Active management of refrigerant charge between condenser loops

Abstract

The refrigeration system comprises an evaporator having an evaporator inlet and an evaporator outlet; (i) a compressor outlet, and (ii) a compressor inlet coupled to the evaporator outlet; a first condenser loop coupled between the compressor outlet and the evaporator inlet, the first condenser loop having a first inlet valve, a first condenser, and a first redistribution valve coupling the first condenser loop to the compressor inlet; and a second condenser loop coupled between the compressor outlet and the evaporator inlet, the second condenser loop having a second inlet valve, a second condenser, and a second redistribution valve coupling the second condenser loop to the compressor inlet.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of and claims priority to U.S. Non-Provisional Patent Application No. 18 / 194,300, filed March 31, 2023, entitled "ACTIVE MANAGEMENT OF REFRIGERANT CHARGE BETWEEN CONDENSER LOOPS," which in turn claims priority to U.S. Provisional Patent Application No. 63 / 370,202, filed August 2, 2022, entitled "ACTIVE MANAGEMENT OF REFRIGERANT CHARGE BETWEEN CONDENSER LOOPS," the disclosures of which are incorporated herein by reference in their entireties.

[0002] This application also claims priority to U.S. Provisional Patent Application No. 63 / 370,202, filed August 2, 2022, the disclosure of which is incorporated by reference herein in its entirety.

[0003] This disclosure relates to active management of refrigerant charge between multiple condenser loops. [Background technology]

[0004] Automotive manufacturers continue to develop their thermal systems to meet changing demands in terms of improved efficiency, increased capacity, or smaller size. For example, increased efficiency may involve improving or optimizing the way thermal system performance impacts the vehicle's range. As another example, increased capacity may involve designing a thermal system to handle significant heat loads from components such as a battery pack or to provide cabin heating. In previous approaches, refrigerant in thermal systems has been managed using accumulators or charge compensators, where a reservoir stores excess refrigerant charge. The reservoir's full refrigerant volume may be moved in or out based on operating mode. Summary of the Invention

[0005] In a first aspect, a refrigeration system includes an evaporator having an evaporator inlet and an evaporator outlet; (i) a compressor outlet, and (ii) a compressor inlet coupled to the evaporator outlet; a first condenser loop coupled between the compressor outlet and the evaporator inlet, the first condenser loop having a first inlet valve, a first condenser, and a first redistribution valve coupling the first condenser loop to the compressor inlet; and a second condenser loop coupled between the compressor outlet and the evaporator inlet, the second condenser loop having a second inlet valve, a second condenser, and a second redistribution valve coupling the second condenser loop to the compressor inlet.

[0006] Implementations may include any or all of the following features: the first redistribution valve connects a point on the first condenser loop before the first condenser to the compressor inlet; the first condenser loop further includes a third condenser; the third condenser and the first condenser are connected in series in the first condenser loop; the first redistribution valve connects a point on the first condenser loop between the third condenser and the first condenser to the compressor inlet; the refrigeration system further includes a third redistribution valve connecting a point on the first condenser loop after the first and third condensers to the compressor inlet; the third condenser and the first condenser are connected in parallel in the first condenser loop; the first redistribution valve connects a point on the first condenser loop before the first and third condensers to the compressor inlet; the refrigeration system further includes a third redistribution valve connecting a point on the first condenser loop after the first and third condensers to the compressor inlet. The first redistribution valve connects a point on the first condenser loop after the first condenser to the compressor inlet. The refrigeration system further includes a sensor for detecting an underfill or overfill condition in the refrigeration system. The refrigeration system further includes a third condenser loop connected between the compressor outlet and the evaporator inlet, the third condenser loop having: a third inlet valve, a third condenser, and a third redistribution valve connecting the third condenser loop to the compressor inlet.

[0007] In a second aspect, a method includes: activating a first condenser loop in a refrigeration system, wherein a second condenser loop is not currently active; monitoring sensor outputs in the refrigeration system that indicate whether an undercharge condition or an overcharge condition exists in the refrigeration system; and managing refrigerant charge distribution between the first and second condenser loops based on whether the undercharge condition or the overcharge condition exists in the refrigeration system.

