specification, the term “glide” shall be interpreted as “intrinsic thermal glide” unless otherwise specified. This meaning follows the custom and practice of those skilled in the art, and the contribution of pressure-induced glide is often ignored. When the net glide obtained from the combination of intrinsic and pressure-induced glide is considered, this is called the “actual glide.”

[0011] When a non-azeotropic mixture is registered with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), it is assigned an "R4XX" number. Some blends, such as R404A and R410A, are formally nonazeotropic mixtures, but typically have a glide of less than 1K and are classified as "quasi-azeotropic mixtures." For practical purposes, they may be treated as azeotropic mixtures.

[0012] It is generally believed that azeotropic mixture-like compositions having a glide of less than 5K, preferably less than 1K, are necessary for the efficient and reliable operation of heat pump systems. Unexpectedly, the inventors have found that non-azeotropic compositions having thermodynamic glides greater than 5K, and even greater than 10K, can be used satisfactorily in specially designed units.

[0013] Various refrigerants are commercially available for heat pump equipment. For coolers with condensing pressures of less than 2 bara, low-volatility refrigerants such as R123 (boiling point 28°C) can be used. R1234ze(E) can be used for coolers and refrigeration at moderate temperatures, but R1234yf may be preferred for mobile air conditioning. Some of these refrigerants have certain drawbacks. R123 has an ODP of 0.06 and a GWP of 77, and is therefore being phased out. R1233zd(E) (boiling point 18.3°C, ODP 0, GWP 1) can be an alternative to R123, but its condensing pressure can exceed 2 bara.

[0014] R404A and R507 are widely used in refrigeration, and R410A is widely used in air conditioning and heat pumps. They are excellent refrigerants in terms of energy efficiency, non-flammability, low toxicity, and thermodynamic properties. However, they have a global warming potential (GWP) of over 2000 and are therefore considered environmentally unacceptable. Regulations are being introduced globally to reduce their use, and they may eventually be phased out. The European Union (EU) and other regions have imposed GWP quotas and / or taxes to gradually reduce the availability of R404A, R507, and R410A along with other HFC refrigerants. EU F-gas regulations substantially reduce the amount of refrigerants that can be sold based on their GWP. The EU also restricts the use of refrigerants with a GWP of over 150 in some applications.

[0015] R32 was introduced as a replacement for R410A, but it still has an unacceptably high GWP of 675 and is flammable (ASHRAE rating A2L). R13B1 (boiling point -58°C) is a very low-temperature refrigerant with an extremely high ODP of 10 on a scale where R11 has an ODP of 1, and a GWP of 6900. R22 is an excellent refrigerant, but its use is being phased out due to its ODP of 0.055.

[0016] With its very low global warming potential, R1234yf is thermodynamically comparable to the highly global warming R134a and is being used as an alternative to the latter in mobile (automotive) air conditioning systems. Nevertheless, R1234yf is flammable and has an ASHRAE safety classification of A2L. Its flammability, along with its operating pressure of at least 100 bar, lower energy efficiency, susceptibility to performance degradation even from slight leaks, and high compressor starting torque that can stall small internal combustion engines, has led to industrial resistance to its adoption from some automakers who strongly favor carbon dioxide.

[0017] Ammonia, hydrocarbons, and carbon dioxide are established fluids for refrigeration and air conditioning systems and have significantly lower GWPs than hydrofluorocarbons (HFCs). However, they are also either toxic or flammable, or both (in the case of ammonia). Apart from the significant safety hazards in public places such as supermarkets, flammable hydrocarbons can only be used safely in conjunction with secondary refrigeration circuits. This reduces energy efficiency, increases costs, and greatly limits the maximum cooling load of hydrocarbons with minimal input. CO2 must be used in a transcritical state on the high-pressure side of the system to allow heat dissipation into the ambient air. The pressure often exceeds 100 bara, resulting in energetically unfavorable conditions and significantly higher capital costs compared to conventional R404A, R507, and R410A systems.

[0018] Although HFCs contribute less to global warming compared to CO2 and methane, their use is being controlled by EU F-gas regulations and the Kigali Amendment to the Montreal Protocol, and they may eventually be phased out. While the world is becoming accustomed to the safe and practical global use of HFCs, increasingly stringent international regulations restricting their use are creating significant uncertainty among original equipment manufacturers (OEMs) regarding the selection of refrigerants that may be used in the long term. This uncertainty is hindering the development of improved heat pump technologies. The object of this invention is to address the problem of developing improved heat pump technologies.

[0019] Since its inception in the mid-19th century, heat pump technology has been dominated by single-component or azeotropic refrigerants, a trend that continues to this day. In the 1870s, ammonia emerged as the primary industrial refrigerant, followed by carbon dioxide, sulfur dioxide, methyl chloride, and hydrocarbons. The introduction of the much safer CFCs and HCFCs in the 1930s, along with the introduction of single-component refrigerants CFC-12, CFC-114, and HCFC-22, as well as azeotropic mixtures R500 and R502, led to the rapid growth of refrigeration and air conditioning.

[0020] The equipment was specifically designed to optimize the performance of single-component and azeotropic refrigerants, and therefore further new refrigerants were expected to meet these engineering standards. A fundamental characteristic is that these refrigerants evaporate and condense at constant temperature and pressure. This is confirmed by saturation tables, superheat tables, and pressure-enthalpy charts provided by refrigerant suppliers to optimize the operation of existing equipment and used throughout the industry by both OEMs and service technicians. However, these limiting standards, influenced by early refrigerant development, have hindered the adoption of new refrigerants that combine low environmental impact with low hazards at the point of use and acceptable heat pump performance. This specification discloses that refrigerants with thermodynamic temperature glides above 5K, so-called "broad-glide refrigerants" or "very broad-glide refrigerants" with even higher glides, can overcome the problem of how to provide new refrigerants that combine low environmental impact with low hazards at the point of use and acceptable heat pump performance.

[0021] In this specification, the Global Warming Potential (GWP) values ​​refer to the 100-year integrated time range (ITH) included in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report. [Overview of the project]

[0022] According to the present invention, the refrigerant is a) Non-flammable, highly volatile carbon dioxide, and b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene, or mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), and HFO1243zf or mixtures thereof, and d) optionally, a component selected from HFC-227ea, HFC-152a, HFC-32 or a mixture thereof consisting of or consisting essentially of those.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] The refrigerant of the present invention can have a global warming potential of up to 400.

[0024] In this specification, percentages or other amounts are on a mass basis unless otherwise specified. Amounts are selected from any range given such that the total is 100%. Pressures are referred to in absolute bar (bara).

