Low Temperature Discharge Into Medium Temperature Vapor Injection Port

Abstract

A climate-control system includes a first compressor having a first compression mechanism, a first inlet of the first compressor and a first outlet of the first compressor, a second compressor in fluid communication with the first compressor and having a second compressor inlet, a second compression mechanism, the first inlet of the second compressor fluidly coupled with the second compression mechanism, which is configured to receive working fluid from the first compressor through the first inlet of the second compressor. A fluid passageway extends from the first compressor outlet to the first inlet of the second compressor, a heat exchanger is disposed on the fluid passageway, and a fan is configured to force air over the heat exchanger.

Description

FIELD

[0001] The present disclosure relates to a climate-control system having vapor-injection compressors.BACKGROUND

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

[0003] A climate-control system such as, for example, a heat-pump system, a refrigeration system, or an air conditioning system, may include a fluid circuit having an outdoor heat exchanger, one or more indoor heat exchangers, one or more expansion devices, and one or more compressors circulating a working fluid (e.g., refrigerant or carbon dioxide) through the fluid circuit. Efficient and reliable operation of the climate-control system is desirable to ensure that the climate-control system is capable of effectively and efficiently providing a cooling and / or heating effect on demand.SUMMARY

[0004] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0005] An aspect of a climate control system may have a first compressor having a first compression mechanism, a first first compressor inlet (viz., a first inlet of a first compressor) and a first compressor outlet; a second compressor in fluid communication with the first compressor and having a first second compressor inlet, a second compression mechanism, the first second compressor inlet may be fluidly coupled to the second compression mechanism, the second compression mechanism may be configured to receive working fluid from the first compressor through the first second compressor inlet; a fluid passageway may extend from the first compressor outlet to the first second compressor inlet; a heat exchanger may be disposed on the fluid passageway; and a fan may be configured to force air over the heat exchanger.

[0006] In another aspect, a climate control system may have a second second compressor inlet, the second second compressor inlet fluidly coupled to the second compression mechanism; and a multiport valve, the multiport valve comprising a multiport valve inlet, a first multiport valve outlet, and a second multiport valve outlet, the multiport valve inlet fluidly coupled to the first compressor outlet, the first multiport valve outlet fluidly coupled to the first second compressor inlet, and the second multiport valve outlet fluidly coupled to the second second compressor inlet.

[0007] In another aspect, a climate control system may have a second second compressor inlet fluidly coupled to the second compression mechanism and a second compressor outlet. It may also have a second heat exchanger comprising a second heat exchanger inlet and a second heat exchanger outlet, the second heat exchanger inlet fluidly coupled to the second compressor outlet (viz., a second outlet of a second compressor). A third heat exchanger includes a third heat exchanger inlet and third heat exchanger outlet, which is fluidly coupled to the first second compressor inlet (viz., a first inlet of a second compressor). A fourth heat exchanger includes a fourth heat exchanger inlet and fourth heat exchanger outlet, which is fluidly coupled to the first first compressor inlet.

[0008] In another aspect, a climate control system may have a second first compressor inlet (viz., a second inlet of a first compressor) fluidly coupled to a first compression mechanism, a flash tank having a flash tank inlet fluidly coupled to the second heat exchanger outlet, a flash tank vapor outlet fluidly coupled to the second first compressor inlet, and a flash tank liquid outlet fluidly coupled to the third and fourth heat exchanger inlets.

[0009] In other aspects, a climate control system may have more than one first compressor and / or more than one second compressor.

[0010] In a variation or in combination with other aspects, a climate control system may have a first compressor comprising a first first compressor inlet and first compressor outlet (viz., a first inlet of a first compressor) and a second compressor in fluid communication with the first compressor and having a first second compressor inlet (viz., a first inlet of a second compressor), a second second compressor inlet (viz., a second inlet of a second compressor), a second compressor outlet, and a second compression mechanism. The first second compressor inlet and second second compressor inlet fluidly are coupled to the second compression mechanism, which is configured to receive working fluid from the first compressor through the second second compressor inlet. It may also have a first heat exchanger comprising a first heat exchanger outlet and first heat exchanger inlet, the first heat exchanger inlet fluidly coupled to the second compressor outlet. It may also have a fluid passageway extending from the first compressor outlet to the second second compressor inlet. A second heat exchanger may be disposed on the fluid passageway, as well as a refrigerant-to-refrigerant heat exchanger loop including a refrigerant-to-refrigerant heat exchanger loop pump. The working fluid may flow through the refrigerant-to-refrigerant heat exchanger loop pump, the second heat exchanger, and the first heat exchanger, and return to the refrigerant-to-refrigerant heat exchanger loop pump. Alternatively or in combination, the climate control system may have a plurality of second compressors.

[0011] In a variation or in combination with other aspects, a climate control system may have a check valve between the refrigerant-to-refrigerant heat exchanger loop pump and second heat exchanger. Alternatively or in combination, the refrigerant-to-refrigerant heat exchanger loop pump may be a self-powered circulation pump having a first pump set with a first pump set case, a first rotor disposed within the first pump set case, and a first shaft extending through the first rotor; and a second pump set with a second pump set case, and a second rotor disposed within the second pump set case and configured to receive the first shaft.

[0012] In various aspects, alternatives, or combinations, the first pump set and second pump set are gear pump, and / or gerotors. In another aspect, a volume enclosed by the first pump set case may be greater than the volume enclosed by the second pump set case.

[0013] In another aspect a climate control system may have a first compressor having a first compression mechanism, a first first compressor inlet and a first compressor outlet. It may also have a second compressor in fluid communication with the first compressor and having a first second compressor inlet, a second compression mechanism, the first second compressor inlet fluidly coupled to the second compression mechanism, the second compression mechanism may be configured to receive working fluid from the first compressor through the first second compressor inlet. A first fluid passageway may extend from the first first compressor inlet to the first second compressor inlet and a second fluid passageway may extend from the first fluid passageway to a switch.

[0014] In another aspect, a switch may be configured to turn off the first compressor. In combination or alternatively, the climate control system may have a plurality of first compressors and a plurality of corresponding switches configured to turn off a corresponding first compressor. In another aspect, each switch may have a different cut-out set point.

[0015] In another aspect, a second second compressor inlet may be fluidly coupled to the second compression mechanism. A second heat exchanger may have a second heat exchanger inlet and a second heat exchanger outlet, which may be fluidly coupled to the second compression mechanism. A third heat exchanger may have a third heat exchanger inlet, and a third heat exchanger outlet, which may be fluidly coupled to the first second compressor inlet. A fourth heat exchanger may have a fourth heat exchanger inlet and a fourth heat exchanger outlet, which may be fluidly coupled to the first first compressor inlet. A third fluid passageway may extend from the third heat exchanger outlet to the second second compressor inlet.

[0016] Alternatively or in combination, the climate control system may have a fourth fluid passageway extending between the first fluid passageway and the third fluid passageway. The fourth fluid passageway may have a variable flow rate valve.

[0017] Further areas of applicability will become apparent from the description. 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 DRAWINGS

[0018] The drawings are provided for illustrative purposes only. Selected embodiments, but not all possible implementations, are shown. The drawings are not intended to limit the scope of the disclosure.

[0019] FIG. 1 is a schematic representation of a climate-control system according to the principles of the present disclosure.

[0020] FIG. 2 is a cross-sectional view of an example compressor for the climate-control system of FIG. 1.

[0021] FIG. 3 is a graph showing the relationship between power consumption, injection temperature, and injection pressure in the climate-control system of FIG. 1.

[0022] FIG. 4 is a schematic representation of another climate-control system according to the principles of the present disclosure.

[0023] FIG. 5 is a schematic representation of another climate-control system according to the principles of the present disclosure.

[0024] FIG. 6 is a schematic representation of another climate-control system according to the principles of the present disclosure.

[0025] FIG. 7 is a schematic representation of another climate-control system according to the principles of the present disclosure.

[0026] FIG. 8 is an isometric view of a self-powered circulation pump according to the principles of the present disclosure.

[0027] FIG. 9 is a cut-away view of a gear pump of a self-powered circulation pump according to the principles of the present disclosure.

[0028] FIG. 10 is a schematic representation of a self-powered circulation pump of FIG. 9 in operation.

[0029] FIG. 11 is a schematic representation of another climate-control system according to the principles of the present disclosure.

[0030] FIG. 12 is a graph depicting an inverse time algorithm according to the principles of the present disclosure.

[0031] FIG. 13 is a flowchart depicting a flood-back mitigation strategy according to the principles of the present disclosure.

[0032] Corresponding reference numerals indicate corresponding parts throughout several views of the drawings.DETAILED DESCRIPTION

[0033] Example embodiments, which will be described more fully with reference to the accompanying drawings, are provided so that this disclosure will be thorough and fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of 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 embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some examples, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,”“an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,”“comprising,”“including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0035] When an element or layer is referred to as being “on,”“engaged to,”“connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. 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 present. Other words used to describe the relationship between elements should be interpreted in a like fashion (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.

[0036] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,”“second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0037] Spatially relative terms, such as “inner,”“outer,”“beneath,”“below,”“lower,”“above,”“upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0038] With reference to FIG. 1, a climate-control system 10 is provided. The climate-control system 10 may include a fluid circuit having one or more first compressors 12, one or more second compressors 14, a first heat exchanger 16 (an outdoor heat exchanger such as a condenser or gas cooler, for example), a first expansion device 18, a flash tank 20 (a second heat exchanger), a third heat exchanger 22 (an indoor heat exchanger such as a medium-temperature evaporator, for example), a fourth heat exchanger 24 (an indoor heat exchanger such as a low-temperature evaporator, for example). The first heat exchanger has a first heat exchanger inlet 16a and a first heat exchanger outlet 16b. The third heat exchanger has a third heat exchanger inlet 22a and a third heat exchanger outlet 22b. The fourth heat exchanger has a third heat exchanger inlet 24a and a third heat exchanger outlet 24b. The first compressors 12 and / or the second compressors 14 may pump working fluid (e.g., refrigerant, carbon dioxide, etc.) through the circuit.

