Dynamic liquid receiver and control strategy

Abstract

A dynamic receiver is connected in parallel with an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system and is included in the HVACR system. The dynamic receiver allows control of refrigerant charge of the HVACR system in response to different operating conditions. The dynamic receiver can be filled or evacuated in response to a subcooling observed in the HVACR system compared to a required subcooling for various operating modes. The HVACR system can include a line to directly transport working fluid from a compressor discharge to the dynamic receiver to allow for assisted evacuation of the dynamic receiver by injection of compressor discharge.

Description

[0001] This application is a divisional application of the invention patent with the application date of June 30, 2021, the application number of 202110738888.9, and the invention name of “Dynamic liquid receiver and control strategy”. TECHNICAL FIELD

[0002] The present disclosure relates to a dynamic liquid receiver in a refrigeration circuit and a control strategy for the dynamic liquid receiver. BACKGROUND

[0003] Refrigeration circuits typically include a liquid receiver with a fixed fill process. As a result, the refrigerant charge in the receiver remains at a fixed level. The receiver fill has different impacts on efficiency at different parts of the load and operating map. Under certain operating conditions, the fixed receiver fill setting must sacrifice local efficiency improvements in order to be set to a value that provides sufficient efficiency at different parts of the operating map. SUMMARY

[0004] The present disclosure relates to a dynamic liquid receiver in a refrigeration circuit and a control strategy for the dynamic liquid receiver.

[0005] By dynamically controlling the amount of refrigerant charge in the system, more efficient operating conditions can be selected for full and partial load conditions, and the operating map of the refrigeration system can be increased.

[0006] In one embodiment, a heating, ventilation, air conditioning, and refrigeration (HVACR) system includes a compressor, a first heat exchanger, an expander, a second heat exchanger, and a dynamic receiver in a fluid circuit. The dynamic receiver is in parallel with the expander with respect to the fluid circuit. The HVACR system further includes a fluid line configured to deliver a discharge from the compressor to the dynamic receiver.

[0007] In one embodiment, the HVACR system further includes a four-way valve.

[0008] In one embodiment, the HVACR system further includes a third heat exchanger. The first heat exchanger is configured to exchange heat between a working fluid in the fluid circuit and a first process fluid, the second heat exchanger is configured to exchange heat between the working fluid and a second process fluid, and the third heat exchanger is configured to exchange heat with ambient air.

[0009] In one embodiment, the HVACR system further includes a controller configured to operate an inlet valve positioned directly upstream of the dynamic receiver, an outlet valve positioned directly downstream of the dynamic receiver, and a compressor discharge injection valve positioned along a fluid line to adjust an amount of working fluid stored in the dynamic receiver. In one embodiment, the controller is configured to determine a target amount of working fluid to store in the dynamic receiver based on a measured liquid line subcooling value and a subcooling threshold. In one embodiment, the measured liquid line subcooling value is based on a liquid line temperature measurement and a liquid line pressure measurement. In one embodiment, the target amount of working fluid is further based on a K P value. In one embodiment, the controller is configured to decrease the amount of working fluid stored in the dynamic receiver by opening the outlet valve and the compressor discharge injection valve until the target amount of working fluid is stored in the dynamic receiver. In one embodiment, the controller is configured to increase the amount of working fluid stored in the dynamic receiver by opening the inlet valve until the target amount of working fluid is stored in the dynamic receiver. In one embodiment, the subcooling threshold is based on an operating mode of the HVACR system.

[0010] A method of controlling a heating, ventilation, air conditioning, and refrigeration (HVACR) system according to embodiments includes determining, using a controller, a target amount of working fluid to store in a dynamic receiver included in the HVACR system, the target amount based on a subcooling threshold and a measured subcooling value. The method further includes comparing an amount of working fluid in the dynamic receiver to the target amount. When the amount of working fluid in the dynamic receiver exceeds the target amount, working fluid is removed from the dynamic receiver by opening an outlet valve positioned directly downstream of the dynamic receiver and opening a compressor discharge injection valve disposed along a fluid line connecting a discharge of a compressor of the HVACR system to the dynamic receiver. When the amount of working fluid in the dynamic receiver is less than the target amount, working fluid is added to the dynamic receiver by opening an inlet valve positioned directly upstream of the dynamic receiver with respect to a working fluid flow path in the HVACR system. The dynamic receiver is in parallel with an expander included in the HVACR system.

[0011] In one embodiment, the measured liquid line subcooling value is based on a liquid line temperature measurement and a liquid line pressure measurement. In one embodiment, the target amount of working fluid is further based on a K P value. In one embodiment, the subcooling threshold is based on an operating mode of the HVACR system. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1A A schematic diagram of a heating, ventilation, air conditioning, and refrigeration (HVACR) system according to an embodiment operating in a cooling mode is shown.

[0013] Figure 1B An HVACR system is shown operating in a heating mode. Figure 1A

[0014] Figure 1C An HVACR system is shown operating in a combination mode providing both heating and cooling. Figure 1A

[0015] Figure 2 A logic flow diagram for controlling a dynamic receiver according to an embodiment is shown. DETAILED DESCRIPTION

[0016] The present disclosure relates to a dynamic liquid receiver in a refrigeration circuit and control strategies for the dynamic liquid receiver.

