CN117249595A

CN117249595A - Multistage low GWP air conditioning system

Info

Publication number: CN117249595A
Application number: CN202311190250.1A
Authority: CN
Inventors: A·塞蒂; S·F·亚纳莫塔; E·d·C·贝拉韦塞拉
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2016-02-16
Filing date: 2017-02-16
Publication date: 2023-12-19
Also published as: EP3417215A1; CN109073284A; CN114061163A; CN117213084A; EP3417215A4; EP4365513A2

Abstract

The present application relates to multi-stage low GWP air conditioning systems. A refrigerant system for conditioning air and/or items located in a residence occupied by a human or other animal is disclosed, the refrigerant system preferably comprising: at least a first heat transfer circuit comprising a first heat transfer fluid in the form of a vapor/compression cycle loop, substantially external to the residence; and at least a second heat transfer circuit comprising a second heat transfer fluid different from the first heat transfer fluid, substantially located inside the residence.

Description

Multistage low GWP air conditioning system

The present application is a divisional application of the invention patent application of the application date 2017, 02, 16, 202110993068.4 and the invention name of the multistage low GWP air conditioning system, wherein the aforementioned invention patent application 202110993068.4 indicates a singleness problem in the first review of opinion notice.

Technical Field

The present invention relates to efficient low global warming potential ("low GWP") air conditioning and related refrigeration systems and methods that are safe and effective.

Background

In a typical air conditioning and refrigerant system, a compressor is used to compress heat transfer steam from a lower pressure to a higher pressure, which in turn adds heat to the steam. This added heat is typically rejected in a heat exchanger (commonly referred to as a condenser). In the condenser, the vapor (at least a greater proportion) is condensed to produce a liquid heat transfer fluid at a relatively high pressure. Typically, condensers use a large amount of fluid available in the surrounding environment (such as ambient outside air) as a heat sink (heat sink). Once it has been condensed, the high pressure heat transfer fluid undergoes a substantially isenthalpic expansion, such as by passing through an expansion device or valve where it is expanded to a lower pressure, which in turn results in the fluid experiencing a decrease in temperature. The low-pressure low-temperature heat transfer fluid from the expansion operation is then typically routed to an evaporator, where it absorbs heat and evaporates in doing so. This evaporation process in turn results in cooling of the fluid or body intended to be cooled. In a typical air conditioning application, the cooled fluid is the indoor air of an air conditioned residence. In a refrigeration system, cooling may include cooling air inside a cold box or storage unit. After the heat transfer fluid is evaporated in the evaporator at low pressure, it is returned to the compressor where the cycle begins again.

The complex and related combination of various factors and requirements is associated with creating an efficient, effective, and safe air conditioning system that is both environmentally friendly, that is, has both a low GWP impact and a low ozone depletion ("ODP") impact. Regarding efficiency and effectiveness, it is important to have the heat transfer fluid operate in an air conditioning system having a high level of efficiency and high capacity. At the same time, since it is possible that the heat transfer fluid may escape into the atmosphere over time, it is important that the fluid have both a low GWP value and a low ODP value.

While certain fluids are capable of achieving both high levels of efficiency and effectiveness and simultaneously achieving both low levels of GWP and ODP, applicants gradually understand that many fluids meeting this combination of requirements suffer from drawbacks related to safety. For example, otherwise perhaps acceptable fluids may be detrimental to use due to flammability properties and/or toxicity issues. The applicant has increasingly appreciated that the use of fluids having these properties is particularly undesirable in typical air conditioning systems, as such flammable and/or toxic fluids may inadvertently be released into the dwelling being cooled (or heated in the case of heat pump applications), thereby exposing or potentially exposing its occupants to hazardous conditions.

Disclosure of Invention

In accordance with one aspect of the present invention, a refrigerant system for conditioning air and/or items located in a residence occupied by a human or other animal is provided. A preferred embodiment of such a system comprises at least a first heat transfer circuit, preferably comprising a first heat transfer fluid in the form of a vapor/compression cycle loop, which is located substantially outside the residence. This first loop is sometimes referred to herein conveniently as an "outdoor loop". The outdoor loop preferably comprises a compressor, a heat exchanger for condensing a heat transfer fluid in the outdoor loop, preferably by heat exchange with outdoor ambient air, and an expansion device. The preferred system further includes at least a second heat transfer circuit containing a second heat transfer fluid different from the first heat transfer fluid, substantially located inside the residence. This second loop is sometimes referred to herein conveniently as an "indoor loop". The indoor loop preferably comprises an evaporator heat exchanger for evaporating the second heat transfer fluid in the indoor loop, preferably by heat exchange with the indoor air. In a preferred embodiment, the second heat transfer circuit does not include a vapor compressor.

The preferred system preferably comprises at least one intermediate heat exchanger which allows heat exchange between the first heat transfer fluid and the second heat transfer fluid so as to cause heat transfer to the first heat transfer fluid, preferably thereby evaporating the first heat transfer fluid, and heat transfer from the second heat transfer fluid thereby condensing the second heat transfer fluid. Preferably, the intermediate heat exchanger is located outside the residence or outside the area where air conditioning is to be performed.

An important aspect of the preferred system is that the first heat transfer fluid comprises a refrigerant having a GWP of not greater than about 500 (more preferably not greater than about 400, and even more preferably not greater than about 150), and the second heat transfer fluid comprises a refrigerant also having a GWP of not greater than about 500 (more preferably not greater than about 400, and even more preferably less than 150), and the refrigerant has low flammability and low toxicity, and even more preferably is substantially less flammable than the refrigerant in the first heat transfer fluid and/or is substantially less toxic than the toxicity of the refrigerant in the first heat transfer fluid.

