Vapor compression system and method for operating a heat exchanger

Abstract

The present invention relates to a vapor compression system and method for operating a heat exchanger, and more particularly to a vapor compression method and system comprising: a compressor configured to circulate a working fluid and operate under a plurality of operating conditions; an evaporator in fluid communication with the compressor, the evaporator heat exchanger comprising: a shell configured to allow the working fluid to flow therethrough; a plurality of parallel spaced tubes disposed within the shell, the plurality of parallel spaced tubes configured to allow a heat transfer fluid to flow therethrough; and at least one baffle operably coupled to the plurality of parallel spaced tubes, the at least one baffle configured to divide the shell into at least two chambers; an expansion valve assembly in fluid communication with the evaporator; and a control device operably coupled to the compressor and the expansion valve assembly, the control device configured to operate the valve assembly based at least in part on the plurality of operating conditions.

Description

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 62 / 705,236, filed on June 17, 2020, the contents of which are hereby incorporated in their entirety. Technical Field

[0002] The present invention generally relates to vapor compression systems, and more particularly to endothermic heat exchangers having an internal baffle system and an external expansion valve assembly. Background Technology

[0003] Vapor compression systems, commonly referred to as "refrigeration units," are widely used in air conditioning applications for cooling water. Such systems are large-capacity, typically 100 tons or more, and are used to cool large structures such as office buildings, large stores, and ships. Generally, a vapor compression system employing a refrigeration unit consists of a closed loop of chilled water circulating from a heat exchanger (e.g., an evaporator) to numerous water-air heat exchangers located in one or more spaces to be cooled. Another application of refrigeration units is as process coolers for liquids in industrial applications, where chilled water or other fluids from the refrigeration unit can be pumped through process or laboratory equipment to cool it. In recent years, variable speed drive (VSD) technology has been developed to improve the efficiency of vapor compression refrigeration units. Such refrigeration units can be called "variable speed refrigeration units" and are capable of efficiently matching the cooling requirements of systems in which they are deployed.

[0004] Generally, variable-speed refrigeration systems utilize a working fluid (e.g., refrigerant) flowing in a closed loop from the compressor to a heat exchanger (such as a condenser), to an expansion unit, to an absorption heat exchanger, and back to the compressor. In the cooling cycle, refrigerant vapor is compressed substantially by the compressor and then condenses into liquid refrigerant in the condenser. The liquid refrigerant can then be directed through the expansion unit to reduce its pressure and temperature, thereby substantially changing the liquid refrigerant into a liquid / vapor refrigerant mixture (a two-phase or two-phase refrigerant mixture). The refrigerant is directed to the evaporator to exchange heat with a heat transfer fluid (such as water moving through the evaporator or any other suitable coolant fluid). The refrigerant can be vaporized in the evaporator, and the refrigerant vapor can then be returned to the compressor to repeat the refrigerant cycle.

[0005] Some variable-speed refrigeration systems use endothermic heat exchangers such as shell-and-tube evaporators, in which heat exchange occurs between the refrigerant and the fluid to be cooled (such as water). A shell-and-tube evaporator (sometimes called a "flood" evaporator) generally consists of an outer shell enclosing multiple tubes (called a "tube bundle" through which water flows) so that the water is isolated from the refrigerant.

[0006] The desired heat transfer is achieved through the change of the refrigerant's state from liquid to vapor. Since the vaporized refrigerant absorbs minimal heat from the heat transfer fluid or coolant (such as water), it is important for effective and efficient heat transfer performance to keep the tube bundles in the evaporator covered or wetted with liquid refrigerant during operation. Typically, this is accomplished by operating the evaporator in "flood mode" such that the level of the two-phase refrigerant in the evaporator is high enough that the tubes are below the level of the liquid refrigerant.

[0007] However, in some instances where VSD is used, it can be difficult to optimize the refrigerant charge in the flow loop and / or the evaporator to match both full compressor load operation and partial compressor load operation, because partial load requires more refrigerant for optimal operation. When operating at the lowest compressor stage, the evaporator becomes oversized and accumulates more liquid refrigerant, which can cause refrigerant shortages for other components of the loop (e.g., the condenser and liquid lines).

[0008] Therefore, there is a need for methods and systems for operating vapor compression systems at the lowest capacity level, which reduce the volume of two-phase refrigerant allocated to the evaporator to achieve better refrigerant adequation when using the same amount optimized for full-load operation. Summary of the Invention

[0009] According to a non-limiting embodiment, a vapor compression system includes: a compressor configured to circulate a working fluid and operate under multiple operating conditions; an evaporator in fluid communication with the compressor, the evaporator heat exchanger including: a shell configured to allow the working fluid to flow through it; a plurality of parallel-spaced tubes disposed within the shell, the plurality of parallel-spaced tubes configured to allow a heat transfer fluid to flow through it; and at least one baffle operably coupled to the plurality of parallel-spaced tubes, the at least one baffle configured to divide the shell into at least two chambers; an expansion valve assembly in fluid communication with the evaporator; and a control device operably coupled to the compressor and the expansion valve assembly, the control device configured to operate the expansion valve assembly at least in part based on the multiple operating conditions.