[0025] The term "hydrofluoro-olefin" may be abbreviated as "HFO" and includes compounds containing hydrogen, fluorine and carbon atoms, and optionally chlorine and bromine atoms.

[0026] The term "consisting of" is used herein to refer to a composition containing only the recited components, excluding any trace amounts of any impurities.

[0027] The term "consisting essentially of" is used herein to refer to a composition that includes the recited components and may have added thereto small amounts of any additional components that do not substantially modify the essential refrigerant properties of the composition. These compositions include compositions consisting of the recited components. Compositions consisting of the recited components may be particularly advantageous.

[0028] The present invention relates to very low GWP blends, which are compositions that can be used, although not particularly limited, in new refrigeration, air conditioning and heat pump systems.

[0029] The blend has an ozone depletion potential of zero and thus has no harmful effect on stratospheric ozone. The blend additionally or alternatively has a GWP of 400 or less, preferably 150 or less, more preferably less than 10.

[0030] A method for ranking the relative flammability of refrigerants is provided by the ASHRAE 34 Committee Scale, which simply classifies refrigerants into the following four flammability classes: Class 1, no flame propagation. Lower flammability than Class 2L Class 2 Flammable Class 3: Higher flammability

[0031] The blend may have an ASHRAE safety classification of A1 (non-flammable) or alternatively A2L (lower flammability), which, combined with its low GWP of less than 400, preferably less than 150, most preferably less than 10, and high efficiency, provides a novel combination of properties. The present invention relates in particular to refrigerant compositions containing one or more hydrofluoroolefins (HFOs).

[0032] The ASHRAE scale does not further distinguish the degree of flammability within each class. However, this distinction can be made by considering the lower flammability limit (LFL) of the blend. The LFL of refrigerant vapor in air at ambient pressure and temperature is the lower end of the concentration range in which the vapor can be ignited. If the vapor cannot be ignited, it has no LFL at temperatures up to 60°C, and its ASHRAE rating is Class 1.

[0033] The refrigerant of the present invention may be called a broad glide or very broad glide refrigerant.

[0034] In one embodiment, the highly volatile component has a vapor pressure of 1 atm at a temperature at least 10°C lower than that of the moderately volatile component, and the moderately volatile component has a vapor pressure of 1 atm at a temperature at least 10°C lower than that of the lowly volatile component.

[0035] In the embodiment, the highly volatile component may have a vapor pressure of 1 atmosphere (atm) at temperatures in the range of -80°C to -45°C.

[0036] In one embodiment, the moderately volatile component may have a vapor pressure of 1 atmosphere (atm) at temperatures in the range of -35°C to -15°C.

[0037] In one embodiment, the low-volatility component may have a vapor pressure of 1 atmosphere (atm) at temperatures in the range of 0°C to 40°C.

[0038] In the embodiment, the highest and lowest volatile components may be non-flammable, while the medium volatile components may be flammable.

[0039] The presence of non-flammable components suppresses the flammability of flammable components, and therefore the blend is non-flammable, which has the effect of raising the lower flammability limit (LFL) of the blend. Flammable components with an ASHRAE safety classification of A2L have a higher GWP due to the presence of HFC components, which provides additional beneficial properties in specific applications, such as replacing HFCs with blends that have a lower global warming potential, and similar technical properties.

[0040] At the onset of a vapor or liquid leak, for example under conditions specified by the ASHRAE 34 standard flammability test criteria, highly volatile non-flammable CO2 suppresses the flammability of R32, if present, and the flammable HFO components, and R152a, if present. As the leak progresses, the concentrations of CO2 and R32, if present, decrease, while the concentrations of flammable HFO, and R152a, if present, and non-flammable HFO increase.

[0041] The presence of non-flammable CO2 in the early stages of a leak, and non-flammable HFOs in the later stages of a leak, suppresses the flammability of more volatile HFOs, and, if present, HFC32 and HFC152a. Vapors and liquids with higher concentrations of non-flammable components have a higher LFL and are therefore less flammable, but are still ASHRAE Class 2L. Preferably, the ratio of non-flammable components to flammable components throughout the leak is such that both the vapor and liquid compositions are always non-flammable, i.e., all compositions conform to ASHRAE Safety Class A1 Class 1.

[0042] In particular, the present invention relates to a blend of a highly volatile, non-flammable component CO2, and a non-flammable HFO component with low volatility (boiling point > 0°C) and very low GWP (< 10), and a moderately volatile component (boiling point approximately -19°C), which provides a common basis for a range of low-hazard, environmentally friendly blends that can replace currently used commercial refrigerants in a wide range of heat pump applications, including but not limited to refrigeration, automotive and indoor air conditioning, heat pumps, and low-pressure (< 2 bara) coolers. The carbon dioxide / low-volatility HFO blend contains moderately volatile components (boiling points > -53°C and < -10°C) to provide a blend with properties required for specific heat pump applications.

[0043] We have found that these refrigerant compositions can be used in heat pump applications where fluids with unacceptably high GWP or ODP or flammability, including but not limited to R13B1, R32, R410A, R404A, R507, R290 (propane), R22, R1234yf, R600 (butane), R600a (isobutane), HFO1224yd(Z), HFO1224zd(E), HFO1233zd(E), HFO1234ze(E), HFO1336mzz(Z), and HFO1336mzz(E), are currently in use, and some of these fluids may be components in the refrigerant compositions.

[0044] In one embodiment, the refrigerant consists of, or is essentially composed of, the following components: Highly volatile components, medium-volatile components, and low-volatile components; the highly volatile components have a vapor pressure at least 1 atmosphere higher than the medium-volatile components, and the low-volatile components have a vapor pressure at least 1 atmosphere (atm) lower than the medium-volatile components.

[0045] In one embodiment, the refrigerant composition is A non-flammable, highly volatile component consisting of carbon dioxide; A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof. Optionally, one or more components selected from the group consisting of HFC227ea, HFC32, and HFC152a. It consists of, or essentially consists of.

[0046] In one embodiment, the refrigerant is a) A non-flammable, highly volatile component consisting of carbon dioxide, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) Optionally, an HFC selected from the group consisting of HFC227ea, HFC152a HFC and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 85% by weight. The amount of low-volatile components is in the range of 5% to 95% by weight. The amount of moderately volatile components is in the range of 10% to 90% by weight. The amount of HFC32, if present, is in the range of 2% to 59% by weight. The amount of HFC227ea, if present, is in the range of 1% to 12.4% by weight. The amount of HFC152a, if present, is in the range of 2% to 10% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0047] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 400.