In a preferred embodiment, the first heat transfer fluid comprises a refrigerant having a GWP of not greater than about 500 and the second heat transfer fluid comprises a refrigerant also having a GWP of not greater than about 500 and the refrigerant has a flammability substantially less than the flammability of the refrigerant in the first heat transfer fluid and/or a toxicity substantially less than the toxicity of the refrigerant in the first heat transfer fluid.

In a preferred embodiment, the first heat transfer fluid comprises a refrigerant having a GWP of not greater than about 400 and the second heat transfer fluid comprises a refrigerant also having a GWP of not greater than about 400 and the refrigerant has a flammability substantially less than the flammability of the refrigerant in the first heat transfer fluid and/or a toxicity substantially less than the toxicity of the refrigerant in the first heat transfer fluid.

In a preferred embodiment, the first heat transfer fluid comprises a refrigerant having a GWP of not greater than about 150 and the second heat transfer fluid comprises a refrigerant also having a GWP of not greater than about 150 and the refrigerant has a flammability substantially less than the flammability of the refrigerant in the first heat transfer fluid and/or a toxicity substantially less than the toxicity of the refrigerant in the first heat transfer fluid.

In a preferred embodiment, the second refrigerant comprises, more preferably comprises, at least about 50% by weight and even more preferably at least about 75% by weight of trans-1-chloro-3, 3-trifluoropropene (HCFO-1233 zd (E)), and the first refrigerant has a flammability greater than (and preferably substantially greater than) the flammability of HCFO-1233zd (E).

In a preferred embodiment, the second refrigerant comprises, more preferably comprises, at least about 75% by weight and even more preferably at least about 80% by weight of trans-1-chloro-3, 3-trifluoropropene (HCFO-1233 zd (E)), and the first refrigerant has a flammability greater than (and preferably substantially greater than) the flammability of HCFO-1233zd (E).

Drawings

Fig. 1 is a general process flow diagram of a preferred embodiment of an air conditioning system according to the present invention.

Fig. 2 is a general process flow diagram of another preferred embodiment of an air conditioning system according to the present invention.

Fig. 3 is a general process flow diagram of another preferred embodiment of an air conditioning system according to the present invention.

Fig. 4 is a schematic representation of a heat exchanger according to one embodiment of the invention.

Fig. 5 is a general process flow diagram of another preferred embodiment of an air conditioning system that can operate both cooling and heating in accordance with the present invention.

Detailed Description

Preferred heat transfer compositions

In various embodiments described herein, a system includes a first heat transfer component including a first refrigerant and a lubricant, preferably for a compressor, and a second heat transfer component including a second refrigerant. Preferably, the second refrigerant comprising at least about 50% by weight, more preferably at least about 80% trans 1-chloro-3, 3-trifluoropropene (HCFO-1233 zd (E)) or at least about 75% by weight, more preferably at least about 80% by weight trans 1, 3-tetrafluoropropene (HFO-1234 ze (E)) is a low flammability and low toxicity refrigerant, preferably having class a toxicity and class 1 or 2L flammability according to ASHRAE standard 34. In highly preferred embodiments, the second refrigerant comprises, and in some embodiments consists essentially of, or consists of, at least about 95% by weight of HFCO-1233zd (E).

In highly preferred embodiments, the second refrigerant comprises from about 95% to about 99% by weight of a five carbon saturated hydrocarbon, preferably one or more of isopentane (iso-pentane), n-pentane (n-pentane), or neopentane (neo-pentane), and in preferred aspects of such embodiments, the combination of HFCO-1233zd (E) and the pentane is in the form of an azeotropic component.

In a highly preferred embodiment of the present invention, the second refrigerant comprises from about 85% to about 90% by weight of trans 1, 3-tetrafluoropropene (HFO-1234 ze @; E)) and from about 10% by weight to about 15% by weight of 1,2, 3-heptafluoropropane (HFC-227 ea), and in some embodiments even more preferably about 88% by weight of trans 1, 3-tetrafluoropropene (HFO-1234 ze (E)) and about 12% by weight of 1,2, 3-heptafluoropropane (HFC-227 ea).

In highly preferred embodiments, the second refrigerant comprises from about greater than about 50% by weight to about 67.5% by weight trans 1, 3-tetrafluoropropene (HFO-1234 ze (E)) and from greater than about 9.7% by weight to less than about 50% by weight HFCO-1233zd (E), and in some embodiments even more preferably about 67% by weight trans 1, 3-tetrafluoropropene (HFO-1234 ze (E)) and about 33% by weight HFCO-1233zd (E). Applicants have found that such a preferred embodiment unexpectedly provides a second refrigerant that is immediately non-flammable (which measures the flammability of the initial vapor from fractionation of the mixture as would occur in the event of a refrigerant leak) in accordance with ASHRAE standards 34 and also produces a pressure in the indoor loop of the refrigeration system of greater than about 1 bar.

Those skilled in the art will appreciate in view of the disclosure contained herein that such embodiments of the invention provide the following advantages: only relatively safe (low toxicity and low flammability) low GWP refrigerants are used, which makes them highly preferred for use near occupied human or other animal sites, as is commonly encountered in air conditioning applications.

Preferably, in a preferred embodiment, the first refrigerant may comprise one or more components that may render the refrigerant substantially less desirable than the second refrigerant in terms of toxicity and/or flammability criteria, and all such first refrigerants are included within the scope of the present invention. For example, the first refrigerant may include one or more mixtures including one or more of the following: HFC-32 (preferably from about 0% to about 22% by weight in amount), HFO-1234ze (preferably from about 0% to about 78% by weight in amount), HFO-1234yf (preferably from about 0% to about 78% by weight in amount), and propane. In contrast to the first heat transfer component, the second heat transfer component of the present invention generally does not include a lubricant because the fluid does not need to pass through the compressor.