[0008] Implementations may include any or all of the following features: Monitoring the sensor output for whether the undercharge condition exists in the refrigeration system includes monitoring at least one of an evaporator outlet pressure, an evaporator outlet temperature, or an opening of an expansion valve coupled to an inlet of an evaporator in the refrigeration system; Managing the refrigerant charge distribution in response to the sensor output indicating the undercharge condition exists in the refrigeration system includes opening a redistribution valve of the second condenser loop; Managing the refrigerant charge distribution in response to the sensor output indicating the undercharge condition exists in the refrigeration system further includes opening an inlet valve of the second condenser loop; Monitoring the sensor output for whether the overcharge condition exists in the refrigeration system includes monitoring at least one of subcooling, compressor discharge pressure, or suction superheat; Subcooling is monitored, where monitoring subcooling includes detecting pressure and temperature at an evaporator outlet in the refrigeration system. In response to the sensor output indicating the existence of the overcharge condition in the refrigeration system, managing the refrigerant charge distribution comprises opening a redistribution valve of the second condenser loop. In response to the sensor output indicating the existence of the overcharge condition in the refrigeration system, managing the refrigerant charge distribution further comprises activating a heat removal mechanism of the second condenser loop. The activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a cooling mode. The cooling mode comprises a first inlet valve of the first condenser loop being open, and the method further comprises temporarily opening a second inlet valve of the second condenser loop, an outlet valve of the second condenser loop, and a redistribution valve of the second condenser loop upon initiation of the cooling mode. The activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a heating mode. The heating mode comprises a second inlet valve of the second condenser loop and an outlet valve of the second condenser loop being open.The activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a combined cooling and heating mode. The method further includes, in response to a thermal interruption through the first condenser loop exceeding a threshold, at least partially opening each of: (i) a first inlet valve of the first condenser loop, (ii) a second inlet valve of the second condenser loop, and (iii) an outlet valve of the second condenser loop. [Brief explanation of the drawings]

[0009] [Figure 1] 1 illustrates an example of a refrigeration system that may actively manage refrigerant charge between multiple condenser loops. [Figure 2] 1 illustrates an example of a refrigeration system that may actively manage refrigerant charge between multiple condenser loops. [Figure 3] 1 illustrates an example of a refrigeration system that may actively manage refrigerant charge between multiple condenser loops. [Figure 4] 1 illustrates an example of a refrigeration system that may actively manage refrigerant charge between multiple condenser loops.

[0010] [Figure 5] A flowchart is shown with an example method. [Figure 6] A flowchart is shown with an example method. [Figure 7] A flow chart is shown with an example method.

[0011] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE INVENTION

[0012] This specification describes example systems and techniques for actively managing refrigerant charge between multiple condenser loops. In some implementations, a network of refrigerant control valves and sensors are used to move refrigerant charge between different loops of a refrigeration system. Based on the system's operating mode, different amounts of refrigerant may be required in the operating portions of the system to obtain optimal performance and efficiency. Quantities such as superheat and subcooling can be monitored using sensors within the system to determine whether the operating portions of the system are undercharged, normal, or overcharged. Based on the existing status, the refrigerant control valves operate to move the required amount of refrigerant in / out of the operating portions of the system.

[0013] Advantages of the present subject matter may include one or more of the following: A more compact cooling system may be designed. The need for an accumulator or refrigerant reservoir in the cooling loop may be eliminated. The capacity and efficiency of the cooling system under various operating conditions may be improved / optimized. For example, a cooling system may be provided that operates with an optimal amount of refrigerant charge for each operating condition. This feature is not possible in conventional systems because the entire volume of the refrigerant reservoir is moved between different loops and the capacity and efficiency may only be optimized for some of the operating modes.

[0014] Examples described herein refer to the coupling of two or more components or connecting them together. Unless otherwise indicated, coupling of components or connecting them together means allowing fluid flow in one or more directions between the components. Fluid flow may include, but is not limited to, the passage of refrigerant in liquid, two-phase, and / or gas form.