[0010] In addition to one or more of the features described above, or as an alternative, in another embodiment, the vapor compression system further includes a condenser in fluid communication with the compressor and expansion valve assembly.

[0011] In addition to one or more of the features described above, or as an alternative, in another embodiment of the vapor compression system, at least one baffle includes a first baffle and a second baffle, wherein the first baffle and the second baffle are configured to divide the shell into a first chamber, a second chamber, and a third chamber.

[0012] In addition to one or more of the features described above, or as an alternative, in another embodiment of the vapor compression system, the expansion valve assembly includes: a first valve configured to allow working fluid to flow into a first chamber; a second valve configured to allow working fluid to flow into a second chamber; and a third valve configured to allow working fluid to flow into a third chamber.

[0013] In addition to one or more of the features described above, or as an alternative, in another embodiment of the vapor compression system, the control device is configured to: operate the compressor under operating conditions; compare the operating conditions with a plurality of predetermined conditions; open a first valve when the compressor operating conditions are less than or equal to a first predetermined condition; open a first valve and a second valve when the compressor operating conditions are greater than the first predetermined condition and less than or equal to a second predetermined condition; and open the first valve, the second valve, and the third valve when the compressor operating conditions are greater than the second predetermined condition.

[0014] In addition to one or more of the features described above, or as an alternative, in another embodiment of the vapor compression system, at least one baffle is positioned such that the lower portion of at least one baffle is operatively coupled to the lower portion of the housing, and the upper portion of at least one baffle extends above and adjacent to the upper portion of the housing, a plurality of parallel spaced-apart tubes.

[0015] In addition to one or more of the features described above, or as an alternative, in another embodiment of the vapor compression system, the operating conditions of the vapor compression system include at least one of the following: compressor operating stage capacity, compressor load, working fluid temperature, working fluid pressure, absorbed electrical power, and system efficiency.

[0016] According to a non-limiting embodiment, a heat exchanger assembly includes: an absorber heat exchanger comprising: a shell including at least two inlets and at least one outlet; a plurality of parallel-spaced tubes disposed within the shell; and at least one baffle operatively connected to the plurality of parallel-spaced tubes, the at least one baffle configured to divide the shell into at least two chambers; wherein each of the at least two inlets is configured to allow working fluid to flow into each of the at least two chambers; an expansion valve assembly in fluid communication with the absorber heat exchanger, the expansion valve assembly including conduits operatively connected to each of the at least two inlets; and a valve operatively connected to each conduit.

[0017] In addition to one or more of the features described above, or as an alternative, in another embodiment of the heat exchanger assembly, each of at least one baffle is positioned such that the lower portion of the at least one baffle is operatively coupled to the lower portion of the shell, and the upper portion of the at least one baffle extends over and adjacent to the upper portion of the shell above a plurality of parallel spaced-apart tubes.

[0018] In addition to one or more of the features described above, or as an alternative, in another embodiment of the heat exchanger assembly, each valve is configured to open and close in part based on compressor operating conditions.

[0019] In addition to one or more of the features described above, or as an alternative, in another embodiment of the heat exchanger assembly, the at least two inlets include at least two working fluid inlets and at least one heat transfer fluid inlet.

[0020] In addition to one or more of the features described above, or as an alternative, in another embodiment of the heat exchanger assembly, at least one outlet includes at least one working fluid outlet and at least one heat transfer fluid outlet.

[0021] In addition to one or more of the features described above, or as an alternative, in another embodiment of the heat exchanger assembly, the working fluid is configured to flow into at least two chambers through at least two working fluid inlets and exit through at least one working fluid outlet; and the heat transfer fluid is configured to flow into a plurality of parallel spaced tubes through at least one heat transfer fluid inlet and exit through at least one heat transfer fluid outlet.

[0022] According to a non-limiting embodiment, a method of operating a vapor compression system includes: operating a control device to operate a compressor to circulate working fluid; operating the control device to determine operating conditions of the vapor compression system; operating the control device to compare the operating conditions of the vapor compression system with a plurality of predetermined conditions; and operating a valve assembly at least in part based on the operating conditions of the compressor to allow working fluid to flow into at least one of a plurality of chambers within an evaporator.