[0017] Figure 1A A schematic diagram of a heating, ventilation, air conditioning, and refrigeration (HVACR) system according to an embodiment operating in a cooling mode is shown. The HVACR system 100 includes one or more compressors 102 and a four-way valve 104. The HVACR system 100 also includes a first heat exchanger 106 having a first heat exchanger isolation valve 108 between the four-way valve 104 and the first heat exchanger 106, a second heat exchanger 110 having a second heat exchanger isolation valve 112 between the four-way valve 104 and the second heat exchanger 110, and a third heat exchanger 114 having a third heat exchanger isolation valve 116. The HVACR system 100 also includes an expander 118 and a dynamic receiver 120. With respect to the direction of flow of working fluid through the HVACR system 100, an inlet valve 122 is upstream of the dynamic receiver 120 and an outlet valve 124 is downstream of the dynamic receiver 120. A compressor discharge injection line 126 extends directly from the discharge of the one or more compressors 102 to the dynamic receiver 120 with a compressor discharge injection valve 128 disposed along the compressor discharge injection line 126. Check valves 130 are included along various fluid lines to allow flow in only one direction through those particular lines. A controller 132 controls at least the inlet valve 122, the outlet valve 124, and the compressor discharge injection valve 128. The controller 132 can receive data from one or more pressure sensors 134 and / or temperature sensors 136 that measure conditions of the working fluid at various points in the HVACR system 100.

[0018] The HVACR system 100 is an HVACR system for providing climate control to at least one air conditioned space. In the embodiment shown, the HVACR system is a four-pipe HVACR system including separate heating and cooling lines to appropriate respective heat exchangers so that one or both of heating and cooling can be provided simultaneously. Figure 1A In the embodiment shown, the HVACR system is a four-pipe HVACR system including separate heating and cooling lines to appropriate respective heat exchangers so that one or both of heating and cooling can be provided simultaneously. ​​

[0019] One or more compressors 102 are provided. Compressor(s) 102 can be any suitable compressor or compressors for compressing a working fluid, such as a screw compressor, scroll compressor, etc. Where multiple compressors 102 are included in HVACR system 100, the compressors can be connected in parallel to one another. Compressor(s) 102 discharge compressed working fluid into a discharge line that delivers the discharge to a four-way valve 104. In one embodiment, compressor(s) 102 can be one to four compressors.

[0020] Four-way valve 104 is configured to selectively control fluid communication between the discharge of compressor(s) 102 and one of second heat exchanger 110 and third heat exchanger 114. Four-way valve 104 is also configured to selectively control communication of the other of second heat exchanger 110 and third heat exchanger 114 with the suction of compressor(s) 102. Four-way valve can be any suitable valve or arrangement of valves to provide the selectively controllable fluid communication described above.

[0021] First heat exchanger 106 is a heat exchanger configured to receive working fluid and exchange heat between the working fluid and a heating process fluid used to provide heating. First heat exchanger 106 can be any suitable type of heat exchanger for providing heat exchange between working fluid and a heating process fluid. The heating process fluid can be any suitable process fluid used to provide heating, such as water. The heating process fluid can be received from a heating process fluid inlet line 138 and discharged at a relatively high temperature from a heating process fluid outlet line 140 in modes in which heating is provided, such as those shown in FIG. 1. Figure 1B and 1C

[0022] First heat exchanger isolation valve 108 is a valve positioned between four-way valve 104 and first heat exchanger 106. First heat exchanger isolation valve 108 can be any suitable valve having an open position that permits flow therethrough and a closed position that prohibits flow therethrough. First heat exchanger isolation valve 108 can be selectively controlled based on the operating mode of HVACR system 100, such as being closed in a cooling mode as shown in FIG. 1. It should be understood that a valve such as first heat exchanger isolation valve 108 or any other valve described herein can permit a small amount of leakage in the closed position, e.g., due to wear, manufacturing tolerances, or defects, and that the closed position of the valve is still understood to prohibit flow even if such leakage can occur. Figure 1A

[0023] ​​In one embodiment, a defrost valve 142 can be positioned along a fluid line providing communication between the expander 118 and the first heat exchanger 106. The defrost valve 142 can be a controllable valve having at least a closed position that prohibits flow therethrough and an open position that permits flow. The defrost valve 142 can be placed in the open position to perform a defrost operation and closed during other operating modes of the HVACR system 100, such as the cooling only, heating only, and heating and cooling modes shown in FIGS. 1-3, respectively. Figures 1A-1C

[0024] The second heat exchanger 110 is a heat exchanger configured to receive the working fluid and exchange heat between the working fluid and a heat exchange medium, rather than heating or cooling the heating process fluid or the cooling process fluid, respectively, by the HVACR system 100. The heat exchange medium can be, for example, the ambient environment. The second heat exchanger 110 can be any suitable type of heat exchanger for providing heat exchange between the working fluid and the ambient environment. In one embodiment, the ambient environment can accept heat rejected at the second heat exchanger 110 in a cooling mode, such as shown in FIG. 1, where the second heat exchanger 110 functions as a condenser to condense the discharge from one or more of the compressors 102. Figure 1A In one embodiment, the working fluid can absorb heat from the ambient environment at the second heat exchanger 110 in a heating mode, such as shown in FIG. 3, where the second heat exchanger 110 functions as an evaporator for the working fluid received from the expander 118. Figure 1B