[0015] Examples described herein refer to top, bottom, front, or rear. These and similar expressions identify things or aspects relative to one another based on an explicit or arbitrary notion of perspective. That is, these terms are merely examples used for illustrative purposes and do not necessarily indicate the only possible positions, orientations, etc. As used herein, the terms inlet and outlet used in connection with any component may reflect the manner in which the component is installed and do not necessarily indicate that the component does or does not have any particular configuration.

[0016] 1-3 illustrate an example of a refrigeration system 100 that can actively manage refrigerant charge between condenser loop 101 and condenser loop 102. Refrigeration system 100 or any component thereof can be used with one or more other examples described elsewhere herein.

[0017] The cooling system 100 may include one or more evaporators. Here, the cooling system 100 includes evaporators 104 and 106. Each of the evaporators 104 and 106 is a device capable of evaporating (vaporizing) a refrigerant from a liquid state to a gas state. Any type of evaporator compatible with the refrigerant of the cooling system 100 may be used. The evaporators 104 and 106 may be the same type or different types. The evaporators 104 and 106 may have the same capacity or different capacities. Each of the evaporators 104 and 106 has an inlet and an outlet. Here, the inlets of the evaporators 104 and 106 are oriented toward the top of the drawing, and the outlets are oriented toward the bottom.

[0018] One or more expansion valves may be used in the refrigeration system 100, including, but not necessarily associated with, the evaporators 104 and / or 106. For example, the expansion valve 108 is here located at the inlet of the evaporator 104. As another example, the expansion valve 110 is here located at the inlet of the evaporator 106. Other approaches may be used.

[0019] The refrigeration system 100 may include a compressor 112. The compressor 112 is a device that can increase the pressure of a gas (e.g., a refrigerant). Any type of compressor compatible with the refrigerant of the refrigeration system 100 may be used. The compressor 112 has an inlet (sometimes referred to as the suction side) and an outlet (sometimes referred to as the discharge side). Here, the inlet of the compressor 112 is oriented toward the top of the drawing and the outlet is oriented toward the bottom of the drawing. The inlet of the compressor 112 is connected to the outlets of each of the evaporators 104 and 106.

[0020] Condenser loop 101 includes inlet valve 114. Any type of valve compatible with the refrigerant of refrigeration system 100 may be used, where inlet valve 114 is coupled to the outlet of compressor 112. Inlet valve 114 may be used, for example, in managing refrigerant charge distribution within refrigeration system 100, as described below.

[0021] The condenser loop 101 may include one or more condensers. A condenser is a device that condenses a substance in a gaseous state into a liquid state. Any type of condenser compatible with the refrigerant of the cooling system 100 may be used. Here, the condenser loop 101 includes condensers 116 and 118. The condensers 116 and 118 may be the same type or different types. The condensers 116 and 118 may have the same capacity or different capacities. Here, the condensers 116 and 118 are arranged in series in the condenser loop 101, with the condenser 116 connected to the inlet valve 114.

[0022] The condenser loop 101 may include one or more filters. In some implementations, the condenser loop 101 includes a receiver / dryer, which term, as used herein, may include one or more of a receiver, a dryer, or a combination of a receiver and a dryer. The receiver / dryer may remove particles or other debris, or moisture, from the refrigerant and separate liquid refrigerant from gaseous refrigerant for further subcooling. Any type of receiver / dryer compatible with the refrigerant of the refrigeration system 100 may be used. For example, a receiver / dryer 120 is coupled after the condenser 118.

[0023] The condenser loop 101 may include one or more components to cause the refrigerant to fall below its saturation temperature. In some implementations, the condenser loop 101 includes a subcooler that can cause the refrigerant to fall into liquid form. Any type of subcooler compatible with the refrigerant of the refrigeration system 100 may be used. For example, a subcooler 122 may be coupled after the receiver / dryer 120.