[0023] In addition to one or more of the features described above, or as an alternative, in another embodiment of the method, the operating valve assembly includes: opening a first valve when the compressor operating conditions are less than or equal to a first predetermined condition; opening a first valve and a second valve when the compressor operating conditions are greater than the first predetermined condition and less than or equal to a second predetermined condition; and opening the first valve, the second valve, and the third valve when the compressor operating conditions are greater than the second predetermined condition.

[0024] In addition to one or more of the features described above, or as an alternative, in another embodiment, the method further includes: directing the working fluid through a first valve to a first chamber of the evaporator when the compressor operating conditions are less than or equal to a first predetermined condition; directing the working fluid through the first valve to the first chamber of the evaporator and through a second valve to a second chamber of the evaporator when the compressor operating conditions are greater than the first predetermined condition and less than or equal to a second predetermined condition; and directing the working fluid through the first valve to the first chamber of the evaporator, through the second valve to the second chamber of the evaporator, and through a third valve to a third chamber of the evaporator when the compressor operating conditions are greater than the second predetermined condition.

[0025] In addition to one or more of the features described above, or as an alternative, in another embodiment of the method, the operating conditions of the compressor include at least one of the following: compressor operating stage capacity, compressor load, working fluid temperature, working fluid pressure, absorbed electrical power, and system efficiency.

[0026] In addition to one or more of the features described above, or as an alternative, in another embodiment of the method, the working fluid is a refrigerant. Attached Figure Description

[0027] The accompanying drawings form part of the specification. Throughout the drawings, the same reference numerals denote the same elements.

[0028] Figure 1 The figure illustrates a vapor compression system according to an embodiment of the present disclosure.

[0029] Figure 2 The figure illustrates a vapor compression system according to an embodiment of the present disclosure.

[0030] Figure 3 A method for operating a vapor compression system according to embodiments of the present disclosure is disclosed.

[0031] These and other advantages and features will become more apparent from the following description in conjunction with the accompanying drawings. Detailed Implementation

[0032] Detailed descriptions of one or more embodiments of the disclosed apparatus and methods are presented herein by way of example rather than limitation, with reference to the accompanying drawings. As described below, a system and method for operating a vapor compression system 100 having an endothermic heat exchanger (e.g., an evaporator 30) configured with an internal baffle system 34 and an adjacent expansion valve assembly 40 for operation under variable (including low) compressor loads are disclosed. This system and method allow for a reduced heat transfer surface within the evaporator 30 while improving the system equivalence of the refrigerant dosage and providing higher overall system efficiency.

[0033] Figure 1 The illustration shows a vapor compression system 100 according to an embodiment of the present disclosure. The vapor compression system 100 may include many other conventional features not depicted for simplicity of the drawings. The vapor compression system 100 relates to a refrigeration system and may include a refrigeration system and a system having a multi-stage compressor arrangement. Those skilled in the art will readily understand that embodiments and features of the invention are conceived to include and be applicable not only to single-stage compressors / refrigeration units but also to multi-stage compression refrigeration units. As shown, the vapor compression system 100 includes a compressor 10, a heat exchanger (hereinafter, "condenser") 20, an expansion valve assembly 40, and a heat exchanger (hereinafter, "evaporator") 30, which are connected in series to form a semi-hermetic or hermetic, closed-loop refrigeration system.

[0034] In the depicted embodiment, the evaporator 30 may be Figure 1 and Figure 2 The illustration depicts one type of flood evaporator, such as a shell-and-tube flood evaporator. Evaporator 30 can be implemented in various configurations of HVAC or refrigeration systems and can be incorporated within a refrigeration unit, which can be implemented in such systems. However, it will be appreciated that the disclosed embodiments are applicable to a wide variety of other heat exchangers that can be used in numerous configurations of HVAC and / or refrigeration systems.

[0035] The vapor compression system 100 can circulate a working fluid to control the temperature in a space (such as a room, residence, or building). The working fluid can be circulated to absorb and remove heat from the space, and can subsequently be discharged elsewhere. The working fluid can be a refrigerant or a mixture of a refrigerant and a non-refrigerant (e.g., oil), or a blend of a refrigerant and a non-refrigerant in a gaseous, liquid, or multiple phases (hereinafter, "refrigerant").

[0036] An exemplary compressor 10 may be a screw compressor having a motor (not shown) with the ability to operate at varying speeds (e.g., VSD capability) and thus with the ability to operate under varying load conditions. Alternative compressors 10 may include centrifugal compressors, scroll compressors, reciprocating compressors, or screw compressors utilizing slide valve capacity adjustment. Compressor 10 may also include single-stage and / or multi-stage compressors. Compressor 10 has a suction inlet port 62 and a discharge port 63. In operation, compressor 10 compresses the refrigerant to drive a recirculated refrigerant flow through vapor compression system 100.

