Heating, ventilation, air conditioning and / or refrigeration system with heating and cooling operations

Abstract

The present disclosure provides a method for heating, ventilation, air conditioning and / or refrigeration (HVACamp; r) system (100), the HVACamp; an R system includes an evaporator (112) configured to place a working fluid in a heat exchange relationship with a cooling load (106) to cool the cooling load (106) and heat the working fluid; a first compressor (108) configured to receive the working fluid heated via the evaporator (112), and configured to pressurize the working fluid; a second compressor (114) configured to receive the working fluid pressurized by the first compressor (112); a condenser (118) configured to receive the working fluid from the second compressor (114) and to place the working fluid in a heat exchange relationship with a heating load (107) to heat the heating load (107) and cool the working fluid; and an economizer (120) configured to receive the working fluid cooled by the condenser (118), place the working fluid in a heat exchange relationship with an external fluid to condition the working fluid in the economizer (120), separate the working fluid into a vapor working fluid and a liquid working fluid, and direct the liquid working fluid towards the evaporator (112).

Description

BACKGROUND OF THE INVENTION

[0001] This section is intended to introduce to the reader various aspects of the technology that may be relevant to the various aspects of the present disclosure described below. It is believed that this discussion will help to provide the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light and not as an admission of prior art.

[0002] In response to exposure to different temperatures and pressures within components of a vapor compression system, a vapor compression system, such as a chiller system, utilizes a working fluid (e.g., a refrigerant) to change phase between vapor, liquid, and combinations thereof. The vapor compression system may place the working fluid in a heat exchange relationship with a conditioning fluid (e.g., water) and may deliver the conditioning fluid to equipment and / or an environment served by the vapor compression system. In some embodiments, the vapor compression system may include an economizer configured to improve the efficiency of the vapor compression system. For example, a first heat exchanger (e.g., a condenser) may cool the working fluid and direct the cooled working fluid to the economizer, which may reduce the pressure of the working fluid and separate the working fluid into a liquid-phase working fluid and a gas-phase working fluid. The economizer may direct the liquid-phase working fluid to a second heat exchanger (e.g., an evaporator), which may heat the working fluid. The economizer may direct the gas-phase working fluid to a compressor for pressurization. However, existing vapor compression systems, such as those including an economizer, may not provide efficient cooling and heating operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Aspects of the present disclosure may be better understood after reading the following detailed description and with reference to the drawings, in which: Figure 1 is a perspective view of a building in which an embodiment of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system may be utilized in a commercial environment according to one aspect of the present disclosure;

[0004] Figure 2 is a perspective view of an embodiment of a vapor compression system according to one aspect of the present disclosure;

[0005] Figure 3 is according to one aspect of the present disclosure Figure 2 a schematic diagram of an embodiment of a vapor compression system;

[0006] Figure 4 is according to one aspect of the present disclosure Figure 2 a schematic diagram of an embodiment of a vapor compression system;

[0007] Figure 5 is a schematic diagram of an embodiment of a vapor compression system configured to provide heating and cooling operations according to one aspect of the present disclosure;

[0008] Figure 6 is a front cross-sectional axial view of an economizer according to one aspect of the present disclosure, the economizer being usable in a vapor compression system configured to provide heating and cooling operations; and

[0009] Figure 7 is a schematic diagram of an embodiment of a vapor compression system according to one aspect of the present disclosure, the vapor compression system being configured to provide heating and cooling operations. DETAILED DESCRIPTION

[0010] One or more specific embodiments will be described below. To provide a concise description of these embodiments, all features of the actual implementation are not described in the specification. It should be understood that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the specific goals of the developer, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. In addition, it should be understood that such development work may be complex and time-consuming, but will be a routine task for those of ordinary skill in the art who benefit from the present disclosure in terms of design, production, and manufacturing.

[0011] When introducing elements of various embodiments of the present disclosure, the articles "a / an" and "the" are intended to indicate the presence of one or more of the recited elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that additional elements may exist in addition to the listed elements. Additionally, it should be understood that reference to "one embodiment" or "an embodiment" of the present disclosure is not intended to be construed as excluding the presence of additional embodiments incorporating the recited features.

[0012] Embodiments of the present disclosure relate to a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system having a vapor compression system (e.g., a vapor compression circuit). The vapor compression system may include a compressor configured to pressurize a working fluid within the vapor compression system and direct the working fluid to a condenser, which may cool and condense the working fluid. The condensed working fluid may be directed toward an expansion device, which may reduce the pressure of the working fluid. The cooled working fluid may be directed from the expansion device to an evaporator, in which the working fluid may be in a heat exchange relationship with a conditioning fluid to cool the conditioning fluid. Subsequently, the compressor may receive the working fluid from the evaporator for pressurization, thereby restarting the vapor compression cycle.

[0013] In some embodiments, a vapor compression system may include an economizer configured to receive a working fluid from a condenser. The economizer may be configured to reduce the pressure of the working fluid and separate the working fluid into a liquid working fluid and a vapor working fluid. The economizer may direct the liquid working fluid to an evaporator such that the evaporator can place the liquid working fluid in a heat exchange relationship with a conditioning fluid. The vapor working fluid may be directed from the economizer to a compressor. The economizer may increase the operating efficiency of the vapor compression system, such as by increasing the cooling capacity of the condenser for the conditioning fluid.