[0039] Each first compressor 12 may be a low-side compressor (i.e., a compressor in which the motor assembly is disposed within a suction pressure chamber within the shell), for example, and may be any suitable type of compressor such as a scroll, rotary, reciprocating, or screw compressor, for example. Each first compressor 12 includes a compression mechanism 28 disposed within a shell 30 having an inlet 32 (e.g., a first first compressor inlet or first inlet fitting), and an outlet 34 (e.g., a first first compressor outlet or outlet fitting). The inlet 32 may provide fluid to a suction inlet (not shown) of the compression mechanism 28 (e.g., a radially outermost pocket of a scroll compression mechanism). Suction lines 36 may be fluidly coupled to a first header 38 and corresponding inlets 32 of the first compressors 12. In this manner, working fluid exiting the third heat exchanger 24 may flow into the first header 38 where it is distributed to the suction lines 36 and the inlets 32 of the first compressors 12 to be compressed by the compression mechanisms 28 of the first compressors 12. After the working fluid is compressed by the compression mechanisms 28 of the first compressors 12, the working fluid can be discharged from the first compressors 12 through the outlets 34 to a second header 39 via discharge lines 40.

[0040] In some configurations, each first compressor 12 could be a high-side compressor (i.e., a compressor in which the motor assembly is disposed within a discharge-pressure chamber within the shell). In some configurations, each of the first compressors 12 may have different capacities than one another or than the second compressors 14. In some configurations, one or more of the first compressors 12 or one or more of the second compressors 14 may include a fixed-speed or variable-speed motor.

[0041] Referring now to FIG. 2, each second compressor 14 may be a low-side scroll compressor including a hermetic shell assembly 1050, a main bearing housing assembly 1052, a motor assembly 1054, a compression mechanism 67, a seal assembly 1058, a discharge fitting 1059, a discharge valve assembly 1060, a suction gas inlet fitting 1061 and an S-shaped vapor-injection conduit 1062 (e.g., a second second compressor inlet). The shell assembly 1050 may house the main bearing housing assembly 1052, the motor assembly 1054, the compression mechanism 67 and the seal assembly 1058, and may at least partially house the vapor-injection conduit 1062.

[0042] The shell assembly 1050 may generally form a compressor housing and may include a cylindrical shell 1064, an end cap 1066 at the upper end thereof, a transversely extending partition 68 and a base 1070 at a lower end thereof. The end cap 1066 and the partition 1068 may generally define a discharge chamber 1072, while the cylindrical shell 1064, the partition 1068 and the base 1070 may generally define a suction chamber 1074. The discharge fitting 1059 may be attached to the shell assembly 1050 at an opening 1076 in the end cap 1066 and may be in fluid communication with a third header 1078 via a discharge line 1080. The discharge valve assembly 1060 may be located within the discharge fitting 1059 and may generally prevent a reverse flow condition. The suction gas inlet fitting 1061 may be attached to the shell assembly 1050 at an opening 1082 such that the suction gas inlet fitting 1061 is in fluid communication with the suction chamber 1074 and a fourth header 1084 via a suction line 1086. The partition 1068 may include a discharge passage 1088 therethrough that provides communication between the compression mechanism 1056 and the discharge chamber 1072.

[0043] The main bearing housing assembly 1052 may be affixed to the shell at a plurality of points in any desirable manner, such as staking, for example. The main bearing housing assembly 1052 may include a main bearing housing 1090, a first bearing 1092 disposed therein, bushings 1094 and fasteners 1096. The main bearing housing 1090 may include a central body portion 1098 having a series of arms 1100 that extend radially outwardly therefrom. The central body portion 1098 may include first and second portions 1102 and 1104 having an opening 1105 extending therethrough. The second portion 1104 may house the first bearing 1092 therein. The first portion 1102 may define an annular flat thrust bearing surface 106 on an axial end surface thereof. Each arm 100 may include an aperture 1108 extending therethrough that receives a respective fastener 1096.

[0044] The motor assembly 1054 may generally include a motor stator 1110, a rotor 1112, and a drive shaft 1114. The motor stator 1110 may be press-fit into the shell 1064. The drive shaft 1114 may be rotatably driven by the rotor 1112. The rotor 1112 may be press-fit onto the drive shaft 1114. The drive shaft 1114 may include an eccentric crank pin 1116 having a flat 1118 thereon.

[0045] The compression mechanism 67 may generally include an orbiting scroll 1120 and a non-orbiting scroll 1122. The orbiting scroll 1120 may include an endplate 1124 having a spiral vane or wrap 1126 on the upper surface thereof and an annular flat thrust surface 1128 on the lower surface. The thrust surface 1128 may interface with the annular flat thrust bearing surface 1106 on the main bearing housing 1090. A cylindrical hub 1130 may project downwardly from the thrust surface 1128 and may have a drive bushing 1132 rotatably disposed therein. The drive bushing 1132 may include an inner bore in which the crank pin 1116 is drivingly disposed. The crank pin flat 1118 may drivingly engage a flat surface of the inner bore of the drive bushing 1132 to provide a radially compliant driving arrangement. An Oldham coupling 1134 may be engaged with the orbiting and non-orbiting scrolls 1120, 1122 to prevent relative rotation therebetween.

[0046] The non-orbiting scroll 1122 may include an endplate 1136 having a spiral wrap 138 on a lower surface 1140 thereof and a series of radially outwardly extending flanged portions 1142. The spiral wrap 1138 may form a meshing engagement with the wrap 1126 of the orbiting scroll 1120, thereby creating compression pockets, including an inlet pocket 1144, intermediate pockets 1146, 1148, 1150, 1152, and an outlet pocket 1154. The non-orbiting scroll 1122 may be axially displaceable relative to the main bearing housing assembly 1052, the shell assembly 1050, and the orbiting scroll 1120. The non-orbiting scroll 1122 may include a discharge passage 1156 in communication with the outlet pocket 1154 and an upwardly open recess 158. The upwardly open recess 1158 may be in fluid communication with the discharge chamber 1072 via the discharge passage 1088 in the partition 1068.

[0047] The endplate 1136 may include an injection passage 1160 formed therein. The injection passage 1160 may be in fluid communication with the vapor-injection conduit 1062 and with one or more of the intermediate pockets 1146, 1148, 1150, 1152 and may include a radially extending portion 1162 and an axially extending portion 1164. The injection passage 1160 may allow working fluid from the vapor-injection conduit 1062 to flow into the one or more of the intermediate pockets 1146, 1148, 1150, 1152.

[0048] The flanged portions 1142 may include openings 1168 therethrough. Each opening 1168 may receive a respective bushing 1094 therein. Each bushing 1094 may receive a respective fastener 1096. The respective fastener 1096 may be engaged with the main bearing housing 1090 to prevent rotation of the non-orbiting scroll 1122 relative to the main bearing housing assembly 1052. The non-orbiting scroll 1122 may include an annular recess 1170 in the upper surface thereof defined by parallel and coaxial inner and outer sidewalls 1172, 1174.

[0049] The seal assembly 1058 may be located within the annular recess 1170. In this way, the seal assembly 1058 may be axially displaceable within the annular recess 1170 relative to the shell assembly 1050 and / or the non-orbiting scroll 1122 to provide for axial displacement of the non-orbiting scroll 1122 while maintaining a sealed engagement with the partition 1068 to isolate the discharge chamber 1072 from the suction chamber 1074. More specifically, in some configurations, pressure within the annular recess 1170 may urge the seal assembly 1058 into engagement with the partition 1068, and the spiral wrap 1138 of the non-orbiting scroll 1122 into engagement with the endplate 1124 of the orbiting scroll 1120, during normal compressor operation.

[0050] The vapor-injection conduit 1062 may be at least partially disposed in the shell 1064 and may be attached to the shell 1064 at an opening thereof. The vapor-injection conduit 1062 may include a first end 1176 in fluid communication with the injection passage 1160 and a second end 1178 attached to the shell 1064 and in fluid communication with a fifth header 1179 (via a vapor inlet line 1180).

[0051] While each second compressor 14 is described above as a low-side scroll compressor (i.e., a compressor in which the motor assembly is disposed within a suction-pressure chamber within the shell), in some configurations, each second compressor 14 could be a high-side compressor (i.e., a compressor in which the motor assembly is disposed within a discharge-pressure chamber within the shell). For example, each second compressor 14 could be a high-side or low-side compressor and could be a rotary, reciprocating, or screw compressor, or any other suitable type of compressor. It is understood that, in some configurations, each first compressor 12 may be similar or identical to each second compressor 14.

[0052] Referring again to FIG. 1, the first heat exchanger 16 may be in fluid communication with the second compressors 14 via a third header 78. That is, the third header 78 may receive the compressed working fluid from the discharge lines 81 and the discharge fittings 59 of the second compressors 14 and may direct the compressed working fluid to the first heat exchanger 16. The first heat exchanger 16 may transfer heat from the compressed working fluid to ambient air that may be forced over the first heat exchanger 16 by a fan (not shown). In some configurations, the first heat exchanger 16 may transfer heat from the compressed working fluid to a stream of liquid such as water, for example. From the first heat exchanger 16, the working fluid may flow through the first expansion device 18 (e.g., an expansion valve or capillary tube), thereby lowering the temperature and pressure of the working fluid. From the first expansion device 18, the working fluid may flow into a flash tank inlet 182 of the flash tank 20.