The first heat transfer component typically also includes a lubricant, from about 30% to about 50% by weight of the heat transfer component, typically in an amount based on the total weight of the refrigerant, and other optional components present in the system. Other optional components include compatibilizers, such as propane, which are used for the purpose of aiding the compatibility and/or solubility of the lubricant. When present, such compatibilizers (including propane, butane, and pentane) are preferably present in amounts from about 0.5% to about 5% by weight of the ingredients. A combination of surfactants and solubilizing agents may also be added to the present ingredients to aid in oil solubility, as disclosed in U.S. patent No. 6,516,837, the disclosure of which is incorporated herein by reference. Commonly used refrigeration lubricants such as Polyol esters (POE) and polyalkylene glycols (PAG, poly Alkylene Glycol), silicone oils, mineral oils, alkylbenzenes (AB), and poly (alpha-olefins), which are used in refrigeration machinery with Hydrofluorocarbon (HFC) refrigerants, may be used with the refrigerant compositions of the present invention. The preferred lubricant is POE.

An embodiment of the type illustrated in FIG. 1

In the following description, components or elements of the system that are or may be substantially the same or similar in different embodiments are designated with the same reference numerals or signs.

A preferred air conditioning system, generally designated 10, is illustrated in fig. 1, wherein the dashed line represents an approximate boundary between an indoor loop and an outdoor loop, wherein a compressor 11, a condenser 12, an intermediate heat exchanger 13, and an expansion valve 14 are located outdoors along with any of associated conduits 15 and 16, as well as other connections and related equipment (not shown). The outdoor loop (which is sometimes referred to herein as a "high temperature refrigerant loop") preferably includes a first heat transfer component, preferably according to one or more of the preferred embodiments described above, that includes a first refrigerant and a lubricant for the compressor, wherein at least the first refrigerant circulates in the loop through conduits 15 and 16 and other related conduits and equipment.

The indoor loop (which is sometimes referred to herein as a "low temperature refrigerant loop") preferably includes at least a second heat transfer component comprising a second refrigerant, wherein the second refrigerant has at least one safety property (such as flammability and toxicity) that is superior to the corresponding safety property of the first refrigerant. In highly preferred embodiments, the second refrigerant preferably has sufficiently low toxicity (designated as class a according to ASHRAE standard 34) and preferably also has sufficiently low flammability so as to have a class 1 or class 2L flammability rating. In highly preferred embodiments, the second refrigerant comprises (preferably consists essentially of, and in some embodiments consists of): HFCO-1233zd, and even more preferably transhfco-1233 zd. In other highly preferred embodiments, the second refrigerant comprises (preferably consists essentially of, and in some embodiments consists of): a combination of HFO-1234ze (E) and 1,2, 3-heptafluoropropane (HFC-227 ea). Those skilled in the art will appreciate in view of the disclosure contained herein that such embodiments of the invention provide the following advantages: only relatively safe (low toxicity and low flammability) low GWP refrigerants, such as HFCO-1233zd (E) and HFO-1234ze (E)/HFC-227 ea, are used near the site of a human or other animal occupying or entering the conditioned space while separating the human or animal in or likely to be in the conditioned space from the first refrigerant. Accordingly, the preferred configuration and selection of refrigerants allows for providing a system that benefits from the use of refrigerants having many desirable properties, such as capacity, efficiency, low GWP, and low ODP, but at the same time possessing one or more properties that might otherwise make them highly adverse and/or prevent their use near humans or other animals at a restricted and/or enclosed location. Such a combination provides excellent advantages in terms of all desired properties for such refrigerant systems.

In a preferred embodiment, for example, the first refrigerant may comprise one or more mixtures comprising one or more of the following: HFC-32 (preferably from about 0% to about 22% by weight in amount), HFO-1234ze (preferably from about 0% to about 78% by weight in amount), HFO-1234yf (preferably from about 0% to about 78% by weight in amount), and propane.

The heat transfer fluid in the outdoor loop will typically and preferably include a lubricant for the compressor, typically from about 30% to about 50% by weight of the heat transfer fluid, the remainder including refrigerant and other optional components that may be present. Other optional components include compatibilizers, such as propane, which are used for the purpose of aiding the compatibility and/or solubility of the lubricant. When present, such compatibilizers (including propane, butane, and pentane) are preferably present in amounts from about 0.5% to about 5% by weight of the ingredients. A combination of surfactants and solubilizing agents may also be added to the present ingredients to aid in oil solubility, as disclosed in U.S. patent No. 6,516,837, the disclosure of which is incorporated herein by reference. Commonly used refrigeration lubricants such as polyol esters (POE) and polyalkylene glycols (PAGs), silicone oils, mineral oils, alkylbenzenes (AB), and poly (alpha-olefins) (PAOs), which are used in refrigeration machinery with Hydrofluorocarbon (HFC) refrigerants, may be used with the refrigerant compositions of the present invention. The preferred lubricant is POE.

In operation, the second refrigerant according to the present invention circulates through the circuit by flowing through the intermediate heat exchanger 13, wherein it transfers heat to the first refrigerant, and in so doing, condenses at least a portion, and preferably substantially all, of the second refrigerant into liquid form, where it exits the intermediate heat exchanger through conduit 17. In a preferred embodiment, the second refrigerant leaving the intermediate heat exchanger enters the receiver 18, and a liquid reservoir of the second refrigerant is provided in the receiver 18. Although the receiver 18 is shown in this figure as being located indoors, the container may also be located outdoors and it may also be preferable to locate the pump 20 (when present) outdoors. The liquid refrigerant from the separation vessel is led to the evaporator via conduit 21. In the view shown in fig. 1, a liquid pump 20 is shown to assist in transporting liquid refrigerant through conduits 21, 22 and valve 23 to an evaporator 24. However, in other embodiments, other ways or techniques that can be used alone or in combination with a liquid pump to transport the second refrigerant liquid from the receiver may be used. For example, in some embodiments, the transport of liquid refrigerant may be accomplished through the use of gravity feeding the liquid to the evaporator, while in other embodiments, a thermosiphon arrangement may be used to transport the second liquid refrigerant to the evaporator 24 and from the evaporator to the intermediate heat exchanger 13.