[0014] A vapor compression system may need to provide effective cooling and heating operations. That is, the vapor compression system may be operated to cool a conditioning fluid and heat the conditioning fluid or an additional conditioning fluid. Embodiments of the present disclosure relate to a vapor compression system having an evaporator and a condenser, the evaporator being configured to provide a cooling capacity and the condenser being configured to provide a heating capacity. For example, the vapor compression system may include a first flow path (e.g., a first circuit, a first loop) having an evaporator, and the vapor compression system may include a second flow path (e.g., a second circuit, a second loop) having a condenser. The first flow path may include a first compressor and a first expansion valve, and the second flow path may include a second compressor and a second expansion valve.

[0015] The vapor compression system further includes an economizer fluidly coupled to the first flow path and the second flow path. The economizer can operate in different configurations to improve the regulation performed by the vapor compression system. For example, in a first configuration, the economizer can direct the vapor working fluid to the second compressor. When the economizer is in the first configuration, the first compressor of the first flow path can pressurize the working fluid and direct the pressurized working fluid to the second compressor of the second flow path. The second compressor can further pressurize the working fluid and then direct the working fluid to the condenser. The condenser can allow heat from the working fluid to be ejected for heating purposes, such as for heating a fluid, thereby cooling the working fluid. The condenser can direct the cooled working fluid from the condenser to the second expansion valve, which can reduce the pressure of the working fluid and direct the working fluid to the economizer. The economizer can reduce the pressure of the working fluid to produce a liquid working fluid and a vapor working fluid. The economizer can direct the liquid working fluid to the first expansion valve, which can further reduce the pressure of the working fluid and direct the working fluid to the evaporator. The evaporator can utilize the working fluid to absorb heat for cooling purposes, such as for cooling a fluid, thereby heating the working fluid. The evaporator can direct the heated working fluid to the first compressor. In the first configuration, the economizer can also receive an external fluid from an external source and place the external fluid in a heat exchange relationship with the working fluid in the economizer. For example, the external fluid can heat the working fluid to evaporate the working fluid in the economizer. Thus, in the first configuration, the economizer can supply the heated vapor working fluid to the second flow path and increase the heating capacity of the second flow path.

[0016] In a second configuration, the economizer can receive additional vapor working fluid from the first compressor and can block the flow of the working fluid from the economizer to the second compressor. The economizer can also receive an external fluid in the second configuration, the external fluid can cool the working fluid in the economizer to condense the working fluid, and the economizer can direct the condensed working fluid toward the evaporator. Thus, in the second configuration, the economizer can increase the cooling capacity of the evaporator. In this way, the economizer can switch between the first configuration and the second configuration to utilize the external fluid to improve the efficient operation (such as heating operation and / or cooling operation) of the vapor compression system.

[0017] Turning now to the drawings, Figure 1A perspective view of an embodiment of an environment of a heating, ventilation, air conditioning, and refrigeration (HVAC&R) system 10 in a building 12 for a typical commercial environment. The HVAC&R system 10 may include a vapor compression system 14 (e.g., a chiller) that supplies a cooling liquid that can be used to cool the building 12. The HVAC&R system 10 may also include a boiler 16 for supplying a warm liquid to heat the building 12 and an air distribution system for circulating air through the building 12. The air distribution system may also include an air return duct 18, an air supply duct 20, and / or an air handler 22. In some embodiments, the air handler 22 may include a heat exchanger that is connected to the boiler 16 and the vapor compression system 14 by pipes 24. Depending on the operating mode of the HVAC&R system 10, the heat exchanger in the air handler 22 may receive heated liquid from the boiler 16 or cooled liquid from the vapor compression system 14. The HVAC&R system 10 is shown having a separate air handler on each floor of the building 12, but in other embodiments, the HVAC&R system 10 may include the air handler 22 and / or other components that may be shared between floors.

[0018] Figure 2 and Figure 3 is an embodiment of a vapor compression system 14 that can be used in the HVAC&R system 10. The vapor compression system 14 may circulate a refrigerant through a loop that begins with a compressor 32. The loop may also include a condenser 34, an expansion valve or device 36, and a liquid cooler or evaporator 38. The vapor compression system 14 may further include a control panel 40 having an analog-to-digital (A / D) converter 42, a microprocessor 44, a non-volatile memory 46, and / or an interface board 48.

[0019] Some examples of fluids that can be used as refrigerants in the vapor compression system 14 are hydrofluorocarbon (HFC)-based refrigerants such as R-410A, R-407, R-134a, R-1234ze, R1233zd, hydrofluoroolefins (HFOs), "natural" refrigerants such as ammonia (NH3), R-717, carbon dioxide (CO2), R-744, or hydrocarbon-based refrigerants, water vapor, or any other suitable refrigerant. In some embodiments, the vapor compression system 14 may be configured to effectively utilize a refrigerant having a standard boiling point of about 19 degrees Celsius (66 degrees Fahrenheit) at one atmosphere, which is also referred to as a low-pressure refrigerant relative to a medium-pressure refrigerant such as R-134a. As used herein, "standard boiling point" may refer to the boiling point temperature measured at one atmosphere.

[0020] In some embodiments, the vapor compression system 14 may utilize one or more of a variable speed drive (VSD) 52, an electric motor 50, a compressor 32, a condenser 34, an expansion valve or device 36, and / or an evaporator 38. The electric motor 50 may drive the compressor 32 and may be powered by the variable speed drive (VSD) 52. The VSD 52 receives AC power having a specific fixed line voltage and fixed line frequency from an alternating current (AC) power source and supplies power having a variable voltage and frequency to the electric motor 50. In other embodiments, the electric motor 50 may be directly powered by an AC or direct current (DC) power source. The electric motor 50 may include any type of motor that may be powered by the VSD or directly by an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor.