[0048] In one embodiment, the refrigerant is a) A non-flammable, highly volatile component consisting of carbon dioxide, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), and HFO1243zf or mixtures thereof, and d) Optionally, HFC selected from the group consisting of HFC32, HFC227ea, HFC152a and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 60% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 2% to 59% by weight. The amount of HFC227ea, if present, is in the range of 1% to 12.4% by weight. The amount of HFC152a, if present, is in the range of 2% to 5% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0049] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 400.

[0050] In one embodiment, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), and HFO1243zf and mixtures thereof, and d) Optionally, HFC selected from HFC32, HFC152a and HFC227ea and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 22.2% to 59% by weight. The amount of HFC227ea, if present, is in the range of 4.7% to 12.4% by weight. The amount of HFC152a, if present, is in the range of 2% to 10% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0051] The sum of the percentage-weighted GWP contributions of the components may exceed 150, but not exceed 400.

[0052] In one embodiment, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) Optionally, HFC selected from HFC32, HFC152a and HFC227ea and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 2% to 22% by weight. The amount of HFC227ea, if present, is in the range of 1% to 4.7% by weight. The amount of HFC152a, if present, is in the range of 2% to 5% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0053] The sum of the percentage-weighted GWP contributions of the components may exceed 14, but not exceed 150.

[0054] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32 Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 60% by weight. The amount of HFC32 is in the range of 2% to 22% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0055] The sum of the percentage-weighted GWP contributions of the components may exceed 14, but not exceed 150.

[0056] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32 Consists of, or essentially consists of, The amount of highly volatile components is in the range of 6% to 25% by weight. The amount of low-volatile components is in the range of 7% to 30% by weight. The amount of moderately volatile components is in the range of 40% to 60% by weight. The amount of HFC32 is in the range of 10% to 21.5% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0057] The sum of the percentage-weighted GWP contributions of the components may exceed 14, but not exceed 150.

[0058] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32 Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 15% by weight. The amount of low-volatile components is in the range of 6% to 35% by weight. The amount of moderately volatile components is in the range of 46% to 55% by weight. The amount of HFC32 is in the range of 15% to 21.5% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0059] The sum of the percentage-weighted GWP contributions of the components may exceed 14, but not exceed 150.

[0060] In one embodiment, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC227ea Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC227ea is in the range of 2% to 4.7% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0061] The sum of the percentage-weighted GWP contributions of the components may exceed 64, but not exceed 150.

[0062] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of carbon dioxide, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 60% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 75% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0063] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 10.

[0064] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of carbon dioxide, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 10% to 50% by weight. The amount of low-volatile components is in the range of 5% to 35% by weight. The amount of moderately volatile components is in the range of 12% to 70% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0065] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 10.

[0066] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 10% to 40% by weight. The amount of moderately volatile components is in the range of 15% to 55% by weight. The amount of low-volatile components is in the range of 7% to 25% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0067] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 10.

[0068] In one embodiment of the present invention, the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 20% to 40% by weight. The amount of moderately volatile components is in the range of 30% to 55% by weight. The amount of low-volatile components is in the range of 7% to 25% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0069] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 10.

[0070] One embodiment of the present invention provides a refrigerant having a GWP of less than 400, suitable for systems containing components having a rated pressure for use with R32 and R410A, which can be used in new split A / C units or incorporated into existing split A / C units.

[0071] In one embodiment of the present invention, a refrigerant suitable for incorporation into a pure R32 in an existing split heat pump unit is: a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32 Consists of, or essentially consists of, The amount of highly volatile components is in the range of 8% to 19% by weight. The amount of low-volatile components is in the range of 5% to 8% by weight. The amount of moderately volatile components is in the range of 39% to 51% by weight. The amount of HFC32 is in the range of 35% to 44% by weight. The amount of each component is selected from the listed range so that the total amount is 100% by weight. The foaming point vapor pressure of the blend at 40°C should not exceed 30 bara.

[0072] The sum of the percentage-weighted GWP contributions of the components may exceed 14, but not exceed 300.

[0073] One embodiment of the present invention provides a refrigerant having a GWP of less than 150, suitable for use in refrigeration applications where R404A currently plays a role. Preferred blends have a foaming point pressure of 30 bara or less at 35°C. More preferred blends have a foaming point pressure of 20 bara or less at 35°C.

[0074] In one embodiment of the present invention, a refrigerant suitable for refrigeration applications in which R404A is currently used is: a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32, HFC227ea, or mixtures thereof Consists of, or essentially consists of, The amount of highly volatile components is in the range of 10% to 35% by weight. The amount of low-volatile components is in the range of 5% to 20% by weight. The amount of moderately volatile components is in the range of 40% to 80% by weight. The amount of HFC32, if present, is in the range of 18% to 22% by weight. The amount of HFC227ea, if present, is in the range of 2% to 4.5% by weight. The amount of each component is selected from the listed range so that the total amount is 100% by weight. The foaming point vapor pressure of the blend at 35°C should not exceed 30 bara.

[0075] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 150.

[0076] One embodiment of the present invention provides a refrigerant having a GWP of less than 150, suitable for use in refrigeration applications where R410A and HFC32 currently play a role. Preferred blends have a foaming point pressure of 35 bara or less at 35°C. More preferred blends have a foaming point pressure of 25 bara or less at 35°C.

[0077] In one embodiment of the present invention, a refrigerant suitable for refrigeration applications in which HFC32 and R410A are currently used is: a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32, HFC227ea, or mixtures thereof Consists of, or essentially consists of, The amount of highly volatile components is in the range of 8% to 25% by weight. The amount of low-volatile components is in the range of 5% to 20% by weight. The amount of moderately volatile components is in the range of 35% to 70% by weight. The amount of HFC32, if present, is in the range of 18% to 22% by weight. The amount of HFC227ea, if present, is in the range of 2% to 5% by weight. The amount of each component is selected from the listed range so that the total amount is 100% by weight. The foaming point vapor pressure of the blend at 35°C should not exceed 35 bara.

[0078] The sum of the percentage-weighted GWP contributions of the components does not need to exceed 150.

[0079] One embodiment of the present invention provides a refrigerant having a GWP of less than 10, suitable for use in refrigeration applications where R404A currently plays a role. A preferred blend has a foaming point pressure of 30 bara or less at 35°C. A more preferred blend has a foaming point pressure of 20 bara or less at 35°C.

[0080] In one embodiment of the present invention, a refrigerant suitable for refrigeration applications in which R404A is currently used is: a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, The amount of highly volatile components is in the range of 9% to 35% by weight. The amount of low-volatile components is in the range of 5% to 12% by weight. The amount of moderately volatile components is in the range of 39% to 62% by weight. The amount of each component is selected from the listed range so that the total amount is 100% by weight. The foaming point vapor pressure of the blend at 35°C should not exceed 30 bara.