[0053] In the flash tank 20, liquid working fluid is separated from vapor working fluid. Vapor working fluid may exit the flash tank 20 through a flash tank vapor outlet 184. Liquid working fluid may exit the flash tank 20 through a flash tank liquid outlet 186. From the vapor outlet 184, the vapor working fluid flows into a first fluid passageway 46 extending from the vapor outlet 184 to a third header 42. The first fluid passageway 46 may include a first expansion device 56 (e.g., an expansion valve or capillary tube). Vapor working fluid in the first fluid passageway 46 flows through the first expansion device 56 where its temperature and pressure are lowered. The vapor working fluid then flows through the third header 42 where it is distributed to vapor inlet lines 44 and into intermediate pockets of the compression mechanisms 28 of the first compressors 12 (via the vapor-injection conduits 30).

[0054] The second fluid passageway 48 extends from a liquid conduit 58 (that is fluidly coupled to a liquid outlet 60 of the flash tank 20) to a fourth header 62 that is in fluid communication with the second compressors 14 via suction lines 64. The second fluid passageway 48 includes a second device 66 (e.g., an expansion valve or capillary tube) and the second heat exchanger 22. A portion of the working fluid flowing through the liquid conduit 58 flows through the second expansion device 66 of the second fluid passageway 48 where its temperature and pressure is lowered. In the second heat exchanger 22, the working fluid may absorb heat from a first space to be cooled (e.g., an interior of a refrigerator, a refrigerated display case, or a cooler). From the second heat exchanger 22, the working fluid flows to the fourth header 62 where it is distributed to the suction lines 64 and the second compressors 14 to be compressed by compression mechanisms 67 of the second compressors 14.

[0055] The third fluid passageway 50 extends from the liquid conduit 58 to the first header 38 that is in fluid communication with the inlet 32 of the first compressors 12 via the suction lines 36. The third fluid passageway 50 includes a fourth expansion device 68 and the third heat exchanger 24. Another portion of the working fluid flowing through the liquid conduit 58 flows through the fourth expansion device 68 of the third fluid passageway 50 where its temperature and pressure is lowered. In the third heat exchanger 24, the working fluid may absorb heat from a second space to be cooled (e.g., freezer or a frozen food display case). In some configurations, the working fluid in the third heat exchanger 22 of the second fluid passageway 48 and the working fluid in the fourth heat exchanger 24 of the third fluid passageway 50 may absorb heat from the same space (e.g., the third heat exchanger 22 of the second fluid passageway 48 and the fourth heat exchanger 24 of the third fluid passageway 50 may operate at different times to switch the space between a freezer and a cooler, for example). From the fourth heat exchanger 24, the working fluid may flow into the first header 38 where it is distributed to the suction lines 36 and the inlets 32 of the first compressors 12 to be compressed by the compression mechanisms 28 of the first compressors 12.

[0056] The fourth fluid passageway 52 extends from the second header 39 to a fifth header 70. The working fluid discharged from the first compressors 12 flows through the fourth fluid passageway 52 (via the discharge lines 40) and into the fifth header 70 where it is distributed to intermediate pockets of the compression mechanisms 67 of the second compressors 14 (via vapor inlet lines 74 and vapor conduits 76).

[0057] The fourth fluid passageway 52 may include a fifth heat exchanger (e.g., a refrigerant to air heat exchanger such as a coil) 80. In the fourth fluid passageway 52, working fluid heated by the first compressors 12 may flow into the fifth heat exchanger 80, where heat inside the working fluid is released into the ambient air before it enters the fifth header 70 where it is distributed to the intermediate pockets of the compression mechanisms 67 of the second compressors 14 (via vapor inlet lines 74 and vapor conduits 76). A fan 82 may be placed such that it blows fluid (e.g., air) over the fifth heat exchanger 80 and is configured to force air over the fifth heat exchanger 80, thereby increasing the cooling rate of the working fluid in the fifth heat exchanger 80.

[0058] With reference to FIG. 3, a graph showing some of the benefits of the climate control system 10 is shown. One of the benefits of the climate-control system 10 of the present disclosure is that the fifth heat exchanger 80 removes heat generated from the first compressors 12 in the working fluid prior to the working fluid entering the second compressors 14. By removing heat from the working fluid, injection temperature 84 (i.e., the temperature of the working fluid entering the second compressors 16) is lowered. Thereby, the discharge pressure 86 of the first compressors 12 is lowered, as is the power consumption 88 of the first compressors 12. Further, the discharge temperature of the second compressors 14 is lowered as well, with corresponding benefits to the power consumption of the second compressors 14.

[0059] For instance, with reference to FIG. 4, a climate control system 210 may be provided that may be generally similar to the climate-control system 10 described above, apart from any exception noted below. The climate-control system 210 may include a fluid-circuit having a first compressor 212, a second compressor 214, a first heat exchanger 216, a second heat exchanger 222, a third heat exchanger 224, and a fourth heat exchanger 280. The structure and function of the first compressor 212 may be similar or identical to that of the compressors 12 described above, and therefore, will not be described again in detail. The structure and function of the second compressor 214 may be similar or identical to that of second compressors 14 described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger 216 may be similar or identical to that of heat exchanger 16 described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger 222 may be similar or identical to that of heat exchanger 22 described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger 224 may be similar or identical to that of heat exchanger 24 described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger 280 may be similar or identical to that of the sixth heat exchanger 280 described above, and therefore, will not be described again in detail.

[0060] The climate-control system 210 also includes a first fluid passageway 230, a vapor inlet line 232, and a second fluid passageway 234. The first fluid passageway 230 extends from a discharge line 236 of the first compressor 212 to an inlet 238 of a multiport valve 240 (e.g., a 3-way valve as shown). A fourth heat exchanger 280 may be placed on the first fluid passageway 230. A fan 282 may be provided to force a fluid (e.g., air) over the fourth heat exchanger 280. The vapor inlet line 232 extends from a first outlet 243 of the multiport valve 240 to intermediate pockets of a compression mechanism 242 of the second compressor 214 (via a vapor-injection conduit 244). The second fluid passageway extends from a second outlet 246 of the multiport valve 240 to a suction line 248 of the second compressor 214.

[0061] Compressed working fluid discharged from the first compressor 212 may flow to the inlet 238 of the multiport valve 240. If the climate-control system 210 does not have a medium temperature load (i.e., the climate-control system 210 does not require the second heat exchanger 224 to absorb heat from a space to be cooled), for example, the working fluid flowing through the multiport valve 240 is directed out the second outlet 246 of the multiport valve 240 to the suction line 248 of the second compressor 214 to be compressed by the compression mechanism 242 of the second compressor 214. In this way, the second compressor 214 acts as a second-stage pump, for example, to circulate the working fluid through the fluid-circuit of the climate-control system 210. A check valve 252 may be disposed along a third fluid passageway 254 extending from the second heat exchanger 222 to the suction line 248 to prevent back-flow into the second heat exchanger 222.

[0062] If the climate-control system 210 does have a medium temperature load (e.g., the climate-control system 210 requires the second heat exchanger 224 to absorb heat from the space to be cooled), the working fluid flowing through the inlet 238 of the multiport valve 240 is directed out the first outlet 243 of the multiport valve 240 to the vapor inlet line 232 where it flows to intermediate pockets of the compression mechanism 242 of the second compressor 214 (via the vapor-injection conduit 244).

[0063] With reference to FIG. 5, a climate-system 310 may be provided that may be generally similar to the climate-control systems 10, 210 described above, apart from any exception noted below. The climate-control system 310 may include a fluid-circuit having a first compressor 312, a second compressor 314, a first heat exchanger 316, a second heat exchanger 322, a third heat exchanger 324, and a fourth heat exchanger 380. The structure and function of the first compressor 312 may be similar or identical to that of the compressors 12, 212 described above, and therefore, will not be described again in detail. The structure and function of the second compressor 314 may be similar or identical to that of second compressors 14, 214 described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger 316 may be similar or identical to that of heat exchangers 16, 216 described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger 322 may be similar or identical to that of heat exchangers 22, 222 described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger 326 may be similar or identical to that of heat exchangers 26, 226 described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger 380 may be similar or identical to that of heat exchangers 280, 80 described above, and therefore, will not be described again in detail.

[0064] The climate-control system 310 also includes a first fluid passageway 330, a vapor inlet line 332, and a second fluid passageway 334. The first fluid passageway 330 extends from a discharge line 336 of the first compressor 312 to an inlet 338 of a multiport valve 340. A fourth heat exchanger 380 may be placed on the first fluid passageway 330. The first fluid passageway 330 then extends from the fourth heat exchanger 380 to an inlet 338 of a multiport valve 340. The vapor inlet line 332 extends from a first outlet 343 of the multiport valve 340 to intermediate pockets of a compression mechanism 342 of the second compressor 314 (via a vapor-injection conduit 344). The second fluid passageway 334 extends from a second outlet 346 of the multiport valve 340 to a suction line 348 of the second compressor 314. A check valve 352 may be placed along the second fluid passageway 334 to prevent working fluid from flowing back into the second heat exchanger 322.

[0065] The climate-control system 310 may also include a refrigerant-to-refrigerant heat exchanger loop 384. The refrigerant-to-refrigerant heat exchanger loop 384 may include a refrigerant-to-refrigerant heat exchanger loop pump 386, configured to pump working fluid through the refrigerant-to-refrigerant heat exchanger loop 384. From the refrigerant-to-refrigerant heat exchanger loop pump, the refrigerant-to-refrigerant heat exchanger loop 384 may continue to the fourth heat exchanger 380. In the fourth heat exchanger 380, the working fluid in the refrigerant-to-refrigerant heat exchanger loop absorbs heat from the working fluid in the first fluid passageway 330. From the fourth heat exchanger 380, the refrigerant-to-refrigerant heat exchanger loop may continue to the discharge line 374 of the second compressor 314. A check valve 388 may be disposed on the refrigerant-to-refrigerant heat exchanger loop 384 between the fourth heat exchanger 380 and the discharge line 374 of the second compressor 314 to prevent back-flow of working fluid into the fourth heat exchanger 380.