[0025] A second heat exchanger isolation valve 112 is positioned between the four-way valve 104 and the second heat exchanger 110. The second heat exchanger isolation valve 112 can be any suitable valve having an open position that permits flow therethrough and a closed position that prohibits flow therethrough. The second heat exchanger isolation valve 112 can be selectively controlled based on the operating mode of the HVACR system 100, such as closed in the heating and cooling mode shown in FIG. 2. Figure 1C

[0026] In one embodiment, a heat pump valve 144 is positioned along a fluid line providing fluid communication between the expander 118 and the second heat exchanger 110. The heat pump valve 144 is a controllable valve having at least an open position that permits flow from the expander 118 to the second heat exchanger 110 and a closed position that prohibits flow from the expander 118 to the second heat exchanger 110. The heat pump valve 144 can be in the open position during heating operations, such as the heating operation of the HVACR system 100 shown in FIG. 3. Figure 1B The heat pump valve 144 can be closed during at least some other operating modes, such as the cooling operating mode shown in FIG. 1 and the heating and cooling operating mode shown in FIG. 2. Figure 1A Figure 1C ​​​​​

[0027] The third heat exchanger 114 is a heat exchanger configured to receive a working fluid and exchange heat between the working fluid and a cooling process fluid used to provide cooling. The third heat exchanger 114 can be any suitable type of heat exchanger used to provide heat exchange between the working fluid and the cooling process fluid. The cooling process fluid can be any suitable process fluid used to provide cooling, such as water, a combination of water and ethylene glycol, etc. The cooling process fluid can be received from the cooling process fluid inlet line 146, and in, for example... Figure 1B and 1C In the cooling modes shown, the cooling process fluid is discharged from the cooling process fluid outlet line 148 at a relatively low temperature. The third heat exchanger 114 acts as an evaporator, evaporating the working fluid received from the expander 118 by absorbing heat from the cooling process fluid.

[0028] The third heat exchanger isolation valve 116 is a valve located between the four-way valve 104 and / or the suction inlet of one or more compressors 102 and the third heat exchanger 114. The third heat exchanger isolation valve 116 can be any suitable valve having an open position that allows flow through it and a closed position that prohibits flow through it. The third heat exchanger isolation valve 116 can be selectively controlled based on the operating mode of the HVACR system 100, for example, separately in… Figure 1B In the heating mode shown, turn off, in Figure 1A The cooling modes shown are neutral Figure 1C Turn on the cooling and heating modes shown.

[0029] Cooling valve 150 is positioned along a fluid line from expander 118 to third heat exchanger 114. Cooling valve 150 is a controllable valve having at least an open position that allows flow from expander 118 to third heat exchanger 114 and a closed position that prevents flow from expander 118 to third heat exchanger 114. Cooling valve 150 can be in the open position, for example, in... Figure 1A The cooling operation of the HVACR system 100 shown is or Figure 1C During the cooling operation of the heating and cooling operations shown, the cooling valve 150 can be closed in at least some other operating modes, such as... Figure 1B The heating operation mode is shown in the figure.

[0030] Expander 118 is configured to expand the working fluid received from either the first heat exchanger 106 or the second heat exchanger 110. Expander 118 can be any suitable expander for the working fluid, such as an expansion valve, expansion plate, expansion vessel, one or more expansion orifices, or any other known suitable structure for expanding the working fluid.

[0031] Dynamic receiver 120 is a receiver of liquid configured to store working fluid. Dynamic receiver 120 can be any suitable receiver for storing working fluid, such as, but not limited to, a reservoir, a vessel, a container, a tank, or other suitable volume. Dynamic receiver 120 can store working fluid as a liquid. Working fluid stored in dynamic receiver 120 is removed from circulation through the remainder of HVACR system 100 as it is stored, allowing the amount of working fluid circulating through HVACR system 100 to be controlled by varying the amount of working fluid stored in dynamic receiver 120. The amount of working fluid in dynamic receiver 120 can be controlled in response to operating modes and / or operating conditions, such as by controller 132 controlling inlet valve 122, outlet valve 124, and compressor discharge injection valve 128, or in accordance with a method as shown and described below. Dynamic receiver 120 can be sized such that it can hold enough liquid working fluid to cover the difference in charge amounts between any or all of the operating modes of HVACR system 100. Dynamic receiver 120 can be sized such that the amount of working fluid that can be stored further accounts for transitions between those operating modes or other operating conditions. For example, in the embodiment shown in FIG. 1, dynamic receiver 120 can be sized such that it can hold up to approximately 60% of the maximum charge amount of working fluid for HVACR system 100. In one embodiment, dynamic receiver 120 can be sized such that it can hold up to approximately 40% of the maximum charge amount of working fluid for HVACR system 100. Figure 2 Figures 1A-1C Figure 1A The liquid level shown in dynamic receiver 120 in FIG. 1 illustrates one potential approximate working fluid amount for the operating modes shown in FIG. 1. Figure 1A

[0032] Inlet valve 122 is upstream of dynamic receiver 120 and outlet valve 124 is downstream of dynamic receiver 120 with respect to the direction of flow of working fluid through HVACR system 100. Inlet valve 122 is a controllable valve having an open position that allows working fluid to pass therethrough and a closed position that prohibits flow therethrough. When in the open position, inlet valve 122 allows working fluid from upstream of expander 118 to be transferred to dynamic receiver 120, where the working fluid can be conserved, thereby reducing the charge amount of working fluid circulating through HVACR system 100. Outlet valve 124 is a controllable valve having an open position that allows working fluid to pass therethrough and a closed position that prohibits flow therethrough. When in the open position, outlet valve 124 allows working fluid from dynamic receiver 120 to enter the working fluid flow downstream of expander 118, rejoining the working fluid circulating through HVACR system 100.

