Climate control system and method for operating climate control system

Abstract

The present invention relates to a climate control system and a method for operating a climate control system that circulates a refrigerant blend having a high slip (the difference in boiling point of each refrigerant at atmospheric pressure > = 25 DEG R (about 14K)), the climate control system comprising: a reservoir; a compressor; a first heat exchanger for at least partially condensing the refrigerant blend; a liquid suction heat exchanger disposed downstream of the first heat exchanger and upstream of the reservoir; a first expansion device; a receiver; a second expansion device; and a second heat exchanger that at least partially evaporates the refrigerant blend; and a fluid conduit. The concentration of the refrigerant blend may be controlled by adjusting the storage liquid level in the reservoir and receiver.

Description

Technical Field

[0001] The present disclosure relates to climate control systems for use with a working fluid having a refrigerant blend exhibiting high glide and methods for operating the climate control systems, and more particularly to climate control systems having a liquid suction heat exchanger, a accumulator, and a receiver for controlling refrigerant concentration. Background Art

[0002] This section provides background information related to the present disclosure which is not necessarily prior art.

[0003] Conventional thermodynamic climate control systems, such as heat pump systems, refrigeration systems, or air conditioning systems, for example, may include a fluid circuit having: a first heat exchanger (e.g., a condenser that facilitates a phase change of a refrigerant from a gas phase / vapor phase to a liquid), which is typically located outdoors; a second heat exchanger (e.g., an evaporator that facilitates a phase change of a refrigerant from a liquid to a gas phase / vapor phase), which is typically located indoors or within an environment to be cooled; an expansion device disposed between the first heat exchanger and the second heat exchanger; and a compressor that operates via a vapor compression cycle (VCC) to circulate and pressurize a gas phase / vapor phase refrigerant (and optional lubricating oil) between the first heat exchanger and the second heat exchanger (e.g., between the condenser and the evaporator). The compressor is typically a mechanical compressor for pressurizing a refrigerant, which may then be condensed and evaporated to transfer heat to or from the system as it circulates within the system.

[0004] Refrigeration and air conditioning applications are facing increasing regulatory pressure to reduce the global warming potential of the refrigerants they use. Some of the challenges of current climate control working media include meeting device suitability, environmental acceptability, and safety. For this reason, synthetic refrigerants are expected to be replaced by natural refrigerants in some vapor compression applications. In addition, in order to use lower global warming potential refrigerants, the flammability of the refrigerant may increase.

[0005] Several refrigerants have been developed that are considered low GWP options and have an ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) classification as A2 (relatively lower flammability compared to A3 refrigerants), A2L (slightly flammable / less flammable than A2 and A3 refrigerants and lower toxicity), or A1 (no flame propagation / lower toxicity level). Examples of A2 refrigerants include 1,1-difluoroethane (R-152A - as used herein, refrigerants may be described interchangeably by the conventional nomenclature "R" for refrigerants or their specific chemical class codes, such as HFC-152A) having a global warming potential of about 124, while examples of A2L refrigerants include difluoromethane (CH2F2 or R-32 - as used herein, refrigerants may be described interchangeably by the conventional nomenclature "R" for refrigerants or their specific chemical class codes, such as HFC-32) having a global warming potential of about 677, and hydrofluoroolefins (HFOs), such as 2,3,3,3,-tetrafluoroprop-1-ene (HFO-1234yf or R-1234yf), trans-1,3,3,3,-tetrafluoroprop-1-ene (HFO-1234ze or R-1234ze). A1 refrigerants include carbon dioxide (CO2 or R-744), which has a desirable low global warming potential of 1, 1-chloro-3,3,3-trifluoropropene (cis- and trans-HFO-1233zd(Z) or R-1233zd(Z) and HFO-1233zd(E) or R-1233zd(E)), monochlorodifluoromethane (R-22 or CHClF2), and R-410A, which is a near-azeotropic mixture of difluoromethane (HFC-32) and pentafluoroethane (HFC-125).

[0006] In particular, the heating, ventilation, air conditioning and refrigeration (HVAC / R) industry has been looking for A1 (non-toxic and non-flammable) refrigerants, including blends with such A1 refrigerants, that have high cooling capacity per displacement while desirably avoiding supercritical operation and subatmospheric pressures to achieve low-cost compression and piping while protecting the safety of equipment operators and users. Therefore, it would be desirable to adopt climate control systems that can successfully utilize such environmentally friendly refrigerants with low global warming potential. Summary of the invention

[0007] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0008] In certain aspects, the present disclosure relates to a climate control system that circulates a working fluid including a refrigerant blend having high slip. The climate control system may include a working fluid that includes a first refrigerant and a second refrigerant. In various aspects, the boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 25°R (about 14K) at atmospheric pressure. The climate control system also includes a accumulator and a compressor that receives a vapor flow of the working fluid from the accumulator and produces a pressurized vapor flow. The climate control system also includes a first heat exchanger disposed downstream of the compressor that receives the pressurized vapor flow and cools the pressurized vapor flow to produce a multiphase or liquid condensed flow of the working fluid. A liquid suction heat exchanger is disposed downstream of the first heat exchanger and upstream of the accumulator. A receiver is disposed downstream of the liquid suction heat exchanger. The climate control system also includes: a first expansion device, which is arranged between the liquid suction heat exchanger and the receiver, and processes the multiphase or liquid condensate flow from the liquid suction heat exchanger; and a second expansion device, which is arranged between the receiver and the second heat exchanger, and processes the multiphase or liquid condensate flow to reduce the pressure before the second heat exchanger to form a reduced pressure multiphase flow of the working fluid. The climate control system also includes a second heat exchanger, which receives the reduced pressure multiphase flow from the second expansion device and at least partially evaporates the reduced pressure multiphase flow to form an evaporation flow of the working fluid, which is then directed to the liquid suction heat exchanger and the reservoir. The fluid conduit circulates the working fluid and establishes fluid communication between the reservoir, the compressor, the first heat exchanger, the liquid suction heat exchanger, the first expansion device, the receiver, the second expansion device and the second heat exchanger, and the working fluid circulates through the fluid communication.

[0009] In certain aspects, a liquid suction heat exchanger receives a multiphase or liquid condensate stream from a first heat exchanger in a first flow direction and receives an evaporation stream from a second heat exchanger in a second flow direction to transfer heat between the multiphase or liquid condensate stream and the evaporation stream.

[0010] In some ways, the climate control system doesn't have any pumps.

[0011] In certain aspects, the climate control system further includes a liquid bypass line that diverts a portion of the working fluid exiting the receptor to the reservoir.

[0012] In certain other aspects, the liquid bypass line further includes a liquid metering valve.

[0013] In certain aspects, the climate control system includes a vapor bypass line that diverts a portion of the working fluid exiting the compressor into a receiver.

[0014] In certain aspects, the first refrigerant and the second refrigerant are selected from the group consisting of carbon dioxide (R-744), chlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), 1,1-difluoroethane (R-152A), dimethyl ether (R-E170), propane (R-290), 2,3,3,3,-tetrafluoropropane ... 1-ene (R-1234yf), cis- and trans-1,3,3,3,-tetrafluoropropene (HFO-1234ye), cis- and trans-1,3,3,3,-tetrafluoroprop-1-ene (R-1234ze), 3,3,3,-trifluoropropene (HFO-1234zf), trifluoromonochloropropene (HFO-1233), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)), cis-1-chloro-3,3 ,3-trifluoropropylene (HFO-1233zd(Z)), 2-chloro-3,3,3-trifluoropropylene (HFO-1233xf), trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E)), pentafluoropropylene (HFO-1225), 1,1,3,3,3-pentafluoropropylene (HFO-1 225zc), 1,2,3,3,3-pentafluoropropylene (HFO-1225yez), hexafluorobutene (HFO-1336), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), trans-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(E)), trans-1,2-difluoroethylene (R-1132(E)), and any isomers or combinations thereof.

[0015] In certain aspects, the first refrigerant comprises carbon dioxide (R-744) and the second refrigerant comprises a hydrofluoroolefin.

[0016] In certain aspects, the working fluid also includes a lubricant having a first solubility for the first refrigerant that is greater than a second solubility of the lubricant for the second refrigerant.

[0017] In certain other aspects, the present disclosure relates to a method for operating a climate control system that circulates a working fluid including a refrigerant blend having a high glide. The method includes pressurizing a vapor flow of the working fluid by passing the vapor flow of the working fluid through a compressor in a fluid conduit. At least a portion of the working fluid is condensed in a first heat exchanger disposed downstream of the compressor. The method also includes cooling the working fluid by passing the working fluid through a liquid suction heat exchanger in a first flow direction, and reducing the pressure of the working fluid by passing the working fluid through a first expansion device disposed downstream of the liquid suction heat exchanger and the first heat exchanger. The method includes allowing the working fluid from the first expansion device to enter a receiver, and then further reducing the pressure of the working fluid leaving the receiver by passing the working fluid leaving the receiver through a second expansion device disposed downstream of the receiver. The method also includes evaporating at least a portion of the working fluid in a second heat exchanger disposed downstream of the second expansion device, and heating the working fluid leaving the second heat exchanger by passing the working fluid leaving the second heat exchanger through the liquid suction heat exchanger in a second flow direction. The method includes passing a working fluid into a reservoir upstream of a compressor so that a vapor flow of the working fluid leaves the reservoir and enters the compressor, wherein the working fluid includes a refrigerant blend with high glide, the refrigerant blend including a first refrigerant and a second refrigerant, wherein the boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 25°R (about 14K) at atmospheric pressure.

[0018] In certain aspects, the method includes controlling the concentration of a first refrigerant and a second refrigerant in a refrigerant blend in a climate control system by: (i) adjusting a first storage amount of liquid in a receiver; (ii) adjusting a second storage amount of liquid in a reservoir; or (iii) performing both (i) and (ii).

[0019] In certain aspects, the first refrigerant has a first critical point that is lower than a second critical point of the second refrigerant, and the method includes controlling the concentration of the refrigerant blend in the climate control system by one or more of: (i) adjusting a first storage amount of the first refrigerant as a liquid in a receiver; (ii) adjusting a second storage amount of the second refrigerant as a liquid in a reservoir; or (iii) performing both (i) and (ii).