In a preferred embodiment, wherein the refrigerant comprises (preferably consists essentially of, and preferably consists of) at least about 90% by weight HCFO-1233zd (E) or HFO-1234ze (E), the operating conditions correspond to the values described in the following table.

An embodiment of the type illustrated in FIG. 2

Another preferred embodiment of the present invention is illustrated in fig. 2, wherein the compressor 11, condenser 12, intermediate heat exchanger 13, expansion valve 14, and suction line heat exchanger 30 are located outdoors along with any of the associated conduits 15A, 15B, 16A and 16B and other connected and associated equipment (not shown). The outdoor loop (which is sometimes referred to herein as a "high temperature refrigerant loop") preferably includes a first heat transfer component comprising a first refrigerant and lubricant for the compressor, wherein at least the refrigerant circulates in the loop through conduits 17, 19, 21 and 22, as well as other related conduits and equipment.

The indoor loop is configured substantially as described above for the indoor loop of fig. 1, and the first and second heat transfer components are preferably also as otherwise indicated herein.

In operation, a first refrigerant according to the present invention is discharged from the compressor 11 as a relatively high pressure refrigerant vapor, which may include entrained lubricant, and it then enters the condenser 12, where it transfers heat to (preferably) ambient air and is at least partially condensed. The refrigerant effluent from condenser 12 is transported via conduit 15A to a suction line heat exchanger 30 where additional heat is lost to the effluent from 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 pressure of the refrigerant is reduced, which in turn reduces the temperature of the refrigerant. The relatively cool liquid refrigerant from the expansion valve then enters the intermediate heat exchanger 13 where it gains heat from the second refrigerant vapor leaving the evaporator 24 in the indoor loop. The first refrigerant effluent vapor from the intermediate heat exchanger is then transported via conduit 16A to a suction/liquid line heat exchanger 30, where it takes heat from the condenser effluent from conduit 15A and produces a second refrigerant vapor at a higher temperature, which is transported by conduit 16B to the inlet of compressor 11.

The evaporator effluent is transported via conduit 19 to the intermediate heat exchanger 13 where it loses heat to the effluent from the suction line heat exchanger, which is transported via conduit 15B to the intermediate heat exchanger and produces a relatively cool second refrigerant stream. This cold flow of the second refrigerant leaving the intermediate heat exchanger 13 is transported to a receiver tank 18, which receiver tank 18 provides a reservoir of cold liquid refrigerant, which cold liquid refrigerant is transported from the tank via conduit 21 and then fed into the evaporator 24 through control valve 23. In some embodiments, a pump 20 is provided for providing a flow of liquid to a control valve 23. The ambient air to be cooled loses heat to the cold liquid refrigerant in the evaporator 24, which in turn causes the liquid refrigerant to evaporate and produce refrigerant vapor with little or no superheat, and the vapor then flows back to the intermediate heat exchanger 13.

An embodiment of the type illustrated in FIG. 3

Another preferred embodiment of the present invention is illustrated in fig. 3, wherein the two-stage compressor 11, condenser 12, intermediate heat exchanger 13, expansion valve 14, and steam injection heat exchanger 40 (including associated intermediate expansion valve 41) are located outdoors along with any of the associated conduits 15A-15 and other connections and related equipment (not shown and/or not labeled). The outdoor loop (which is sometimes referred to herein as a "high temperature refrigerant loop") preferably includes a first heat transfer component comprising a first refrigerant and lubricant for the compressor, wherein at least the refrigerant circulates in the loop through conduits 15 and 16 and other related conduits and equipment.

In operation, a first refrigerant (which may include entrained lubricant) according to the present invention is discharged from the compressor 11 as a relatively high pressure refrigerant vapor, which may include entrained lubricant, and which then enters the condenser 12, where it transfers heat to (preferably) ambient air and at least partially condenses. The effluent stream from condenser 12 comprises at least partially and preferably substantially entirely condensed refrigerant. The refrigerant effluent from condenser 12 is transported via conduit 15A and a portion of the refrigerant effluent is routed via conduit 15B to intermediate expansion device 41 and another portion of the effluent (preferably the remaining portion of the effluent) is transported to steam injection heat exchanger 40.

The intermediate expansion device 41 causes the pressure of the effluent stream to be reduced (preferably substantially isenthalpically) to about the pressure of the second stage suction of the compressor 11 or sufficiently above such pressure to account for the pressure drop by way of the heat exchanger 41 and associated conduits, fixtures, etc. Due to the pressure drop across the expansion device 41, the pressure of the refrigerant flowing to the heat exchanger 40 is reduced relative to the temperature of the high pressure refrigerant flowing to the heat exchanger 40. In the heat exchanger 40, heat is transferred from the high pressure stream to the stream passing through the expansion valve 41. Thus, the intermediate pressure stream exiting the heat exchanger 40 is at a higher temperature than the inlet stream, thereby producing a superheated steam stream that is transported via conduit 19C to the second stage of the compressor 11.

As the higher pressure stream transported through conduit 15A travels through heat exchanger 40, it loses heat to the lower pressure stream exiting expansion valve 41 and exits the heat exchanger through conduit 15C and then flows to expansion valve 14 and then onwards to the intermediate heat exchanger where it takes heat and is transported to the first stage of compressor suction.

An embodiment of the type illustrated in FIG. 5

The embodiment disclosed in fig. 5 is similar to the embodiment of fig. 1 except that the system is equipped with a reversing valve so that it can be operated in a heating mode, as described below.