[0081] The sum of the percentage-weighted GWP contributions of the components may or may not exceed 10.

[0082] One embodiment of the present invention provides a refrigerant having a GWP of less than 10, suitable for use in refrigeration applications where R410A and R32 currently play a role. Preferred blends have a foaming point pressure of 45 bara or less at 35°C. More preferred blends have a foaming point pressure of 35 bara or less at 35°C.

[0083] One embodiment of the present invention provides a refrigerant suitable for heat pump applications where R410A or R32 is currently used, wherein the refrigerant is a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, d) The amount of highly volatile components is in the range of 9% to 30% by weight. The amount of low-volatile components is in the range of 5% to 25% by weight. The amount of moderately volatile components is in the range of 39% to 62% by weight. The amount of each component is selected from the listed range so that the total amount is 100% by weight. The foaming point vapor pressure of the blend at 35°C should not exceed 40 bara.

[0084] The sum of the percentage-weighted GWP contributions of the components may or may not exceed 10.

[0085] In heat pump applications where equipment footprint is a critical factor, such as marine refrigeration or air conditioning, high-capacity refrigerants may be preferred, but these may require high-pressure components rated up to approximately 100 bar. Pure CO2 operating in a transcritical cycle may offer higher capacity, but may be less energy-efficient than the blends provided by the present invention, which operate in a reverse Rankine cycle.

[0086] One embodiment of the present invention provides a refrigerant having a GWP of less than 10, which is suitable for use in high-capacity heat pump applications where R404A, R410A, and R32 currently play a role.

[0087] In one embodiment of the present invention, a refrigerant suitable for refrigeration applications in which R404A, R410A, or R32 are currently used is: a) A non-flammable, highly volatile component consisting of CO2, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1233zd(E), HFO1233zd(Z), HFO1233xf, HFO1336mzz(E), HFO1336mzz(Z), 2-bromo-3,3,3-trifluoropropane-1-ene and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO-1225ye(Z), HFO1243zf, and mixtures thereof. Consists of, or essentially consists of, d) The amount of highly volatile components is in the range of 70% to 85% by weight. The amount of low-volatile components is in the range of 5% to 25% by weight. The amount of moderately volatile components is within the range of 5% to 25% by weight. The amount of each component is selected from a range of listed components so that the total amount is 100% by weight.

[0088] The sum of the percentage-weighted GWP contributions of the components may or may not exceed 10.

[0089] The hydrofluoroolefin (HFO) used in the present invention is HFO1234yf(2,3,3,3-tetrafluoropropane-1-ene); HFO1234ze(E)(E-1,3,3,3-tetrafluoropropane-1-ene); HFO1216 (Hexafluoropropene); HFO1243zf(3,3,3-trifluoropropane-1-ene); HFO1225ye(Z)(Z-1,2,3,3,3-pentafluoropropane-1-ene); HFO1224yd(Z)(Z-1-chloro-2,3,3,3-tetrafluoropropene); HFO1233zd(E)(E-1-chloro-3,3,3-trifluoropropa-1-ene); HFO1233zd(Z)(Z-1-chloro-3,3,3-trifluoropropa-1-ene); HFO1233xf(2-chloro-3,3,3-trifluoropropa-1-ene); 2-bromo-3,3,3-trifluoropropa-1-ene; HFO1336mzz(Z)(Z-1,1,1,4,4,4-hexafluorobuta-1-ene; HFO1336mzz(E)(E-1,1,1,4,4,4-hexafluorobuta-1-ene); HFO1234ze(Z) HFO1234ze(Z), which contains and has a boiling point of 9.8°C, may be considered a low-volatility HFO, but does not satisfy the requirement herein that low-volatility HFOs are non-flammable. Nevertheless, non-flammable mixtures of HFO1234ze(Z) and other non-flammable low-volatility HFOs may be used in the compositions of the present invention.

[0090] HFO1224 is a preferred hydrofluorocarbon.

[0091] The GWP values ​​of the listed low-volatility HFOs are very low, for example, in the range of 1 to 18.

[0092] [Table 1]

[0093] The equipment described herein incorporates a condenser and an evaporator. These may be of the "DX" type, in which the refrigerant flows from one end of a "coil" to the other. "Coil" is a term commonly used to refer to the length of piping used in a heat exchanger.

[0094] In one embodiment, the heat pump device is The circuit comprises an evaporator, a compressor, a condenser, an expansion device, and a circulating refrigerant fluid as claimed in the present invention, The heat pump device further comprises a refrigerant fluid according to the present invention, The circuit consists of the following components: Cooling means for cooling the compressor, An internal heat exchanger (IHX) transfers heat from the high-pressure fluid flowing between the condenser and expansion device to the low-pressure fluid flowing between the evaporator and compressor. Includes one or more of the following.

[0095] The circuit may further include an accumulator for the liquid refrigerant. The accumulator may be located downstream of the evaporator.

[0096] The use of CO2 in refrigerant blends can, unfortunately, increase the release temperature and reduce the energy efficiency of the composition. High release temperatures can lead to excessive compressor wear, reducing reliability and operating life.

[0097] Means for cooling the compressor may be provided to control the compressor discharge temperature to maintain it below the maximum temperature, for example below 110°C, preferably below 100°C, and to provide energy efficiency at least equivalent to existing devices using CO2, R32, R410A, R404A, R507, R1234yf, R134a, R1234ze(E), R123, R1336mzz(Z), R290, R600, and R600a.

[0098] Various cooling methods can be used to cool the compressor. A combination of two or more cooling methods may be provided.

[0099] Supercooling can also lead to compressor damage. If liquid refrigerant is still present at the end of compression, it can damage the exhaust valve just before entering the discharge line, or in extreme cases, result in a "liquid lock" that can damage the compressor drive mechanism.

[0100] In one advantageous embodiment of the present invention, the discharge temperature and the temperature of the vapor exiting the compressor may exceed the dew point of the refrigerant at that point in the circuit, for example, by 5°C or more, for example by 10°C or more. This may help minimize the risk of the liquid damaging the compressor.

[0101] The cooling method is, 1. A liquid injector configured to inject liquid refrigerant into a compressor. 2. Cooling jacket in thermal contact with the compressor, 3. A compressor having channels in the compressor head and / or body through which a fluid flows to remove the heat generated by the compression of the refrigerant. 4. A liquid refrigerant injection port through a channel in the cooling jacket or compressor head and / or body, located between the end of the condenser and the expansion device. 5. The injection point for liquid refrigerant into the compressor discharge pipe from between the end of the condenser and the expansion device. 6. Cooling coil in thermal contact with the compressor, 7. Heat pipe in thermal contact with the compressor, 8. A thermal siphon in thermal contact with the compressor, and 9. Means for injecting cold steam into the compressor It may include one or more of the following.