[0020] In certain aspects, the method includes controlling the concentration of a first refrigerant and a second refrigerant in a refrigerant blend in a climate control system by adjusting a storage amount of liquid in a reservoir.

[0021] In certain aspects, the working fluid exiting the second heat exchanger is heated by passing the working fluid exiting the second heat exchanger along a second flow direction through a liquid suction heat exchanger so that the working fluid is regulated to have a positive or negative superheat level when it enters the reservoir (before being pressurized in the compressor), wherein the superheat level regulates the storage amount of liquid in the reservoir.

[0022] In certain aspects, the method further includes diverting a portion of the working fluid exiting the receptor into a liquid bypass line that directs the portion of the working fluid into the reservoir.

[0023] In certain other aspects, the liquid bypass line further includes a liquid metering valve that regulates a flow rate of the working fluid in the liquid bypass line.

[0024] In certain aspects, the method also includes diverting a portion of the working fluid exiting the compressor into a steam bypass line that directs the portion of the working fluid into the receiver.

[0025] In certain aspects, the refrigerant blend with high glide limits the complete phase change of condensation, and the condensation only partially condenses the working fluid into a liquid phase and allows only a portion of the complete phase change to occur, so that after condensation, the second refrigerant is primarily liquid, and when the first refrigerant enters the liquid suction heat exchanger, a portion of the first refrigerant is liquid and a portion of the first refrigerant remains as a vapor.

[0026] In certain aspects, the refrigerant blend with high glide limits the complete phase change of evaporation, and the evaporation only partially evaporates the working fluid into the vapor phase and allows only a portion of the complete phase change to occur, so that after evaporation, the first refrigerant is a vapor, and when the second refrigerant enters the liquid suction heat exchanger, a portion of the second refrigerant is a vapor and a portion of the second refrigerant remains in a liquid state.

[0027] In certain aspects, condensation only partially condenses the working fluid into a liquid phase, and evaporation only partially evaporates the working fluid into a vapor phase.

[0028] In certain aspects, the first refrigerant and the second refrigerant are selected from the group consisting of carbon dioxide (R-744), chlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), 1,1-difluoroethane (R-152A), dimethyl ether (R-E170), propane (R-290), 2,3,3,3,-tetrafluoropropane ... 1-ene (R-1234yf), cis- and trans-1,3,3,3,-tetrafluoropropene (HFO-1234ye), cis- and trans-1,3,3,3,-tetrafluoroprop-1-ene (R-1234ze), 3,3,3,-trifluoropropene (HFO-1234zf), trifluoromonochloropropene (HFO-1233), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)), cis-1-chloro-3,3 ,3-trifluoropropylene (HFO-1233zd(Z)), 2-chloro-3,3,3-trifluoropropylene (HFO-1233xf), trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E)), pentafluoropropylene (HFO-1225), 1,1,3,3,3-pentafluoropropylene (HFO-1 225zc), 1,2,3,3,3-pentafluoropropylene (HFO-1225yez), hexafluorobutene (HFO-1336), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), trans-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(E)), trans-1,2-difluoroethylene (R-1132(E)), and any isomers or combinations thereof.

[0029] In certain aspects, the first flow direction and the second flow direction are countercurrent within the liquid suction heat exchanger.

[0030] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0032] Figure 1A schematic diagram of an example embodiment of a climate control system prepared according to certain aspects of the present disclosure for circulating a working fluid having a blended refrigerant exhibiting high glide, the climate control system including a liquid suction heat exchanger, a accumulator, and a receiver is shown.

[0033] Figure 2 A schematic diagram of another example embodiment of a climate control system prepared according to certain aspects of the present disclosure is shown, the climate control system for circulating a working fluid having a blended refrigerant exhibiting high glide, the climate control system including a liquid suction heat exchanger, a liquid reservoir, a receiver, and also including a liquid bypass line.

[0034] Figure 3 A schematic diagram of yet another example embodiment of a climate control system prepared according to certain aspects of the present disclosure is shown, the climate control system for circulating a working fluid having a blended refrigerant exhibiting high glide, the climate control system including a liquid suction heat exchanger, a accumulator, a receiver, and also including a vapor bypass line.

[0035] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0036] These exemplary embodiments are provided so that the present disclosure will be thorough and will fully convey the scope to those skilled in the art. Many specific details, such as examples of specific compositions, parts, devices and methods, are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be implemented in many different forms, and none of these should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0037] The terms used herein are only used for the purpose of describing specific example embodiments and are not intended to be restrictive. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "a kind of" and "the" may also be intended to include plural forms. The terms "include", "comprise", "include", "contain" and "have" are inclusive, and therefore specify the presence of the features, elements, compositions, steps, wholes, operations and / or parts, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, parts and / or their groups. Although the open term "include" should be understood as a non-limiting term for describing and requiring the various embodiments set forth herein, in some respects, the term may alternatively be understood as a more restrictive and constraining term, such as "consisting of" or "consisting essentially of". Thus, for any given embodiment reciting ingredients, materials, parts, elements, features, integers, operations, and / or process steps, the present disclosure also specifically includes embodiments consisting of, or consisting essentially of, such recited ingredients, materials, parts, elements, features, integers, operations, and / or process steps. In the case of "consisting of," alternative embodiments exclude any additional ingredients, materials, parts, elements, features, integers, operations, and / or process steps, while in the case of "consisting essentially of," any additional ingredients, materials, parts, elements, features, integers, operations, and / or process steps that materially affect the basic and novel characteristics are excluded from such embodiments, but any ingredients, materials, parts, elements, features, integers, operations, and / or process steps that do not materially affect the basic and novel characteristics may be included in the embodiments.

[0038] Unless specifically identified as an order of performance, any method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order discussed or illustrated. It should also be understood that additional or alternative steps may be employed unless otherwise specified.

[0039] When a part, element, or layer is considered to be "on," "engaged to," "connected to," or "coupled to" another element or layer, the part, element, or layer may be directly on, engaged, connected, or coupled to another part, element, or layer, or there may be intermediate elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in the same manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] Although the term first, second, third, etc. can be used to describe different steps, elements, components, regions, layers and / or parts in this article, unless otherwise stated, these steps, elements, components, regions, layers and / or parts should not be limited by these terms. These terms can only be used to distinguish a step, element, component, region, layer or part from another step, element, component, region, layer or part. Unless clearly indicated by the context, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, the first step, the first element, the first component, the first area, the first layer or the first part discussed below can be referred to as the second step, the second element, the second component, the second area, the second layer or the second part without departing from the teaching of exemplary embodiments.

[0041] Spatially or temporally relative terms, such as "before," "after," "inside," "outside," "under," "below," "below," "above," "over," etc., may be used herein to simplify the description of the relationship of one element or feature to another element or feature as illustrated in the drawings. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the drawings.

[0042] Throughout this disclosure, numerical values ​​represent approximate measurements or limits of ranges to cover minor deviations from a given value as well as embodiments having approximately the value mentioned and embodiments having exactly the value mentioned. Except in the working examples provided at the end of the detailed description, all numerical values ​​of parameters (e.g., quantities or conditions) in this specification, including the appended claims, should be understood to be modified by the term "about" in all cases, regardless of whether "about" actually appears before the numerical value. "About" indicates that the numerical value allows some slight imprecision (the accuracy of the value is achieved in some way; approximately or reasonably close to the value; almost equal to the value). If the imprecision provided by "about" cannot be understood as this ordinary meaning in the art, the "about" used herein at least indicates the variation that may be caused by the ordinary methods of measuring and using such parameters. For example, "about" can include the following variations: less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and optionally less than or equal to 0.1% in some aspects.

[0043] Additionally, disclosure of ranges includes disclosure of all values ​​within the entire range and further divided ranges, including endpoints and sub-ranges given for the ranges.

[0044] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0045] In various aspects, the present disclosure relates to a climate control system and a method of operating such a system, the climate control system providing the ability to use a working fluid having a refrigerant blend that exhibits extreme glide during operation. In various aspects, the present disclosure contemplates a climate control system, such as a heating, ventilation, air conditioning and refrigeration (HVAC / R) system, that is capable of using a refrigerant blend of different refrigerants having significantly different critical temperatures, wherein the concentration of the respective refrigerants in the system varies. In the case of utilizing such extreme glide, the climate control system can advantageously perform capacity modulation. In certain aspects of the present disclosure, a "working fluid" composition for a refrigeration system used by a heat transfer device, such as a compressor, comprises a blend of at least two refrigerants. Certain refrigerant blends may be subject to fractionation and high glide, which are traditionally considered to be problems to be avoided in climate control systems. Many refrigerant blends exhibit temperature glide when they undergo phase changes in both the evaporator and the condenser. As described above, in the evaporator, the refrigerant evaporates or undergoes a phase change from liquid to vapor. In the condenser, the refrigerant condenses or undergoes a phase change from vapor to liquid. Refrigerant blends exhibit temperature glide because there are multiple refrigerant molecules with different properties. When these refrigerant blends change phase (evaporation and condensation), changes in the refrigerant blend composition are observed due to the preferential evaporation or condensation of the more volatile or less volatile refrigerant components (also known as high-pressure and low-pressure refrigerants) in the refrigerant blend. This process is called blend fractionation. Therefore, the total temperature glide of the refrigerant blend can be defined as the temperature difference between the saturated vapor temperature and the saturated liquid temperature at constant pressure. In other words, glide can be considered as the temperature difference between the start temperature and the end temperature of the refrigerant phase change in the system at constant pressure.

[0046] Thus, in some aspects, the concentration of the refrigerant blend in the system can be changed by changing (i) the storage amount of the high critical point rich blend as a liquid in the reservoir or (ii) the storage amount of the low critical point rich blend as a liquid in the receiver. For example, in some aspects, the use of superheat and subcooling close to the compressor provides control over the change of the liquid storage amount / liquid level in the reservoir. In some variations, because the refrigerant blend has a high glide that tends to have a high vapor quality, when the blend includes multiple low critical point fluids, the system includes a heat exchanger (e.g., a liquid suction heat exchanger) to limit the glide operation in the evaporator and to subcool the temperature of the high pressure liquid leaving the evaporator.

[0047] The working fluid may be modified during operation by further adding a lubricant having a preferential affinity, such as a greater solubility, for at least one of the refrigerants to change the concentration of the refrigerant blend circulating in the system. Working fluids for refrigeration systems typically include a small amount of a lubricant composition, wherein the lubricant and refrigerant are combined in amounts such that there is relatively more refrigerant than lubricant in the lubricant-refrigerant composition.