[0033] ​​​A compressor discharge injection line 126 extends directly from a discharge of one or more compressors 102 to the dynamic receiver 120, with a compressor discharge injection valve 128 disposed along the compressor discharge injection line 126. The compressor discharge injection line 126 provides direct fluid communication between the discharge of one or more compressors and the dynamic receiver 120, such that the compressor discharge can be directed to the dynamic receiver 120 without passing through the four-way valve 104 or any further downstream components of the HVACR system 100, such as the first heat exchanger 106, the second heat exchanger 110, etc. The compressor discharge injection valve 128 is a controllable valve having at least an open position that allows flow through and a closed position that prohibits flow. When the compressor discharge injection valve 128 is open, some of the discharge from one or more compressors 102 can enter the dynamic receiver 120. The discharge from one or more compressors 102 is relatively hot gas form of working fluid that can displace a relatively large mass of liquid state working fluid stored in the dynamic receiver 120 to facilitate removal of working fluid from the dynamic receiver 120. The working fluid displaced from the dynamic receiver 120 by the compressor discharge can be added to the flow of working fluid downstream of the expander 118 by the outlet valve 124.

[0034] Check valves 130 can be positioned along various fluid lines in the HVACR system 100, as shown. Figures 1A-1C The check valves 130 can be passive one-way valves that allow flow through a fluid line in only one direction to facilitate operation in various modes, each responsive to flow present in different modes of operation, as shown in Figures 1A-1C The check valves 130 can be placed, for example, between the first heat exchanger 106 and the second heat exchanger 110 or the third heat exchanger 114, between the outlet valve 124 and the remainder of the HVACR system 100.

[0035] Controller 132 controls at least inlet valve 122, outlet valve 124, and compressor discharge injection valve 128 to control the amount of working fluid circulating in HVACR system 100 and the amount of working fluid stored in dynamic receiver 120. Controller 132 can control the amount of working fluid stored in dynamic receiver 120 to achieve a target amount or within a defined range of the amount of working fluid stored in dynamic receiver 120. Controller 132 is operatively connected to inlet valve 122, outlet valve 124, and compressor discharge injection valve 128, allowing commands to be sent from controller 132 to those valves. The operative connection can be, for example, a direct wired connection or wireless communication. Controller 132 can be configured to open inlet valve 122 when working fluid is added to dynamic receiver 120. Controller 132 can be configured to open compressor discharge injection valve 128 and outlet valve 124 when working fluid is to be removed from dynamic receiver 120. The controller 132 can also be configured to close the inlet valve 122 when working fluid is stored in or removed from the dynamic receiver 120. The controller 132 can also be configured to close the compressor discharge injection valve 128 and the outlet valve 124 when working fluid is stored in or added to the dynamic receiver 120.

[0036] Controller 132 can also be configured to determine a target amount or defined range of working fluid volume stored in dynamic receiver 120. In one embodiment, the target amount or defined range can be determined based on the current operating mode of HVACR system 100, for example... Figure 1A The cooling modes shown Figure 1B The heating mode shown or Figure 1C The heating and cooling modes are shown in the diagram. In one embodiment, the target quantity or defined range may be determined based on the operating conditions of the HVACR system 100, such as its position on an operating chart. In one embodiment, the target quantity or defined range may be based on the subcooling value of the HVACR system 100, such as the subcooling value compared to a subcooling threshold. The subcooling threshold may in turn be associated with a specific operating mode or operating condition. In one embodiment, a fixed subcooling threshold is set for each operating mode. In one embodiment, the subcooling threshold may be adapted to optimize efficiency or allow a larger operating envelope for the HVACR system 100, for example, by providing a range or otherwise allowing certain measurements to deviate from the subcooling threshold. The controller 132 may also be configured to control the fluid level in the dynamic receiver 120 not only in a specific operating mode but also during transitions between operating modes (e.g., from heating only to heating and cooling, from heating only to cooling only, from cooling only to heating only, etc.).