One preferred air conditioning system, generally designated 10, operable in both cooling and heating modes is illustrated in fig. 1, wherein the indicated lines represent approximate boundaries between the indoor and outdoor loops, with the compressor 11, the outdoor coil 12, the intermediate heat exchanger 13, the expansion valve 14 and the reversing valve 500 being located outdoors along with any of the associated conduits 15 and 16, as well as other connections and related equipment (not shown). The outdoor loop preferably comprises a first heat transfer component, preferably according to one or more of the preferred embodiments described above, comprising a first refrigerant and a lubricant for the compressor, wherein at least the first refrigerant circulates in the loop through conduits 15 and 16 and other related loops and devices.

The indoor loop preferably includes at least a second heat transfer component comprising a second refrigerant, wherein the second refrigerant has at least one safety property (such as flammability and toxicity) that is superior to the corresponding safety property of the first refrigerant. In highly preferred embodiments, the second refrigerant preferably has sufficiently low toxicity (designated as class a according to ASHRAE standard 34) and preferably also has sufficiently low flammability so as to have a class 1 or class 2L flammability rating. In highly preferred embodiments, the second refrigerant comprises (preferably consists essentially of, and in some embodiments consists of): HFCO-1233zd, and even more preferably transhfco-1233 zd. In other highly preferred embodiments, the second refrigerant comprises (preferably consists essentially of, and in some embodiments consists of): a combination of HFO-1234ze (E) and 1,2, 3-heptafluoropropane (HFC-227 ea). Those skilled in the art will appreciate in view of the disclosure contained herein that such embodiments of the invention provide the following advantages: only relatively safe (low toxicity and low flammability) low GWP refrigerants, such as HFCO-1233zd (E) and HFO-1234ze (E)/HFC-227 ea, are used near the site of a human or other animal occupying or entering the conditioned space while separating the human or animal in or likely to be in the conditioned space from the first refrigerant. Accordingly, the preferred configuration and selection of refrigerants allows for providing a system that benefits from the use of refrigerants having many desirable properties, such as capacity, efficiency, low GWP, and low ODP, but at the same time possessing one or more properties that might otherwise make them highly adverse and/or prevent their use near humans or other animals at a restricted and/or enclosed location. Such a combination provides excellent advantages in terms of all desired properties for such refrigerant systems.

In operation, according to the heating mode embodiment of fig. 5 of the present invention, the second refrigerant circulates through the circuit by flowing through the intermediate heat exchanger 13, wherein it picks up heat from the first refrigerant and in so doing evaporates at least a portion (and preferably substantially all) of the second refrigerant into a vapor form, where it exits the intermediate heat exchanger through conduit 17. The vaporized refrigerant is directed via conduit 21 to a condenser where it rejects heat to the residence upon condensation. In the view shown in fig. 1, liquid pump 20 is shown to assist in transporting liquid refrigerant through conduits 21, 22 and valve 23 to condenser 24. In addition, the indoor loop includes a reversing valve 501, which reversing valve 501 allows the system to operate in both a heating mode and a cooling mode.

In preferred embodiments, wherein the refrigerant comprises (preferably consists essentially of, and preferably consists of) at least about 90% by weight HCFO-1233zd (E) or HFO-1234ze (E).

Example

Comparative example 1

An air conditioning system according to a typical arrangement using R-410A as refrigerant operates according to the following parameters:

operating conditions-R410A basic cycle

1. Condensation temperature=45 ℃, corresponding outdoor ambient temperature=35℃

2. Condensation temperature-ambient temperature=10℃

3. Expansion device subcooling (sub-cooling) =5.0 DEG C

4. Evaporating temperature=7℃, corresponding indoor room temperature=27℃

5. Evaporator superheat = 5.0 °c

6. Isentropic efficiency = 72%

7. Volumetric efficiency = 100%

The capacity and COP of the system were determined and used as baseline values for determining the relative capacity and COP in the following examples.

Example 1A

Example 1A (FIG. 1) operating conditions

A system configured as illustrated herein in fig. 1 operates using a series of different first (outdoor) and second (indoor) refrigerants according to the following operating parameters:

2. Condensation temperature-ambient temperature=10℃

3. Expansion device subcooling = 5.0 °c

4. Evaporating temperature=7℃, corresponding indoor room temperature=27℃

5. Evaporator superheat = 0.0 ℃ (submerged)

6. Intermediate heat exchanger superheat = 5.0 °c

7. Isentropic efficiency = 72%

8. Volumetric efficiency = 100%

9. Difference in saturation temperature of intermediate heat exchanger = 5 °c

The results (the percentage of the mixture is shown in wt%) are provided in table 1A below.

TABLE 1A

As can be seen from the above results, each air conditioning system according to the present invention is able to provide an accurate capability of matching with existing R410A air conditioning systems operating as indicated and a COP (efficiency) of at least 85% in all cases with respect to such existing systems. Importantly, in all cases, the system uses refrigerants each having a GWP of less than 150, which improves by a factor of about 10 for R-410A based refrigeration systems. This combination of properties can be achieved, which is a highly beneficial but unexpected result.

Example 1B (FIG. 1) operating conditions

The system configured as illustrated herein in fig. 1 operates according to the same operating parameters using a series of different first (outdoor) and second (indoor) refrigerants, except that the condensing temperature is adjusted for each mixture in order to obtain an efficiency substantially matching that achieved according to comparative example 1. The results are provided in table 1B below.

Table 1B

The above results indicate that a system according to the present invention can be implemented with only relatively small changes in condenser temperature, which system yields an efficiency that substantially matches that of an R-410A based system. As an alternative, the efficiency according to the present method is preferably increased by slightly increasing the heat transfer area in the condenser compared to the amount of heat transfer area in a condenser using the comparative R-410A system without reducing or changing the comparative condenser temperature. Furthermore, the system using a suction line heat exchanger according to fig. 2 shows an advantageous improvement in efficiency even compared to the inventive arrangement without such a heat exchanger as reported in example 1A.