[0037] A condenser 20, in fluid communication with compressor 10, receives vaporized refrigerant through inlet port 64. The condenser 20 removes heat from the refrigerant and transfers heat to a heat transfer fluid (e.g., water, air, or a fluid mixture) that moves rapidly through the condenser 20 in a separate system 22. For example, water returning from a cooling tower (not shown) enters the condenser 20 via inlet port 22a, which is typically at a temperature of 27 °C. After heat exchange, the water exits the condenser 20 via outlet port 22b, which is typically at a temperature of 32 °C. During the heat exchange process, the refrigerant undergoes a phase change from vapor to liquid and flows as a high-pressure liquid through outlet port 65. The condenser 20 may include a float valve (not shown) acting as an expansion device. Alternative embodiments may include an alternative expansion device.

[0038] Evaporator 30 is located downstream of condenser 20, and receives two-phase refrigerant through expansion valve assembly 40 disposed between condenser 20 and evaporator 30. Figure 1 and Figure 2An embodiment of the evaporator 30 is shown, illustrating an exemplary arrangement and orientation of the evaporator 30 and the expansion valve assembly 40 in further detail. It will be appreciated that the evaporator 30 is a simplified illustration and end plates, tube sheets, oil return lines, and other common components that can be used in a typical evaporator are not shown. In the cooling cycle, water is frozen in the evaporator 30 to a typical temperature of 6°C and discharged from the evaporator 30 via outlet port 39a. The frozen water is typically distributed throughout the space(s) to be cooled using, for example, one or more air handling units. The frozen water absorbs heat from the space to be cooled and returns to the evaporator 30 via inlet 39b at a typical temperature of 12°C, where the frozen water circulation can be repeated. The refrigerant receives heat from the returning water, causing some of the refrigerant to undergo a phase change (from liquid to vapor), allowing vapor to flow through outlet port 68 and into the suction inlet 62 of the compressor 10.

[0039] refer to Figure 1 In one non-limiting embodiment, the evaporator 30 includes: a shell 32; a baffle system 34 having one or more baffles forming at least two or more chambers (e.g., 35a, 35b, 35c) discussed below, each chamber being in fluid communication with a corresponding inlet port (e.g., 36a, 36b, 36c); and the evaporator 30 further including a tube bundle 38 disposed therein.

[0040] The shell 32 is generally a cylindrical container, but can have any shape. A bundle of tubes 38 is disposed therein, moving rapidly along the longitudinal length of the shell 32. The bundle of tubes 38 comprises multiple tubes through which a heat transfer fluid (e.g., water or a fluid mixture or air) can flow in another closed-loop system 39 discussed below. The shell 32 also includes one or more inlet ports, such as 36a, 36b, 36c, which are operatively coupled to an expansion valve assembly 40 described below, allowing two-phase refrigerant to enter one or more chambers 35a, 35b, 35c of the evaporator 30.

[0041] The baffle system 34 may include one or more baffles that divide the shell 32 into two or more chambers (e.g., 35a, 35b, 35c). Each baffle is generally perpendicular (e.g., 90 degrees) to the longitudinal direction of the X-axis of the shell 32. Each baffle has a lower portion and an upper portion. The lower portion of the baffle is operatively coupled to the lower portion of the shell 32, thereby forming a seal between the lower portion of the baffle and an adjacent chamber (e.g., between chambers 35a and 35b). Multiple tubes of the tube bundle 38 may pass through the closely contacting baffles to inhibit the flow of liquid refrigerant from one chamber to an adjacent chamber. The upper end of each baffle extends to a point in the shell 32 generally above the tube bundle 38. The upper end of each baffle is not coupled to the shell 32, thereby forming one or more chambers 35a, 35b, 35c that allow any vapor that may form during the heat exchange process to flow through the outlet port 68. The liquid refrigerant will remain in the room until it comes into contact with the tubes of tube bundle 38 and evaporates.

[0042] It can be appreciated that the baffle system 34 can have a single baffle forming two chambers or form multiple chambers 35. n+1 Multiple baffles 34 n Number of baffles () n The capacity of the vapor compression system 100, compressor 10, and housing 32 can be determined by a variety of factors, including the capacity of the vapor compression system 100, compressor 10, housing 32, as well as operational metrics such as compressor speed and load, temperature and pressure of the refrigerant as it circulates through the vapor compression system 100, volume optimization, and manufacturing costs.