[0048] Based on the combined weight of the lubricant and the refrigerant, the refrigerant is greater than or equal to about 50% of the combined weight by weight, and the lubricant is less than or equal to about 50% of the combined weight by weight. In various embodiments, the lubricating oil is greater than or equal to about 1% to less than or equal to about 30% of the combined weight of the lubricant and the high-energy refrigerant by weight, and is greater than or equal to about 5% to less than or equal to about 20% of the combined weight of the working fluid by weight. Typically, the working fluid includes greater than or equal to about 5% by weight to less than or equal to about 20% by weight, or optionally greater than or equal to about 5% by weight to less than or equal to about 15% by weight of the lubricant, and the balance is the refrigerant. In the context of the present disclosure, the working fluid may include at least two different refrigerants that form a blend of the refrigerant composition.

[0049] In the context of certain aspects of the current technology, a working fluid having a high glide refrigerant blend is intentionally counterintuitively selected. As will be described herein, the respective refrigerants in the refrigerant blend can be selected for environmental characteristics, such as global warming potential, avoidance of decomposition products of trifluoroacetic acid (TFA) or other perfluoroalkyl substances (PFAS), or for their ability to outperform conventional refrigerants in terms of energy efficiency. Thus, the high glide refrigerant blend can include an environmentally friendly refrigerant (e.g., including one or more Al refrigerants). In certain aspects, the refrigerant blend can include a first refrigerant having a relatively low normal boiling point (also referred to herein as a high pressure or low critical point refrigerant) and a second refrigerant having a relatively high normal boiling point (also referred to herein as a low pressure or high critical point refrigerant).

[0050] In some aspects, the first refrigerant can have a first (low) boiling point of greater than or equal to about -270°C to less than or equal to about 8°C. Thus, the low boiling point refrigerant can have a boiling point in the range of -267°C for hydrogen to 7.5°C for R-1336mzz (E). In some aspects, the second refrigerant can have a second (high) boiling point of greater than or equal to about -55°C to less than or equal to about 100°C. For example, the range of high boiling point refrigerants can be from about -52°C R-32 to 100°C water (H2O). As will be understood by those skilled in the art, the refrigerant components are selected to form a blend that meets the goals of the system in the application. Different blends can be selected for use in low temperature applications, low temperature refrigeration, medium temperature refrigeration, air conditioning, and cooling applications for different processes, etc.

[0051] Thus, the working fluid may include a first refrigerant and a second refrigerant having a normal boiling point difference (e.g., ΔT = first refrigerant boiling point (BP1) - second refrigerant boiling point (BP2)) greater than or equal to about 25°R (about 14°K) at atmospheric pressure. The first refrigerant and the second refrigerant may be selected for various properties including respective normal boiling points, glide efficiency, global warming potential, environmental impact, such as polyfluoroalkyl substances (PFAS) impact, capacity, pressure, safety, etc. In certain aspects, the normal boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 50°R (28K) at atmospheric pressure, optionally greater than or equal to about 75°R (42K), optionally greater than or equal to about 100°R (55K), optionally greater than or equal to about 125°F (69K), and in certain aspects, optionally greater than or equal to about 150°R (83K).

[0052] By way of example, the present disclosure contemplates employing a refrigerant blend including at least one refrigerant having a low global warming potential, such as ASHRAE classified A1, A2, and A2L refrigerants. In certain aspects, the refrigerant blend includes an A1 refrigerant. As described above, examples of A1 refrigerants include: carbon dioxide (R-744); monochlorodifluoromethane (R-22); 1,1,1,2-tetrafluoroethane (R-134A); and R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)); and trifluoro, monochloropropylene (R-1233), including cis- and trans-1-chloro-3,3,3-trifluoropropylene (HFO-1233zd) isomers (HFO-1233zd(Z) and HFO-1233zd(E)); and hexafluorobutene (HFO-1336, including HFO-1336mzz(Z), 1336mzz(E)). In certain aspects, the refrigerant blend includes an A2 refrigerant. As described above, examples of A2 refrigerants include 1,1-difluoroethane (R-152A). Many suitable HFO refrigerants are described in U.S. Pat. No. 4,788,352 to Smutny and U.S. Pat. No. 8,444,874 to Singh et al., the relevant portions of which are incorporated herein by reference. HFOs may include 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf) and trans-1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze). Non-limiting suitable examples of specific HFO refrigerants include: 3,3,3,-trifluoropropylene (HFO-1234zf); HFO-1234 refrigerants, such as 2,3,3,3,-tetrafluoropropylene (HFO-1234yf), 1,2,3,3,-tetrafluoropropylene (HFO-1234ze), cis- and trans-1,3,3,3,-tetrafluoropropylene (HFO-1234ye); pentafluoropropylene (HFO-1225), such as 1,1,3,3,3, pentafluoropropylene (HFO-1225zc); hexafluorobutene (HFO-1336), such as cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz -Z) and trans-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(E)); or those with hydrogen on the terminal unsaturated carbon, such as 1,2,3,3,3, pentafluoropropylene (HFO-1225yez); fluorochloropropylenes, such as trifluoro, monochloropropylene (HFO-1233), such as CF3CCl=CH2 (HFO-1233xf) and CF3CH=CHCl (HFO-1233zd) (including trans (E) and cis (Z) isomers (HFO-1233zd(E) and HFO-1233zd(Z)), (E)-1,2-difluoroethylene (R-1132(E)); and any combination thereof.In certain aspects, the HFO refrigerant can be selected from the group consisting of R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z), R-1336mzz(Z), R-1336mzz(E), R-1132(E), and combinations thereof.

[0053] According to certain variations, at least one refrigerant in the working fluid refrigerant blend used with the present technology may include a refrigerant selected from the group consisting of: R-744, R-22, R-134A, R-410A, R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z), R-1336mzz(Z), R-1336mzz(E), R-152A and combinations thereof.

[0054] In certain aspects, the first refrigerant and the second refrigerant are independently selected from the group consisting of: carbon dioxide (R-744), monochlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near-azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), dimethyl ether (R-E170), difluoromethane (R-32), hydrofluoroolefins (HFO), dimethyl ether (R-E170), propane (R-290), 1,1-difluoroethane (R-152A), and combinations thereof.

[0055] The refrigerant may be used in combination with other A1, A2 or A2L refrigerants or yet other refrigerants such as A3 or B1 or B2 refrigerants, including natural or flammable refrigerants such as dimethyl ether (R-E170), propane (C3H8 or R-290).

[0056] In certain variations, the first refrigerant is selected from the group consisting of carbon dioxide (R-744), monochlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), dimethyl ether (R-E170), difluoromethane (R-32), hydrofluoroolefins (HFO), and combinations thereof, and the second refrigerant is selected from the group consisting of: 2,3,3,3,-tetrafluoroprop-1-ene (R-1234yf), 1,3,3,3,-tetrafluoroprop-1-ene (R-1234ze), 1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E), 1-chloro-3,3,3-trifluoropropene (HFO-1233zd(Z), HFO-1233zd(Z)), 1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz) and combinations thereof.

[0057] In some aspects, the refrigerant blend includes an A1 refrigerant mixed with at least one other refrigerant, such as carbon dioxide (R-744). Carbon dioxide refrigerants are ideally used in subcritical system designs. An example of a suitable non-limiting refrigerant blend includes CO2 (R-744) as a more volatile high-pressure refrigerant mixed with R-1234yf as a less volatile low-pressure fluid. In such an example, the refrigerant blend has a first refrigerant including CO2 and a second refrigerant including R-1234yf, the normal boiling point of CO2 (at a pressure of 1 atmosphere (atm)) being about -78°C, and the normal boiling point of R-1234yf at a pressure of 1atm being about -29°C, so that the boiling point difference is about 88°R (49K).

[0058] In another variation, the refrigerant blend may include an A1 refrigerant, such as CO2 (R-744), mixed with a flammable refrigerant (ASHRAE 34A3 class), such as propane (C3H8 or R-290) or dimethyl ether (R-E170). In this example, the refrigerant blend has a first refrigerant including CO2, which has a normal boiling point of about -78°C, and a second refrigerant including R-E170, which has a normal boiling point of about -24°C, such that the boiling point difference is about 97.2°R (54K). As further described below, the climate control system can maintain a proportion of the A1 refrigerant to limit the amount of flammable refrigerant on the indoor side of the system to a safe level.

[0059] Although the amount of refrigerant present in the working fluid may vary at different points in the system and may be based on specific system requirements, in some variations, the working fluid charged into the system may include a first refrigerant and a second refrigerant, the first refrigerant being a more volatile high pressure / low critical point refrigerant present at about 5% by weight or more to about 95% by weight or less, and the second refrigerant being a less volatile low pressure / high critical point refrigerant present at about 5% by weight or more to about 95% by weight or less based on the combined weight of all refrigerants. In one example, the working fluid does not need to have a large amount of a fluid with a lower critical point, i.e., a second refrigerant, blended with the first refrigerant, such as CO2 (R-744), to advantageously keep CO2 out of a transcritical operating state. In some variations, the first refrigerant may be a more volatile high pressure refrigerant present at about 50% by weight or more, and the second refrigerant may be a less volatile low pressure refrigerant present at about 50% by weight or less based on the combined weight of all refrigerants.

[0060] In this way, fractionation can be a phenomenon that enables variable blending of refrigerants, such that fractionation can be used, for example, in climate control systems by using heat exchangers (e.g., evaporators and condensers) and / or storage vessels to separate the stream into different concentrations. Thus, the refrigerant stream may only be allowed to undergo a small portion of the phase change in each heat exchanger, and only experience a portion of the total glide in the partial phase change.