[0024] Condenser loop 101 may include one or more check valves or one-way valves, such as shut-off valves with minimal or no reverse leakage, or any valve capable of preventing refrigerant flow in the reverse direction. Any type of valve capable of preventing reverse refrigerant flow and compatible with the refrigerant of refrigeration system 100 may be used. In some implementations, check valve 124 is coupled after subcooler 122. For example, check valve 124 may be coupled to the inlet of evaporator 104 and / or 106 (e.g., before expansion valves 108 or 110, respectively).

[0025] The refrigeration system 100 may include one or more redistribution valves for use in managing refrigerant charge distribution. Any type of valve compatible with the refrigerant of the refrigeration system 100 may be used. In some implementations, a redistribution valve 126 may be included in the condenser loop 101. For example, the redistribution valve 126 connects a point on the condenser loop 101 to the inlet of the compressor 112 before the condenser 116. In some implementations, a redistribution valve 128 may be included in the condenser loop 101. For example, the redistribution valve 128 connects a point on the condenser loop 101 to the inlet of the compressor 112 between the condensers 116 and 118. In some implementations, a redistribution valve 130 may be included in the condenser loop 101. The redistribution valve 130 may connect a point on the condenser loop 101 after the condensers 116 and 118 to the inlet of the compressor 112. For example, redistribution valve 130 may be coupled after subcooler 122. Where possible, multiple valves may be combined into a single valve. For example, in cooling system 100, valve 124 and valve 130 may be combined as a three-way valve. Similarly, in cooling system 100, valve 114, valve 132, and valves 126 / 128 / 130 may be combined in multiple ways to reduce the number of valves and achieve the same function. In some designs, the valves may have more than two (inlet / outlet) ports. Other approaches may be used.

[0026] Referring now to condenser loop 102, it includes inlet valve 132. Any type of valve compatible with the refrigerant of refrigeration system 100 may be used, where inlet valve 132 is coupled to the outlet of compressor 112. Inlet valve 132 may be used, for example, in managing refrigerant charge distribution within refrigeration system 100, as described below.

[0027] Condenser loop 102 may include one or more condensers. Any type of condenser compatible with the refrigerant of cooling system 100 may be used. Here, condenser loop 102 includes condenser 134 coupled to inlet valve 132.

[0028] The condenser loop 102 may include an outlet valve. Any type of valve compatible with the refrigerant of the refrigeration system 100 may be used, where the outlet valve 136 is coupled after the condenser 134. For example, the outlet valve 136 may be coupled to the inlets of the evaporators 104 and / or 106. The outlet valve 136 may be used, for example, in managing refrigerant charge distribution within the refrigeration system 100, as described below.

[0029] In some implementations, a redistribution valve 138 may be included in the condenser loop 102. For example, the redistribution valve 138 connects a point on the condenser loop 102 to the inlet of the compressor 112 before the condenser 134. Other approaches may be used.

[0030] The refrigeration system 100 may include one or more sensors. The sensors may detect under-fill and / or over-fill conditions within the refrigeration system 100. In some implementations, a sensor 140 may be located at each end of the condenser loops 101 and 102. The sensor 140 may indicate the pressure and / or temperature of the refrigerant on the high-pressure side of the refrigeration system. For example, the sensor 140 may be coupled to the inlet of the evaporator 104 and / or 106 (e.g., before the expansion valves 108 and 110, respectively). In some implementations, the sensor 142 may be located at the outlet of the evaporator 104. In some implementations, the sensor 144 may be located at the outlet of the evaporator 106. At least one of the sensors 142-144 may indicate the pressure and / or temperature on the low-pressure side of the refrigeration system. The sensors 140 and 142 / 144 may be the high-pressure and low-pressure sides, respectively, of the same pressure-temperature refrigerant sensor. In some implementations, the sensors may be located at the inlet of the compressor 112.