[0037] A pressure sensor 134 and / or a temperature sensor 136 can be included to measure the pressure and temperature of the working fluid at one or more locations within the HVACR system 100. The pressure sensor 134 can be any suitable pressure sensor for measuring the pressure of the working fluid at a point within the HVACR system 100. The temperature sensor 136 can be any suitable temperature sensor for measuring the temperature of the working fluid at a point within the HVACR system 100. In one embodiment, the pressure sensor 134 and / or the temperature sensor 136 can be configured to provide pressure measurements and / or temperature measurements to the controller 132, for example, through a wired connection or wireless communication. In one embodiment, at least one pressure sensor 134 and at least one temperature sensor 136 can be included along a liquid line of the HVACR system 100 between the first heat exchanger 106 or the second heat exchanger 110 (depending on which is functioning as a condenser in the current mode of operation) and the expander 118. In one embodiment, the pressure sensor 134 and the temperature sensor 136 disposed along the liquid line can be positioned directly upstream of the expander 118 with respect to the flow direction of the working fluid. In one embodiment, at least one pressure sensor 134 and / or temperature sensor 136 can be disposed at the suction inlet of the one or more compressors 102. In one embodiment, at least one pressure sensor 134 and / or temperature sensor 136 can be disposed at the discharge of the one or more compressors 102. The pressure sensor 134 and / or the temperature sensor 136 can be further disposed at other points of interest along the HVACR system 100, for example, a temperature sensor disposed directly upstream of the third heat exchanger 114 with respect to the flow direction of the working fluid through the HVACR system 100.

[0038] In Figure 1A the illustrated embodiment, in which the HVACR system 100 is functioning as a chiller, the four-way valve 104 directs the discharge from the one or more compressors 102 to the second heat exchanger 110 and provides a passageway for return from the third heat exchanger 114 to the suction inlet of the one or more compressors 102. The four-way valve also provides a passageway for fluid communication between the first heat exchanger 106 and the suction inlet of the one or more compressors 102, however, in Figure 1A the passageway from the first heat exchanger 106 is closed off by the isolation valve 108 being in the closed position due to the first heat exchanger. The four-way valve also provides a passageway for fluid communication between the first heat exchanger 106 and the suction inlet of the one or more compressors 102, however, in Figure 1A the passageway from the first heat exchanger 106 is closed off by the isolation valve 108 being in the closed position due to the first heat exchanger.

[0039] Figure 1B the HVACR system 100 is operating in a heating mode is shown. Figure 1AHVACR system 100. In Figure 1B In the heating mode shown, the four-way valve 104 is positioned with the discharge of the one or more compressors 102 directed to the first heat exchanger 106, and the second heat exchanger 110 in communication with the suction of the one or more compressors 102. The cooling valve 150 and the third heat exchanger isolation valve 116 are in the closed position, preventing the flow of working fluid to the third heat exchanger 114. In this embodiment, working fluid discharged by the one or more compressors 102 is transferred to the first heat exchanger 106, where the working fluid rejects heat and the heating process fluid accepts the heat. The working fluid then continues to the expander 118, and when the inlet valve 122 is open based on instructions from the controller 132, some of the working fluid can be transferred to the dynamic receiver 120 through the inlet valve 122 before reaching the expander 118. When the outlet valve 124 is open, the working fluid expanded by the expander 118 and any working fluid exiting the dynamic receiver 120 through the outlet valve 124 is then transferred to the second heat exchanger 110 through the heat pump valve 144, which is in the open position. At the second heat exchanger 110, the working fluid absorbs heat from the ambient air, and is then directed by the four-way valve to the suction of the one or more compressors 102. Thus, in the heating mode shown, the HVACR rejects heat to the heating process fluid at the first heat exchanger 106 and absorbs heat from the ambient environment at the second heat exchanger 110, acting as a heat pump to heat the heating process fluid. Figure 1B In the heating mode shown, the HVACR rejects heat to the heating process fluid at the first heat exchanger 106 and absorbs heat from the ambient environment at the second heat exchanger 110, acting as a heat pump to heat the heating process fluid.

[0040] Figure 1B The amount of working fluid stored in the dynamic receiver 120 in the heating mode shown can be relatively greater than the amount stored in the dynamic receiver 120 during the cooling mode shown, meaning that a smaller volume of working fluid is circulated through the HVACR system 100. However, it should be understood that the amount of working fluid in the dynamic receiver 120 and circulating through the remainder of the HVACR system 100 can be determined based on particular operating conditions and other factors as described herein. Figure 1A The amount of working fluid stored in the dynamic receiver 120 in the heating mode shown can be relatively greater than the amount stored in the dynamic receiver 120 during the cooling mode shown, meaning that a smaller volume of working fluid is circulated through the HVACR system 100. However, it should be understood that the amount of working fluid in the dynamic receiver 120 and circulating through the remainder of the HVACR system 100 can be determined based on particular operating conditions and other factors as described herein.

[0041] Figure 1C HVACR system 100 is shown operating in a combined mode to provide both heating and cooling. In Figure 1A HVACR system 100. In Figure 1CIn the heating and cooling modes shown, the four-way valve 104 is positioned where the discharge port of one or more compressors 102 is directed to the first heat exchanger 106. The second heat exchanger isolation valve 112 and the heat pump valve 144 are in the closed position, preventing working fluid from flowing to the second heat exchanger 110. The four-way valve 104 also provides communication between the third heat exchanger 114 and the suction port of one or more compressors 102. In this embodiment, the working fluid discharged by one or more compressors 102 is transferred to the first heat exchanger 106, where the working fluid discharges heat and the heating process fluid receives this heat. The working fluid then continues into the expander 118, and some of the working fluid can be transferred to the dynamic receiver 120 via the inlet valve 122 before reaching the expander 118, when the inlet valve 122 opens based on a command from the controller 132. The working fluid expanded by expander 118 and any working fluid exiting dynamic receiver 120 through outlet valve 124 are then transferred to third heat exchanger 114 via cooling valve 150 in the open position. At third heat exchanger 114, the working fluid absorbs heat from the cooling process fluid and is then transferred to the suction inlet of one or more compressors 102. Therefore, in Figure 1C In the heating and cooling modes shown, the HVACR discharges heat to the heating process fluid at the first heat exchanger 106 and absorbs heat from the cooling process fluid at the third heat exchanger 114, cooling the cooling process fluid while simultaneously heating the heating process fluid.