Example 1C (FIG. 1) -change of environmental Condition

The system configured as illustrated herein in fig. 1 was operated according to the same operating parameters as example 1A using a series of different first (outdoor) and second (indoor) refrigerants, except that the ambient temperature was adjusted to 35 ℃, 45 ℃ and 55 ℃ for each mixture. The results are provided in table 1C below.

Table 1C

The above results indicate that embodiments according to the present invention can provide superior performance compared to the R-410A system when the ambient temperature rises above 35 ℃.

Example 2A

Example 2A (FIG. 2) operating conditions

A system configured as illustrated herein in fig. 2 operates using a series of different first (outdoor) and second (indoor) refrigerants according to the following operating parameters:

2. Condensation temperature-ambient temperature=10℃

3. Expansion device subcooling = 5.0 °c

4. Evaporating temperature=7℃, corresponding indoor room temperature=27℃

5. Evaporator superheat = 0.0 ℃ (submerged)

6. Intermediate heat exchanger superheat = 5.0 °c

7. Isentropic efficiency = 72%

8. Volumetric efficiency = 100%

9. Difference in saturation temperature of intermediate heat exchanger = 5 °c

The results (the percentage of the mixture is shown in wt%) are provided in table 2A below.

Table 2A

As can be seen from the above results, each air conditioning system according to the present invention is able to provide an accurate capability of matching with existing R410A air conditioning systems operating as indicated and a COP (efficiency) of at least 90% in all cases with respect to such existing systems. Importantly, in all cases, the system uses refrigerants each having a GWP of less than 150, which improves by a factor of about 10 for R-410A based refrigeration systems. This combination of properties can be achieved, which is a highly beneficial but unexpected result.

Example 2B

Example 2B (FIG. 2) -change of condenser temperature

The system configured as illustrated herein in fig. 2 was operated according to the same operating parameters as example 2A using a series of different first (outdoor) and second (indoor) refrigerants except that the condensing temperature was adjusted for each mixture in order to obtain an efficiency substantially matching that achieved according to comparative example 1. The results are provided in table 2B below.

Table 2B

The above results indicate that a system according to the present invention can be implemented with only relatively small changes in condenser temperature, which system yields an efficiency that substantially matches that of an R-410A based system. As an alternative, the efficiency according to the present method is preferably increased by slightly increasing the heat transfer area in the condenser compared to the amount of heat transfer area in a condenser using the comparative R-410A system without reducing or changing the comparative condenser temperature.

Example 2C

Example 2C (FIG. 2) -change of environmental Condition

The system configured as illustrated herein in fig. 2 was operated according to the same operating parameters as example 2A using a series of different first (outdoor) and second (indoor) refrigerants, except that the ambient temperature was adjusted to 35 ℃, 45 ℃ and 55 ℃ for each mixture. The results are provided in table 2C below.

Table 2C

Example 3A

Example 3A (FIG. 3) operating conditions

The system configured as illustrated herein in fig. 3 operates according to the following operating parameters by using a series of different first (outdoor) and 100% transhfco-1233 zd as indoor refrigerants:

2. Condensation temperature-ambient temperature=10℃

3. Expansion device subcooling = 5.0 °c

4. Evaporating temperature=7℃, corresponding indoor room temperature=27℃

5. Evaporator superheat = 0.0 ℃ (submerged)

6. Intermediate heat exchanger superheat = 5.0 °c

7. Isentropic efficiency of the two stages=72%

8. Volumetric efficiency = 100%

9. Difference in saturation temperature of intermediate heat exchanger = 5 °c

10. Steam jet heat exchanger efficiency = 35%, 55%, 75%, 85%

The results (the percentage of the mixture is shown in wt%) are provided in table 3A below.

Table 3A

Example 3B

Example 3B (FIG. 3) -change in condenser temperature

The system configured as illustrated herein in fig. 3 operates according to the same operating parameters as example 3A by using a series of different first (outdoor) and 100% transhfco-1233 zd as indoor refrigerants, except that the condensing temperature is adjusted for each mixture in order to obtain an efficiency that substantially matches the efficiency achieved according to comparative example 1. The results are provided in table 3B below.

Table 3B

Example 3C

Example 3C (FIG. 3) -change of environmental Condition

The system configured as illustrated herein in fig. 3 was operated according to the same operating parameters as example 2A using a series of different first (outdoor) and second (indoor) refrigerants, except that the ambient temperature was adjusted to 35 ℃, 45 ℃ and 55 ℃ for each mixture. The results are provided in table 3C below.

Table 3C

Example 4

The air conditioning system of example 1 operates with indoor refrigerants including various binary mixtures of trans HCFO-1233zd and trans HFO-1234ze using evaporator temperatures in the range of from about-1 ℃ to about 10 ℃, which typically encompass condenser temperatures used in many important air conditioning systems. The results of the test are reported in table 4A below.

Table 4A

Applicants have found that a composition of at least about 50% by weight (as shown above in table 4) of transhfo-1234 ze allows the indoor circuit to operate at pressures greater than one atmosphere, thus avoiding the need for a purge system, while at the same time providing a system pressure low enough to allow for the use of relatively low cost vessels and conduits and/or advantageously avoiding refrigerant leaks that might otherwise occur in high pressure systems. Furthermore, the applicant has tested the flammability of transhfo-1234 ze/transhcfo-1233 zd, the fractional flammability of the mixture (which is related to the flammability of the refrigerant in case of leakage of the system) and reported the results of this work in table 4B below.