[0061] As will be described in more detail below, it is conceivable that known refrigeration lubricants suitable for use with this refrigerant are used. The working fluid may include synthetic oils. In some variations, lubricants may include polyvinyl ether (PVE) oils, polyalphaolefins (PAO), polyalkylene glycols (PAG), alkylbenzenes, mineral oils, or ester-based oils such as polyol esters (POE) oils. In some variations, for example, lubricants may include polyol esters (POE) compounds formed by carboxylic acids and polyols. In some variations, this POE may be formed by carboxylic acids selected from the group comprising n-pentanoic acid, 2-methylbutyric acid, n-hexanoic acid, n-heptanoic acid, 3,3,5-trimethylhexanoic acid, 2-ethylhexanoic acid, n-octanoic acid, n-nonanoic acid and isononanoic acid and combinations thereof, and by polyols selected from the group comprising pentaerythritol, dipentaerythritol, neopentyl glycol, trimethyl propanol and combinations thereof. In the case of carbon dioxide (R-744) in the refrigerant blend, in some variations, lubricants may include polyol esters (POE) oils. For example, one particularly suitable lubricating oil is a polyol ester oil designated 3MAF, which is the reaction product of a polyol of pentaerythritol (nominally about 78% to 91%) and dipentaerythritol (nominally about 9% to 22%) with carboxylic acids (nominally 29% to 34% valeric acid, nominally 34% to 44% heptanoic acid, and nominally 22% to 37% 3,5,5-trimethylhexanoic acid).

[0062] In various aspects, the climate control systems contemplated by the present disclosure provide the ability to use the extreme glide characteristics of refrigerant blends during operation, which allows the components to be isolated and stored in a concentrated state and then the blend concentration at the compressor suction inlet can be varied to enable, for example, high density gas compression for increased capacity and variable density gas compression for system capacity modulation.

[0063] In certain aspects, methods of operating a climate control system may include using such a working fluid comprising at least a first refrigerant and a different second refrigerant, wherein evaporation and condensation of the refrigerant blend / working fluid is only partial, thereby producing a dedicated vapor compression cooling cycle / vapor compression heating cycle.

[0064] Certain aspects of the present disclosure contemplate a conventional thermodynamic climate control system, such as a heat pump system, a refrigeration system, or an air conditioning system, configured to use a high glide refrigerant blend. In various aspects, the present disclosure relates to climate control systems for a variety of refrigeration and thermal energy transfer applications, in some cases, to industrial or commercial air conditioning units or refrigeration units, such as for factories, office buildings, apartment buildings, warehouses, and skating rinks, or for retail air conditioning units or refrigeration units.

[0065] Figure 1 A variation of a vapor compression system 20 prepared according to certain aspects of the present disclosure is shown. This system is similar to a typical vapor compression circuit, and its main components include an evaporator, a condenser, and a compressor. However, as described herein, additional components in the system include a reservoir, a liquid suction heat exchanger, a receiver, and at least one expansion valve, which provide the ability to utilize a high-slip refrigerant blend in a working fluid as described herein. For example, in a vapor compression system, the refrigerant blend in the working fluid is processed by changing the mass of the liquid refrigerant in the reservoir and the receiver (or other container). Therefore, the vapor compression system provides the ability to change the refrigerant blend by changing the mass of the liquid refrigerant in the reservoir and the receiver (or other container). In addition, superheating and subcooling the working fluid flow close to the compressor is used to intentionally drive the liquid level change of the selected refrigerant in the reservoir. In order to reduce the liquid level of the liquid in the receiver, a condenser and a liquid suction heat exchanger bypass for exhausting gas / steam can be used. Alternatively, allowing a higher supercooling at the inlet or inlet to the receiver will increase the liquid level in the receiver. In other variations, a liquid bypass may be used to direct at least a portion of the liquid of the refrigerant blend into the accumulator and thereby avoid the evaporator and the liquid suction heat exchanger.

[0066] By way of example, Figure 1 A schematic diagram of an example of a simplified climate control system 20, such as a refrigeration system, that processes and circulates a working fluid, the composition of which includes at least a first refrigerant (A) and a second refrigerant (B) exhibiting high glide. The capacity of the climate control system 20 can be adjusted by changing the relative proportions of the first refrigerant (A) and the second refrigerant (B) in the working fluid blend at different points in the system. Thus, the resulting compressor suction density is changed by preferentially storing concentrated amounts of the first refrigerant (A) or the second refrigerant (B) in one or more selected areas of the system. In certain aspects, the present disclosure provides a vapor compression system that can be configured to cause incomplete evaporation and incomplete condensation of a refrigerant.

[0067] As described above, there may be more than two refrigerants, but for simplicity, two refrigerants are used in this example, and the boiling point difference between the first refrigerant (A) and the second refrigerant (B) is greater than or equal to about 25°R at atmospheric pressure. As will be described in more detail below, at certain points in the system, the working fluid may also include oil. The term "fluid" as used herein encompasses liquids, gases, and any combination thereof, including vapor (e.g., a gas phase with atomized droplets). The term gas or gas phase as used herein is intended to encompass both vapor phases and pure gas phases.

[0068] The climate control system 20 has a fluid flow path or fluid conduit 22 that establishes fluid communication between various components so that the working fluid can be circulated in a loop as further discussed herein. First, a working fluid including a first refrigerant (A) and a second refrigerant (B) can enter a first heat exchanger in the form of an evaporator 40. When the first refrigerant (A) and / or the second refrigerant (B) leave the evaporator 40 at point 30, the evaporator 40 converts the first refrigerant (A) and / or the second refrigerant (B) from a liquid phase to a gas phase or a vapor phase, wherein a cooling effect of heat absorption energy absorption occurs. Refrigerants usually evaporate at a relatively low pressure and recover heat from the surrounding area. The air flowing through the evaporator 40 is shown by arrows, and the air is cooled. As shown, the air flows in a countercurrent arrangement, but a downstream configuration or other air flow configurations may also be used. The heat exchanger (the evaporator 40 and the condenser 62 discussed below) may include concentric finned tubes, brazing plates, plates and frames, microchannels or other heat exchangers. There may be a single evaporator and condenser, or there may be multiple evaporators or condensers in a parallel configuration or a series configuration. The refrigerant flow therein may be controlled via capillary tubes, thermal expansion valves, electronic expansion valves, or other methods. In a heat pump system, the role of the evaporator 40 and condenser 62 may be changed based on whether heating or cooling of the space is being performed.

[0069] The evaporator 40 may be located in a room or space to be cooled by the climate control system 20, or may be used to cool air flowing into a room or space desired to be cooled. Thus, the evaporator 40 receives and at least partially evaporates a low-pressure multiphase working fluid at point 39, and directs the working fluid to a downstream liquid suction heat exchanger 42 after point 30. More specifically, the low-pressure multiphase working fluid passes within a first side 42A of the liquid suction heat exchanger 42 in a first flow direction indicated by an arrow.

[0070] At point 30 in the fluid conduit 22, the working fluid includes a combination of the first refrigerant (A) and the second refrigerant (B) that are partially or completely in the gas phase. The working fluid at point 30 can be a multiphase composition. As described above, one aspect of the present technology is that the working fluid including a refrigerant blend having the first refrigerant (A) and the second refrigerant (B) can be only partially evaporated to form a mixture of both gas / vapor and liquid. For example, the first refrigerant (A) can have a lower boiling point / lower critical point and is therefore more volatile, so that a large amount of the first refrigerant (A) is volatilized or evaporated, while the second refrigerant (B) has a higher boiling point / higher critical point, and therefore a smaller proportion of the second refrigerant (B) is evaporated or volatilized in the working fluid, and therefore a larger proportion of the second refrigerant remains in liquid form. By way of example, depending on the amount of liquid evaporated, the vapor quality or vapor mass fraction of the working fluid at point 30 leaving the evaporator can be predetermined to any amount, by way of non-limiting example, such as a vapor quality greater than or equal to about 15% to about 100%.

[0071] Thus, a portion of the working fluid in the conduit 22 at point 30 may include the second refrigerant (B) in liquid form. The working fluid enters the first side 42A of the liquid suction heat exchanger 42 along a first flow direction, and heat will be transferred as a different working fluid stream passes along a second flow direction of the second side 42B of the liquid suction heat exchanger 42. The first flow direction and the second flow direction of the working fluid stream within the liquid suction heat exchanger 42 may be a countercurrent heat transfer relationship, a parallel flow heat transfer relationship, etc.

[0072] Typically, the liquid suction heat exchanger 42 transfers heat between the relatively hot condensed liquid leaving the condenser 62 and the cooler two-phase fluid leaving the evaporator 40. More specifically, the hotter condensed liquid can increase the temperature and vapor quality of the flow leaving the evaporator in the liquid suction heat exchanger to provide a condensed effluent with a higher level of subcooling (or a lower temperature and a lower vapor quality), thereby increasing the capacity of the evaporator. Therefore, the liquid suction heat exchanger 42 can provide certain advantages in the climate control system 20, including further cooling the liquid refrigerant before it enters the evaporator 40, thereby improving system efficiency, reducing flash evaporation that may occur in the liquid line, and enabling the expansion valve to operate with higher stability. In this way, the partially evaporated refrigerant is further evaporated by heat transfer with a slightly warmer partially condensed (or subcooled) refrigerant from the same cycle. In addition, in some variations, the suction to the liquid suction heat exchanger 42 does not superheat the suction gas.

[0073] In certain aspects, the amount of heat transferred by the liquid suction heat exchanger 42 is represented by the temperature difference (ΔT) between the first temperature ( T1 ) of the working fluid at point 36 and the second temperature ( T2 ) of the working fluid at point 30 . In some embodiments, the difference between the first temperature (T1) at point 36 and the second temperature (T2) at point 30 can be greater than or equal to about 5K (or 9°R, wherein the second temperature T2 is at least about 5K lower than the first temperature T1), optionally greater than or equal to about 10K (18°R), optionally greater than or equal to about 15K (27°R), optionally greater than or equal to about 20K (36°R), optionally greater than or equal to about 30K (54°R), optionally greater than or equal to about 40K, optionally greater than or equal to about 50K (90°R), optionally greater than or equal to about 60K (108°R), optionally greater than or equal to about 70K (126°R), optionally greater than or equal to about 80K (144°R), optionally greater than or equal to about 90K (162°R), and in some embodiments, optionally greater than or equal to about 100K (180°R).