[0102] Other cooling methods may be used.

[0103] A liquid injector may be configured to inject liquid refrigerant into a suction line or into the compression space of a compressor.

[0104] Various compressor types can be used with the low GWP blend of the broad glide of the present invention. Positive displacement compressors may include, but are not limited to, scroll, spool, blade, rotary rolling piston, screw, lobe, and reciprocating compressors. Dynamic compressor types may include, but are not limited to, centrifugal and axial flow. The electric motor driving the compressor may be housed in a common enclosure. This configuration is known as a closed or semi-closed compressor. When the motor is outside the compressor enclosure, this is known as an open compressor. For the blend of the present invention, a preferred compressor design has equipment for liquid injection to reduce the release temperature by injection into the suction port or into the compressed volume. Alternatively, cold steam may be injected into the compressed volume.

[0105] The evaporator may be “submerged.” In this specification, a submerged evaporator means that the existing refrigerant may be a two-phase mixture of liquid and vapor. In many modern refrigeration and air conditioning systems, the refrigerant may be completely evaporated and then further superheated, for example, by 3-10K, or 5K, to ensure that no liquid enters the suction line and is subsequently transported to the compressor. This is typically achieved by using a thermostatic expansion valve whose degree of opening varies in response to a gas-valve sensor installed in the suction line after the evaporator. The valve is adjusted so that the superheating of the vapor exiting the compressor is set to a specific value, for example, 3-10K, or 5K. As the cooling load on the evaporator increases, the sensor detects superheating above 5K and opens the valve to allow more refrigerant into the evaporator and restore the superheating to a preset value. It will be understood by those skilled in the art that if superheated vapor enters the compressor, the discharged vapor may also be superheated.

[0106] However, for broad glide and very broad glide refrigerants disclosed herein, refrigerant superheating may not be practical. As a result, the evaporator may become waterlogged, and the departing mixture is a two-phase liquid / vapor, which enters the suction line. To evaporate any further amount of liquid in the suction line, an internal heat exchanger (IHX) may be incorporated to transfer heat from the hotter, higher-pressure refrigerant returning from the condenser to the expansion device. The refrigerant exiting the IHX may be superheated to be substantially liquid-free, thereby ensuring that no liquid enters the compressor. Alternatively, and advantageously, the refrigerant exiting the IHX may still contain some liquid, which is allowed to enter the compressor and flash-evaporate as the refrigerant temperature increases due to compression or heat from an electric motor in a sealed unit. This arrangement reduces the refrigerant exit temperature to below the temperature that would be reached if no liquid entered the compressor. This may help protect the compressor from excessive wear caused by superheating.

[0107] The released refrigerant may be superheated by at least 5K to "dry" it to avoid damage to the compressor due to excessive moisture in the suctioned refrigerant. To ensure this condition is met when the heat pump load fluctuates, pressure and temperature sensors may be provided to the release line near the compressor. The sensor signals may be fed to a microprocessor containing thermodynamic data of the refrigerant, so that the microprocessor can calculate the superheating of the released vapor. The superheating value can control the degree of opening of the electronic expansion valve (EEV), and thus the flow of refrigerant into the evaporator. If the load on the evaporator decreases, the release superheating decreases, with the risk of liquid being present in the compressor at the end of compression. Controlled by the pressure and temperature sensors, the EEV can reduce the flow of refrigerant and thus increase the release superheating to a preset value. This is a method for controlling the injection of liquid into the compressor.

[0108] In another embodiment, the thermal expansion value (TXV) from a gas valve sensor on the discharge line may be used to control the flow of refrigerant entering the evaporator and thus ensure that the discharge temperature does not drop below a preset value.

[0109] The operation of a heat pump system using a submerged evaporator and a composition with a very wide glide offers further advantages compared to conventional operation where the refrigerant is completely evaporated and superheated. Firstly, incomplete evaporation reduces the temperature glide, which can be closer to the temperature profile required for a particular application. Secondly, the entire internal surface area of ​​the evaporator is used for evaporation, which is a more efficient heat transfer mode compared to vapor superheating. Thirdly, by removing the liquid from the evaporator, the composition can include low-volatility, non-flammable HFO components to suppress the flammability of flammable components such as R32, particularly R1234yf and R1234ze(E), thereby facilitating the reduction or elimination of the overall flammability of the composition.

[0110] The common understanding is that non-azeotropic blends with broad and very broad intrinsic glides do not work in heat pump equipment. However, the applicant has surprisingly found that refrigerants with broad or very broad glides of the present invention can be used in heat pump equipment. In conventional refrigeration equipment using a typical evaporator, a pressure drop of about 0.3 to about 0.7 bar can induce an actual temperature glide of about 4 to about 6 K. Thus, evaporator glide is characteristic of existing refrigeration equipment using conventional HFC refrigerants, despite the assumption of a simplistic modeling that evaporation occurs at constant pressure and temperature. The intrinsic glides of the blends of the present invention can offset the pressure-induced glide, and therefore the actual evaporator glides can be in the range of 1 to 4 K, i.e., they can be smaller than those of existing equipment. Preferably, the actual glide should be approximately equal to the glide of the heat source being cooled.

[0111] In conventional designs, the pressure drop between the condenser and evaporator is primarily through the expansion device. The pressure drop through the heat exchanger is minimized. However, the inventors have surprisingly found that the total pressure drop can be favorably divided between the expansion device and the evaporator by a broad and very broad glide blend. The greater the pressure drop through the evaporator, the smaller the observed glide, because the pressure-induced glide counteracts the intrinsic refrigerant glide. Surprisingly, however, energy efficiency and suction capacity are independent of the evaporator pressure drop.

[0112] The evaporator pressure drop can be varied by making one or more of the following modifications to the evaporator coil. In this specification, the term “coil” means a length of piping which may or may not have a coil configuration. 1. Reduce the diameter of the coil. 2. Increase the length of the coil. 3. Increase the surface roughness of the inner surface of the coil.

[0113] By combining a broad glide blend with the appropriate evaporator, it may be advantageous to select a glide that matches the required temperature profile of the fluid used as the heat source for the evaporator.

[0114] The above means for varying the evaporator pressure drop can also increase the heat range available for heat transfer, which can improve energy efficiency.