[0021] The compressor 32 compresses the refrigerant vapor and delivers the vapor to the condenser 34 through a discharge passage. In some embodiments, the compressor 32 may be a centrifugal compressor. The refrigerant vapor delivered by the compressor 32 to the condenser 34 may transfer heat to a cooling fluid (e.g., water or air) in the condenser 34. As a result of the heat transfer with the cooling fluid, the refrigerant vapor may condense into a refrigerant liquid in the condenser 34. The liquid refrigerant from the condenser 34 may flow through the expansion device 36 to the evaporator 38. In Figure 3 the illustrated embodiment, the condenser 34 is water-cooled and includes a tube bundle 54 connected to a cooling tower 56 that supplies the cooling fluid to the condenser 34.

[0022] The liquid refrigerant delivered to the evaporator 38 may absorb heat from another cooling fluid, which may or may not be the same cooling fluid used in the condenser 34. The liquid refrigerant in the evaporator 38 may undergo a phase change from the liquid refrigerant to a refrigerant vapor. As Figure 3 shown in the illustrated embodiment, the evaporator 38 may include a tube bundle 58 having a supply line 60S and a return line 60R connected to a cooling load 62. The cooling fluid (e.g., water, ethylene glycol, calcium chloride brine, sodium chloride brine, or any other suitable fluid) of the evaporator 38 enters the evaporator 38 via the return line 60R and exits the evaporator 38 via the supply line 60S. The evaporator 38 may reduce the temperature of the cooling fluid in the tube bundle 58 via heat transfer with the refrigerant. The tube bundle 58 in the evaporator 38 may include multiple tubes and / or multiple tube bundles. In any case, the vapor refrigerant exits the evaporator 38 and returns to the compressor 32 via a suction line to complete the cycle.

[0023] Figure 4is a schematic diagram of a vapor compression system 14, in which an intermediate circuit 64 is incorporated between a condenser 34 and an expansion device 36. The intermediate circuit 64 may have an inlet line 68 that is directly fluidly connected to the condenser 34. In other embodiments, the inlet line 68 may be indirectly fluidly coupled to the condenser 34. As Figure 4 shown in the illustrated embodiment, the inlet line 68 includes a first expansion device 66 positioned upstream of an intermediate vessel 70. In some embodiments, the intermediate vessel 70 may be a flash tank (e.g., a flash intercooler, an economizer). In other embodiments, the intermediate vessel 70 may be configured as a heat exchanger or a "surface economizer". In Figure 4 the illustrated embodiment of, the intermediate vessel 70 serves as a flash tank, and the first expansion device 66 is configured to reduce (e.g., expand) the pressure of the liquid refrigerant received from the condenser 34. During the expansion process, a portion of the liquid may vaporize, and thus the intermediate vessel 70 can be used to separate the vapor from the liquid received from the first expansion device 66.

[0024] Additionally, due to the pressure drop experienced by the liquid refrigerant when entering the intermediate vessel 70 (e.g., due to the rapid increase in volume experienced when entering the intermediate vessel 70), the intermediate vessel 70 can provide further expansion of the liquid refrigerant. The vapor in the intermediate vessel 70 can be suctioned by the compressor 32 through the suction line 74 of the compressor 32. In other embodiments, the vapor in the intermediate vessel can be suctioned into an intermediate stage (e.g., a non-suction stage) of the compressor 32. Due to the expansion in the expansion device 66 and / or the intermediate vessel 70, the enthalpy of the liquid collected in the intermediate vessel 70 can be lower than the enthalpy of the liquid refrigerant leaving the condenser 34. Then, the liquid from the intermediate vessel 70 can flow in line 72 through a second expansion device 36 to the evaporator 38.

[0025] It should be understood that any of the features described herein can be combined with the vapor compression system 14 or any other suitable HVAC&R system. For example, the present technology can be combined with any HVAC&R system having an economizer (such as the intermediate vessel 70) and a compressor (such as the compressor 32). The following discussion describes the present technology in combination with an embodiment of the compressor 32 configured as a single-stage compressor. However, it should be noted that the systems and methods described herein can be combined with other embodiments of the compressor 32 and the HVAC&R system 10.

[0026] In view of the above, Figure 5FIG. 0 is a schematic view of an embodiment of a vapor compression system 100 that includes a first flow path 102 (e.g., a cooler flow path, a cooling flow path, a cooling circuit, a cooling loop) and a second flow path 104 (e.g., a heat pump flow path, a heating flow path, a heating circuit, a heating loop), each of the first and second flow paths being configured to direct a working fluid therethrough. The first flow path 102 may be configured to provide cooling capacity for a cooling load 106, such as a fluid (e.g., water) cooled by the vapor compression system 100 (e.g., to provide cooling for a device). The second flow path 104 may be configured to provide heating capacity for a heating load 107, such as a fluid (e.g., water) heated by the vapor compression system 100 (e.g., to provide heat for a district heating network). For example, the first flow path 102 may include a first compressor 108, a first expansion valve 110 (e.g., a first expansion device), and an evaporator 112. The second flow path 104 may include a second compressor 114, a second expansion valve 116 (e.g., a second expansion device), and a condenser 118. The vapor compression system 100 may further include an economizer 120 configured to receive the working fluid from the first flow path 102 and the second flow path 104. The economizer 120 may be switched between a first configuration and a second configuration to adjust the flow of the working fluid through the vapor compression system 100.