[0074] After leaving the first side 42A of the liquid suction heat exchanger 42, the working flow can be in a near-saturated vapor condition and enter a storage container or tank in the form of a accumulator 44 that receives a working fluid that can include both gas phase and liquid phase. More specifically, the vapor phase of the working fluid in the accumulator 44 includes a gas phase refrigerant or a vapor phase refrigerant, which generally includes a more volatile / low critical point first refrigerant (A) and optionally a portion of a second refrigerant (B) with lower volatility / high critical point, depending on the desired operating conditions. The liquid phase can include the second refrigerant (B) in the liquid phase, for example, in some variations, most of the liquid phase in the liquid phase can be the second refrigerant (B). As described below, the accumulator 44 stores or holds liquid phase refrigerant, and the saturated vapor refrigerant returns to the compressor 50. In some aspects, the accumulator 44 can be sized based on the suction volume flow rate and how much refrigerant can be stored therein. The liquid level of the accumulator 44 can be adjusted by raising or lowering as follows. Superheat can drive the change of the liquid level. For example, heating of the working fluid exiting the liquid suction heat exchanger regulates the working fluid to have a positive superheat level or a negative superheat level when it enters the compressor during condensation, wherein the superheat level regulates the storage amount of liquid in the reservoir 44. With high glide of refrigerant, a measurable negative refrigerant would describe the state of liquid being added to the reservoir 44. Positive superheat would cause refrigerant to boil / evaporate from the reservoir 44 into the suction flow stream (e.g., at point 32), thereby reducing the liquid stored in the reservoir.

[0075] The working fluid stream leaving the accumulator 44 at point 32 may be mainly or completely in the vapor phase, and is therefore referred to as a vapor stream, which enters a compressor 50, where it is compressed to increase the pressure and form a high-pressure vapor or gas stream 34 leaving the compressor 50. The compressor 50 may be a variety of different compressors known in the art. The types of compressors used for the above-mentioned applications can be divided into two major categories, namely positive displacement compressors and dynamic compressors. Positive displacement compressors increase the refrigerant vapor pressure by reducing the volume of the compression chamber by doing work to the compressor mechanism. Positive displacement compressors include various types of compressors currently in use, such as reciprocating compressors, rotary (rolling piston, rotary vane, single screw, twin screw) compressors, and dynamic (scroll or cycloidal) compressors. Dynamic compressors increase the refrigerant vapor pressure by continuously transferring kinetic energy to the vapor in a compression mechanism in the form of a rotating member, and then converting this energy into a pressure rise. Centrifugal compressors work based on these principles. Details of the design and function of these compressors for refrigeration applications can be found in Chapter 37 of the 2010 ASHRAE Handbook, HVAC systems and Equipment, which is incorporated herein by reference. In some variations, by way of example, the compressor 50 can be a scroll compressor or a reciprocating compressor.

[0076] The pressure of the high pressure gas stream 34 or pressurized gas stream 34 of the working fluid exiting the compressor 50 is significantly greater than the pressure of the vapor stream 32. The mechanical energy required to compress the vapor and pump the fluid in the compression mechanism of the compressor is provided by, for example, an electric motor or an internal combustion engine. Notably, in certain aspects, the climate control system 20 provides modulation capability by varying the density of the refrigerant in the working fluid at the inlet of the compressor 50 without requiring conventional compressor modulation techniques.

[0077] The condenser 62 is thus disposed downstream of the compressor 50 and thus receives and cools the pressurized gas stream 34 at the condenser inlet 60 and can produce a multiphase condensed stream 36 of a working fluid. Thus, the working fluid enters the inlet 60 of the condenser 62 as a gas and is partially or completely condensed into a nearly saturated liquid when the working fluid leaves the condenser 62 at point 36. By way of non-limiting example, the vapor mass or vapor mass fraction of the working fluid (liquid stream at point 36) leaving the condenser 62 can be an amount in the range of 0% to less than or equal to about 25% vapor mass, such as 10% vapor mass, optionally 5% vapor mass, optionally 1% vapor mass, etc.

[0078] In the condenser 62, the pressurized gas flow 34 is converted from a vapor phase to a liquid phase (e.g., the first refrigerant (A) is converted from a vapor to a liquid). In the condenser 62, the working fluid is cooled by condensation, which causes heat to be discharged from the climate control system 20, as shown by the arrows reflecting the airflow. The condenser 62 can be located in a room or space where heat can be discharged, such as outdoors. As described above, one aspect of the present technology is that the working fluid including a refrigerant blend having a first refrigerant (A) and a second refrigerant (B) can be only partially condensed to form a multiphase mixture of both a liquid and an optional gas / vapor.

[0079] After passing through the condenser 62, the working fluid is a high-pressure liquid stream 36. The high-pressure liquid stream 36 of the working fluid enters the second side 42B of the liquid suction heat exchanger 42 along the second flow direction, and heat will be transferred along the first flow direction in the first side 42A of the liquid suction heat exchanger 42 with different working fluid streams, wherein the heat transfer relationship is as described above. As shown, the second flow direction is indicated by an arrow and is in a countercurrent heat exchange configuration with the first flow direction. Therefore, the working fluid leaving the condenser 62 can be a nearly saturated liquid or a saturated liquid, which is completely condensed and supercooled in the liquid suction heat exchanger 42.

[0080] After leaving the second side 42B of the liquid suction heat exchanger 42, the working fluid is a condensate at point 38, and then the working fluid circulates in the fluid conduit 22 through a first expansion device, such as a first expansion valve 46. The first expansion valve 46 is disposed between the liquid suction heat exchanger 42 and a second storage container in the form of a receiver 48. In some aspects, the receiver 48 can be sized based on how much refrigerant can be stored therein. Compared to a gas-liquid flat tank, the pairing of the receiver 48 and the accumulator 44 in the climate control system 20 does not require any separate pressurization, and the pairing of the receiver 48 and the accumulator 44 can handle all high-slip refrigerant flows in the high-slip refrigerant flow that will circulate through the system 20. At the first expansion valve 46, the pressure of the working fluid is reduced. In this way, the working fluid vapor is subcooled in the liquid suction heat exchanger 42 and then the pressure is reduced when it passes through the first expansion valve 46.

[0081] The decompressed working fluid stream leaving the first expansion valve 46 thus enters the receiver 48, in which the vapor and liquid are separated, and the liquid circulating through the system can be stored and concentrated. The receiver 48 thus receives such a working fluid, which can include a working fluid in both a vapor phase and a liquid phase, but mainly in a liquid phase. More specifically, the working fluid in the receiver 48 can include a liquid phase refrigerant, which generally includes more of the second refrigerant (B) with a lower volatility / high critical point and optionally a portion of the first refrigerant (A) with a lower critical point, depending on the desired operating conditions. The liquid phase can include the second refrigerant (B) in the liquid phase, for example, in certain variations, most of the liquid phase in the liquid phase can be the second refrigerant (B). By way of non-limiting example, the vapor mass or mass fraction of the vapor of the working fluid (liquid stream at point 36) leaving the receiver can be an amount in the range of 0% to less than or equal to about 10% vapor mass, such as 5% vapor mass, optionally 3% vapor mass, optionally 1% vapor mass, etc. The reduced pressure working fluid exiting the first expansion valve 46 thus enters the receiver 48. The liquid refrigerant continues along a path to exit through the outlet 49 (although not shown, the outlet 49 can be located at the bottom of the container) so that the liquid is drawn out of the receiver 48 as a saturated liquid at a concentration consistent with the fluid circulating in the system 20. More specifically, the working fluid in the liquid portion of the receiver 48 includes a saturated liquid, which will be defined as a portion of the less volatile / high critical point second refrigerant (B) and a portion of the more volatile / low critical point first refrigerant (A), which will continue to flow through the components of the system 20 until reaching the accumulator 44.

[0082] After leaving the receiver 48, the working fluid passes through a second expansion device, such as a second expansion valve 52. The second expansion valve 52 further reduces the pressure of the flow. Therefore, the saturated working fluid leaving the receiver 48 is further expanded into a two-phase working fluid when it passes through the second expansion valve 52. The second expansion valve 52 is disposed between the receiver 48 and the inlet 41 of the evaporator 40. Therefore, at point 39, the working fluid is a low-pressure multiphase flow, which then enters the evaporator 40, thereby completing the refrigerant cycle. Therefore, the two-phase working fluid enters the evaporator 40, where the two-phase working fluid can be partially boiled into a higher vapor quality fluid, as discussed above in the context of the properties of the working fluid at point 30 leaving the evaporator 40. The working fluid of higher vapor quality at point 30 is further boiled in the first side 42A of the liquid suction heat exchanger 42, for example, boiled into a working fluid close to a saturated vapor condition. As described above, the working fluid flow near the saturated vapor condition is therefore returned to the accumulator 44 where the liquid phase refrigerant is contained or stored, while the saturated vapor refrigerant is returned to the compressor 50 .

[0083] like Figure 1 As shown by the arrows in , the working fluid circulates in a countercurrent flow arrangement with an air flow (e.g., ambient air) as a heat transfer medium passing through the evaporator 40 and the condenser 62. The temperature range of the high glide refrigerant blend can be operated to be about 50% to about 200%, optionally about 66% to about 150%, of the temperature range of the air circulating through the evaporator 40 and / or the condenser 62. The flow direction of the refrigerant / working fluid in the conduit 22 is generally opposite to the flow direction of the air to achieve the benefits of countercurrent flow in a high glide system.

[0084] The flow rate of air through the evaporator 40 and condenser 62 can be lower than industry rule of thumb or industry standard flow rates because the counter-flow of the temperature-glide refrigerant in the conduit 22 reduces the impact of high temperature differences on the secondary fluid (air).

[0085] As will be appreciated by those skilled in the art, conventional components used with the climate control system 20 may not be shown, including flow, temperature and pressure monitors, actuators, valves, controllers, etc. Additionally, it should be noted that the climate control system 20 may be devoid of any conventional pumps, and may be considered a "pumpless" design.

[0086] In this way, the climate control system 20 allows the concentration of the corresponding refrigerant in the working fluid with high slip to be controlled by changing the mass of the liquid refrigerant in the reservoir and the receiver (or alternatively, in other containers). Therefore, the climate control system effectively allows the concentration of refrigerant blend components with very different critical temperatures (e.g., CO2 at 87°F and R-1233zd at 330°F) to be changed. Since the second refrigerant (e.g., R-1233zd) has a higher critical temperature (e.g., a critical temperature exceeding 330°F), the total critical temperature of the working fluid blend can be increased to a value far higher than the critical temperature of the first refrigerant (e.g., higher than the critical temperature of CO2, 87.8°F). In this way, the concentration can be kept subcritical and have optimized performance because each environment requires a unique circulating concentration. As described above, in some aspects, the concentration is changed by changing the following: (i) the storage amount of the high critical point rich blend as a liquid in the reservoir, and (ii) the storage amount of the low critical point rich blend as a liquid in the receiver. Since refrigerant blends have high glide tending towards high vapor quality, a system incorporating a liquid suction heat exchanger allows limited glide operation in the evaporator and subcooling of the high pressure liquid leaving the evaporator when the blend contains a low critical point fluid.