[0031] In some implementations, the control system monitors the evaporator outlet pressure, temperature, and / or opening (or closure) of the expansion valve. For example, the control system may consider calculated superheat, expansion valve opening, and previous characterization of the refrigeration system 100 when detecting that an undercharge condition exists (e.g., at least one active condenser loop does not have a sufficient or optimal amount of refrigerant). In response to detecting an undercharge condition, one or more redistribution valves of the inactive condenser loops may be opened. This may couple the inactive condenser loop to the inlet (e.g., low-pressure suction) of the compressor 112. In some implementations, when condenser loop 102 is active and condenser loop 101 is inactive, refrigerant charge distribution may be managed by opening one or more of the redistribution valves 126, 128, or 130. For example, the redistribution valve 126 may provide that refrigerant gas is connected to the compressor suction. As another example, the redistribution valve 128 may provide that a two-phase state of refrigerant is connected to the compressor suction. As another example, redistribution valve 130 may provide refrigerant liquid connected to the compressor suction. Redistribution valves 126, 128, and / or 130 may be opened or restricted as appropriate, thereby allowing a controlled refrigerant charge to be transferred between the condenser loops. Refrigerant charging may be terminated in response to the control system determining that the active condenser loop is operating normally. In some implementations, when condenser loop 102 is active and condenser loop 101 is inactive, inlet valve 114 may be opened to transfer refrigerant (gas) to help manage refrigerant charge distribution. In some implementations, when condenser loop 101 is active and condenser loop 102 is inactive, redistribution valve 138 may be opened or restricted as appropriate, thereby allowing a controlled refrigerant charge to be transferred between the condenser loops. If an adequate pressure differential between the condenser (e.g., condenser 116) and the compressor suction is not available to drive fluid to the compressor suction, the expansion valve opening may be reduced to temporarily further reduce the pressure at the compressor suction and allow refrigerant flow in the desired direction. Other approaches may be used.

[0032] In some implementations, the control system may consider subcooling, compressor discharge pressure, and / or suction superheat when detecting that an overcharge condition exists (e.g., at least one active condenser loop has an excessive or greater than optimal amount of refrigerant). For example, subcooling may be calculated using pressure and temperature signals from a pressure-temperature sensor (e.g., sensor 140). In response to detecting an overcharge condition, an inlet valve of one or more inactive condenser loops may be at least partially opened. For example, this may allow refrigerant to be removed from the active condenser loop and stored in the inactive condenser loop. During this process, the compressor duty cycle may be temporarily adjusted to reduce the pressure difference between the active and inactive loops to move refrigerant in a controlled manner. In some implementations, a heat removal mechanism of the inactive condenser loop may be activated as part of managing refrigerant charge distribution in an overcharge condition. Reducing the pressure of and / or cooling the refrigerant in the inactive condenser loop may aid in refrigerant charge distribution. For example, a secondary fluid (e.g., air or liquid) may be run over / through the condenser 116, or a separate heat exchanger may be used. Other approaches may be used.

[0033] 2 shows another example including some components of cooling system 100 in FIG. 1. Some aspects are the same or similar and will not be described in detail. Here, cooling system 100 does not include condenser 118. Thus, condenser loop 101 now has only one condenser, condenser 116. Redistribution valve 128 may be omitted. For example, condenser loop 101 may now have redistribution valves 126 and / or 130. Other approaches may be used.

[0034] FIG. 3 shows another example including some components of the cooling system 100 in FIG. 1 . Some aspects are the same or similar and will not be described in detail. Here, the cooling system 100 has a condenser 118 connected in parallel with the condenser 116. The redistribution valve 128 may be omitted. In some implementations, the condenser loop 101 may now have redistribution valves 126 and / or 130. For example, the redistribution valve 126 may connect a point on the condenser loop 101 to the inlet of the compressor 112 before the condensers 116 and 118. As another example, the redistribution valve 130 may connect a point on the condenser loop 101 to the inlet of the compressor 112 after the condensers 116 and 118. Other approaches may be used.

[0035] 4 illustrates an example of a refrigeration system 400 that can actively manage refrigerant charge. Refrigeration system 400, or any component thereof, can be used with one or more other examples described elsewhere herein. Some aspects of refrigeration system 400 are not shown for the sake of brevity. For example, refrigeration system 400 can include a control system and one or more sensors to manage refrigerant charge distribution between condenser loops based on whether an undercharge or overcharge condition exists.