[0027] For example, the economizer 120 may operate in a first configuration to enable the vapor compression system 100 to provide heating operation and cooling operation. During such operation of the vapor compression system 100, the first compressor 108 may pressurize the working fluid, thereby heating the working fluid, and direct the pressurized working fluid to the second compressor 114. The second compressor 114 may further pressurize the working fluid, thereby further heating the working fluid, and direct the pressurized working fluid to the condenser 118. The condenser 118 may place the pressurized working fluid in a heat exchange relationship with the heating load 107 to direct heat from the pressurized working fluid to the heating load 107, thereby heating the heating load 107 and cooling the working fluid (e.g., condensing the working fluid into a liquid). Then, the condenser 118 may direct the working fluid (e.g., the liquid working fluid) to the second expansion valve 116, which reduces the pressure of the working fluid and directs the depressurized working fluid to the economizer 120 in the first configuration.

[0028] The economizer 120 can reduce the pressure of the working fluid received from the second expansion valve 116 to separate the working fluid into a vapor working fluid and a liquid working fluid. In a first configuration, the economizer 120 can direct the liquid working fluid to the first expansion valve 110 and the vapor working fluid to the second compressor 114. The first expansion valve 110 can further reduce the pressure of the working fluid and direct the pressure-reduced working fluid to the evaporator 112. The evaporator 112 can place the working fluid (e.g., the liquid working fluid initially generated on the condenser 118) in a heat exchange relationship with the cooling load 106, thereby cooling the cooling load 106 and heating the working fluid (e.g., to evaporate the working fluid). The evaporator 112 can direct the working fluid (e.g., the vapor working fluid) to the first compressor 108 for pressurization and discharge to the second compressor 114 and / or the economizer 120. Additionally, the vapor working fluid from the economizer 120 can be combined with the working fluid discharged from the first compressor 108 to flow toward the second compressor 114. The flow of the working fluid from the compressor 108 to the economizer 120 can be blocked in the first configuration of the economizer 120.

[0029] In a second configuration of the economizer 120, the economizer 120 can receive the pressurized working fluid from the first compressor 108 (e.g., the flow of the vapor working fluid from the economizer 120 toward the second compressor 114 is blocked). Thus, the economizer 120 can separate the working fluid received from the first compressor 108 into a vapor working fluid and a liquid working fluid, and the economizer 120 can direct the liquid working fluid to the first expansion valve 110. However, the discharge of the vapor working fluid from the economizer 120 may be blocked. In some embodiments, the economizer 120 may not receive the working fluid from the second expansion valve 116 in the second configuration. In other or alternative embodiments, the economizer 120 can receive the working fluid from the second expansion valve 116, separate the working fluid into a vapor working fluid and a liquid working fluid, and direct the liquid working fluid to the first expansion valve 110.

[0030] The economizer 120 may be fluidly coupled to an external source 122 (e.g., an external fluid source) to condition a working fluid within the economizer 120. The external source 122 may direct an external fluid (such as water) to the economizer 120. For example, the external fluid source 122 may include a cooling tower, a natural reservoir (e.g., a lake, a pond), a hot fluid storage tank, a process fluid reservoir, another suitable fluid source, or any combination thereof. The economizer 120 may place the external fluid received from the external source 122 in a heat exchange relationship with the working fluid to enable heat transfer between the external fluid and the working fluid to provide conditioning of the working fluid in the economizer 120. In some embodiments, the external fluid 122 directed by the external source may cool the working fluid within the economizer 120, thereby increasing the cooling capacity of the working fluid and improving the operation of the vapor compression system 100 (e.g., of the evaporator 112) to cool the cooling load 106. In other or alternative embodiments, the external fluid directed by the external source 122 may heat the working fluid within the economizer 120, thereby increasing the heating capacity of the working fluid and improving the operation of the vapor compression system 100 (e.g., of the condenser 118) to heat the heating load 108.

[0031] In certain embodiments, the vapor compression system 100 may include or be communicatively coupled to a control system 124 (e.g., a control circuit, an electronic controller, a programmable controller, an automation controller), the control system being configured to control the operation of the vapor compression system 100. The control system 124 may include a memory 126 and a processing circuit 128. The memory 126 may include volatile memory (such as random access memory (RAM)) and / or non-volatile memory (such as read-only memory (ROM), an optical disk drive, a hard disk drive, a solid-state drive, or any other non-transitory computer-readable medium storing instructions that control the operation of the vapor compression system 100). The processing circuit 128 may be configured to execute such instructions stored in the memory 126. As an example, the processing circuit 128 may include one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), one or more general-purpose processors, or any combination thereof.