[0066] From the discharge line 374 of the second compressor 314, the refrigerant-to-refrigerant heat exchanger loop 384 continues to the first heat exchanger 316, where the working fluid may be cooled. From the first heat exchanger, the refrigerant-to-refrigerant heat exchanger loop 384 continues to the refrigerant-to-refrigerant heat exchanger loop pump 386, thereby completing the loop disclosed herein. In this configuration, heat from the first compressor 312 is transferred from the working fluid in the first passageway 336 to the working fluid in the refrigerant-to-refrigerant heat exchanger loop 384 in the fourth heat exchanger 380. Heat from the first compressor 312 thereby bypasses the second compressor 314 and flows to the first heat exchanger 316, where it may be removed from the working fluid. For instance, the first heat exchanger 316 may be an outdoor heat exchanger and the heat from the first compressor 312 may be rejected into the ambient air outdoors.

[0067] With reference to FIG. 6, a climate-system 410 may be provided that is generally similar to the climate-control systems 10, 210, 310 described above, apart from any exception noted below. The climate-control system 410 may include a fluid circuit having one or more first compressors 412, one or more second compressors 414, a first heat exchanger 416 (an outdoor heat exchanger such as a condenser), a flash tank 420, a third heat exchanger 422 (an indoor heat exchanger such as a medium-temperature evaporator, for example), a third heat exchanger 424 (an indoor heat exchanger such as a low-temperature evaporator, for example). The first compressors 412 and / or the second compressors 414 may pump working fluid (e.g., refrigerant, carbon dioxide, etc.) through the circuit.

[0068] The structure and function of the first compressors 412 may be similar or identical to that of the compressors 12, 212, 312 described above, and therefore, will not be described again in detail. The structure and function of the second compressors 414 may be similar or identical to that of second compressors 14, 214, 314 described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger 416 may be similar or identical to that of heat exchangers 16, 216, 316 described above, and therefore, will not be described again in detail. The structure and function of the flash tank 420 may be similar or identical to the structure and function of the flash tank 20 described above, and therefore will not be described again in detail. The structure and function of the third heat exchanger 422 may be similar or identical to that of heat exchangers 22, 222, 322 described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger 424 may be similar or identical to that of heat exchangers 24, 224, and 324 described above, and therefore, will not be described again in detail. The structure and function of the fifth heat exchanger 480 may be similar or identical to that of the heat exchangers 80, 280, and 380 described above, and therefore, will not be described again in detail.

[0069] The climate-control system 410 may also include a second fluid passageway 448, a liquid outlet 460, and a fourth header 462. The second fluid passageway 448 extends from the liquid outlet 460 to the fourth header 462. The structure and function of the second fluid passageway 448 may be similar or identical to that of second fluid passageway 48, and therefore will not be described again in detail. The liquid outlet 460 may be similar or identical to that of the liquid outlet 60 and therefore will not be described again in detail. The fourth header 462 may be similar or identical to that of the fourth header 62, and therefore will not be described again in detail. The climate-control system 410 may also include a refrigerant-to-refrigerant heat exchanger loop 484. The structure and function of the refrigerant-to-refrigerant heat exchanger loop 484 may be similar or identical to the refrigerant-to-refrigerant heat exchanger loop 384 described above, and therefore will not be described again in detail.

[0070] The climate control system 410 may also include a fourth fluid passageway 452, a second header 439 and a fifth header 470. The fourth fluid passageway 452 extends from the second header 439 to the fifth header 470. The structure and function of the fourth fluid passageway 452 may be similar or identical to that of the fourth fluid passageway 52 and therefore will not be described again in detail. The structure and function of the second header 439 may be similar or identical to that of the second header 39 and therefore will not be described again in detail. The structure and function of the fifth header 470 may be identical or akin to the fifth header 70 and will not be described again in detail.

[0071] A fifth fluid passageway 490 may extend between the second fluid passageway 448 and the fourth fluid passageway 452. The fifth fluid passageway 490 may extend from a point in the second fluid passageway 448 between the first heat exchanger 422 and the fourth header 462 to a point in the fourth fluid passageway 452 between the second header 439 and the fifth heat exchanger 480. A variable flow rate valve 492 may be disposed on the second fluid passageway 490. The variable flow rate valve 492 may be, for instance, an electronic expansion valve or a pressure regulator. The variable flow rate valve 492 may be configured to allow a variable flow of working fluid from the first compressors 412 to the suction line 464 of the second compressors 414 through the fifth fluid passageway 490, thereby reducing the discharge pressure of the first compressors 412.

[0072] A sixth fluid passageway 494 may extend from the fourth fluid passageway 452. The sixth fluid passageway 494 may extend from a point in the fourth fluid passageway 452 between the second header 339 and the fourth heat exchanger 480 to one or more pressure switches 496. The number of switches may be equal to the number of first compressors 412. The pressure switches 496 may be configured to shut off one or more of the first compressors 412 when the pressure of the working fluid in the sixth fluid passageway 452 exceeds a setpoint, i.e. a cut-out set point. For instance, one of the first compressors 412, compressor 412 A, may be communicatively connected to one of the pressure switches 496 (e.g., switch A having a setpoint A). When the pressure in the working fluid at switch A exceeds setpoint A, compressor A may turn off. Similarly, another one of the first compressors 412, compressor 412 B, may be communicatively connected to another of switches 496 (e.g., switch B having setpoint B). When the pressure in the working fluid at switch B exceeds setpoint B, compressor B may turn off. Setpoints A and B may be different, thereby allowing the first compressors 412 (e.g., 412A, 412B) to shut off sequentially via switches 496 (e.g., switches A and B), with each having a different cut-out set point.

[0073] With reference to FIG. 7, a climate-system 510 may be provided with a self-powered circulation pump 586. The climate-system 510 may be generally similar to the climate-control systems 10, 210, 310 and 410, apart from any differences or modifications. The climate-control system 510 may include a fluid-circuit having one or more first compressors 512, one or more second compressors 514, a first heat exchanger 516, a second heat exchanger 524, a third heat exchanger 526, and a fourth heat exchanger 580. The structure and function of the first compressors 512 may be similar or identical to that of the compressors 12, 212, 312 and 412 described above, and therefore, will not be described again in detail. The structure and function of the second compressors 414 may be similar or identical to that of second compressors 14, 214, 314 and 414 described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger 516 may be similar or identical to that of heat exchangers 16, 216, 316 and 416 described above, and therefore, will not be described again in detail. The structure and function of the second heat exchanger 524 may be similar or identical to that of heat exchangers 24, 224, 324, and 424 described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger 526 may be similar or identical to that of heat exchangers 26, 226, 326, and 426 described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger 580 may be similar or identical to that of the sixth heat exchanger 280 and fourth heat exchanger 480 described above, and therefore, will not be described again in detail.

[0074] The climate-control system 510 also includes a first fluid passageway 530. The structure and function of the first fluid passageway 530 may be similar or identical to the structure and function of the first fluid passageway 430 above and therefore will not be described again in detail. The climate-control system 510 also includes a refrigerant-to-refrigerant heat exchanger loop 584. The structure and function of the refrigerant-to-refrigerant heat exchanger loop 584 may be similar or identical to the refrigerant-to-refrigerant heat exchanger loops 484 and 384 described above, and therefore will not be described again in detail.

[0075] The climate-control system 510 may include a self-circulation pump 586. The self-circulation pump 586 may be placed on the refrigerant-to-refrigerant heat exchanger loop 584. The self-circulation pump 586 may include a first pump set 588 and a second pump set 590. Working fluid in the refrigerant-to-refrigerant heat exchanger loop 584 may flow from the first pump set 588 to the fourth heat exchanger 580. From the fourth heat exchanger 580 the working fluid continues to the second pump set 590. From the second pump set 590 the working fluid continues to the first heat exchanger 516. From the first heat exchanger 516 the working fluid returns to the first pump set 586, thereby completing the refrigerant-to-refrigerant heat exchanger loop 584.

[0076] With reference to FIG. 8, the self-powered circulation pump 586 is shown. The self-powered circulation pump 586 may include a case 602. The case 602 may extend from a case cover 604 to a case base 606, from a first case sidewall 608 to a second case side wall 610, and from a fluid entry wall 612 to a fluid exit wall 614. The entry wall 612 defines a first fluid entry hole 628 and a second fluid entry hole 630. The exit wall 614 defines a first fluid exit hole 632 and a second fluid exit hole 634.

[0077] The self-powered circulation pump 586 includes a first pump 616, and a second pump 618 disposed within the case 602. The first pump 616 and second pump 618 may be attached to the case 602 by one of the many attachment options known in the art (e.g., welding or bolting). The first pump 616 includes a first pump case 619, which includes a first pump case wall 620, a first pump case second wall 622, and a first pump case side wall 636 extending between the first pump case first wall 620 and the first pump case second wall 622. A first pump entry pipe 638 extends from the first pump side wall 636, and a first pump exit pipe 640 extends from the first pump side wall 636 on the opposite side of the first pump entry pipe 638. The second pump 618 includes a second pump case 641. The second pump case 641 includes a second pump case first wall 642, a second pump case second wall 644, and a second pump case side wall 646 extending from the second pump case first wall 642 to the second pump case second wall 644. A second pump exit pipe 648 extends from the second pump case side wall 646, and a second pump entry pipe 650 extends from the second pump side wall 646 opposite the second pump exit pipe 648.

[0078] The first pump 616 is disposed within the case 602 such that the first pump fluid entry pipe 638 extends through the first fluid entry hole 628 and the first pump exit pipe 640 extends through the first exit hole 632. The second pump 618 is disposed within the case 602 such that the second pump exit pipe 648 extends through the second fluid exit hole 634 and the second pump entry pipe 650 extends through the second fluid entry hole 630.