[0043] The baffle can be made of a rigid material (such as a metal or metal alloy) or a semi-rigid or flexible material (such as a plastic). The baffle can be substantially planar, having a generally flat surface with multiple orifices or openings (not shown) for receiving multiple tubes from the tube bundle 38. In some embodiments, a complete or partial seal can be formed between the tube and the orifice when the tubes from the tube bundle 38 are positioned in the orifice to inhibit the flow of refrigerant from one side of the baffle to the opposite side. In the case of a partial seal, some refrigerant may leak from one chamber to an adjacent chamber through the orifice. By way of example, refer to Figure 2 Chamber 35a contains liquid refrigerant, partially indicated by a plurality of “dots” as shown in the illustration. Chamber 35b will contain vaporized refrigerant and may contain a minimal amount of liquid refrigerant, depicted only by the absence of “dots” and shown only by the tube bundle 38. If liquid refrigerant leaks from chamber 35a into chamber 35b, the refrigerant in chamber 35b will evaporate over time, but especially when the refrigerant comes into contact with the dry portion of the tube bundle, thereby minimizing the accumulation of refrigerant in chamber 35b.

[0044] In a non-limiting embodiment, such as Figure 1 and Figure 2 As illustrated, expansion valve assembly 40 may be adjacent to evaporator 30. Expansion valve assembly 40 may include a first valve (e.g., 40a) for directing a refrigerant flow through inlet port 36a to at least a first chamber (e.g., 35a). First valve 40a may include an expansion valve for depressurizing the refrigerant. Expansion valve assembly 40 may include a second valve (e.g., 40b) positioned along conduit 42 between first valve 40a and inlet port 36b to direct a liquid refrigerant flow to the second chamber (e.g., 35b). Expansion valve assembly 40 may include a third valve (e.g., 40c) positioned along conduit 42 between first valve 40a and inlet port 36c to direct a liquid refrigerant flow to the third chamber (e.g., 35b). In some embodiments, at least one of the second valve (e.g., 40b) and the third valve (e.g., 40c) may be selected from a group consisting of expansion valves or solenoid valves. It will be appreciated that expansion valve assembly 40 may have functions for directing liquid refrigerant to an equal number of ( n ) room (e.g., 35) n The same number of ( ) n The number of valves. As discussed above, the number of valves ( n It can depend on the same factors as the number of rooms.

[0045] In a non-limiting embodiment, such as Figure 1 As illustrated, the second valve 40b and the third valve 40c can be connected in series along conduit 42 with the first valve 40a located downstream of conduit 42. In another non-limiting embodiment, all valves (e.g., 40a, 40b, 40c) can be connected in parallel along conduit 42 with, for example, valve 40c located at junction 42a. In this configuration, valves 40a, 40b, 40c may include expansion valves of an adjustable opening type. In some embodiments, valve 40a remains open throughout compressor operation but may be open to varying degrees. For example, if valve 40a is an expansion valve, the opening may be adjustable depending on operating conditions.

[0046] In some embodiments, the expansion valve assembly 40 may include a control device (e.g., microprocessor-based) 70 having a memory and a processor coupled to the memory. The control device 70 may be configured to operate the compressor 10 at multiple variable speeds based at least in part on a determined output of the compressor 10.

[0047] The control device 70 may also be configured to receive input signals from various sensors to control the vapor compression system 100 and / or the expansion valve assembly 40. For example, the control device 70 may communicate with the expansion valve assembly 40 and at least one valve (e.g., 40a) of the compressor 10. In a non-limiting embodiment, the control device 70 may be configured to operate the expansion valve assembly 40 (e.g., valves 40a, 40b, 40c) in part based on a plurality of predetermined operating conditions that may include upper and / or lower limits and / or ranges. In a non-limiting embodiment, the control device 70 may be configured to store at least one predetermined operating condition or range having at least one upper limit and at least one lower limit for determining when to open, close (or partially open / close) and / or adjust at least two or more valves (e.g., 40a, 40b, 40c). In another non-limiting embodiment, the control device 70 may be configured to store operating condition limit ranges in which a plurality of inputs selected from a plurality of operating conditions can be used to dynamically determine when to open, close, or adjust at least two or more valves. Operating conditions may include compressor operating stage capacity, temperature and / or pressure of the refrigerant at different locations throughout the refrigerant cycle, electrical power absorbed, and system efficiency.

[0048] Go to Figure 2 This illustrates a vapor compression system 100 according to an embodiment of the present disclosure. Figure 2 In the middle, the evaporator 30 is consistent with all materials. Figure 1 The same applies, and the illustration shows the evaporator 30 with valves 40b and 40c closed. In this example, two-phase refrigerant is allowed to flow through the first valve (e.g., 40a) to one chamber, e.g., 35a. Figure 2 As illustrated in the diagram, the "dot" in chamber 35a indicates the presence of two-phase refrigerant, while the absence of a "dot" in chambers 35b and 35c indicates the absence (or the presence of a minimal amount) of liquid refrigerant.