[0042] exist Figure 1C In the heating and cooling modes shown, the amount of working fluid stored in the dynamic receiver 120 can be relatively greater than that in... Figure 1A The amount stored in the dynamic receiver 120 during the cooling mode shown is relatively smaller than that in the... Figure 1B The amount of working fluid stored in the dynamic receiver 120 during the heating mode shown implies that, in this mode, a moderate volume of working fluid circulates through the HVACR system 100. However, it should be understood that the amount of working fluid in the dynamic receiver 120 and circulating through the rest of the HVACR system 100 can be determined specifically based on particular operating conditions and other factors as described herein.

[0043] Although Figures 1A-1C An HVACR system including three heat exchangers and piping is shown for selection to meet different heating and / or cooling needs, including simultaneous heating and cooling. However, it is understood that the embodiment may include other HVACR system designs, such as air conditioning systems, general heat pump systems, etc. Figure 1A In the cooling mode shown, an example of an air conditioner or cooler according to an embodiment may include, for example, only the active components of the HVACR system 100. When in... Figure 1CIn the heating mode shown, an example heat pump may include, for instance, only the active components of HVACR system 100. These embodiments will continue to include a dynamic receiver 120, inlet valve 122, and outlet valve 124 connected in parallel with an expander (e.g., expander 118), and also include a compressor discharge injection line 126. An HVACR system according to an embodiment may include any two heat exchangers, such as two of a first heat exchanger 106, a second heat exchanger 110, and a third heat exchanger 114, wherein one of these heat exchangers operates as a condenser and the other as an evaporator. Although Figures 1A-1C The HVACR system 100 shown includes a first heat exchanger 106, a second heat exchanger 110, and a third heat exchanger 114, but any one or more of these heat exchangers may be excluded depending on the specific system, such as in systems that strictly provide heating or cooling, or in standard reversible heat pumps.

[0044] Apart from Figures 1A-1C In addition to the illustrated mode, various valves, including the first heat exchanger isolation valve 108, the second heat exchanger isolation valve 112, and the third heat exchanger isolation valve 116, the cooling valve 150, the heat pump valve 144, the defrost valve 142, and the four-way valve 104, can be combined and positioned to achieve other operating modes of the HVACR system 100, such as purging, defrosting, or lubricant recovery. The check valve 130 responds to the flow direction provided by controlling those other valves to achieve a specific desired operation of the HVACR system 100. Examples of other modes that may be included include a defrost mode or any other suitable type of operation for a particular HVACR system 100. In such a mode, control of the dynamic receiver 120 may be to provide a charge of working fluid at or near minimum within the HVACR system 100 for a specific operating mode.

[0045] Figure 2 A flowchart illustrating the logic of a dynamic receiver for controlling a heating, ventilation, air conditioning, and refrigeration (HVACR) system according to an embodiment is shown. Method 200 includes obtaining a subcooling threshold 202, obtaining a measured subcooling value 204, determining a target amount of working fluid 206, comparing the target amount of working fluid with the actual amount of working fluid in the receiver 208, and based on the comparison, performing one of adding working fluid to the receiver 210 or removing working fluid from the receiver 212. Optionally, obtaining the measured subcooling at 204 may include obtaining the liquid line temperature 214 and / or obtaining the liquid line pressure 216.

[0046] The supercooling threshold is obtained at 202. The supercooling threshold can be related to a specific operating mode (e.g., ...). Figures 1A-1CA supercooling threshold can be associated with a particular operating mode or operating condition. In one embodiment, there is a fixed supercooling threshold set for each operating mode. In one embodiment, the supercooling threshold can be adaptive to optimize efficiency or allow for a greater operating envelope of the HVACR system 100, for example by providing a range or otherwise allowing for some measured deviation from the supercooling threshold.

[0047] The measured supercooling can be obtained at 204. Optionally, obtaining the measured supercooling at 204 can include obtaining a liquid line temperature 214 and / or obtaining a liquid line pressure 216. In one embodiment, the measured supercooling is a value representative of the supercooling currently occurring in the HVACR system. The measured supercooling can be calculated from a temperature in the liquid line of the HVACR system obtained at 214 and / or a pressure in the liquid line obtained at 216. The measured supercooling can be obtained, for example, as a difference between a saturated liquid temperature and the liquid line temperature. In one embodiment, the saturated liquid temperature can be determined based on the pressure in the liquid line obtained at 216. Optionally, a smoothing function can be used when obtaining the measured supercooling at 204. Obtaining the liquid line temperature 214 can include measuring a temperature in the liquid line carrying working fluid from a heat exchanger used as a condenser to an expander. The liquid line temperature can be obtained at 214 by measuring the temperature using a temperature sensor disposed along the liquid line, for example directly upstream of the expander. Obtaining the liquid line pressure at 216 can include measuring a pressure in the liquid line, for example by a pressure sensor disposed along the liquid line, for example a pressure sensor directly upstream of the expander. In one embodiment, the temperature sensor used at 214 and the pressure sensor used at 216 can be located at approximately the same location along the liquid line.