[0079] The first pump case first wall 620 may define a first pump case first wall first shaft hole 652 and a first pump case first wall second shaft hole 654. The first pump case second wall 622 may define a first pump case second wall first shaft hole 656 and a first pump case second wall second shaft hole 658. The second pump case first wall 624 may define a second pump case first wall first shaft hole 664 and a second pump case first wall second shaft hole 666. A first shaft 660 may be disposed through the first pump case first wall first shaft hole 652, the first pump case second wall first shaft hole 565 the second pump case first wall first shaft hole 664, and the second pump case second wall first shaft hole 668. A second shaft 662 may be disposed through the first pump case first wall second shaft hole 654, the first pump case second wall second shaft hole 658, the second pump case first wall second shaft hole 666 and the second pump case second wall second shaft hole 670.

[0080] The volume enclosed by the first pump case, i.e. the volume bounded by the first pump case first wall 620, the first pump case second wall 622, and the first pump case side wall 636 defines a displacement D1. The volume enclosed by the second pump case, i.e., the volume bounded by the second pump case first wall 624, the second pump case second wall 626 and the second pump case side wall 646 defines a displacement D2. The displacement D2 is greater than the displacement D1. For instance, the distance between the first pump case first wall 620 and the first pump case second wall 622 may be less than the distance between the second pump case first wall 624 and second pump set case second wall 626, thereby creating a displacement D2 that is greater than displacement D1.

[0081] With reference to FIG. 9, a cut-away view of an exemplary first pump 616 and second pump 618 is shown. FIG. 8 may show the first pump 616 and the second pump 618 as they may be identical in this view. The first pump 616 and second pump 618 may be external gear pumps. The first pump 616 and second pump 618 may include a first rotor 672 (e.g., a first gear) located in the first pump case 619 and second pump case 641. The first rotor 672 may include a plurality of first gear teeth 676 and defines a first rotor hole 678 at the center of the first gear 672. The first shaft 660 is disposed inside the first rotor hole 678 and is rigidly attached to the first rotor 672. The first rotor 672 and the first shaft 660 may rotate within the first pump case 619 or second pump case 641. The first pump 616 and second pump 618 may include a second rotor 674 (e.g., a second gear), which may include a plurality of second gear teeth 680 which intermesh with the plurality of first gear teeth 676 at an intermeshing zone 682. The second rotor 674 may define a second rotor hole 684 at the center of the second rotor 674. The second shaft 662 is disposed within the second gear hole 684 rigidly attached to the second rotor 674. The second rotor 674 and second shaft 662 may rotate within the first pump case 619 or second pump case 641. It should be appreciated that the first pump 616 and second pump 618 may be any type of positive displacement pump, for instance the first pump 616 and second pump 618 may comprise gerotors or another internal gear pump.

[0082] With reference to FIG. 10, as working fluid in the refrigerant-to-refrigerant heat exchanger loop 584 flows through the fourth heat exchanger 580, it receives heat generated from working fluid in the first fluid passageway 530 as it flows between the first pump 616 and second pump 618. The working fluid flowing from the first pump 616 through the first pump set exit pipe 640, to the fourth heat exchanger 580 to the second pump set 618 via the second pump set entry pipe 650 has a pressure P2. Working fluid flowing from the second pump set 618 via the second pump set exit pipe 648 flows to the first heat exchanger 516, where it is cooled. Working fluid flowing from the second pump set 618 to the first heat exchanger 516 has a pressure P3. Working fluid cooled by the first heat exchanger 516 flows into the first pump 616 via the first pump set entry pipe 638. Working fluid flowing from the first heat exchanger 516 to the first pump 616 has a pressure P1. From the first pump 616, working fluid flows into the fourth heat exchanger 580, completing the refrigerant-to-refrigerant loop 584.

[0083] The working fluid in the refrigerant-to-refrigerant loop 584 flowing from the first heat exchanger 516 to the first pump 616 via the first pump entry pipe 638 has a pressure P1. The working fluid in the refrigerant-to-refrigerant loop 584 flowing from the second pump 618 via the second pump exit pipe 648 to the first heat exchanger 516 has a pressure P3. The first heat exchanger 516 causes the pressure of the working fluid to decrease due to the cooling of the working fluid in the first heat exchanger 516. Therefore, the pressure of the working fluid flowing from first heat exchanger 516 to the first pump 616, P1, is lower than the pressure of the working fluid flowing to the first heat exchanger 516 from the second pump 618. The pressure in the working fluid in the refrigerant-to-refrigerant loop 584 flowing from the first pump 616, through the fourth heat exchanger 580, to the second pump 618, P2, is greater than P1 due to pressure added by the first pump 616. The manner in which the first pump 616 adds pressure to the working fluid is described in detail below.

[0084] When the working fluid in the first fluid passageway 530 is warmer than the working fluid in the refrigerant-to-refrigerant loop 584, heat is transferred from the working fluid in the first fluid passageway 530 to the working fluid in the refrigerant-to-refrigerant loop 584 in the fourth heat exchanger 580. Therefore, when heat is transferred to the refrigerant-to-refrigerant loop 584, the working fluid between the fourth heat exchanger 580 and the second pump entry pipe 650 has a higher temperature than that of the working fluid flowing between the first pump exit pipe 640 and the fourth heat exchanger 580. This increase in temperature causes the density of the working fluid to increase as it flows through the fourth heat exchanger 580.

[0085] The mass flow rate of the working fluid flowing through the refrigerant-to-refrigerant loop 584 flowing from the first pump exit pipe 640 to the second pump entry pipe 650 in conserved, i.e., no mass is added or removed. The mass flow rate relates to the volumetric flow rate per the following equation:{dot over (m)}=ρ{dot over (V)}where {dot over (m)} is the mass flow rate, ρ is the density of the fluid, and {dot over (V)} is the volumetric flow rate. The mass flow rate {dot over (m)} of the working fluid is conserved, i.e., the mass flow rate {dot over (m)} of the working fluid flowing from the first pump exit pipe 640 to the fourth heat exchanger 580 is the same as the mass flow rate {dot over (m)} of the working fluid flowing from the fourth heat exchanger 580, as no mass is added or removed from the working fluid in this segment of the refrigerant-to-refrigerant loop 584. However, the density ρ of the working fluid flowing from the first pump exit pipe 640 to the fourth heat exchanger 580 is higher than the density ρ of the working fluid flowing from the fourth heat exchanger 580 to the second pump entry pipe 650 due to the above-described increase in temperature. Therefore, the volumetric flow rate {dot over (V)} of the working fluid increases when it receives heat in the fourth heat exchanger 580. This increase in the volumetric flow rate {dot over (V)} may drive the second pump 618.As described above, the first pump 616 and second pump 618 are mechanically linked, e.g., by the first shaft 660. A driving torque imparted on the second pump 618 may be transferred to the first pump 616 by the first shaft 660. The second pump 618 tends to be driven by the pressure drop across the second pump (i.e., P2-P3). In addition, the second pump 618 tends to be driven by the increase in the volumetric flow rate caused by the addition of the energy added to the working fluid which was added to the working fluid as it passed through heat exchanger 580.

[0087] Pressure changes across the first pump (i.e., P1-P2) tends to impede the flow of working fluid through the refrigerant-to-refrigerant loop 584 as P2 tends to be greater than P1. The first pump 616 is driven by the second pump 618 to overcome this tendency. That is, the second pump 618, driven by the change in pressure P2-P3 and the increase in the volumetric flow rate V, drives the first pump 616 by, for instance, turning the first shaft 680 which in turn drives the first pump 616. The first pump 616 and second pump 618 have different displacements, D1 and D2 respectively, with D2 being greater than D1. The driving torque may be approximated by the following formula:(P2−P3)D2=(P1−P2)D1 As D2 is greater than D1, a smaller pressure differential across the second pump 618 can generate a larger pressure differential across the first pump 616.The self-powered circulation pump 586 is thereby self-regulating. If, for example, the heat transferred from the working fluid in the first passageway 536 to the working fluid in the refrigerant-to-refrigerant loop 584 in the fourth heat exchanger 580 increase, the temperature of the working fluid exiting the fourth heat exchanger 580 will increase. The increase in temperature of the working fluid causes the density ρ of the working fluid exiting the fourth heat exchanger 580 to decrease. The decrease of the density ρ causes an increase in the volumetric flow rate V, which in turn drives the second pump 618 by applying a torque to the first gear 672 and second gear of the second pump 618. The second pump 618 then drives the first pump 616 by transferring this torque via the mechanical link, e.g., the first shaft 680. The first pump 616, driven by the second pump 618, thereby causes the pressure (P2) of the working fluid that flows from the first pump 616, through the fourth heat exchanger 580, to the second pump 618 to increase. The increase in pressure P2 in turn increases the torque applied to the first gear and second gear of second pump 618, causing the first gear and second gear of the second pump 618, the first shaft 680, and the first gear and second gear of the first pump 616, to spin faster, increasing the flow rate of the working fluid flowing through the fourth heat exchanger 580. The increased flow rate thereby enables the working fluid in the refrigerant-to-refrigerant loop 584 to absorb more heat from working fluid in the first fluid passageway 530.

[0089] This process continues until the difference in temperature (ΔT) between the working fluid in the first fluid passageway 530 and the refrigerant-to-refrigerant loop 584 begins to decrease. As ΔT decreases, less heat is absorbed by the working fluid in the refrigerant-to-refrigerant loop 584 and its temperature decreases. As the temperature decreases, the density ρ of the working fluid increases, and the volumetric flow rate V of the working fluid decreases. As the volumetric flow rate V decreases, a lower driving torque is imparted on the second pump 618, which in turn imparts a lower torque on the first pump 616 via the first shaft 680, lowering the displacement rates of both the first pump 616 and second pump 618. The lowering of the torque imparted on the first pump 616 causes the pressure P2 to decrease, further lowering the driving torque imparted on the second pump 618, which in turn imparts a lower driving torque on the first pump 616.