[0032] The control system 124 can be configured to operate the economizer 120 in a first configuration or in a second configuration. In other words, the control system 124 can control the flow of a working fluid (e.g., from the first compressor 108) into and / or out of the economizer 120 (e.g., flowing to the second compressor 114). For example, the control system 124 can be communicatively coupled to a first valve 130 that is configured to control the flow of the working fluid through a first conduit 132. In the first configuration, the first valve 130 can enable the working fluid (e.g., a vapor working fluid) to flow from the economizer 120 to the second compressor 114 in a first flow direction 134, such as to combine with the working fluid discharged from the first compressor 108 to the second compressor 114. The control system 124 can operate the first valve 130 in the first configuration to control the flow rate of the working fluid from the economizer 120 to the second compressor 114. In the second configuration, the first valve 130 can enable the working fluid (e.g., a vapor working fluid) to flow from the first compressor 108 to the economizer 120 in a second flow direction 136. The control system 124 can operate the first valve 130 in the second configuration to control the flow rate of the working fluid from the first compressor 108 to the economizer 120. In some embodiments, the control system 124 can be configured to operate (e.g., close) the first valve 130 to control the pressurization of the working fluid via the first compressor 108. For example, controlling the opening of the first valve 130 can control the exposure of the pressurized working fluid to the conditions within the economizer 120 (e.g., the working fluid directed in the first direction 134 in the first configuration), and thus the pressure of the economizer 120 (e.g., of the working fluid within the economizer 120) can affect the pressure of the working fluid discharged by the first compressor 108. Accordingly, the control system 124 can operate the first valve 130 to adjust the pressure of the working fluid discharged by the first compressor 108 toward the second compressor 114.

[0033] The control system 124 can also control the flow of an external fluid from an external source 122 to the economizer 120. For example, the vapor compression system 100 can include a second valve 138 that is configured to control the flow of the external fluid through a second conduit 140 to the economizer 120. The control system 124 can operate the second valve 138 to enable the external fluid to flow from the external source 122 to the economizer 120 or to block the flow of the external fluid from the external source 122 to the economizer 120.

[0034] As an example, the control system 124 can operate the vapor compression system 100 in a first operating mode in which the economizer 120 may not be able to regulate the working fluid flow via an external fluid. For example, based on a relatively low cooling demand associated with the cooling load 106 and / or a relatively low heating demand associated with the heating load 108, the control system 124 can operate the vapor compression system 100 in the first operating mode such that additional regulation of the working fluid at the economizer 120 (e.g., via heat transfer between the working fluid and the external fluid) may not be desirable. Additionally or alternatively, in response to determining that the difference between the temperature of the working fluid in the economizer 120 and the temperature of the external fluid is below a threshold temperature (e.g., the temperature of the working fluid in the economizer 120 is similar to the temperature of the external fluid), the control system 124 can operate the vapor compression system 100 in the first operating mode such that the external fluid may not be able to provide substantial regulation of the working fluid in the economizer 120. In the first operating mode, the control system 124 can operate the second valve 138 (e.g., adjust the second valve 138 to a closed position) to block the flow of the external fluid from the external source 122 to the economizer 120. Additionally, in the first operating mode, the control system 124 can operate the first valve 130 in a first position to enable the working fluid to flow from the economizer 120 to the second compressor 114 (e.g., vapor working fluid flow). Thus, the economizer 120 can be in a first configuration during the first operating mode.

[0035] The control system 124 can also operate the vapor compression system 100 in a second operating mode in which the economizer 120 can cool the working fluid. For example, in response to determining that there is a relatively high cooling demand associated with the cooling load 106 and / or the temperature of the external fluid is below the temperature of the working fluid in the economizer 120 by a threshold temperature, the control system 124 can operate the vapor compression system 100 in the second operating mode. The cooling provided by the external fluid can reduce the temperature and / or increase the mass flow rate of the working fluid directed to the evaporator 112, and thus increase the cooling capacity provided by the evaporator 112 to the cooling load 106. In the second operating mode, the control system 124 can operate the second valve 138 (e.g., adjust the second valve 138 to an open position) to enable the flow of the external fluid from the external source 122 to the economizer 120. The control system 124 can also operate the first valve 130 in a second position to control the flow of the working fluid from the first compressor 108 to the economizer 120. That is, the economizer 120 can be in a second configuration during the second operating mode. In this way, the flow of the working fluid cooled by the external fluid can be blocked from flowing to the second flow path 104 for providing heating.

[0036] In some embodiments, in the second operating mode, the flow of the working fluid from the first compressor 108 to the second compressor 114 can also be blocked. To this end, the control system 124 can pause the operation of the second compressor 114, adjust (e.g., close) the expansion valve 116 and / or adjust the third valve 142 (e.g., to a closed position) to block the flow of the working fluid from the first compressor 108 and / or from the economizer 120 to the second compressor 114. In fact, the operation of the second compressor 114 can be paused in the second operating mode to block the flow of the working fluid through the second flow path 104, thereby pausing the heating operation of the vapor compression system 100. Instead, substantially all of the working fluid flow from the first compressor 108 can be cooled and condensed by the economizer 120 (e.g., via an external fluid) and directed through the first flow path 102 to provide a cooling operation.

[0037] Such as in response to determining that there is a relatively high heating demand associated with the heating load 107 and / or the temperature of the external fluid is above the threshold temperature of the working fluid in the economizer 120, the control system 124 can further operate the vapor compression system 100 in a third operating mode, in which the economizer 120 can heat the working fluid. The heating provided by the external fluid can increase the temperature of the working fluid directed to the condenser 118 and thus increase the heating capacity provided by the condenser 118 to the heating load 107. To this end, in the third operating mode, the control system 124 can operate the second valve 138 (e.g., adjust the second valve 130 to an open position) to enable the external fluid to flow from the external source 122 to the economizer 120. The control system 124 can also operate the first valve 130 in a first position to enable the working fluid to flow from the economizer 120 to the second compressor 114 (e.g., the vapor working fluid heated by the external fluid). Thus, the economizer 120 can be in a first configuration during the third operating mode.