[0036] The refrigeration system 400 includes an evaporator 402 having an outlet coupled to an inlet of a compressor 404. The outlet of the compressor 404 is coupled to each of condenser loops 406-1, 406-2, ..., 406-N, where N is an integer. That is, the refrigeration system 400 may include N condenser loops, and each of the condenser loops 406-1, 406-2, ..., 406-N may include one or more condensers. The condenser loops may include respective inlet valves 408-1, 408-2, ..., 408-N. The condenser loops may include respective redistribution valves 410-1, 410-2, ..., 410-N. The refrigeration system 400 includes an expansion valve 412 positioned between the condenser loops 406-1, 406-2, ..., 406-N and the inlet of the evaporator 402.

[0037] During operation, one or more of the condenser loops 406-1, 406-2, ..., 406-N may be activated and referred to as active condenser loops. The remaining condenser loops 406-1, 406-2, ..., 406-N may be inactive and referred to as inactive condenser loops. In response to detecting an underfill condition, one or more of the redistribution valves 410-1, 410-2, ..., 410-N of the inactive condenser loops may be opened. In response to detecting an overfill condition, one or more of the inlet valves 408-1, 408-2, ..., 408-N of the inactive condenser loops may be at least partially opened.

[0038] 5, 6, and 7 show flowcharts using examples of methods 500, 600, and 700, respectively. Methods 500, 600, or 700 may be used with one or more other examples described elsewhere herein. More or fewer operations than shown may be performed. Unless otherwise indicated, two or more operations may be performed in a different order.

[0039] In method 500, operation 510 includes activating a first condenser loop in a refrigeration system, where a second condenser loop is currently inactive. For example, condenser loop 101 or 102 in FIG. 1 may be activated.

[0040] Operation 520 includes monitoring the outputs of sensors within the cooling system that indicate whether an underfill or overfill condition exists within the cooling system. For example, the control system may use the outputs of sensors 140, 142, and / or 144 in FIG. 1 .

[0041] Operation 530 includes managing refrigerant charge distribution between the first condenser loop and the second condenser loop based on whether an undercharge or overcharge condition exists in the refrigeration system. For example, one or more of redistribution valves 126, 128, 130, or 138 in Figure 1 may be at least partially open. As another example, one or more of inlet valves 114 or 132 in Figure 1 may be at least partially open.

[0042] Method 500 can be performed while the cooling system is operating in any of a number of modes. In some implementations, the cooling can operate in a cooling mode. Such a cooling mode can include an inlet valve of an active condenser loop being opened. At the start of cooling mode operation, some valves of an inactive condenser loop can be temporarily opened. For example, an inlet valve, an outlet valve, and a redistribution valve can be temporarily opened.

[0043] In some implementations, cooling may operate in a heating mode. Such a heating mode may include an inlet valve of an active condenser loop being open. In cooling mode operation, some valves of an inactive condenser loop may be open. For example, an inlet valve and an outlet valve may be open.

[0044] In heating mode, the valves can be configured to achieve a hot gas loop. In this mode, the power consumed by the compressor becomes the main source of heat. For example, in refrigeration system 100, to activate condenser loop 102, valves 132 and 136 are opened and valve 114 is closed. Hot discharge gas from the compressor flows through condenser 134, heating the secondary fluid flowing through / over the condenser. In the evaporator, the secondary fluid (air / water / refrigerant, etc.) is bypassed, preventing heat extraction from the secondary fluid. The expansion valve is appropriately adjusted to fully / partially open to allow expansion of the refrigerated gas from the condenser. Charge management routines can be performed as needed during hot gas loop mode, similar to regular cooling or heating modes.

[0045] In some implementations, the cooling may be operating in a combined cooling and heating mode. In such a combined cooling and heating mode, in response to heat rejection through the active condenser loop exceeding a threshold, the control system may at least partially open one or more valves in the cooling system. For example, an inlet valve of the active condenser loop, an inlet valve of the inactive condenser loop, and / or an outlet valve of the inactive condenser loop may be at least partially opened. The goal may be simply to provide a desired amount of heat rejection in the active condenser loop. This mode may be referred to as a proportioning mode.