[0090] With reference to FIG. 11, another climate-system 710 may be provided flood-back mitigation valve 784. The climate-system 710 may be like the climate-control systems 10, 210, 310, 410, and 510, apart from any differences or modifications. The climate-control system 710 may include a fluid-circuit having one or more first compressors 712, one or more second compressors 714, a first heat exchanger 716, a second heat exchanger 720, and a third heat exchanger 724 and a fourth heat exchanger 726. The structure and function of the first compressors 712 may be similar or identical to that of first compressors 12, 212, 312, 412, and 512. The structure and function of the second compressors 714 may be similar or identical to that of second compressors 14, 214, 314, 414, and 514 described above, and therefore, will not be described again in detail. The structure and function of the first heat exchanger 716 may be similar or identical to that of heat exchangers 16, 216, 316, 416, and 516 described above, and therefore, will not be described again in detail. The structure and function of the flash tank 720 may be similar or identical to that of flash tanks 20, 220, 320, 420, and 520 described above, and therefore, will not be described again in detail. The structure and function of the third heat exchanger 724 may be similar or identical to that of third heat exchangers 24, 224, 324, 424, and 524 described above, and therefore, will not be described again in detail. The structure and function of the fourth heat exchanger 726 may be similar or identical to that of fourth heat exchangers 26, 226, 326, 426, and 526, and therefore will not be described again in detail.

[0091] Each first compressor 712 may include a shell 727, a compression mechanism 728 and a vapor-injection conduit 730 (e.g., a vapor-injection inlet). The compression mechanism 728 may be disposed within the shell 727 having an inlet 732 (e.g., a first inlet fitting) and an outlet 734 (e.g., an outlet fitting). The inlet 732 may provide fluid to a suction inlet (not shown) of the compression mechanism 728 (e.g., a radially outermost pocket of a scroll compression mechanism). Suction lines 736 may be fluidly coupled to a first header 738 and corresponding inlets 732 of the first compressors 712. In this manner, working fluid exiting the fourth heat exchanger 726 may flow into the first header 738 where it is distributed to the suction lines 736 and the inlets 732 of the first compressors 712 to be compressed by the compression mechanisms 728 of the first compressors 712. After the working fluid is compressed by the compression mechanisms 728 of the first compressors 712, the working fluid can be discharged from the first compressors 712 through the outlets 734 to a second header 739 via discharge lines 740.

[0092] The second fluid passageway 748 extends from a liquid conduit 758 (that is fluidly coupled to a liquid outlet 760 of the flash tank 720) to a fourth header 762 that is in fluid communication with the second compressors 714 via suction lines 764. The second fluid passageway 748 includes a third expansion device 768 (e.g., an expansion valve or capillary tube) and the third heat exchanger 724. A portion of the working fluid flowing through the liquid conduit 758 flows through the third expansion device 766 of the second fluid passageway 748 where its temperature and pressure is lowered. In the third heat exchanger 724, the working fluid may absorb heat from a first space to be cooled (e.g., an interior of a refrigerator, a refrigerated display case, or a cooler). From the third heat exchanger 724, the working fluid flows to the fourth header 762 where it is distributed to the suction lines 764 and the second compressors 714 to be compressed by compression mechanisms 767 of the second compressors 714.

[0093] The first fluid passageway 746 may extend from a vapor outlet 754 of the flash tank 720 to the third header 742 and may include a second expansion device 756 (e.g., an expansion valve or capillary tube). Vapor working fluid in the first fluid passageway 746 flows through the second expansion device 756 where its temperature and pressure is lowered. The vapor working fluid then flows into the second fluid passageway 748 at a location downstream of the second heat exchanger 724.

[0094] The third fluid passageway 750 extends from the liquid conduit 758 to the first header 738 that is in fluid communication with the inlet 332 of the first compressors 712 via the suction lines 736. The third fluid passageway 750 includes a fourth expansion device 768 and the fourth heat exchanger 726. Another portion of the working fluid flowing through the liquid conduit 758 flows through the fourth expansion device 768 of the third fluid passageway 750 where its temperature and pressure is lowered. In the fourth heat exchanger 726, the working fluid may absorb heat from a second space to be cooled (e.g., freezer or a frozen food display case). In some configurations, the working fluid in the third heat exchanger 724 of the second fluid passageway 748 and the working fluid in the fourth heat exchanger 726 of the third fluid passageway 750 may absorb heat from the same space (e.g., the third heat exchanger 724 of the second fluid passageway 748 and the fourth heat exchanger 726 of the third fluid passageway 750 may operate at different times to switch the space between a freezer and a cooler, for example). From the fourth heat exchanger 726, the working fluid may flow into the first header 738 where it is distributed to the suction lines 736 and the inlets 732 of the first compressors 712 to be compressed by the compression mechanisms 728 of the first compressors 712.

[0095] The fourth fluid passageway 752 extends from the second header 739 to a fifth header 770. The working fluid discharged from the first compressors 712 flows through the fourth fluid passageway 752 (via the discharge lines 740) and into the fifth header 770 where it is distributed to intermediate pockets of the compression mechanisms 767 of the second compressors 714 (via vapor inlet lines 774 and vapor conduits 776).

[0096] A flood back mitigation passageway 782 may extend from the second fluid passageway 748 at a location downstream of the second heat exchanger 748 to the fourth fluid passageway 752 at a location downstream of the second header 739. A flood back mitigation valve 784 may be placed on the flood back mitigation passageway 782. The flood back mitigation valve includes a flood back mitigation valve controller 784 which opens and closes the flood back mitigation valve 784 to varying degrees.

[0097] Each of the first compressors 712 and second compressor 714 has an associated compressor controller 772 that monitors and controls operation of the first compressors 712 and second compressors 714. For example, the compressor controller 772 may monitor suction or discharge temperatures or pressures of the first compressors 712 and second compressors 714 with suction or discharge temperature or pressure sensors. For example, a discharge outlet of each first compressor 712 or second compressor 714 can include a respective discharge temperature sensor 775. A discharge pressure sensor 776 can be used in addition to, or in place of, the discharge temperature sensor 777. An input to the fourth header 762 or first header 738 can include both a suction pressure sensor 778 and a suction temperature sensor 780. Further, a discharge outlet of the second header 739 or fifth header 770 can include an associated discharge pressure sensor 776. A discharge temperature sensor 777 can be used in addition to, or in place of, the discharge pressure sensor 776.

[0098] The compressor controllers 774 are in communication with the flood back mitigation valve controller 784. The compressor controllers 774 may instruct the flood back mitigation valve controller 784 to open or close the flood back mitigation valve to varying degrees.

[0099] With reference to FIG. 4, the multiport valve 240 may include a multiport valve controller 241. The multiport valve controller controls the multiport valve 240 by switching the multiport valve 240 between the state in which it directs working fluid from the discharge line 236 of the first compressor 212 to the vapor-injection conduit 244 of the second compressor 214, and the state in which it directs working fluid from the discharge line 236 of the first compressor 212 to the suction line 248 of the second compressor 214.

[0100] Each of the first compressors 212 and second compressor 214 may have an associated compressor controller 215 that monitors and controls operation of the first compressors 212 and second compressors 214. For example, the compressor controller 215 may monitor suction or discharge temperatures or pressures of the first compressor 212 and second compressor 214 with suction or discharge temperature or pressure sensors. For example, a discharge outlet of each first compressor 212 or second compressor 214 can include a respective discharge temperature sensor 284. A discharge pressure sensor 286 can be used in addition to, or in place of, the discharge temperature sensor 284. An input to the suction line 248 of the second compressor 214 or the suction line 292 of the first compressor 212 can include both a suction pressure sensor 288 and a suction temperature sensor 290.

[0101] The present disclosure also relates to systems and methods for flood-back condition mitigation. The present disclosure monitors a rate of change of compressor temperature during compressor operation to determine whether a flood back condition exists. When a flood back condition is detected but is below a limit, heat from the discharge lines of the one or more first compressors may be applied to the suction lines of the one or more second compressors.

[0102] When a negative rate of change of compressor temperature is detected, a function of a compressor's temperature profile (e.g., temperature gradient) is integrated, and the integrated value of the function is compared to a threshold to determine whether to shut down the compressor. If the integrated value is below the threshold, but above zero, a mitigation strategy is implemented. The systems and methods of the present disclosure do not require knowledge of system conditions (e.g., suction superheat or system pressures) but one or more of the thresholds and the terms of the integration function can be adjusted based on a minimum allowable discharge temperature if available. Feedback from the compressor regarding the effectiveness of the protection may be used to adjust one or more terms (e.g., constants) of the integration function and / or the threshold to increase the effectiveness of the protection.

[0103] While controlled liquid injection may be used for cooling and modulating capacity of compressors, unintentional introduction of liquid refrigerant into a compressor can significantly degrade the reliability of the compressor. Determination of a likelihood of having liquid refrigerant in the suction gas of a compressor (flood-back) is often done by determining a degree of superheat in the suction gas or by using a discharge gas temperature to determine the suction gas condition. While the suction superheat method does not easily portray the quality of the return gas if the value is less than one (1), the discharge temperature method can provide some insight into the degree of severity of the flooding condition. Knowing a relative rate of liquid refrigerant return is important for determining an appropriate course of action to protect the compressor.

[0104] While continuous flooding at a low rate may eventually lead to reduced oil viscosity and associated bearing lubrication issues, ring wear, or other lubrication-type failures, the response time to protect against this problem is relatively long. A higher rate of liquid ingestion increases the risk of damage due to lubrication issues but also (and sometimes more importantly) due to the increased risk of damage from high pressures associated with the compression of liquid.