[0038] It should be noted that, in some embodiments, the control system 124 may operate the vapor compression system 100 in other operating modes, such as the operating modes between the first operating mode, the second operating mode, and the third operating mode. For example, the control system 124 may operate the first valve 130 and / or the third valve 142 to enable the working fluid to flow from the first compressor 108 to the economizer 120 and the second compressor 114. That is, the working fluid from the first compressor 108 may be distributed between the second compressor 114 and the economizer 120. Additionally or alternatively, the control system 124 may operate the second valve 138 (e.g., between an open position and a closed position, such as a partially open position) to control a specific flow rate of the external fluid from the external source 122 to the economizer 120. The control system 124 may further operate the third valve 142 (e.g., adjust the opening size of the third valve 142) to control a specific flow rate of the working fluid from the first compressor 108 to the second compressor 114. For example, the control system 124 may operate the valves 130, 138, 142 to more sensitively control the regulation of the working fluid in the economizer 120 by the external fluid, the cooling capacity of the evaporator 112, and / or the heating capacity of the condenser 118.

[0039] In addition, in other or alternative embodiments, the working fluid flow can be directed in different ways. As an example, the economizer 120 may receive a first working fluid flow from the first compressor 108 (e.g., via a first opening), and at the same time direct a second working fluid flow to the second compressor 114 (e.g., via a second opening). As another example, the working fluid flow directed by the second expansion valve 116 may bypass the economizer 120 and, for example, flow directly to the first expansion valve 110.

[0040] The control system 124 can control the valves 130, 138, 142 based on data received from the sensors 144. For example, the data may indicate various operating parameters, such as the ambient temperature; the temperature of the working fluid (e.g., in the economizer 120, in the evaporator 112, in the condenser 118); the temperature of the external fluid; the cooling demand associated with the cooling load 106; the heating demand associated with the heating demand 107; the operating capabilities of the first compressor 108 and / or the second compressor 114; the positions of the valves 130, 138, 142; the flow rate of the working fluid (e.g., through any one of the valves 130, 138, 142); another suitable parameter; or any combination thereof. Thus, the control system 124 can operate the vapor compression system 100 in the first operating mode, the second operating mode, the third operating mode, or any other operating mode based on the data received from the sensors 144.

[0041] Figure 6Is an axial cross-sectional view of an embodiment of the economizer 120. The economizer 120 may include a shell 168 (e.g., outer shell, housing), which defines an internal volume 170 in which a working fluid and / or an external fluid is guided. For example, the economizer 120 may include a vapor portion 172 and a regulating portion 174 (e.g., cooling portion, heating portion) within the internal volume 170. The regulating portion 174 may include a first set of tubes 176 (e.g., first tube bundle, first flow channel) through which the external fluid may flow. In some embodiments, the economizer 120 may further include a second set of tubes 177 (e.g., second tube bundle, second flow channel, subcooler, superheater) through which the external fluid may flow. Thus, the external fluid flow may circulate between the economizer 120 and an external source 122 via the first set of tubes 176 and / or the second set of tubes 177. Although the illustrated economizer 120 includes two sets of tubes 176, 177, the economizer 120 may include any suitable number of tube sets, such as three or more sets of tubes, for regulating the working fluid via the external fluid.

[0042] The economizer 120 may include an inlet 178 configured to enable the economizer 120 to receive a working fluid flow (e.g., a mixture of liquid working fluid and vapor working fluid) from the second expansion valve 116. The economizer 120 may further include an outlet 180 configured to enable the economizer 120 to discharge the working fluid to the first expansion valve 110. As an example, the pressure of the working fluid flow guided from the second expansion valve 116 may be partially reduced, and the economizer 120 may further reduce the pressure of the working fluid flow received from the second expansion valve 116 to separate the working fluid into a liquid working fluid and a vapor working fluid within the internal volume 170. The vapor working fluid may be guided to the vapor portion 172, and the liquid working fluid may be guided toward the outlet 180 through the regulating portion 174 (e.g., by gravity).

[0043] In addition, the economizer 120 may include an opening 182 through which the working fluid may flow. For example, in a first configuration of the economizer 120, the working fluid (e.g., vapor working fluid) may flow out of the internal volume 170 through the opening 182 in a first direction 134, such as toward the second compressor 114. Additionally, in a second configuration of the economizer 120, the working fluid may flow into the internal volume 170 through the opening 182 in a second direction 136, such as starting from the first compressor 108. Thus, based on the configuration of the economizer 120, the working fluid may flow through the opening 182 in any direction.

[0044] The first set of tubes 176 and / or the second set of tubes 177 may place an external fluid in a heat exchange relationship with the working fluid for the first set of tubes 176, such as a liquid working fluid flowing toward the outlet 180. As an example, in the second operating mode, the first set of tubes 176 may enable the external fluid to cool the working fluid, thereby condensing the working fluid. The second set of tubes 177 may enable the external fluid to further cool (e.g., subcool) the working fluid, and the working fluid cooled by the first set of tubes 176 and / or the second set of tubes 177 may be discharged from the economizer 120 via the outlet 180. Thus, the regulating section 174 may cause condensation of the working fluid to provide more liquid working fluid in the second operating mode. Additionally, in the second operating mode, the working fluid may flow through the opening 182 in the first direction 136 into the economizer 120. In the third operating mode, the first set of tubes 176 may enable the external fluid to heat the working fluid, thereby vaporizing the working fluid. The second set of tubes 177 may further heat the working fluid via the external fluid to facilitate vaporization of the working fluid. Thus, heating of the working fluid may produce a vapor working fluid that flows toward the vapor section 172, and the vapor working fluid may be discharged from the economizer 120 via the opening 182 in the first direction 134. Thus, the regulating section 174 may provide more vapor working fluid in the third operating mode. Any liquid working fluid remaining after heating the working fluid via the external fluid may be discharged from the economizer 120 via the outlet 180.