[0048] A target amount of working fluid is determined at 206. The target amount of working fluid can be based on a difference between the measured supercooling and the supercooling threshold. In one embodiment, the target amount can also be based on a K P value of the HVACR system, where K P is a gain adjustment factor. K P may be used at least in part to match the HVACR system dynamics to the control action to address the reactive nature of the valve controlling the flow into or out of the dynamic receiver. In one embodiment, the target amount can be based directly on a current operating mode of the HVACR system, for example heating, cooling, heating and cooling, purge, defrost, or other possible operating modes of the HVACR system, which can each have a charge amount associated with that operating mode.

[0049] At 208, the target amount of working fluid is compared to the actual amount of working fluid in the receiver. Based on the comparison, the method 200 can proceed to add working fluid to the receiver 210 when the actual amount of working fluid in the receiver is less than the target amount, or proceed to remove working fluid from the receiver 212 when the actual amount of working fluid in the receiver exceeds the target amount.

[0050] Working fluid can be added to the receiver at 210. Adding working fluid to the receiver 210 can include opening an inlet valve. Adding working fluid to the receiver 120 can also include ensuring that an outlet valve of the receiver and a compressor discharge injection valve are both closed. Some working fluid flowing through the fluid circuit of the HVACR system passes through the inlet valve into the receiver, where it can be stored. The fluid line connected to the receiver to introduce working fluid into the receiver can be located upstream of an expander of the HVACR system relative to a direction of flow of working fluid through the HVACR system. Adding working fluid from the receiver 210 can be performed based on the comparison performed at 208, as long as the amount of working fluid is below the target amount of working fluid determined at 206.

[0051] Working fluid can be removed from the receiver at 212. Working fluid can be removed from the receiver 212 by opening an outlet valve of the receiver and opening a compressor discharge injection valve. Removing working fluid from the receiver 212 can also include ensuring that an inlet valve for the receiver is closed. Compressor discharge fluid introduced by the compressor discharge injection valve is hot gas, and introduction of the compressor discharge fluid can drive out a greater amount of working fluid stored in the receiver, which exits the receiver through the outlet valve. The working fluid removed from the receiver is introduced to the HVACR system downstream of an expander of the HVACR system relative to a direction of flow of working fluid through the HVACR system. Removing working fluid from the receiver at 212 can continue as long as the amount of working fluid remains greater than the target amount of working fluid, as determined by the comparison at 208.

[0052] Aspects:

[0053] It should be understood that any of aspects 1-10 can be combined with any of aspects 11-14.

[0054] Aspect 1, a heating, ventilation, air conditioning, and refrigeration (HVACR) system, comprising:

[0055] a compressor;

[0056] a first heat exchanger;

[0057] an expander;

[0058] a second heat exchanger;

[0059] a dynamic receiver, the dynamic receiver being parallel to the expander with respect to the fluid circuit; and

[0060] a fluid line, the fluid line being configured to deliver the discharge from the compressor to the dynamic receiver.

[0061] Aspect 2. The HVACR system of aspect 1, further comprising a four-way valve.

[0062] Aspect 3. The HVACR system of aspect 2, further comprising a third heat exchanger, and wherein the first heat exchanger is configured to exchange heat between the working fluid and a first process fluid in the fluid circuit, the second heat exchanger is configured to exchange heat between the working fluid and a second process fluid, and the third heat exchanger is configured to exchange heat with ambient air.

[0063] Aspect 4. The HVACR system of any of aspects 1-3, further comprising a controller configured to operate an inlet valve positioned directly upstream of the dynamic receiver, an outlet valve positioned directly downstream of the dynamic receiver, and a compressor discharge injection valve positioned along the fluid line to regulate an amount of working fluid stored in the dynamic receiver.

[0064] Aspect 5. The HVACR system of aspect 4, wherein the controller is configured to determine a target amount of working fluid to store in the dynamic receiver based on a measured liquid line subcooling value and a subcooling threshold value.

[0065] Aspect 6. The HVACR system of aspect 5, wherein the measured liquid line subcooling value is based on a liquid line temperature measurement and a liquid line pressure measurement.

[0066] Aspect 7. The HVACR system of any of aspects 5-6, wherein the target amount of working fluid is further based on a K P value.

[0067] Aspect 8. The HVACR system of any of aspects 5-7, wherein the controller is configured to decrease the amount of working fluid stored in the dynamic receiver by opening the outlet valve and the compressor discharge injection valve until the target amount of working fluid is stored in the dynamic receiver.

[0068] Aspect 9. The HVACR system of any of aspects 5-8, wherein the controller is configured to increase the amount of working fluid stored in the dynamic receiver by opening the inlet valve until the target amount of working fluid is stored in the dynamic receiver.