[0049] The refrigerant in chamber 35a will exchange heat with the water flowing through that portion of the tube bundle 38. In contrast, because valves 40b and 40c are closed in this example, the liquid refrigerant level in chamber 40b and / or valve 40c is lower than that in all tube bundles 38. As a result, the volume in chambers 35b and 35c surrounding and above the tube bundles 38 will be occupied by vapor refrigerant, which may flow through outlet port 68 or remain largely stationary because there is no forced circulation in those chambers. In this example, valves 40b and 40c remain closed until control device 70 receives a signal indicating a change in predetermined operating conditions. For example, control device 70 may be configured to actuate (open) valves 40b and / or 40c depending on the change in condenser load capacity, such as when the condenser load capacity changes from a low load capacity to a medium load capacity or to a high load capacity. It should be appreciated that the control device 70 can be configured to open and / or close, or partially open or close, valves 40a, 40b, 40c at varying rates and / or under varying conditions. It should also be appreciated that various combinations of opening and closing the valves are possible under a range of operating conditions, such as many combinations of when the chamber can be fully or partially filled with two-phase refrigerant and to what capacity.

[0050] refer to Figure 3 According to embodiments of the present disclosure, a method for controlling a vapor compression system is shown, the vapor compression system having a compressor 10, an endothermic heat exchanger (e.g., an evaporator) 30 operatively coupled to an expansion valve assembly 40, and each of the compressor 10 and the expansion valve assembly 40 communicating with a control device 70.

[0051] In an operational vapor compression system 100, compressor 10 directs the working fluid (hereinafter, "refrigerant") in the vapor phase through a heat exchanger (such as condenser 20), through an expansion valve assembly 40, and to an evaporator 30 before returning to compressor 10 to complete the refrigerant cycle. Compressor 10 may include a screw compressor. Alternative compressor 10 may include a centrifugal compressor, a scroll compressor, or a reciprocating compressor. Compressor 10 may also include a single-stage and / or multi-stage compressor refrigeration unit. Compressor 10 may be configured to operate at variable speeds and loads. For example, compressor 10 may have a motor (not shown) with the capability to operate at variable speeds (e.g., VSD capability) and thus with the capability to operate under varying load conditions.

[0052] Evaporator 30 can be one of the following types of flood evaporators (such as, e.g.) Figure 1The shell-and-tube evaporator illustrated in the figure further comprises one or more baffles forming at least two or more chambers (e.g., 35a, 35b, 35c), each chamber being in fluid communication with a corresponding inlet port (e.g., 36a, 36b, 36c). The evaporator 30 further includes a tube bundle 38 disposed therein. One or more inlet ports (e.g., 36a, 36b, 36c) are operatively coupled to an expansion valve assembly 40 described below, which allows two-phase refrigerant to enter one or more chambers 35a, 35b, 35c of the evaporator 30.

[0053] The expansion valve assembly 40 may include a first valve (e.g., 40a) for directing a refrigerant flow through inlet port 36a to at least a first chamber (e.g., 35a). The first valve 40a may include an expansion valve for depressurizing the refrigerant. The expansion valve assembly 40 may include a second valve (e.g., 40b) between the first valve 40a and inlet port 36b to direct a liquid refrigerant flow to a second chamber (e.g., 35b). The expansion valve assembly 40 may include a third valve (e.g., 40c) between the first valve 40a and inlet port 36c to direct a liquid refrigerant flow to a third chamber (e.g., 35c).

[0054] The vapor compression system 100 may include a control device 70 that communicates with the compressor 10 and the expansion valve assembly 40. The control device 70, having a memory and a processor coupled to the memory (e.g., microprocessor-based), may be configured to receive multiple input signals from various sensors representing multiple operating conditions for controlling the vapor compression system 100 and / or the expansion valve assembly 40.

[0055] As described more fully below, in one non-limiting embodiment, the control device 70 may be configured to store in a memory a plurality of predetermined operating conditions that may include upper and / or lower limits or ranges that can be used to operate the expansion valve assembly 40. In another non-limiting embodiment, the control device 70 may be configured to receive a plurality of input signals representing the plurality of operating conditions and dynamically control the operation of the expansion valve assembly 40 based on such inputs to achieve an overall improved operation of the vapor compression system 100.