[0105] The present disclosure uses the rate of temperature change from sensor inputs to obtain an indication regarding the severity of the liquid slug (i.e., a flood-back condition). The present disclosure also includes provisions for initiating a flood-back mitigation strategy or protecting the compressor by turning it off.

[0106] The following terms are used in the present disclosure.

[0107] Quality—Mass ratio of gaseous refrigerant to the total (gas+liquid refrigerant) in the return (suction) fluid to a compressor. Quality of one (1) equal (=) no liquid refrigerant.

[0108] Slug—A quantity of liquid that is generally moving with the suction gas flow in the suction line of a compressor, ultimately entering the compressor. A slug generally refers to a condition whereby the bulk density of the suction flow is rapidly increasing due to larger volumetric percentages of liquid. This event is usually associated with the termination of a defrost cycle and is often called a defrost protection routine, although defrost termination may not be the sole cause.

[0109] Flood-back—A quality of suction refrigerant less than 1 (i.e., some continuous return of liquid). This term describes a less rapidly changing scenario than when a compressor is slugged.

[0110] DLT—Discharge line temperature, which is typically the discharge port, head, or top-cap temperature of a compressor.

[0111] dT / dt—Rate of change of temperature with respect to time.

[0112] The present disclosure utilizes an inverse time algorithm to determine when to declare a flood-back condition. A response to the flood-back condition is initiate a flood-back mitigation strategy. Constants used in the algorithm may be adjusted to accommodate different compressor platforms that have different liquid sensitivities, sensor response times, or sensor location changes. If the system monitoring one or more sensors and running the algorithm detects an unsafe condition, the system may take advantage of any communication network or on-board display capability to annunciate that the compressor has been turned off due to slugging and is initiating the liquid clearing procedure.

[0113] FIG. 12 shows the inverse-time algorithm, triggered by a negative rate of discharge temperature versus time. The temperature may be sensed by a probe in the compressor at the discharge port, in the discharge line, or in the head, for example (e.g., sensors 286, 294, 288, 290, 776, 778, 780). The algorithm is triggered by a temperature slope, and the rate at which the integration parameter accumulates depends upon the rate of change. If the parameter (the integrated or accumulated value) exceeds a limit (a predetermined threshold), the compressor is turned off. If the parameter (the integrated or accumulated value) is below the limit (a predetermined threshold), the variable flow rate valve 784 is adjusted to allow working fluid from a discharge line of another compressor into a suction line of the compressor.

[0114] The algorithm includes the following equations:G⁡(t)=T⁢M⁢S*{c[δδs]a-1+β}(Eq. 1)∫0T1G⁡(t)⁢dt=parameter(Eq. 2)∫0T01G⁡(t)⁢dt=parameter⁢ limit(Eq. 3)

[0115] In Eq. 1, the term G(t) denotes an operating compressor temperature gradient function that may indicate a flood back condition. The term TMS denotes a time multiplier setting factor. The terms C and β each denotes an inverse characteristic constant. The term a denotes an inverse characteristic exponent. The terms C, β, and α set the inverse time type. The term δ denotes the rate of change of compressor temperature dT / dt. The term δs denotes a negative rate of change (or temperature slope) used to turn on (i.e., trigger) the algorithm.

[0116] In Eq. 2, the term T denotes operating time since the integration began. Eq. 2 denotes the integration of the function 1 / G (t) over time T. The term parameter on the right-hand side of Eq. 2 is the value of the integral at any time T. In Eq. 3, the value of the integral at time To is the parameter limit. The parameter limit is a pre-determined threshold which defines when the compressor will be tripped (turned off). As will be explained below, these terms can be adjusted based on a minimum allowable discharge temperature if available and feedback from the compressor regarding the effectiveness of the protection if available.

[0117] The term inverse time describes a relationship where the greater the deviation in the error in a term from the target, the faster the term integrates. In other words, if the goal is to correct a term to fix a problem, the corrective action is accelerated the further the term is from the target point. In FIG. 12, a value of rate of change of temperature (δs) is used as a trigger point to turn on the integration function. When turned on, the term 1 / G (t) is integrated over To. When the summation (i.e., the result of the integration) is greater than zero, but below the target point (i.e., the predetermined threshold or parameter limit in Eq. 3), the result of the integration is compared to the previously determined result of the integration. If the result of the integration is higher than the previously determined result of the integration, the flood-back condition is determined to be not improving, and a valve is adjusted to apply additional heat from the discharge lines of the first compressors to the suction lines of the second compressors. When the summation (i.e., the result of the integration) reaches (i.e., becomes greater than or equal to) the target point (i.e., the predetermined threshold or parameter limit in Eq. 3), the compressor is shut down or an alternate mitigation strategy is initiated. Accordingly, the further the value of the negative rate of change of temperature δ is from the target trigger slope δs (i.e., the faster the compressor temperature is decreasing), the faster the result of the integration will sum up to the threshold value, and the faster the algorithm reaches the shutdown point. As will be described in detail below, additional actions may be taken to mitigate the immediate effects of the flood-back event and to reduce the significance of repeated flood-back events through system learning processes.

[0118] The algorithm can operate standalone without any knowledge of system conditions (e.g., suction superheat or system pressures). The algorithm operates with the assumption regarding what the superheat is before the flood-back event occurs. The assumption depends on the application. For example, 50 degrees Fahrenheit (50° F.) superheat may be a reasonable assumption for many refrigeration systems.

[0119] The algorithm can be enhanced using information regarding a minimum allowable discharge temperature, which represents zero degrees Fahrenheit (0° F.) suction superheat (i.e., a temperature that will be developed by a compressor if the compressor is running with no superheat in the suction gas). This information, if available, is incorporated into the algorithm (by considering the difference between actual and minimum allowable compressor temperature) to adjust the parameter limit used by the algorithm to decide when to shut down the compressor and can therefore provide improved protection and / or prevent nuisance shut-down of the compressor or system.

[0120] Knowledge of system conditions (e.g., refrigerant type, compressor efficiency, system pressures) is required to generate a minimum allowable discharge temperature. Other factors that may be considered include whether liquid injection is being used for cooling and modulating the capacity of the compressor. A remote controller may preferably calculate the minimum allowable discharge temperature and provide it to a compressor-based controller that may preferably implement the algorithm for flood-back protection, where real-time compressor temperature is available.

[0121] These embodiments assume that feedback regarding the effectiveness of the protection is unavailable from the compressor. The feedback, if available, can be used to adjust the algorithm's threshold. For example, the algorithm can include an adjustment factor that is incremented each time the feedback indicates insufficient protection. This factor could be applied to the threshold or a time multiplier constant used in the algorithm.

[0122] For example, the feedback may be available from a knock sensor (piezoelectric transducer), indirectly indicating high cylinder pressure by sensing compressor acceleration caused by excessive liquid entering the cylinder. In another example, the feedback may be in the form of a temperature measurement of the lubricant sump. Other examples of the feedback may include variations in the amperage of the compressor motor or power consumption of the compressor, indicating liquid entering the compression chamber of the compressor.

[0123] While the discharge temperature may be a preferred sensor input for the algorithm, the rate of change of temperature from a sensor on the suction side of the compressor can also be effective. For example, this sensor can be a motor temperature sensor (e.g., a Negative Temperature Coefficient (NTC) thermistor or a Resistance Temperature Detector (RTD)), a suction line sensor (e.g., a clip-on external sensor), or a sensor inside the compressor measuring the gas temperature as it enters the compressor.

[0124] Adjustments to the algorithm's constants may be made to account for the differences in the sensor's location and the characteristics of the compressor. For example, compressors that are refrigerant-cooled and have suction gas flowing through the motor may have more reserve thermal energy to flash the liquid than a directed suction gas compressor that must respond quickly to prevent mechanical damage. This can be accounted for by adjusting the algorithm's constants. In the suction-side approach, however, the signal strength may be low if the superheat is low.

[0125] Further, a notification of the detection of liquid, even if the amount of liquid detected is not severe enough to warrant turning off the compressor, can be provided as part of the system's learning process to optimize the system's controls and settings for flood-back protection.

[0126] In sum, the present disclosure proposes a system and a method for detecting a potentially damaging rate of liquid ingestion into a running compressor and reacting to this indication to prevent mechanical damage to the compressor. The system and the method are based on the rate of change of compressor temperature. Also proposed are ways in which the effectiveness of the method can be enhanced if additional sensor inputs are available. These and other aspects of the present disclosure are now described in further detail.

[0127] With reference to FIG. 13, a method 900 for providing flood back protection in compressors (e.g., the second compressors 714 shown in FIG. 10 or the second compressor 214) is shown. The method 900 is performed a compressor controller (e.g., compressor controller 772 or compressor controller 215).

[0128] At 902, the controller 215, 772 determines whether one or more of a minimum allowable discharge temperature of the compressor and feedback from the compressor regarding the effectiveness of the protection are available. For example, data reflecting the above-described system conditions (e.g., refrigerant type, compressor efficiency, system pressures) may be stored on a data storage device connected to the controller. The controller 215, 772 proceeds to 906 if the minimum allowable discharge temperature of the compressor is unavailable and feedback from the compressor regarding the effectiveness of the protection is unavailable. At 904, if one or more of a minimum allowable discharge temperature of the compressor and feedback from the compressor regarding the effectiveness of the protection are available, the controller 215, 772 adjusts the threshold and / or one or more terms (e.g., multiplier, constants, and so on) of the integration function. The controller 215, 772 uses the adjusted values in subsequent processing.

[0129] At 906, the controller 215, 772 determines a rate of change of compressor temperature (e.g., discharge temperature of the second compressor). At 908, the controller 215, 772 determines whether to integrate a function of temperature gradient of the compressor based on the rate of change of compressor temperature. For example, the controller 215, 772 initiates the integration procedure if the rate of change of suction temperature of the compressor is less than or equal to the trigger slope δs. If the rate of change of suction temperature is below the trigger slope, integration is not triggered and the controller 215, 772 returns to 902 if the rate of change of compressor temperature is greater than the trigger slope δs.