[0115] In a typical system, the refrigerant enters the condenser from a superheated compressor. The vapor is then cooled to its dew point and condenses until it is completely converted to a liquid at its foaming point. Heat is removed from the liquid refrigerant, and it thus escapes the subcooled state in the condenser by, for example, 5K. A broad-glide refrigerant blend claimed herein may also follow the same sequence in the condenser. However, it has been found that a broad-glide blend can advantageously minimize condenser temperature glide by exiting the condenser at its foaming point or with a mass quality above 0. The refrigerant then enters the higher-pressure side of the IHX, and subcooling following condensation is achieved by transferring heat to a lower temperature, lower-pressure flow in the suction flow.

[0116] If the actual temperature glide is too large in a particular application, a recirculating condenser design can be used, in which a portion of the liquid refrigerant from the condenser outlet is pumped back into the condenser inlet and mixed with the exhaust gas from the compressor to thermodynamically equilibrate. This can cool the compressor by deheating the exhaust gas and removing heat from the compressor head.

[0117] To pump liquid refrigerants, various means may be used, including, but are not limited to, ejector pumps or electric turbopumps that are operated by the flow of exhaust gas.

[0118] The actual temperature glide is reduced by an amount dependent on the recycling ratio, with higher ratios resulting in smaller glide. This is particularly advantageous for heat pumps installed in loads where the temperature difference between the inlet and outlet temperatures of the secondary refrigerant that removes heat from the condenser is smaller than the actual glide in a single-pass condenser, i.e., one without recirculation.

[0119] The refrigerant blends disclosed herein may possess a combination of properties such as non-flammability and heat capacity, very low GWP, and compatibility with commonly used building materials (steel, copper-aluminum alloys, polymer seals) and polyol ester (POE) lubricants in the refrigeration and HVAC industries, which are equivalent to or better than currently used commercial refrigerants and do not require strict matching of the thermodynamic properties of these refrigerants. By employing particularly appropriate techniques in the novel blends disclosed herein, performance can be optimized for specific applications in which existing refrigerants are used. Conventional design constraints related to the use of currently used commercial refrigerants are no longer applicable. Importantly, the drawbacks of low-GWP broad-glide blends, as recognized by conventional evaluations of low or zero-glide refrigerants, can be overcome by employing appropriate techniques.

[0120] For safety reasons, the maximum operating pressure of a given design must not be exceeded. However, higher operating pressures may be considered when designing new equipment for blends claimed herein, if they are advantageous. For example, a blend may offer a higher capacity and therefore require the use of a relatively smaller compressor. In this specification, the selection of a new blend is not limited by the recognized need to conform to the normally permissible maximum operating pressure of commercially available refrigerants currently in use.

[0121] The present invention offers several advantages. The GWP of the refrigerant composition may be less than 400, more preferably less than 150, and most preferably less than 10. Efficiency and capacity performance may be at least equal to those achieved with units operating on commercially available refrigerants currently in use. Emission temperatures of less than 100°C may be achieved. The maximum operating pressure may be similar to that of units operating on commercially available refrigerants currently in use. This allows the use of existing engineering components such as heat exchangers. The composition may provide non-flammability to ASHRAE safety classification A1. In a preferred embodiment, a single refrigerant blend may be used for refrigerant, air conditioning, and heat pump applications.

[0122] Each of the blends that are the subject of this invention may be used in refrigeration equipment lubricated by oxygen-containing oils, such as polyol esters (POE) or polyalkyl glycols (PAG), or by such oils mixed with up to 50% hydrocarbon lubricants, such as mineral oil, alkylbenzene, or polyalpha-olefin. Those skilled in the art will understand that the compressor lubricant in a heat pump system must be compatible with the properties of the refrigerant. The higher solubility of some HFOs in POE may require the use of these lubricants in higher viscosity grades along with the refrigerant blends of this invention. This is particularly important in the case of lower volatile HFOs, which are essential components in the blends of this invention. Alternatively or additionally, lubricants with a higher alkyl group-to-ester group ratio may be preferred to reduce the solubility of HFOs. This can be achieved by using POE with a higher alkyl / ester ratio, or by mixing separate hydrocarbon and POE lubricants.

[0123] The present invention will be further described using examples, but this will not limit the present invention. [Examples]

[0124] Comparative calculations were performed for R410A used in a typical segmented air conditioning system, as shown in Figure 1, which includes a sealed compressor 2 (both components enclosed within a pressure housing 12) driven by an electric motor 1, an air-cooled condenser 3, an electronic expansion valve 4, an air-heated evaporator 5, and an accumulator 6. The condenser outlet temperature of the liquid refrigerant was 40°C with a 5K subcooling. The vapor outlet temperature from the evaporator was 12°C with a 5K superheating. The unit was controlled by a microprocessor 8 that received the refrigerant temperature value from the evaporator via a data line 11 from a temperature sensor 7 and via a data line 14 from a room thermostat 13. The 8 controls the system to maintain the room temperature at the required level according to the input data by adjusting 4 via a single line 10 and by adjusting the speed of 1, and consequently the compressor capacity, via a single line 9.

[0125] Table 1 shows the values ​​of the main parameters that indicate refrigerant performance. [Examples]

[0126] Comparative calculations were performed for R404A, used in a typical freezer, also shown in Figure 1, which includes a sealed compressor 2 (both components enclosed within a pressure housing 12) driven by an electric motor 1, an air-cooled condenser 3, an electronic expansion valve 4, an air-heated evaporator 5, and an accumulator 6. The condenser outlet temperature of the liquid refrigerant was 30°C with a 5K subcooling. The vapor outlet temperature from the evaporator was -30°C with a 5K superheating. The unit was controlled by a microprocessor 8 that received the refrigerant temperature value from the evaporator via a data line 10 from a temperature sensor 7 and via a data line 14 from a thermostat 13 located inside the freezer. The 8 controlled the system to maintain the freezer within the range of -18 to -23°C according to the input data by adjusting 4 via a single line 10 and by adjusting the speed of 1, and consequently the compressor capacity, via a single line 9.

[0127] Table 2 shows the values ​​of the main parameters that indicate refrigerant performance. [Examples]

[0128] Calculations were performed for a non-flammable blend with a GWP of less than 400 in a segmented air conditioning system (as shown in Figure 2) comprising an accumulator 14, a sealed compressor 1, a condenser 4, an internal heat exchanger 5 that transfers heat from a higher temperature, higher pressure refrigerant stream to a lower temperature, lower pressure refrigerant stream, an electronic expansion valve 6, and an evaporator 10. The refrigerant flow in the circuit was controlled by pressure and temperature sensors in the discharge line immediately after the compressor. The compressor was driven by a variable-speed electric motor 12 and cooled by heat removal using a heat pipe 13. The unit was controlled by a microprocessor 9 programmed with respect to the thermodynamic properties of the refrigerant. The microprocessor received input data from the temperature sensor 2 via data line 8 and from the pressure sensor 3 via data line 7, the sensors located on the discharge line close to the compressor. The microprocessor transmitted output signals to change the motor speed via signal line 15 and output signals to change the opening of the expansion valve via signal line 11, so that the unit's performance was adapted to the required room temperature. In particular, the microprocessor ensured that the refrigerant entering the discharge line was at least 5K to avoid potentially damaging wet compression.