[0046] Referring now to method 600, operation 610 includes activating a first condenser loop in a refrigeration system, where a second condenser loop is currently inactive. For example, condenser loop 101 or 102 in FIG. 1 may be activated.

[0047] Operation 620 includes monitoring the outputs of sensors within the cooling system that indicate whether an underfill or overfill condition exists within the cooling system. For example, the control system may use the outputs of sensors 140, 142, and / or 144 in FIG. 1 .

[0048] Operation 630 includes determining whether an under-fill condition exists in the refrigeration system. If an under-fill condition does not currently exist, method 600 may return via path 640 to operation 610, where the condenser loop remains continuously active.

[0049] If an underfill condition exists at operation 630, method 600 may proceed to operation 650, which includes connecting the inactive condenser loop to the compressor suction. For example, one or more redistribution valves may be used. Method 600 may return to operation 620 via path 660.

[0050] If or when the control system determines that an undercharge condition no longer exists in the refrigeration system, path 640 may respond to discontinuing refrigerant charge distribution management (e.g., by closing the redistribution valve).

[0051] Finally, in method 700, operation 710 includes activating a first condenser loop in the refrigeration system, where a second condenser loop is currently inactive. For example, condenser loop 101 or 102 in FIG. 1 may be activated.

[0052] Operation 720 includes monitoring the outputs of sensors within the cooling system that indicate whether an underfill or overfill condition exists within the cooling system. For example, the control system may use the outputs of sensors 140, 142, and / or 144 in FIG. 1 .

[0053] Operation 730 includes determining whether an overfill condition exists in the refrigeration system. If an overfill condition does not currently exist, method 700 may return via path 740 to operation 710, where the condenser loop remains continuously active.

[0054] If an overfill condition exists at operation 730, the method 700 may proceed to operation 750, which includes connecting the inactive condenser loop to the active condenser loop. For example, one or more inlet valves may be used. The method 700 may return to operation 720 via path 760.

[0055] If or when the control system determines that an overcharge condition no longer exists in the refrigeration system, path 740 may respond to ceasing refrigerant charge dispensing management (e.g., by closing the inlet valve).

[0056] As used throughout this specification, the terms "substantially" and "about" are used to describe and take into account small variations, such as those due to processing variations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Also, as used herein, indefinite articles such as "a" or "an" mean "at least one."

[0057] It should be understood that all combinations of the above concepts, and additional concepts discussed in more detail below, (provided that such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

[0058] Although multiple implementations have been described, it will nevertheless be understood that various modifications may be made without departing from the spirit and scope of the specification.

[0059] Additionally, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Additionally, other processes may be provided or processes may be eliminated from the described flows, and other components may be added to or removed from the described systems. Accordingly, other implementations are within the scope of the following claims.

[0060] While certain features of the described implementations have been shown and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It should therefore be understood that the appended claims are intended to cover all such modifications and variations that fall within the scope of these implementations. They have been presented by way of example only, and not limitation, and it should be understood that various changes in form and detail may be made. Except for mutually exclusive combinations, any portion of the apparatus and / or methods described herein may be combined in any combination. The implementations described herein may include various combinations and / or subcombinations of the functions, components, and / or features of the different implementations described.

Claims

1. an evaporator having an evaporator inlet and an evaporator outlet; (i) a compressor having a compressor outlet, and (ii) a compressor inlet coupled to the evaporator outlet; a first condenser loop connected between the compressor outlet and the evaporator inlet, the first condenser loop having a first inlet valve, a first condenser, and a first redistribution valve connecting the first condenser loop to the compressor inlet; and a second condenser loop connected between the compressor outlet and the evaporator inlet, the second condenser loop having a second inlet valve, a second condenser, and a second redistribution valve connecting the second condenser loop to the compressor inlet; A cooling system comprising:

2. The refrigeration system of claim 1 , wherein the first redistribution valve connects a point on the first condenser loop before the first condenser to the compressor inlet.

3. The cooling system of claim 1 , wherein the first condenser loop further comprises a third condenser.

4. The cooling system of claim 3 , wherein the third condenser and the first condenser are connected in series in the first condenser loop.