[0069] Aspect 10. The HVACR system of any of aspects 5-9, wherein the subcooling threshold value is based on an operating mode of the HVACR system.

[0070] Aspect 11, a method of controlling a heating, ventilation, air conditioning, and refrigeration (HVACR) system, comprising:

[0071] determining, using a controller, a target amount of working fluid to store in a dynamic receiver included in the HVACR system, the target amount based on a subcooling threshold and a measured subcooling value;

[0072] comparing an amount of working fluid in the dynamic receiver to the target amount;

[0073] removing working fluid from the dynamic receiver by opening an outlet valve directly downstream of the dynamic receiver and opening a compressor discharge injection valve disposed along a fluid line connecting a discharge of a compressor of the HVACR system to the dynamic receiver when the amount of working fluid in the dynamic receiver exceeds the target amount.

[0074] adding working fluid to the dynamic receiver by opening an inlet valve directly upstream of the dynamic receiver with respect to a working fluid flow path in the HVACR system when the amount of working fluid in the dynamic receiver is less than the target amount,

[0075] wherein the dynamic receiver is in parallel with an expander included in the HVACR system.

[0076] Aspect 12, the method of aspect 11, wherein the measured liquid line subcooling value is based on a liquid line temperature measurement and a liquid line pressure measurement.

[0077] Aspect 13, the method of any of aspects 11-12, wherein the target amount of working fluid is further based on a K P value.

[0078] Aspect 14, the method of any of aspects 11-13, wherein the subcooling threshold is based on an operating mode of the HVACR system.

[0079] The examples disclosed in this application are to be considered in all respects as illustrative and not restrictive, since the scope of the application is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A heating, ventilation, air conditioning and refrigeration (HVACR) system, characterized in that, Includes a fluid circuit, the fluid circuit comprising: compressor; First heat exchanger; Expander; Second heat exchanger; A dynamic receiver, wherein the dynamic receiver is connected in parallel with the expander relative to the fluid loop; An inlet valve, directly positioned upstream of the dynamic receiver, is located downstream of the first heat exchanger and upstream of the second heat exchanger relative to the fluid circuit; and An outlet valve, positioned directly downstream of the dynamic receiver, is located downstream of the first heat exchanger and upstream of the second heat exchanger relative to the fluid circuit; and A controller, configured to control the inlet valve and the outlet valve, The controller is configured to determine the target amount of working fluid to be stored in the dynamic receiver based on measured liquid line subcooling values ​​and subcooling thresholds. When the amount of working fluid stored in the dynamic receiver exceeds the target amount, the controller is configured to reduce the amount of working fluid stored in the dynamic receiver by opening the outlet valve until the target amount of working fluid is stored in the dynamic receiver.

2. The HVACR system according to claim 1, characterized in that, It also includes a four-way valve.

3. The HVACR system according to claim 2, characterized in that, It also includes a third heat exchanger, wherein the first heat exchanger is configured to exchange heat between the working fluid and the first process fluid in the fluid loop, the second heat exchanger is configured to exchange heat between the working fluid and the second process fluid, and the third heat exchanger is configured to exchange heat with the surrounding air.

4. The HVACR system according to claim 1, characterized in that, The measured liquid pipeline subcooling value is based on liquid pipeline temperature and liquid pipeline pressure measurements.

5. The HVACR system according to claim 1, characterized in that, The target quantity of the working fluid is also based on K. P Value, where K P It is the gain adjustment factor.

6. The HVACR system according to claim 1, characterized in that, The controller is configured to increase the amount of working fluid stored in the dynamic receiver by opening the inlet valve until the target amount of working fluid is stored in the dynamic receiver.

7. The HVACR system according to claim 1, characterized in that, The supercooling threshold is based on the operating mode of the HVACR system.

8. A method for controlling a heating, ventilation, air conditioning, and refrigeration (HVACR) system, characterized in that, include: The controller is used to determine the target amount of working fluid to be stored in the dynamic receiver included in the HVACR system, the target amount being based on a supercooling threshold and a measured supercooling value; The amount of working fluid in the dynamic receiver is compared with the target amount; When the amount of working fluid in the dynamic receiver exceeds the target amount, the working fluid is removed from the dynamic receiver by opening the outlet valve directly downstream of the dynamic receiver. When the amount of working fluid in the dynamic receiver is less than the target amount, working fluid is added to the dynamic receiver by opening the inlet valves downstream of the first heat exchanger and upstream of the second heat exchanger relative to the working fluid flow path in the HVACR system. The dynamic receiver is connected in parallel with the expander included in the HVACR system, the inlet valve is located downstream of the first heat exchanger of the HVACR system and upstream of the second heat exchanger of the HVACR system, and the outlet valve is located downstream of the first heat exchanger of the HVACR system and upstream of the second heat exchanger of the HVACR system.

9. The method according to claim 8, characterized in that, The measured subcooling value is based on liquid line temperature and liquid line pressure measurements.

10. The method according to claim 8, characterized in that, The target quantity of the working fluid is also based on K. P Value, where K P It is the gain adjustment factor.

11. The method according to claim 8, characterized in that, The supercooling threshold is based on the operating mode of the HVACR system.

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