[0129] To provide a suitable comparison with R410A in Example 1, the refrigerant temperature at the condenser outlet was 40°C, the evaporator inlet temperature was 7°C, the compressor isentropy efficiency was 0.7, and the electric motor efficiency was 0.9. A pressure drop across the evaporator was applied to provide an actual temperature glide of 11K.

[0130] The values ​​of the main parameters indicating the refrigerant performance of blends 1 to 12 are shown in Tables 3a and 3b. [Examples]

[0131] Calculations were performed for non-flammable blends with a GWP of less than 400 in a refrigeration system (as shown in Figure 3) comprising an accumulator 14, a sealed compressor 1, a condenser 4, an internal heat exchanger 5 that transfers heat from a higher temperature, higher pressure refrigerant stream to a lower temperature, lower pressure refrigerant stream, an electronic expansion valve 6, and an evaporator 10. The refrigerant flow in the circuit was controlled by pressure and temperature sensors in the discharge line immediately after the compressor. The compressor was driven by a variable-speed electric motor 12 and cooled by removing heat by pumping liquid refrigerant into a heat exchanger 13 in contact with the compressor head using an injection pump or liquid turbopump 16 that draws liquid refrigerant from the liquid line immediately before the expansion valve 6. The unit was controlled by a microprocessor 9 programmed with respect to the thermodynamic properties of the refrigerant. The microprocessor received input data from a temperature sensor 2 via data line 8 and from a pressure sensor 3 via data line 7, the sensors located on the discharge line close to the compressor. The microprocessor transmits an output signal to change the motor speed via signal line 15 and a signal to change the opening degree of the expansion valve via signal line 11, so that the unit's performance is adapted to the required room temperature. In particular, the microprocessor ensures that the refrigerant entering the discharge line is not overheated to at least 5K in order to avoid potentially damaging wet compression.

[0132] To provide a suitable comparison with R404A in Example 2, the refrigerant temperature at the condenser outlet was 30°C, the evaporator inlet temperature was -35°C, the compressor isentropy efficiency was 0.7, and the electric motor efficiency was 0.9. A pressure drop across the evaporator was applied to provide an actual temperature glide of 5K.

[0133] The values ​​of the main parameters for blends 13-24 are shown in Tables 4a and 4b. [Examples]

[0134] Calculations were performed for a non-flammable blend (25) consisting of 5% R1224yd(Z), 69% CO2, and 26% R1234ze(E) with a GWP of 2 in a segmented air conditioning system (Figure 4) comprising an accumulator 13; a variable-speed electric motor 4; a two-stage integrated sealed compressor with a lower-pressure first stage 1 and a higher-pressure second stage 2; a condenser 5; an internal heat exchanger (IHX) 6 that transfers heat from a higher-temperature, higher-pressure refrigerant stream to a lower-temperature, lower-pressure refrigerant stream; an electronic expansion valve 7 and an evaporator 8. The refrigerant flow in the circuit was controlled by pressure and temperature sensors 10 and 11 in the suction line immediately after the IHX 6.

[0135] The gas released from the first compression stage passed through an external heat exchanger called the intercooler 3, where it was cooled by the ambient air before entering the gas volume within the compressor housing surrounding the electric motor and the two-stage compressor. The gas cooled the motor and then entered the suction port of the second compression stage, where it was further compressed and then released into the condenser.

[0136] The unit was controlled by a microprocessor 9 programmed with respect to the thermodynamic properties of the refrigerant. The microprocessor received input data from a temperature sensor 11, a pressure sensor 10, and a temperature sensor 14 that measured room temperature. The microprocessor transmitted output signals to change the motor speed via signal line 15 and output signals to change the opening degree of the expansion valve via signal line 12, so that the unit's performance was optimized to match the required room temperature. In particular, the microprocessor ensured that the refrigerant entering the compressor was not overheated to at least 2K, preferably 5K, to avoid potentially damaging wet compression.

[0137] To provide a suitable comparison with R410A in Example 1, the refrigerant temperature at the condenser outlet was 40°C, the evaporator inlet temperature was 7°C, the compressor isentropy efficiency was 0.7, and the electric motor efficiency was 0.9. A pressure drop across the evaporator was applied to provide an actual temperature glide of 11K.

[0138] Table 5 shows the values ​​of key parameters indicating the refrigerant performance of a blend consisting of 5% R1224yd(Z), 69% CO2, and 26% R1234ze(E). This blend is superior to R410A for air conditioning because it combines a GWP of only 2 with a suction volume of 107808 kJ / kg (R410A: 5832 kJ / kg) but with comparable energy efficiency. This blend is superior to CO2 because it operates at a maximum pressure of approximately 60 bar (CO2: typically 130 bar), which reduces back leakage of vapor in the compressor, provides operation in a subcritical cycle, and thus allows for efficient condensation heat transfer to the surroundings. [Examples]

[0139] Calculations were performed for a non-combustible blend 26 consisting of 10% R1224yd(Z), 67% CO2, and 23% R1234yf with a GWP of 2 in a segmented air conditioning system (as shown in Figure 4) operating under the same conditions as in Example 5. The values ​​of key parameters indicating refrigerant performance are shown in Table 5. This blend is superior to R410A for air conditioning because it combines a GWP of only 2 with a suction volume of 11156 kJ / kg (R410A: 5832 kJ / kg) but with equivalent energy efficiency. This blend is superior to CO2 because it operates at a maximum pressure of approximately 60 bar (CO2: typically 130 bar), which reduces back leakage of vapor in the compressor, and it operates in a subcritical cycle, which allows for efficient condensation heat transfer to the surroundings. [Examples]

[0140] Calculations were performed for a non-flammable blend 27 consisting of 8% R1224yd(Z), 70% CO2, and 22% R1234ze(E) in an electric vehicle air conditioning system (Figure 5) comprising a single-stage sealed compressor driven by a variable-speed electric motor 2; a condenser 3; an internal heat exchanger (IHX) 4 that transfers heat from a higher temperature, higher pressure refrigerant stream to a lower temperature, lower pressure refrigerant stream; an electronic expansion valve 5; an evaporator 6; and an accumulator 13, with a GWP of 2. The refrigerant flow in the circuit included pressure and temperature sensors 7 and 8 in the suction line immediately after the IHX 4.