[0087] Furthermore, by incorporating a liquid suction heat exchanger, the working fluid can be conditioned to have a positive or negative superheat close to the compressor to drive changes in the reservoir liquid level.

[0088] Thus, in certain aspects, efficiency gains in climate control systems are made possible by active control of the critical point of the working fluid, wherein the liquid in the reservoir has a higher concentration of a high critical point / second refrigerant (B) (e.g., R-1233zd) relative to the total amount of the working fluid. The liquid in the receiver has a lower concentration of a high critical point / second refrigerant (B) (e.g., R-1233zd) relative to the total amount of the working fluid in the receiver when compared to the reservoir liquid. Thus, the refrigerant concentration is controlled by transferring liquid between the two containers. In various aspects, the refrigerant concentration depends only on the liquid level in the reservoir. The liquid level changes in the receiver provide a secondary location for refrigerant storage of circulating concentrations. In addition, this efficiency gain can also be attributed to reducing the compressor pressure / head by combining a liquid suction heat exchanger with a high glide working fluid having two different refrigerants. The liquid suction heat exchanger allows condensation to occur at a higher enthalpy range than evaporation. Additionally, in the case of very high glide of the refrigerant blend, the inclusion of a liquid suction heat exchanger allows condensation at lower pressures and evaporation at higher pressures. Furthermore, by varying the capacity of the liquid suction heat exchanger, capacity modulation of the system can be envisaged, for example, by reducing the compressor head as the enthalpy change across the evaporator decreases, effectively reducing capacity.

[0089] In certain variations described herein, the liquid level in the accumulator may be raised by transferring liquid directly from the receiver by using a liquid bypass line that bypasses the expansion valve and evaporator. Figure 2 Such a variation of an alternative climate control system 20A is shown in FIG. 1 . To some extent, the components in the system are similar to those in FIG. Figure 1Components that are the same or similar to those described in the present invention will use the same reference numerals, and unless otherwise specified, will not be discussed again in this document for the sake of brevity. In the climate control system 20A, a first bypass line 70 in the form of a liquid bypass originates from a three-way valve 72, which is disposed in a line 74 between the receiver 48 and the second expansion valve 52. The first bypass line 70 diverts a portion of the working fluid flow leaving the receiver 48 to the reservoir 44. In this way, the working fluid leaving the receiver 48 is a nearly saturated condensed working fluid or a saturated condensed working fluid (e.g., liquid phase) leaving the receiver 48, and when the working fluid returns to the reservoir 44 (bypassing both the second expansion valve 52 and the evaporator 40 in the fluid conduit 22), it is used to reduce the amount of vapor or gas in the reservoir 44, and thus increase the total amount of liquid in the reservoir 44. The first bypass line 70 may also include a metering valve 76 for regulating the flow of the diverted liquid flow of the working fluid entering the reservoir 44. Such a metering valve 76 may be associated with a device that measures flow, pressure, temperature, etc. of the flow in the first bypass line 70 and an associated control system.

[0090] In other variations described herein, the liquid level in the receiver may be lowered by using a condenser and a liquid suction heat exchanger bypass for the exhaust gas, and allowing subcooling to occur to raise the liquid level in the receiver. Figure 3 This variation of an alternative climate control system 20B is shown in FIG. Figure 1 or Figure 2 For components that are the same or similar to those described herein, the same reference numerals will be used and, unless otherwise noted, will not be discussed again herein for the sake of brevity. Figure 3 Any features and components described in the context of Figure 1 or Figure 2 The second bypass line 80 is used alone or in combination in the climate control system described in the context of FIG. In the climate control system 20B, a second bypass line 80 in the form of a steam bypass begins at a three-way valve 82 disposed in a line 84 between the compressor 50 and the inlet 60 to the condenser 62. The second bypass line 80 passes a diverted portion of the working fluid flow leaving the compressor 50 to the receiver 48. In this manner, the working fluid leaving the compressor 50 at point 34 is a high pressure vapor or gas flow, and when the working fluid (bypassing both the condenser 62 and the liquid suction heat exchanger 42 in the fluid conduit 22) returns to the receiver 48, it serves to increase the amount of vapor or gas in the receiver 48, and thereby reduce the total amount of liquid in the receiver 48.

[0091] In other aspects, the cooling capacity of the climate control system can be adjusted to achieve smaller capacity reductions or continuous capacity control by using a combination of staged compression and varying refrigerant concentration, or alternatively using variable speed compression and variable refrigerant concentration, or alternatively cycling each compressor off and varying the refrigerant concentration in a system with multiple compressors.

[0092] In yet another aspect, where another fluid is included in the system (such as oil in the working fluid), the fluid may be preferentially miscible with a single component of the refrigerant blend (e.g., with the first refrigerant (A) or the second refrigerant (B)) (in other words, the fluid has a greater solubility in the single component of the refrigerant blend) so that a concentrated amount of the single component (e.g., the high-pressure first refrigerant (A) or the low-pressure second refrigerant (B)) is stored in an oil sump (typically disposed within the compressor 50) or another tank in a portion of the system 20. Thus, above a given pressure and temperature, the oil may reach the solubility limit of one of the first refrigerant or the second refrigerant, such that only one of the refrigerants remains soluble in the oil, while the other refrigerant does not dissolve and is no longer circulated in the working fluid.

[0093] As will be understood, for a climate control system in the form of a heat pump system, part of the heat pump system may be located indoors or in a confined space, while the remainder of the heat pump system is located outdoors. This heat pump system is described in the co-owned U.S. Publication No. 2023 / 0130167 entitled "Climate Control Systems for Use with High Glide Working Fluids and Methods for Operation Thereof" by Welch et al., which is incorporated herein by reference. The first heat exchanger is disposed indoors and may be operated as a condenser in a first operating mode or heating mode, or may be operated as an evaporator in a second operating mode or cooling mode. The first heat exchanger is generally referred to as an air handling unit, which is provided with a supply side and a return side to process air for an indoor environment. The first heat exchanger may include a fan and a coil. Depending on the operating mode, the supply air (e.g., in a countercurrent direction, but cocurrent flow may also occur) passing through the coil may be heated or cooled.

[0094] The heat pump system also includes a second heat exchanger arranged outdoors, and the second heat exchanger also includes a fan and a coil. The second heat exchanger is generally referred to as an outdoor unit, and circulates ambient air through the coil and produces exhaust gas. Depending on the operating mode, the ambient air passing through the coil (for example, in a countercurrent direction, but downstream flow may also occur) can be cooled or heated. The second heat exchanger can be operated as an evaporator in a first operating mode or a heating mode, or can be operated as a condenser in a second operating mode or a cooling mode. The heat pump system under the first operating mode will be described herein, in which the first operating mode, the first heat exchanger is operated as a condenser to heat the supply air indoors, and the second heat exchanger is operated as an evaporator. As will be appreciated by those skilled in the art, the concept discussed herein can also be applied to the operation under the second operating mode.

[0095] In some aspects, a pair of four-way valves can be used in the fluid conduits between the components so that the flow of the working fluid can be reversed to allow the system to operate in the first operating mode or the second operating mode. As will be appreciated by those skilled in the art, the heat pump system can instead have one or more reversing valves to direct the flow of the working fluid in different directions in the system.

[0096] By way of example, a heat pump system can circulate a working fluid having two refrigerants that have high glide or a boiling point difference between a first refrigerant (A) and a second refrigerant (B) that is greater than or equal to about 269K at atmospheric pressure. In one example, wherein, the first refrigerant (A) can be carbon dioxide (CO2) and the second refrigerant (B) can be R-1233zd. The initial refrigerant blend introduced into the heat pump system 300 can have approximately 93% CO2 by weight and 7% R-1233zd by weight. Similar to the previous embodiment, the working fluid can also include oil at certain points in the system. The heat pump system has a fluid flow path or fluid conduit that establishes fluid communication between the various components so that the working fluid can circulate in a loop as further discussed herein.

[0097] In various aspects, the control of the climate control system described in any of the above embodiments, including the heat pump system, can be implemented by a control module. In the present application, including the following definitions, the term "module" or the term "controller" can be replaced by the term "circuit". The term "module" can refer to, can be part of, or can include: an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.

[0098] The module may include one or more interface circuits. In some examples, the interface circuit may include a wired or wireless interface connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functions of any given module of the present disclosure may be distributed in a plurality of modules connected via the interface circuit. For example, a plurality of modules may allow load balancing. In another example, a server (also referred to as a remote or cloud) module may implement some functionality on behalf of a client module.

[0099] The term "code" used above may include software, firmware and / or microcode, and may refer to a program, a routine, a function, a class, a data structure and / or an object. The term "shared processor circuit" covers a single processor circuit that executes some or all of the code from multiple modules. The term "grouped processor circuit" covers a processor circuit that is combined with an additional processor circuit to execute some or all of the code from one or more modules. Reference to multiple processor circuits covers multiple processor circuits on discrete chips, multiple processor circuits on a single chip, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term "shared memory circuit" covers a single memory circuit that stores some or all of the code from multiple modules. The term "grouped memory circuit" covers a memory circuit that is combined with additional memory to store some or all of the code from one or more modules.

[0100] The term "memory circuit" is a subset of the term "computer-readable medium". As used herein, the term "computer-readable medium" does not encompass transient electrical signals or transient electromagnetic signals propagated through a medium (such as on a carrier wave); therefore, the term "computer-readable medium" may be considered to be tangible and non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital tape or hard drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0101] The apparatus and methods described in this application may be implemented in part or in whole by a special purpose computer created by configuring a general purpose computer to perform one or more specific functions embodied in a computer program. The above-mentioned function blocks, flow chart components and other elements are used as software specifications, which can be compiled into a computer program by the routine work of a skilled technician or programmer.