5. The refrigeration system of claim 4 , wherein the first redistribution valve connects a point on the first condenser loop between the third condenser and the first condenser to the compressor inlet.

6. 6. The refrigeration system of claim 5, further comprising a third redistribution valve connecting a point on the first condenser loop after the first and third condensers to the compressor inlet.

7. The cooling system of claim 3 , wherein the third condenser and the first condenser are connected in parallel in the first condenser loop.

8. 8. The refrigeration system of claim 7, wherein the first redistribution valve connects a point on the first condenser loop before the first and third condensers to the compressor inlet.

9. 8. The refrigeration system of claim 7, further comprising a third redistribution valve connecting a point on the first condenser loop after the first and third condensers to the compressor inlet.

10. 10. The refrigeration system of claim 1, wherein the first redistribution valve connects a point on the first condenser loop after the first condenser to the compressor inlet.

11. 10. The cooling system of claim 1, further comprising a sensor for detecting an underfill or overfill condition in the cooling system.

12. 10. The refrigeration system of claim 1, further comprising a third condenser loop connected between the compressor outlet and the evaporator inlet, the third condenser loop having: a third inlet valve, a third condenser, and a third redistribution valve connecting the third condenser loop to the compressor inlet.

13. activating a first condenser loop in the refrigeration system, where a second condenser loop is not currently active; monitoring sensor outputs within the refrigeration system that indicate whether an underfill or overfill condition exists within the refrigeration system; and managing refrigerant charge distribution between the first condenser loop and the second condenser loop based on whether the undercharge condition or the overcharge condition exists in the refrigeration system. A method comprising:

14. 14. The method of claim 13, wherein monitoring the sensor output for whether the underfill condition exists in the refrigeration system comprises monitoring at least one of an evaporator outlet pressure, an evaporator outlet temperature, or an opening of an expansion valve coupled to an inlet of an evaporator in the refrigeration system.

15. 14. The method of claim 13, wherein managing the refrigerant charge distribution in response to the sensor output indicating the under-charge condition exists in the refrigeration system comprises opening a redistribution valve in the second condenser loop.

16. 16. The method of claim 15, wherein managing the refrigerant charge distribution in response to the sensor output indicating the under-charge condition exists in the refrigeration system further comprises opening an inlet valve of the second condenser loop.

17. 14. The method of claim 13, wherein monitoring the sensor output for the presence of the overfill condition in the refrigeration system comprises monitoring at least one of subcooling, compressor discharge pressure, or suction superheat.

18. 20. The method of claim 17, wherein subcooling is monitored, and wherein monitoring subcooling comprises sensing pressure and temperature at an evaporator outlet in the refrigeration system.

19. 14. The method of claim 13, wherein managing the refrigerant charge distribution in response to the sensor output indicating the overcharge condition exists in the refrigeration system comprises opening a redistribution valve in the second condenser loop.

20. 20. The method of claim 19, wherein managing the refrigerant charge distribution in response to the sensor output indicating the overcharge condition exists in the refrigeration system further comprises activating a heat removal mechanism of the second condenser loop.

21. The method of claim 13 , wherein the activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a cooling mode.

22. 22. The method of claim 21, wherein the cooling mode comprises a first inlet valve of the first condenser loop being open, the method further comprising temporarily opening a second inlet valve of the second condenser loop, an outlet valve of the second condenser loop, and a redistribution valve of the second condenser loop upon initiation of the cooling mode.

23. The method of claim 13 , wherein the activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a heating mode.

24. 24. The method of claim 23, wherein the heating mode comprises a second inlet valve of the second condenser loop and an outlet valve of the second condenser loop being open.

25. 25. The method of any one of claims 13 to 24, wherein the activating of the first condenser loop, the monitoring of the sensor output, and the managing of the refrigerant charge distribution are performed while the refrigeration system is operating in a combined cooling and heating mode.

26. 26. The method of claim 25, further comprising, in response to the heat rejection through the first condenser loop exceeding a threshold, at least partially opening each of: (i) a first inlet valve of the first condenser loop, (ii) a second inlet valve of the second condenser loop, and (iii) an outlet valve of the second condenser loop.

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