[0045] In the first operating mode, the flow of the external fluid through the economizer 120 is blocked, and the working fluid may not exchange heat with the external fluid. Instead, in the first operating mode, the pressure reduction of the working fluid via the economizer 120 may produce a vapor working fluid and a liquid working fluid, the vapor working fluid being discharged from the economizer 120 via the opening 182, and the liquid working fluid being discharged from the economizer 120 via the outlet 180. However, the first set of tubes 176 and / or the second set of tubes 177 may not cause a substantial change in the temperature or state of the working fluid in the first operating mode.

[0046] Figure 7 is a schematic diagram of an embodiment of a vapor compression system 100 having multiple economizers. For example, the vapor compression system 100 may include a first flow path 102, a second flow path 104, and an intermediate flow path 210. The first economizer 212 (e.g., economizer 120) may be configured to receive the working fluid from the first flow path 102 and from the intermediate flow path 210. The second economizer 214 may be configured to receive the working fluid from the intermediate flow path 210 and from the second flow path 104. The intermediate flow path 210 may include an intermediate compressor 216 and an intermediate expansion valve 218 (e.g., an intermediate expansion device).

[0047] For example, the first compressor 108 can pressurize the working fluid and direct the working fluid to the intermediate compressor 216. The intermediate compressor 216 can further pressurize the working fluid and direct the working fluid to the second compressor 114, and the second compressor 114 can further pressurize the working fluid and direct the working fluid to the condenser 118. The condenser can utilize the working fluid to heat the heating load 107. The condenser 118 can direct the working fluid to the second expansion valve 116, which can reduce the pressure of the working fluid and direct the working fluid to the second economizer 214. The second economizer 214 can further reduce the pressure of the working fluid to produce a vapor working fluid and a liquid working fluid. The second economizer 214 can direct the vapor working fluid to the second compressor 114 for pressurization, and the second economizer 214 can direct the liquid working fluid to the intermediate expansion valve 218. The intermediate expansion valve 218 can reduce the pressure of the working fluid and direct the working fluid to the first economizer 212. The first economizer 212 can reduce the pressure of the working fluid and produce a vapor working fluid and a liquid working fluid. The first economizer 212 can direct the liquid working fluid to the first expansion valve 110.

[0048] The first economizer 212 can switch between a first configuration and a second configuration (e.g., via the operation of the control system 124). In the first configuration, the first economizer 212 can discharge the vapor working fluid to the intermediate compressor 216 (such as through the first conduit 132). In the second configuration, the first economizer 212 can receive the working fluid from the first compressor 108 and can block the flow of the working fluid from the first economizer 212 to the intermediate compressor 216. In some embodiments, the first economizer 212 may not be able to receive the working fluid from the intermediate expansion valve 218 in the second configuration, and the operation of the intermediate flow path 210 can be suspended.

[0049] By way of example, the first economizer 212 can receive an external fluid from an external source 122 via a second conduit 140 and can operate in the first configuration or in the second configuration based on the conditioning performed by the external fluid. For example, in a first operating mode, where the external fluid does not provide any conditioning to the working fluid in the first economizer 212, the first economizer 212 can operate in the first configuration to direct the vapor working fluid to the intermediate compressor 216. In a second operating mode, where the external fluid can cool the working fluid in the first economizer 212, the first economizer 212 can operate in the second configuration to receive the working fluid from the first compressor 108. In a third operating mode, where the external fluid can heat the working fluid in the first economizer 212, the first economizer 212 can operate in the first configuration to direct the vapor working fluid to the intermediate compressor 216.

[0050] In some embodiments, the intermediate load 220 can be fluidly connected to the second economizer 214. For example, the intermediate load 220 can direct intermediate fluid to the second economizer 214. The second economizer 214 can place the working fluid in a heat exchange relationship with the intermediate fluid. For example, the second economizer 214 can enable the working fluid to heat the intermediate fluid (e.g., provide heat for a drying process). In other or alternative embodiments, the second economizer 214 can enable the working fluid to cool the intermediate fluid. The control system 124 can operate the fourth valve 222 to control the fluid flow between the second economizer 214 and the intermediate load 220 via the fourth conduit 224 to provide the desired amount of regulation for the intermediate fluid (e.g., adjust the temperature of the intermediate fluid toward a target temperature).

[0051] In certain embodiments, the second economizer 214 can also be switched between a first configuration and a second configuration (e.g., via operation of the control system 124). For example, in the first configuration, the second economizer 214 can discharge the vapor working fluid to the second compressor 114, and in the second configuration, the second economizer 214 can receive the working fluid from the intermediate compressor 216 and block the flow of the working fluid from the second economizer 214 to the second compressor 114. The second economizer 214 may not be able to receive the working fluid from the second expansion valve 116 in the second configuration, and the operation of the second flow path 104 can be suspended.