[0141] The unit was controlled by a microprocessor 9 programmed with respect to the thermodynamic properties of the refrigerant. The microprocessor received input data from a temperature sensor 11 via data line 10, from a pressure sensor 10 via data line 11, and from a temperature sensor 16 measuring the automobile cabin temperature via data line 15. The microprocessor transmitted output signals to change the motor speed via signal line 14 and output signals to change the opening degree of the expansion valve via signal line 12, so that the unit's performance was optimized to match the required cabin temperature. In particular, the microprocessor ensured that the refrigerant entering the compressor was not overheated to at least 2K, preferably 5K, to avoid potentially damaging wet compression.

[0142] Table 6 shows the values ​​of key parameters indicating the refrigerant performance of a blend consisting of 8% R1224yd(Z), 70% CO2, and 22% R1234ze(E). This blend (non-flammable and GWP 2) outperforms both R134a (non-flammable but with a high GWP of 1300) and its substitute R1234yf (very low GWP (2) but flammable) for automotive air conditioning. The blend also benefits from a much higher suction specific volume than these refrigerants. This blend also operates at a maximum pressure of approximately 66 bar (CO2: 130 bar), which reduces back leakage of vapor in the compressor, and operates in a subcritical cycle, which is superior to CO2 as it allows for efficient condensation heat transfer to the surroundings.

[0143] Table 7 also shows performance data for Blend 28 in automotive air conditioning systems. [Examples]

[0144] The performance of blends 29-37 (Tables 7a and 7b) containing HFC152a was calculated in the low-temperature refrigeration unit described in Example 4. The results are shown in Table 7. [Examples]

[0145] The performance of blends 38-42 incorporated into HFC32 in existing segmented air conditioning units was calculated and compared with HFC32 (43 in Table 8b). The results are shown in Tables 8a and 8b. These blends offer acceptable energy efficiency and suction cooling capacity compared to HFC32, with a GWP of less than half that of HFC32, and thus reduce the direct contribution of segmented air conditioning units to global warming. [Examples]

[0146] The performance of blends 44-45 (Table 9) in a refrigeration unit similar to that described in Example 4 was calculated. The results shown in Table 9 indicate that good suction cooling capacity and efficiency were obtained. The blends have a GWP of less than 150, which is a value mandated as a regulatory upper limit by some governments that are enforcing the phased phasing out of high GWP refrigerants such as R404A and R507A. [Examples]

[0147] The performance of blends 48-51 (Table 10) in a segmented air conditioning unit similar to that described in Example 3 was calculated. The results shown in Table 10 demonstrate that good suction cooling capacity and efficiency were obtained that are favorably comparable to the existing refrigerants R410A and HFC32 currently used in this application. The blends have a GWP of less than 150, which is a value mandated as a regulatory upper limit by some governments that are enforcing the phased phasing out of high GWP refrigerants such as R410A and HFC32.

[0148] Table 2

[0149] Table 3

[0150] Table 4

[0151] Table 5

[0152] Table 6

[0153] Table 7

[0154] Table 8

[0155] Table 9

[0156] Table 10

[0157] Table 11

[0158] Table 12

[0159] Table 13

[0160] Table 14

[0161] Table 15

[0162] Table 16

[0163] Table 17

[0164] Table 18

[0165] Table 19

[0166] Table 20

[0167] Table 21

[0168] Table 22

[0169]

Table 23

[0170]

Table 24

[0171]

Table 25

[0172]

Table 26

[0173]

Table 27

Brief Description of the Drawings

[0174] [Figure 1] It is a schematic diagram showing the split air conditioning system used in Example 1 and the refrigerator used in Example 2. [Figure 2] It is a schematic diagram showing the split air conditioning system used in Example 3 and Example 11. [Figure 3] It is a schematic diagram showing the refrigeration system used in Example 4 and the refrigeration unit used in Example 8 and Example 10. [Figure 4] It is a schematic diagram showing the split air conditioning system used in Example 5 and Example 6. [Figure 5] It is a schematic diagram showing the air conditioning system of an electric vehicle used in Example 7.

Claims

1. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC selected from the group consisting of HFC32, HFC227ea, R152a and mixtures thereof, Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 60% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 2% to 59% by weight. The amount of HFC227ea, if present, is in the range of 1% to 12.4% by weight. The amount of R152a, if present, is in the range of 2% to 10% by weight, and is a refrigerant.

2. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC selected from the group consisting of HFC32, HFC227ea, R152a and mixtures thereof, Consists of, or essentially consists of, The amount of highly volatile components is within the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 22.2% to 59% by weight. The amount of HFC227ea, if present, is in the range of 4.7% to 12.4% by weight. The refrigerant according to claim 1, wherein the amount of R152a, if present, is in the range of 3% to 8% by weight.

3. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC selected from the group consisting of HFC32, HFC227ea, R152a and mixtures thereof, Consists of, or essentially consists of, The amount of highly volatile components is within the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 65% by weight. The amount of HFC32, if present, is in the range of 2% to 22% by weight. The amount of HFC227ea, if present, is in the range of 1% to 4.7% by weight. The refrigerant according to claim 1, wherein the amount of R152a, if present, is in the range of 3% to 5% by weight.

4. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32, Consists of, or essentially consists of, The amount of highly volatile components is within the range of 5% to 30% by weight. The amount of low-volatile components is in the range of 5% to 40% by weight. The amount of moderately volatile components is in the range of 10% to 60% by weight. The refrigerant according to claim 3, wherein the amount of HFC32 is in the range of 2% by weight to 22% by weight.

5. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32, Consists of, or essentially consists of, The amount of highly volatile components is in the range of 6% to 25% by weight. The amount of low-volatile components is in the range of 7% to 30% by weight. The amount of moderately volatile components is in the range of 40% to 60% by weight. The refrigerant according to claim 4, wherein the amount of HFC32 is in the range of 10% by weight to 21.5% by weight.

6. a) CO ２ A non-flammable, highly volatile component consisting of, b) A non-flammable, low-volatility component selected from the group consisting of HFO1224yd(Z), HFO1224yd(E), HFO1336mzz(E), HFO1336mzz(Z), and mixtures thereof. c) A medium-volatile component selected from the group consisting of HFO1234yf, HFO1234ze(E), HFO1225ye(Z), HFO1243zf and mixtures thereof, and d) HFC32, Consists of, or essentially consists of, The amount of highly volatile components is in the range of 5% to 15% by weight. The amount of low-volatile components is in the range of 6% to 35% by weight. The amount of moderately volatile components is in the range of 46% to 55% by weight. The refrigerant according to claim 3, wherein the amount of HFC32 is in the range of 15% by weight to 21.5% by weight.

Images