[0056] Generally, this method uses a control device 70 to open, close (partially open or close), and / or adjust at least two or more valves (e.g., 40a, 40b, 40c) in response to signals from the compressor 10 or other components of the vapor compression system 100 to allow two-phase refrigerant flow into one or more chambers of the evaporator 30. It should be appreciated that various combinations of opening and closing valves are possible under a range of operating conditions, such as many combinations of when a chamber can be fully or partially filled with refrigerant and by what capacity. Since multiple inputs to the control device 70 can be used to determine the operation of the expansion valve assembly 40, various methods can be used to achieve the same result of allowing refrigerant to flow through the expansion valve assembly 40 into one or more chambers of the evaporator.

[0057] The method begins at step 302, wherein the operating control device 70 is used to operate the compressor 10 to circulate the working fluid (e.g., refrigerant). Step 302 of the method includes the operating control device 70 determining the operating conditions of the vapor compression system 100 (such as the compressor 10). The operating conditions may include compressor operating stage capacity, compressor load, temperature and / or pressure of the refrigerant at various locations in the refrigerant cycle, absorbed electrical power, and system efficiency.

[0058] In step 306, the method includes an operation control device 70 to compare operating conditions with a plurality of predetermined operating conditions. For example, the control device 70 may compare the operating conditions of the compressor 10 (such as load capacity) with a plurality of predetermined operating condition limits, which may also include the compressor load capacity, but may also include other predetermined operating condition limits as discussed above.

[0059] Step 308 of the method includes operating the expansion valve assembly 40, at least in part, based on the operating conditions of the compressor 10, to allow working fluid to flow into at least one of the plurality of chambers within the evaporator 30.

[0060] Generally, the control device 70 determines whether operating conditions will lead to action, for example, by opening, closing, adjusting, etc., of a valve in part based on comparing the vapor compression operating conditions (e.g., compressor operating conditions) with multiple predetermined operating condition limits or ranges.

[0061] In a non-limiting embodiment, operating the expansion valve assembly 40 includes opening a first valve when the compressor operating conditions are less than or equal to a first predetermined operating condition. By way of example, the first predetermined operating condition may be when the compressor operating load is equal to or less than 25% of the maximum operating load capacity. In this example, the method may include directing refrigerant through the first valve 40a into the first chamber 35a of the evaporator 30.

[0062] In another non-limiting embodiment, the method may include opening the first valve 40a and the second valve 40b when the compressor operating conditions are greater than a first predetermined condition and less than or equal to a second predetermined condition. By way of example, the compressor operating conditions may be greater than 25% of the maximum operating load capacity but less than or equal to 35% of the maximum compressor operating load capacity. In this example, the method may include directing refrigerant through the first valve 40a into the first chamber 35a and through the second valve 40b into the second chamber 35b of the evaporator 30.

[0063] In yet another non-limiting embodiment, the method may include opening the first valve 40a, the second valve 40b, and the third valve 40c when the compressor operating conditions are greater than a second predetermined condition. In this example, when the compressor operating load is greater than 35% of the maximum operating load capacity, the method may include directing the working fluid through the first valve 40a into the first chamber 35a, through the second valve 40b into the second chamber 35b, and through the third valve 40c into the third chamber 35c of the evaporator 30.

[0064] While this disclosure has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various changes may be made without departing from the scope of this disclosure, and equivalents may be substituted for its elements. Furthermore, many modifications may be made to suit particular situations or materials to the teachings of this disclosure without departing from the basic scope of this disclosure. Therefore, this disclosure is intended to be limited to the specific embodiments disclosed as the best mode conceived for carrying out this disclosure, but rather to include all embodiments falling within the scope of the claims.

Claims

1. A vapor compression system, comprising: A compressor, configured to circulate working fluid and operate under multiple operating conditions; An evaporator, which is in fluid communication with the compressor, the evaporator heat exchanger comprising: A shell configured to allow the working fluid to flow through it, wherein the shell includes at least two working fluid inlets and at least one heat transfer fluid inlet, at least one working fluid outlet and at least one heat transfer fluid outlet; A plurality of parallel, spaced-apart tubes disposed within the housing, the plurality of parallel, spaced-apart tubes being configured to allow heat transfer fluid to flow through them; and At least one baffle operably connected to the plurality of parallel spaced-apart pipes, the at least one baffle configured to divide the housing into at least two chambers, each chamber being in fluid communication with a corresponding working fluid inlet, wherein each of the at least one baffle is positioned such that a lower portion of the at least one baffle is operably connected to a lower portion of the housing to form a seal between the lower portion of the at least one baffle and an adjacent chamber, and an upper portion of the at least one baffle extends over the plurality of parallel spaced-apart pipes and is spaced apart from the upper portion of the housing; An expansion valve assembly, in fluid communication with the evaporator, comprising at least two valves, each configured to direct the working fluid through a corresponding working fluid inlet to a corresponding chamber; and A control device operatively coupled to the compressor and the expansion valve assembly, the control device being configured to operate the expansion valve assembly at least in part based on the plurality of operating conditions.