[0102] The computer program includes processor executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer program may also include or rely on stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0103] A computer program may include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated by a compiler from source code; (iv) source code executed by an interpreter; (v) source code compiled and executed by a just-in-time compiler, etc. By way of example only, source code may be written using syntax from a language including: C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language Fifth Edition), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and

[0104] In various aspects, the control module may be used to enable, disable, or adjust the operation of various components and devices in the climate control system, including compressors, fans, pumps, valves, etc. The control module may receive input from various sensors in the climate control system, such as temperature sensors, pressure sensors, flow rate sensors, current meters, voltage meters, etc. These sensors provide measurements from which the control module may determine necessary modifications to the climate control system.

[0105] The control module may include one or more modules and may be implemented as part of a control board, furnace board, thermostat, air handler board, contactor, or other form of control system or diagnostic system. The control module may contain power conditioning circuitry to power various components using 24 volt (V) alternating current (AC), 120V to 240V AC, 5V direct current (DC), etc. The control module may include two-way communications, which may be wired, wireless, or both, thereby enabling system debugging, programming, updating, monitoring, parameter value / status transmission, etc. The climate control system may be more generally referred to as an air conditioning system or a refrigeration system.

[0106] Therefore, the control module can open, close, regulate the working fluid flow (or a portion of the working fluid flow, such as the first refrigerant and / or the second refrigerant) or guide the working fluid flow through conduits into and out of various components and devices in the system, including evaporators, condensers, expansion valves, gas-liquid separators, heat exchangers, storage containers, etc.

[0107] In certain aspects, the present disclosure provides a method for operating a climate control system, which circulates a working fluid including a refrigerant blend with high slip. Such a method can adjust the cooling capacity of the climate control system as described above by utilizing the high slip characteristics or fractionation behavior of a selected refrigerant blend. The method may include circulating the working fluid in any climate control system in the above-mentioned climate control system. For example, the working fluid can circulate through a fluid conduit, which includes a compressor for pressurizing the working fluid, a condenser arranged downstream of the compressor for condensing at least a portion of the working fluid, a liquid suction heat exchanger for exchanging heat between a flow leaving the condenser and a flow leaving the evaporator, at least one expansion valve arranged downstream of the liquid suction heat exchanger for reducing the pressure of the working fluid, a receiver for storing at least a portion of the working fluid, an evaporator arranged downstream of the receiver for evaporating at least a portion of the working fluid, and a liquid reservoir arranged downstream of the liquid suction heat exchanger and upstream of the compressor for storing at least a portion of the working fluid. As previously described above, the working fluid includes a refrigerant blend with high glide, the refrigerant blend including a first refrigerant and a second refrigerant, wherein the boiling point difference between the first refrigerant and the second refrigerant is at least greater than or equal to about 25°R (about 14K) at atmospheric pressure.

[0108] In one aspect, the present disclosure provides a method of operating a climate control system that circulates a working fluid comprising a refrigerant blend having a high glide. The method includes pressurizing the working fluid vapor by passing the working fluid vapor through a compressor in a fluid conduit. At least a portion of the working fluid is condensed in a first heat exchanger disposed downstream of the compressor. The working fluid is then cooled by passing through a liquid suction heat exchanger in a first flow direction. The method also includes reducing the pressure of the working fluid by passing the working fluid through a first expansion device disposed downstream of the liquid suction heat exchanger and the first heat exchanger.

[0109] Thus, the method may include passing a working fluid stream from a condenser through a first side of a liquid suction heat exchanger in a first flow direction and passing a low-pressure multiphase working fluid stream from an evaporator through the liquid suction heat exchanger in a second flow direction to transfer heat between the working fluid stream and the low-pressure multiphase working fluid stream. In certain aspects, the method may include changing the charge balance in the system by operating with less subcooling at a suction outlet of the liquid suction heat exchanger.

[0110] The working fluid then enters the receiver from the first expansion device. At least a portion of the working fluid can be stored in the receiver. For example, a liquid portion of the working fluid can be stored in the receiver. The liquid portion of the working fluid located in the receiver can have a higher storage capacity of a first refrigerant (A) having a relatively high pressure or a relatively low critical point. As described in our new knowledge, the storage capacity of the liquid stored in the receiver is consistent with the range of liquid circulating through the system, and in some aspects, the storage capacity can be greater than or equal to 0% to 15% by weight.

[0111] The method also includes reducing the pressure of the working fluid leaving the receiver by passing the working fluid leaving the receiver through a second expansion device disposed downstream of the receiver. At least a portion of the working fluid is evaporated in a second heat exchanger disposed downstream of the second expansion valve. The method also includes heating the working fluid leaving the second heat exchanger by passing the working fluid leaving the second heat exchanger through a liquid suction heat exchanger along a second flow direction. The working fluid can enter a reservoir upstream of the compressor. At least a portion of the working fluid can be stored in the reservoir. In some aspects, the condition at the reservoir inlet can be a certain degree of superheat, which can range from greater than or equal to about -8.3K (e.g., -15°R) to less than or equal to about 16.7K (e.g., 30°R).

[0112] A working fluid vapor leaves the reservoir and enters the compressor, wherein the working fluid comprises a refrigerant blend with high glide, the refrigerant blend comprising a first refrigerant and a second refrigerant, wherein a boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 25°R (about 14K) at atmospheric pressure.

[0113] In various aspects, the concentration of the second refrigerant (B) having a relatively low pressure or a relatively high critical point in the accumulator is greater than the amount of the second refrigerant (B) circulating in the climate control system 20, and the concentration of the second refrigerant (B) is the same as the amount of the second refrigerant (B) circulating in the climate control system 20. The liquid portion of the working fluid located in the accumulator can have a higher storage amount of the second refrigerant (B), which has a relatively low pressure or a relatively high critical point, and thus a lower amount of the first refrigerant (A) has a relatively high pressure or a relatively low critical point. In addition, as described above, the liquid stored in the receiver has a lower concentration of the second refrigerant (B) or a higher concentration of the first refrigerant (A), the lower concentration of the second refrigerant (B) has a relatively low pressure or a relatively high critical point, and the higher concentration of the first refrigerant (A) has a relatively high pressure or a relatively low critical point. Therefore, in some aspects, the refrigerant concentration in the working fluid can be controlled by adjusting or transferring the liquid between the receiver and the accumulator.

[0114] In certain variations, the method includes controlling the concentration of the first refrigerant and the second refrigerant in the refrigerant blend in the climate control system by: (i) adjusting the first storage amount of the liquid in the receiver; (ii) adjusting the second storage amount of the liquid in the reservoir; or (iii) both (i) and (ii). In certain other variations, where the first critical point of the first refrigerant (A) is less than the second critical point of the second refrigerant (B), the method includes controlling the concentration of the refrigerant blend in the climate control system by one or more of the following: (i) adjusting the first storage amount of the first refrigerant as the liquid in the receiver; (ii) adjusting the second storage amount of the second refrigerant as the liquid in the reservoir; or (iii) performing both (i) and (ii). In certain other aspects, the control of the concentration of the first refrigerant and the second refrigerant in the refrigerant blend in the climate control system can be performed by adjusting the storage amount of the liquid in the reservoir.

[0115] In one aspect, the high-glide refrigerant blend defines a complete phase change for condensation, and condensation only partially condenses the working fluid into a liquid phase and only allows a portion of the complete phase change to occur. In this way, after condensation, a larger portion or a larger percentage of the second refrigerant in the second refrigerant (B) is liquid, and as the first refrigerant (A) enters the liquid suction heat exchanger, a larger portion or a larger percentage of the first refrigerant in the first refrigerant (A) remains as vapor, and a smaller portion of the first refrigerant in the first refrigerant (A) is liquid. In another aspect, the high-glide refrigerant blend defines a complete phase change for evaporation, but evaporation only partially evaporates the working fluid into a vapor phase and only allows a portion of the complete phase change to occur. In this way, after evaporation, a larger portion or a larger amount of the first refrigerant in the first refrigerant (A) is vapor, and as the second refrigerant (B) enters the liquid suction heat exchanger, a smaller portion of the second refrigerant in the second refrigerant (B) is vapor, and a larger portion of the second refrigerant in the second refrigerant (B) remains liquid.

[0116] In certain variations, condensation only partially condenses the working fluid into a liquid phase, and evaporation only partially evaporates the working fluid into a vapor phase.The evaporation is performed on a fluid stream having a first vapor quality higher than a second vapor quality.

[0117] In other aspects, in addition to the accumulator and the receiver, the fluid conduit further comprises at least one storage container, and the method further comprises storing a portion of the first refrigerant and / or the second refrigerant in the at least one storage container to adjust the cooling capacity of the system.

[0118] The method may also include circulating the air through an evaporator and a condenser in heat transfer relationship with the fluid conduit to transfer heat to the working fluid (e.g., prior to entering the evaporator). In certain aspects, the first temperature range of the refrigerant blend is operated to be greater than or equal to about 50% to less than or equal to about 200% of the second temperature range of the air, optionally greater than or equal to about 66% to less than or equal to about 150% of the second temperature range of the air.

[0119] In other aspects, the cooling capacity of a climate control system can be adjusted by utilizing a compressor that implements staged compression, for example, by using a combination of staged compression and varying refrigerant concentration. In another variation, variable speed compression and variable refrigerant concentration can be used to adjust system capacity. In yet another variation, a system having multiple compressors in a fluid conduit can be individually cycled off and refrigerant concentration varied to achieve lower capacity turndown or continuous capacity control.

[0120] In yet another aspect, where another fluid is included in the system (such as oil in the working fluid), that fluid can be preferentially miscible with a single component of the refrigerant blend (e.g., with the first refrigerant or the second refrigerant) so that a concentrated amount of the single component (e.g., the high-pressure first refrigerant or the low-pressure second refrigerant) can be stored in an oil storage container or selected area in a portion of the system.