[0052] Although only certain features and embodiments of the present disclosure have been shown and described, many modifications and variations (e.g., changes in the size, dimensions, structure, shape and proportions of various elements, values of parameters (e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) may be envisioned by those skilled in the art without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be altered or re-ordered according to alternative embodiments. Accordingly, it is to be noted that the appended claims are intended to cover all such modifications and variations that fall within the true spirit of the present disclosure. Additionally, for the sake of brevity in describing exemplary embodiments, not all features of actual implementations may be described (i.e., those features that are not relevant to the currently contemplated best mode of implementing the present disclosure, or those features that are not relevant to implementing the claimed embodiments). It should be understood that in the development of such actual implementations, as in any engineering or design project, numerous implementation-specific decisions may be made. Such development work may be complex and time-consuming, but for those of ordinary skill in the art who benefit from the present disclosure, these are routine tasks of design, fabrication, and production without undue experimentation.

[0053] The techniques presented and claimed herein refer to and are applied to substantial objects and specific instances with a practical nature, which substantially improve the technical field of the present invention in an arguable manner and are thus not abstract, intangible, or purely theoretical. Additionally, if any claim appended at the end of this specification contains one or more elements expressed as "means for [performing] [function]..." or "step for [performing] [function]...", such elements are expected to be construed in accordance with 35 U.S.C. 112(f). However, for any claim containing elements specified in any other way, such elements are not intended to be construed in accordance with 35 U.S.C. 112(f).

Claims

1. A heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system, the HVAC&R system comprising: an evaporator configured to place a working fluid in a heat exchange relationship with a cooling load to cool the cooling load and heat the working fluid; a first compressor configured to receive the working fluid heated by the evaporator, wherein the first compressor is configured to pressurize the working fluid; a second compressor configured to receive the working fluid pressurized by the first compressor; a condenser configured to: receive the working fluid from the second compressor and place the working fluid in a heat exchange relationship with a heating load to heat the heating load and cool the working fluid; and an economizer configured to: receive the working fluid cooled by the condenser, place the working fluid in a heat exchange relationship with an external fluid to condition the working fluid in the economizer, separate the working fluid into a vapor working fluid and a liquid working fluid, and direct the liquid working fluid toward the evaporator.

2. The HVAC&R system according to claim 1, wherein the economizer is configured to switch between a first configuration and a second configuration, the economizer being configured to receive the working fluid from the first compressor in the first configuration, and the economizer being configured to discharge the vapor working fluid toward the second compressor in the second configuration.

3. The HVAC&R system according to claim 2, the HVAC&R system including a valve configured to control fluid flow through a conduit, wherein the valve is configured to enable the working fluid to flow from the first compressor toward the economizer in a first position, and the valve is configured to enable the working fluid to flow from the economizer toward the second compressor in a second position.

4. The HVAC&R system according to claim 2, wherein the economizer includes an opening, the economizer being configured to receive the working fluid from the first compressor via the opening in the first configuration, and the economizer being configured to discharge the vapor working fluid toward the second compressor via the opening in the second configuration.

5. The HVAC&R system according to claim 1, the HVAC&R system including a control system configured to: control the HVAC&R system to block the flow of the external fluid toward the economizer; and in response to blocking the flow of the external fluid toward the economizer, operate the economizer to direct the vapor working fluid toward the second compressor.

6. The HVAC&R system according to claim 1, the HVAC&R system including a control system configured to: control the HVAC&R system to direct the flow of the external fluid toward the economizer to heat the working fluid in the economizer; and In response to guiding the flow of the external fluid toward the economizer to heat the working fluid in the economizer, operate the economizer to direct the vapor working fluid toward the second compressor.

7. The HVAC&R system according to claim 1, the HVAC&R system comprising a control system configured to: control the HVAC&R system to direct the flow of the external fluid toward the economizer to cool the working fluid in the economizer; and in response to directing the flow of the external fluid toward the economizer to cool the working fluid in the economizer, operate the economizer to enable receipt of the working fluid from the first compressor.

8. The HVAC&R system according to claim 1, the HVAC&R system comprising an expansion valve, wherein the economizer is configured to direct the liquid working fluid toward the expansion valve, and the expansion valve is configured to reduce the pressure of the liquid working fluid and direct the liquid working fluid toward the evaporator.

9. The HVAC&R system according to claim 1, the HVAC&R system comprising an expansion valve, wherein the condenser is configured to direct the working fluid toward the expansion valve, and the expansion valve is configured to reduce the pressure of the working fluid and direct the working fluid toward the economizer.

10. The HVAC&R system according to claim 1, wherein the economizer is a first economizer, and the HVAC&R system comprises: a third compressor configured to receive the working fluid pressurized by the first compressor, pressurize the working fluid, and direct the working fluid toward the second compressor; and a second economizer configured to receive the working fluid cooled by the condenser, separate the working fluid into additional vapor working fluid and additional liquid working fluid, direct the additional liquid working fluid toward the first economizer, and direct the additional vapor working fluid toward the second compressor.

11. The HVAC&R system according to claim 10, wherein the second economizer is configured to place an intermediate working fluid in a heat exchange relationship with the working fluid in the second economizer to condition the intermediate working fluid.

12. The HVAC&R system according to claim 10, the HVAC&R system comprising an expansion valve, wherein the second economizer is configured to direct the additional liquid working fluid toward the expansion valve, and the expansion valve is configured to reduce the pressure of the additional liquid working fluid and direct the additional liquid working fluid toward the first economizer.

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