2. The vapor compression system of claim 1, further comprising a condenser in fluid communication with the compressor and the expansion valve assembly.

3. The vapor compression system according to claim 1, wherein, The at least one baffle includes a first baffle and a second baffle, wherein the first baffle and the second baffle are configured to divide the shell into a first chamber, a second chamber and a third chamber.

4. The vapor compression system according to claim 3, wherein, The expansion valve assembly includes: A first valve is configured to allow the working fluid to flow into the first chamber; A second valve, configured to allow the working fluid to flow into the second chamber; and A third valve is configured to allow the working fluid to flow into the third chamber.

5. The vapor compression system according to claim 4, wherein, The control device is configured such that: Operate the compressor under the operating conditions; The operating conditions are compared with multiple predetermined conditions; When the compressor operating conditions are less than or equal to a first predetermined condition, the first valve is opened; When the compressor operating conditions are greater than the first predetermined condition and less than or equal to the second predetermined condition, the first valve and the second valve are opened. as well as When the compressor operating conditions are greater than the second predetermined conditions, the first valve, the second valve, and the third valve are opened.

6. The vapor compression system according to claim 1, wherein, The operating conditions of the vapor compression system include at least one of the following: compressor operating stage capacity, compressor load, working fluid temperature, working fluid pressure, absorbed electrical power, and system efficiency.

7. A heat exchanger assembly, comprising: A heat exchanger for absorbing heat, comprising: The shell includes at least two working fluid inlets and at least one heat transfer fluid inlet, at least one working fluid outlet and at least one heat transfer fluid outlet; Multiple parallel, spaced-apart tubes are disposed within the housing; and At least one baffle operably coupled to the plurality of parallel spaced tubes, the at least one baffle configured to divide the shell into at least two chambers, wherein each of the at least one baffle is positioned such that a lower portion of the at least one baffle is operably coupled to a lower portion of the shell to form a seal between the lower portion of the at least one baffle and an adjacent chamber, and an upper portion of the at least one baffle extends over the plurality of parallel spaced tubes and is spaced apart from the upper portion of the shell; Each of the at least two working fluid inlets is configured to allow working fluid to flow into each of the at least two chambers. An expansion valve assembly, which is in fluid communication with the heat exchanger, includes: Pipes, operably connected to each of the at least two working fluid inlets; and At least two valves are operatively connected to the conduit, each valve configured to direct the working fluid through a corresponding working fluid inlet into a corresponding chamber.

8. The heat exchanger assembly according to claim 7, wherein, Each valve is configured to open and close in part based on the compressor's operating conditions.

9. The heat exchanger assembly according to claim 7, wherein, The working fluid is configured to flow into the at least two chambers through the at least two working fluid inlets and exit through the at least one working fluid outlet; and the heat transfer fluid is configured to flow into the plurality of parallel, spaced-apart pipes through the at least one heat transfer fluid inlet and exit through the at least one heat transfer fluid outlet.

10. A method of operating a vapor compression system according to any one of claims 1 to 6, the method comprising: The operation control device is used to operate the compressor to circulate the working fluid; Operate the control device to determine the operating conditions of the vapor compression system; The control device is operated to compare the operating conditions of the vapor compression system with a plurality of predetermined conditions; as well as The valve assembly is operated at least in part based on the operating conditions of the compressor to allow the working fluid to flow into at least one of the multiple chambers within the evaporator.

11. The method according to claim 10, wherein, Operating the valve assembly includes: When the compressor operating conditions are less than or equal to a first predetermined condition, the first valve is opened; When the compressor operating conditions are greater than the first predetermined condition and less than or equal to the second predetermined condition, the first valve and the second valve are opened; and When the compressor operating conditions are greater than the second predetermined conditions, the first valve, the second valve, and the third valve are opened.

12. The method of claim 11, further comprising: When the compressor operating conditions are less than or equal to a first predetermined condition, the working fluid is directed through the first valve to the first chamber of the evaporator; When the compressor operating conditions are greater than the first predetermined condition and less than or equal to the second predetermined condition, the working fluid is directed through the first valve to the first chamber of the evaporator and through the second valve to the second chamber of the evaporator; as well as When the compressor operating conditions are greater than the second predetermined conditions, the working fluid is directed to the first chamber of the evaporator through the first valve, to the second chamber of the evaporator through the second valve, and to the third chamber of the evaporator through the third valve.

13. The method according to claim 10, wherein, The operating conditions of the compressor include at least one of the following: compressor operating stage capacity, compressor load, working fluid temperature, working fluid pressure, absorbed electrical power, and system efficiency.

14. The method of claim 10, wherein, The working fluid is a refrigerant.

Images