[0130] At 910, having been triggered to do so, the controller 215, 772 initiates the mitigation strategy, which is described below in detail. At 912, the controller 215, 772 integrates the temperature gradient function of the compressor. At 914, the controller 215, 772 determines whether the result of the integration procedure (i.e., accumulated value determined with Eq. 2 above) is less than 0. If during the integration process the value of the parameter procedure (i.e., accumulated value determined with Eq. 2 above) becomes less than 0, the controller 215, 772 stops the mitigation strategy at 916 (e.g., closes the flood back mitigation valve) and returns to 902. This occurs when the flood back situation resolves itself prior to a trip decision (e.g., a decision to adjust the flood back mitigation valve or shut down the compressor).

[0131] If the result of the integration procedure is greater than 0, at 918 the controller 215, 772 determines whether the result of the integration procedure is greater than the predetermined threshold. At 920, if the result of the integration procedure is greater than the predetermined threshold (i.e., the parameter limit determined with Eq. 3), the controller 215, 772 shuts down the compressor or initiates an alternative mitigation strategy (i.e., one other than adjusting the flood back mitigation valve). This occurs when the flood back situation is severe enough to be better addressed by shutting down the compressor or performing another mitigation strategy.

[0132] If the result of the integration procedure is greater than 0, but below the predetermined limit, (i.e., the parameter limit determined in Eq. 3) at 922 the controller 215, 772 determines whether the result of the integration procedure is lower than the previously determined result of the integration procedure (i.e., whether tn<t (n−1)). This occurs when the flood back situation is improving. If the result of the integration procedure is lower than the previously determined result of the integration procedure, at 926 the controller 215, 772 issues a warning message indicating presence of some (but not severe) amount of liquid within the compressor, and the controller 215, 772 returns to 906 for continued integration.

[0133] If the result of the integration procedure is not lower than the result of the previously determined result of the integration procedure (i.e., the flood back situation is not improving), at 924 the controller 215, 772 adjusts the flood back mitigation valve to further warm the working fluid entering the suction lines of the compressors. For example, the flood back mitigation valve 784 may be opened to allow working fluid to flow through the flood back mitigation passageway 782 and to the suction lines 764 of the second compressors 714. If already opened, the flood back mitigation valve 784 may be opened further to allow additional working fluid to flow through the flood back mitigation passageway 782 and to the suction lines 764 of the second compressors 714. Alternatively, the multiport valve 248 may be switched from the state in which it directs working fluid from the discharge line 236 of the first compressor 212 to the vapor inlet line 244 of the second compressor 214 to the state in which it directs working fluid from the discharge line 236 of the first compressor 212 to the suction line 248 of the second compressor 214. At 926 the controller 215, 772 issues a warning message indicating presence of some (but not severe) amount of liquid within the compressor, and the controller 215, 772 returns to 906 for continued integration.

[0134] In this application, the term “module” or “control module” may be replaced with the term circuit. The term “module” may refer to, be part of, or 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 (shared, dedicated, or group) that executes code; memory (shared, dedicated, or group) that stores code executed by a processor; 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-chip.

[0135] The module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing. In a further example, a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.

[0136] The term code, as used above, may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, 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 encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.

[0137] The term memory circuit is a subset of the term computer-readable medium. The term computer-readable medium, as used herein, does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).

[0138] In this application, apparatus elements described as having attributes or performing particular operations are specifically configured to have those particular attributes and perform those particular operations. Specifically, a description of an element to perform an action means that the element is configured to perform the action. The configuration of an element may include programming of the element, such as by encoding instructions on a non-transitory, tangible computer-readable medium associated with the element.

[0139] The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general-purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

[0140] The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input / output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0141] The computer programs 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 from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.

[0142] None of the elements recited in the claims are intended to be a means-plus-function element within the meaning of 35 U.S.C. § 112 (f) unless an element is expressly recited using the phrase “means for,” or in the case of a method claim using the phrases “operation for” or “step for.”

[0143] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A climate control system comprising:a first compressor having a first compression mechanism, a first first compressor inlet and a first compressor outlet;a second compressor in fluid communication with the first compressor and having a first second compressor inlet, a second compression mechanism, the first second compressor inlet fluidly coupled to the second compression mechanism, the second compression mechanism is configured to receive working fluid from the first compressor through the first second compressor inlet;a fluid passageway extending from the first compressor outlet to the first second compressor inlet;a heat exchanger disposed on the fluid passageway; anda fan configured to force air over the heat exchanger.

2. The climate control system of claim 1, further comprising:a second second compressor inlet, the second second compressor inlet fluidly coupled to the second compression mechanism; anda multiport valve, the multiport valve comprising a multiport valve inlet, a first multiport valve outlet, and a second multiport valve outlet, the multiport valve inlet fluidly coupled to the first compressor outlet, the first multiport valve outlet fluidly coupled to the first second compressor inlet, and the second multiport valve outlet fluidly coupled to the second second compressor inlet.

3. The climate control system of claim 1, further comprising:a second second compressor inlet fluidly coupled to the second compression mechanism and a second compressor outlet;a second heat exchanger comprising a second heat exchanger inlet and a second heat exchanger outlet, the second heat exchanger inlet fluidly coupled to the second compressor outlet;a third heat exchanger comprising a third heat exchanger inlet and third heat exchanger outlet, the third heat exchanger outlet fluidly coupled to the first second compressor inlet; anda fourth heat exchanger comprising a fourth heat exchanger inlet and fourth heat exchanger outlet, the fourth heat exchanger outlet fluidly coupled to the first first compressor inlet.

4. The climate control system of claim 3, further comprising:a second first compressor inlet fluidly coupled to a first compression mechanism; anda flash tank comprising a flash tank inlet, the flash tank inlet fluidly coupled to the second heat exchanger outlet, a flash tank vapor outlet, the flash tank vapor outlet fluidly coupled to the second first compressor inlet, and a flash tank liquid outlet, the flash tank liquid outlet fluidly coupled to the third heat exchanger inlet and fourth heat exchanger inlet.

5. The climate control system of claim 1, further comprising at least one more first compressor.

6. The climate control system of claim 1, further comprising at least one more second compressor.

7. A climate control system comprising:a first compressor comprising a first first compressor inlet and first compressor outlet;a second compressor in fluid communication with the first compressor and having a first second compressor inlet, a second second compressor inlet, a second compressor outlet, a second compression mechanism, the first second compressor inlet and second second compressor inlet fluidly coupled to the second compression mechanism, the second compression mechanism is configured to receive working fluid from the first compressor through the second second compressor inlet;a first heat exchanger comprising a first heat exchanger outlet and first heat exchanger inlet, the first heat exchanger inlet fluidly coupled to the second compressor outlet;a fluid passageway extending from the first compressor outlet to the second second compressor inlet;a second heat exchanger disposed on the fluid passageway; anda refrigerant-to-refrigerant heat exchanger loop comprising a refrigerant-to-refrigerant heat exchanger loop pump;wherein working fluid flows from the refrigerant-to-refrigerant heat exchanger loop pump to the second heat exchanger, to the first heat exchanger, and returns to the refrigerant-to-refrigerant heat exchanger loop pump.

8. The climate control system of claim 7, further comprising a check valve between the refrigerant-to-refrigerant heat exchanger loop pump and second heat exchanger.

9. The climate control system of claim 7, wherein the refrigerant-to-refrigerant heat exchanger loop pump is a self-powered circulation pump comprising:a first pump set comprising a first pump set case, a first rotor disposed within the first pump set case, and a first shaft extending through the first rotor; anda second pump set comprising a second pump set case, a second rotor disposed within the second pump set case, the second rotor configured to receive the first shaft.

10. The climate control system of claim 9, wherein the first pump set and second pump set are gear pumps.

11. The climate control system of claim 9, wherein the first pump set and second pump set a gerotors.

12. The climate control system of claim 9, wherein a volume enclosed by the first pump set case is greater than a volume enclosed by the second pump set case.

13. The climate control system of claim 7, further comprising a plurality of first compressors.

14. The climate control system of claim 7, further comprising a plurality of second compressors.

15. A climate control system comprising:a first compressor having a first compression mechanism, a first first compressor inlet and a first compressor outlet;a second compressor in fluid communication with the first compressor and having a first second compressor inlet, a second compression mechanism, the first second compressor inlet fluidly coupled to the second compression mechanism, the second compression mechanism is configured to receive working fluid from the first compressor through the first second compressor inlet;a first fluid passageway extending from the first first compressor inlet to the first second compressor inlet; anda second fluid passageway extending from the first fluid passageway to a switch.

16. The climate control system of claim 15, wherein the switch is configured to turn off the first compressor.

17. The climate control system of claim 15, further comprising a plurality of first compressors and a plurality of corresponding switches, wherein each switch is configured to turn of a corresponding first compressor.

18. The climate control system of claim 17, wherein each switch has a different cut-out set point.

19. The climate control system of claim 15, further comprising a second second compressor inlet fluidly coupled to the second compression mechanism;a second heat exchanger comprising a second heat exchanger inlet and a second heat exchanger outlet, the second heat exchanger inlet fluidly coupled to the second compression mechanism;a third heat exchanger comprising a third heat exchanger inlet and a third heat exchanger outlet, the third heat exchanger outlet fluidly coupled to the first second compressor inlet;a fourth heat exchanger comprising a fourth heat exchanger inlet and fourth heat exchanger outlet, the fourth heat exchanger outlet fluidly coupled to the first first compressor inlet; anda third fluid passageway extending from the third heat exchanger outlet to the second second compressor inlet.

20. The climate control system of claim 19, further comprising a fourth fluid passageway extending between the first fluid passageway and the third fluid passageway, the fourth fluid passageway comprising a variable flow rate valve.

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