Table 4B

Based on the results reported in Table 4B above, the applicants have found that liquid mixtures having more than 67% by weight transHFO-1234 ze are flammable when measured according to the fractionation test conducted by ASTM 34, and that amounts of transHFO-1234 ze of less than about 50% by weight (that is, transHFCO-1233 zd greater than 50%) according to the results in Table 4A, are likely to generate negative system pressures.

Example 5 compatibility with plastics useful in Low pressure systems

The applicant has tested the stability of various plastic materials upon exposure to transhfco-1233 zd by: samples of various plastics were removed from transhfco-1233 zd by immersing them in the transhfco-1233 zd for up to two (2) weeks at ambient pressure conditions (about 24 ℃ -25 ℃) and allowing them to vent for up to 24 hours. The results are reported in table 5 below.

Table 5

As shown by the results in table 5 above, the average percent change in volume for each plastic material tested was less than 5%.

Example 6

The air conditioning system of example 1 operates under the following conditions: under this condition, there is an unintentional leak from the high temperature refrigerant (which is an A2L refrigerant) to the low temperature non-flammable refrigerant, including any of the preferred low temperature refrigerants of the present invention according to ASHRAE34, including: refrigerants including HFO-1234ze (E), HFCO-1233zd (E), and combinations of these. In this case, A2L (moderately flammable) refrigerant is mixed with non-flammable low temperature refrigerant in the event of an unintentional leak inside the intermediate heat exchanger. The resulting mixture of low temperature refrigerant (e.g., R1233zd (E)) and A2L refrigerant may eventually leak into the room. However, in many cases, there will be non-flammable materials leaking into the chamber. In certain embodiments, a hopper (accumulator) may be used in conjunction with appropriate control means to ensure that an appropriate charge ratio is maintained between the high side and the low side in order to ensure a non-flammable mixture. It may also be possible to incorporate in the present system a device or devices that are able to detect leaks of flammable refrigerant into the indoor loop and release all such refrigerant to the outside of the home. One such leak detection system is disclosed in U.S. application 15/400,891 filed on 1/6 in 2017 and provisional application 62/275,382 filed on 1/6 in 2016, each of which is incorporated herein by reference.

Table 6 shows the charge ratios that can prevent dangerous situations from occurring inside the residence in the event of a leakage event.

Table 6: leakage event in an intermediate heat exchanger

Comparative example 2

The reversible heat pump system according to a typical prior art arrangement using R-410A as refrigerant operates in a heating mode according to the following parameters:

operating conditions-R410A basic cycle

1. Condensation temperature=40 ℃, corresponding indoor room temperature=21.1℃

2. Condensation temperature-ambient temperature = 19 °c

3. Expansion device subcooling = 5.0 °c

4. Evaporating temperature=0 ℃, corresponding outdoor ambient temperature=8.3℃

5. Evaporator superheat = 5.0 °c

6. Isentropic efficiency = 72%

7. Volumetric efficiency = 100%

The capacity and COP of the system were determined and used as baseline values for determining the relative capacity and COP in examples 7A and 7B below in accordance with the present invention.

Example 7A

The system herein operates using a series of different first (outdoor) and second (indoor) refrigerants according to the following operating parameters:

2. Condensation temperature-ambient temperature = 19 °c

3. Expansion device subcooling = 5.0 °c

5. Evaporator superheat = 0.0 ℃ (submerged)

6. Intermediate heat exchanger superheat = 5.0 °c

7. Isentropic efficiency = 72%

8. Volumetric efficiency = 100%

9. Difference in saturation temperature of intermediate heat exchanger = 5 °c

The results (the percentage of the mixture is shown in wt%) are provided in table 7A below.

Table 7A

Example 7B (FIG. 5) operating conditions

The system configured as illustrated herein in fig. 5 operates according to the same operating parameters using a series of different first (outdoor) and second (indoor) refrigerants, except that the condensing temperature is adjusted for each mixture in order to obtain an efficiency substantially matching that achieved according to comparative example 2. The results are provided in table 7B below.

Table 7B

Claims

1. A refrigeration system for cooling or heating air of a space occupied by a human or for cooling or heating an item located in the space occupied by the human using air in the space occupied by the human, the system comprising:

(a) An outdoor refrigerant circuit comprising:

(i) An outdoor refrigerant having a GWP of less than about 500, the outdoor refrigerant flowing through at least a portion of the outdoor loop to reject heat from or absorb heat into the system, wherein at least the portion of the outdoor loop through which the outdoor refrigerant flows is not located within the space occupied by the human being;

(ii) A phase change heat exchanger;

(iii) A compressor providing a flow of vapor of the outdoor refrigerant; and

(iv) An intermediate heat exchanger in which at least a portion of the outdoor refrigerant stream absorbs or rejects heat; and

(b) An indoor refrigerant circuit comprising:

(i) An indoor refrigerant flowing through at least a portion of the indoor circuit to absorb heat from or reject heat to a space occupied by the human, wherein at least the portion of the indoor circuit through which the indoor refrigerant flows is located within the space occupied by the human, the indoor refrigerant comprising at least about 50% HCFO-1233zd (E) by weight and: (1) is non-flammable according to ASHRAE standards 34, and (2) has a professional exposure limit (OEL) of greater than 400 and is classified as class a according to ASHRAE standards 34, and (3) has a GWP of less than about 500; and

(ii) The intermediate heat exchanger of the outdoor refrigerant circuit, wherein the outdoor refrigerant flow absorbs heat from or rejects heat to the indoor refrigerant.