[0121] In certain other aspects, the refrigerant blend may include any of the above refrigerants, such as a first refrigerant, the first refrigerant being an A1 refrigerant such as CO2, mixed with a second refrigerant that is a flammable refrigerant (such as ASHRAE 34, A3 grade), such as dimethyl ether. In this variation, the system maintains a proportion of a relatively inert first refrigerant (e.g., an A1 refrigerant) to limit the amount of flammable second refrigerant on the indoor side of the system to a safe level. In addition, the climate control system can have indoor and outdoor portions that can be isolated from each other, such as described in co-owned U.S. Patent Publication No. 2022 / 0082304 to Welch et al., entitled “Refrigerant Isolation Using a Reversing Valve,” the relevant portions of which are incorporated by reference. In other aspects, the present disclosure may contemplate a method for calculating the amount of a flammable second refrigerant component of a binary mixture of a first refrigerant and a second refrigerant in a room, for example, as described in commonly owned U.S. Patent No. 11,131,471 to Butler et al., entitled “Refrigerant Leak Detection,” relevant portions of which are incorporated by reference, wherein the charge amount may be calculated using a proportional relationship between the enthalpy and specific volume of the refrigerant, but using more than the four measurements described.

[0122] Additionally, by allowing refrigerant to store in a portion of the system, the cycle can allow for some limited variation in refrigerant concentration, or can maintain the same concentration under all conditions to maintain the same flammable refrigerant safety level as the baseline operating conditions.

[0123] The foregoing description of the embodiments has been provided for the purpose of illustration and description. The foregoing description is not intended to be exhaustive or to limit the present disclosure. Each element or feature of a particular embodiment is generally not limited to the particular embodiment, but, even if not specifically shown or described, each element or feature of a particular embodiment is interchangeable and can be used for a selected embodiment when applicable. Each element or feature of a particular embodiment can also be changed in many ways. These modifications are not considered to be deviating from the present disclosure, and all these modifications are intended to be included in the scope of the present disclosure.

Claims

1. A climate control system, the climate control system circulating a working fluid comprising a refrigerant blend having high glide, the climate control system comprising: a working fluid comprising a first refrigerant and a second refrigerant, wherein a boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 25°R at atmospheric pressure; Liquid reservoir; a compressor receiving a vapor flow of the working fluid from the reservoir and producing a pressurized vapor flow; a first heat exchanger disposed downstream of the compressor, the first heat exchanger receiving the pressurized vapor stream and cooling the pressurized vapor stream to produce a multiphase or liquid condensed stream of the working fluid; a liquid suction type heat exchanger, the liquid suction type heat exchanger being arranged downstream of the first heat exchanger and upstream of the liquid reservoir; a receiver disposed downstream of the liquid suction heat exchanger; a first expansion device disposed between the liquid suction heat exchanger and the receiver, the first expansion device processing the multiphase or liquid condensate stream from the liquid suction heat exchanger; a second expansion device disposed between the receiver and the second heat exchanger, the second expansion device processing the multiphase or liquid condensed stream to reduce the pressure before the second heat exchanger to form a reduced pressure multiphase stream of the working fluid; a second heat exchanger that receives the reduced pressure multiphase flow from the second expansion device and at least partially vaporizes the reduced pressure multiphase flow to form an evaporated flow of the working fluid that is then directed to the liquid suction heat exchanger and the accumulator; and a fluid conduit for circulating the working fluid and establishing fluid communication among the reservoir, the compressor, the first heat exchanger, the liquid suction heat exchanger, the first expansion device, the receiver, the second expansion device and the second heat exchanger, the working fluid circulating through the fluid communication.

2. The climate control system of claim 1, wherein: The liquid suction heat exchanger receives the multiphase or liquid condensed stream from the first heat exchanger in a first flow direction and the vaporized stream from the second heat exchanger in a second flow direction to transfer heat between the multiphase or liquid condensed stream and the vaporized stream.

3. The climate control system of claim 1 , said climate control system being devoid of any pumps.

4. The climate control system of claim 1 further comprising a liquid bypass line that diverts a portion of the working fluid exiting the receiver into the reservoir.

5. The climate control system of claim 4, wherein: The liquid bypass line also includes a liquid metering valve.

6. The climate control system of claim 1 further comprising a steam bypass line that diverts a portion of the working fluid exiting the compressor into the receiver.

7. The climate control system of claim 1, wherein: The first refrigerant and the second refrigerant are selected from the group consisting of carbon dioxide (R-744), chlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), 1,1-difluoroethane (R-152A), dimethyl ether (R-E170), propane (R-290), 2,3,3,3,-tetrafluoropropane-1 -ene (R-1234yf), cis- and trans-1,3,3,3,-tetrafluoropropene (HFO-1234ye), cis- and trans-1,3,3,3,-tetrafluoroprop-1-ene (R-1234ze), 3,3,3,-trifluoropropene (HFO-1234zf), trifluoromonochloropropene (HFO-1233), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)), cis-1-chloro-3,3, 3-Trifluoropropene (HFO-1233zd(Z)), 2-chloro-3,3,3-trifluoropropene (HFO-1233xf), trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E)), pentafluoropropene (HFO-1225), 1,1,3,3,3-pentafluoropropene (HFO-1 225zc), 1,2,3,3,3-pentafluoropropylene (HFO-1225yez), hexafluorobutene (HFO-1336), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), trans-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(E)), trans-1,2-difluoroethylene (R-1132(E)), and any isomers or combinations thereof.

8. The climate control system of claim 1, wherein: The first refrigerant includes carbon dioxide (R-744), and the second refrigerant includes a hydrofluoroolefin.

9. A method for operating a climate control system that circulates a working fluid comprising a refrigerant blend having high glide, the method comprising: pressurizing the vapor flow of the working fluid by passing the vapor flow of the working fluid through a compressor in a fluid conduit; condensing at least a portion of the working fluid in a first heat exchanger disposed downstream of the compressor; cooling the working fluid by passing the working fluid through a liquid suction heat exchanger in a first flow direction; reducing the pressure of the working fluid by passing the working fluid through a first expansion device disposed downstream of the liquid suction heat exchanger and the first heat exchanger; allowing the working fluid from the first expansion device to enter a receiver; further reducing the pressure of the working fluid exiting the receiver by passing the working fluid exiting the receiver through a second expansion device disposed downstream of the receiver; causing at least a portion of the working fluid to evaporate in a second heat exchanger disposed downstream of the second expansion device; heating the working fluid exiting the second heat exchanger by passing the working fluid exiting the second heat exchanger through the liquid suction heat exchanger in a second flow direction; as well as The working fluid is passed into a reservoir upstream of the compressor such that a vapor flow of the working fluid leaves the reservoir and enters the compressor, wherein the working fluid comprises the refrigerant blend having high glide, the refrigerant blend comprising a first refrigerant and a second refrigerant, wherein the boiling point difference between the first refrigerant and the second refrigerant is greater than or equal to about 25°R at atmospheric pressure.

10. The method of claim 9, comprising controlling the concentration of the first refrigerant and the second refrigerant in the refrigerant blend in the climate control system by: (i) adjusting a first storage amount of liquid in the receiver; (ii) adjusting a second storage amount of liquid in the reservoir; or (iii) performing both (i) and (ii).

11. The method according to claim 9, wherein: The first refrigerant has a first critical point that is lower than a second critical point of the second refrigerant, and the method includes controlling the concentration of the refrigerant blend in the climate control system by one or more of the following: (i) adjusting a first storage amount of the first refrigerant as a liquid in the receiver; (ii) adjusting a second storage amount of the second refrigerant as a liquid in the reservoir; or (iii) performing both (i) and (ii).

12. The method of claim 9, comprising controlling the concentration of the first refrigerant and the second refrigerant in the refrigerant blend in the climate control system by adjusting the storage amount of liquid in the reservoir.

13. The method according to claim 9, wherein: The working fluid exiting the second heat exchanger is regulated to have a positive or negative superheat level by heating the working fluid exiting the second heat exchanger through the liquid suction heat exchanger in a second flow direction, wherein the superheat level regulates the storage amount of liquid in the reservoir.

14. The method of claim 9, further comprising diverting a portion of the working fluid exiting the receiver into a liquid bypass line that directs the portion of the working fluid into the reservoir.

15. The method according to claim 14, wherein: The liquid bypass line further includes a liquid metering valve that adjusts a flow rate of the working fluid in the liquid bypass line.

16. The method of claim 9, further comprising diverting a portion of the working fluid exiting the compressor into a steam bypass line that directs the portion of the working fluid into the receiver.

17. The method according to claim 9, wherein: The refrigerant blend with high glide limits the complete phase change of condensation, and the condensation only partially condenses the working fluid into a liquid phase and allows only a portion of the complete phase change to occur, so that after the condensation, the second refrigerant is mainly liquid, and when the first refrigerant enters the liquid suction heat exchanger, a portion of the first refrigerant is liquid and a portion of the first refrigerant remains as vapor.

18. The method according to claim 9, wherein: The refrigerant blend with high glide limits a complete phase change on evaporation, and the evaporation only partially evaporates the working fluid into a vapor phase and allows only a portion of the complete phase change to occur, so that after the evaporation, the first refrigerant is a vapor, and when the second refrigerant enters the liquid suction heat exchanger, a portion of the second refrigerant is a vapor and a portion of the second refrigerant remains in a liquid state.

19. The method according to claim 9, wherein: The condensation only partially condenses the working fluid into a liquid phase, and the evaporation only partially evaporates the working fluid into a vapor phase.

20. The method according to claim 9, wherein: The first refrigerant and the second refrigerant are selected from the group consisting of carbon dioxide (R-744), chlorodifluoromethane (R-22), 1,1,1,2-tetrafluoroethane (R-134A), R-410A (a near azeotropic mixture of difluoromethane (R-32) and pentafluoroethane (R-125)), 1,1-difluoroethane (R-152A), dimethyl ether (R-E170), propane (R-290), 2,3,3,3,-tetrafluoropropane-1 -ene (R-1234yf), cis- and trans-1,3,3,3,-tetrafluoropropene (HFO-1234ye), cis- and trans-1,3,3,3,-tetrafluoroprop-1-ene (R-1234ze), 3,3,3,-trifluoropropene (HFO-1234zf), trifluoromonochloropropene (HFO-1233), trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)), cis-1-chloro-3,3, 3-Trifluoropropene (HFO-1233zd(Z)), 2-chloro-3,3,3-trifluoropropene (HFO-1233xf), trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E)), pentafluoropropene (HFO-1225), 1,1,3,3,3-pentafluoropropene (HFO-1 225zc), 1,2,3,3,3-pentafluoropropylene (HFO-1225yez), hexafluorobutene (HFO-1336), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(Z)), trans-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(E)), trans-1,2-difluoroethylene (R-1132(E)), and any isomers or combinations thereof.

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