2. A refrigeration system for cooling air of a space occupied by a human being or for cooling an item located in the space occupied by the human being using air in the space occupied by the human being, the system comprising:

(a) A high temperature refrigerant circuit comprising:

(i) A high temperature refrigerant having a GWP of less than about 500, the high temperature refrigerant flowing through at least a portion of the high temperature loop to reject heat from the system, wherein at least the portion of the high temperature loop through which the high temperature refrigerant flows is not located within the space occupied by the human being;

(ii) A condenser providing at least a first condenser effluent stream comprising a liquid high temperature refrigerant stream at a first temperature;

(iii) An expansion valve fluidly connected to the liquid high temperature refrigerant stream from the condenser, and providing a high temperature refrigerant stream at a second temperature lower than the first temperature;

(iv) A compressor providing a vapor stream comprising at least a portion of the refrigerant flowing to the condenser; and

(v) An intermediate heat exchanger in which at least a portion of the high temperature refrigerant stream from the expansion valve absorbs heat and which produces a vapor stream comprising the high temperature refrigerant, the vapor stream from the intermediate heat exchanger being in fluid communication with an inlet of the compressor; and

(b) A cryogenic refrigerant circuit comprising:

(i) A cryogenic refrigerant flowing through at least a portion of the low pressure circuit so as to absorb heat from a space occupied by the human, wherein at least the portion of the cryogenic circuit through which cryogenic refrigerant flows is located within the space occupied by the human, the cryogenic refrigerant comprising at least about 50% by weight HCFO-1233zd (E) and: (1) is non-flammable according to ASHRAE standards 34, and (2) has a professional exposure limit (OEL) of greater than 400 and is classified as class a according to ASHRAE standards 34, and (3) has a GWP of less than about 500;

(ii) A hopper containing at least a portion of the cryogenic refrigerant in a liquid state;

(iii) An evaporator fluidly connected to the accumulator, the evaporator receiving liquid cryogenic refrigerant from the accumulator and producing therefrom a stream of cryogenic refrigerant in a vapor state; and

(iv) The intermediate heat exchanger of the high temperature refrigerant circuit, wherein the high temperature refrigerant stream from the expansion valve absorbs heat from the low temperature refrigerant vapor from the evaporator, the intermediate heat exchanger producing a liquid effluent stream comprising the low temperature refrigerant, the low temperature liquid effluent stream from the intermediate heat exchanger being in fluid communication with an inlet of the accumulator.

3. The refrigeration system of claim 2, wherein at least a portion of the liquid from the accumulator is transported to an inlet of the evaporator by a thermosiphon effect.

4. The refrigeration system of claim 2, wherein the high temperature refrigerant comprises up to about 22% by weight R-32.

5. The refrigeration system of claim 2, wherein the high temperature refrigerant comprises up to about 78% by weight R-1234ze or up to about 78% by weight R-1234yf.

6. The refrigeration system of claim 2, wherein the high temperature refrigerant comprises from about 10% to about 100% propane by weight.

7. The refrigeration system of claim 2, wherein the condenser operates at a temperature in a range from about 35 ℃ to about 70 ℃.

8. A refrigeration system for cooling air of a space occupied by a human being or for cooling an item located in the space occupied by the human being using air in the space occupied by the human being, the system comprising:

(a) A high temperature refrigerant circuit comprising:

(i) A high temperature refrigerant flowing through at least a portion of the high pressure circuit to reject heat from the system, wherein at least the portion of the high temperature circuit through which the high temperature refrigerant flows is not located within the space occupied by the human being;

(iv) A compressor providing a vapor stream comprising at least a portion of the refrigerant flowing to the condenser;

(v) An intermediate heat exchanger in which at least a portion of the high temperature refrigerant stream from the expansion valve absorbs heat and from which the intermediate heat exchanger produces a high Wen Liuchu stream comprising the high temperature refrigerant, the high temperature effluent stream being at a temperature greater than the temperature of the stream from the expansion valve; and

(vi) A suction line heat exchanger connected between the condenser and the expansion valve and between the intermediate heat exchanger and the compressor inlet such that: (1) The suction line heat exchanger receives at least a portion of the liquid high temperature refrigerant stream from the condenser, wherein heat is rejected from the liquid high temperature refrigerant stream prior to the stream entering the expansion valve; and (2) the suction line heat exchanger receiving at least a portion of the high temperature refrigerant exiting the intermediate heat exchanger and absorbing heat from the liquid high temperature refrigerant stream from the condenser, wherein the stream is in fluid communication with an inlet of the compressor after absorbing the heat;

and

(b) A cryogenic refrigerant circuit comprising:

(i) A cryogenic refrigerant flowing through at least a portion of the low pressure circuit so as to absorb heat from a space occupied by the human, wherein at least the portion of the cryogenic circuit through which cryogenic refrigerant flows is located within the space occupied by the human, the cryogenic refrigerant comprising at least about 50% by weight HCFO-1233zd (E) and: (1) is non-flammable according to ASHRAE standards 34, (2) has a professional exposure limit (OEL) of greater than 400 and is classified as class a according to ASHRAE standards 34, and (3) has a GWP of less than about 500;

9. The refrigeration system of claim 8, wherein the high temperature refrigerant comprises one or more of R-32, R-1234ze, R-1234yf, and propane.

10. The refrigeration system of claim 8, wherein the condenser operates at a temperature in a range from about 35 ℃ to about 70 ℃.

11. The refrigeration system of claim 2, further comprising: a sensor for detecting the high temperature refrigerant leaking into the low temperature refrigerant, and a low temperature refrigerant charge controller responsive to the sensor, wherein an additional amount of the low temperature refrigerant is charged into the low temperature refrigeration circuit to ensure that the low temperature refrigerant is maintained as non-flammable refrigerant.

12. A heat transfer fluid, comprising: lubricants, compatibilizers, surfactants and solubilizing agents for compressors.

13. A mixture, comprising: HFC-32, HFO-1234ze and propane.

14. A composition, comprising: a lubricant selected from the group consisting of polyol esters (POE) and polyalkylene glycols (PAGs), silicone oils, mineral oils, and poly (alpha-olefins) (PAOs).