Low-charge chillers and free cooling

Abstract

The system includes a vapor compression assembly and a free cooling assembly. The free cooling assembly corresponds to a cooling fluid and includes an air-cooled heat exchanger, an additional heat exchanger, and a valve. The system also includes a controller configured to receive data indicative of the ambient conditions, operating conditions, or both of the system. The controller is also configured to, based on the data, operate the valve between a first setting in which the cooling fluid is directed to the additional heat exchanger and blocked from the condenser of the vapor compression assembly, a second setting in which the cooling fluid is directed to the condenser and blocked from the additional heat exchanger, and a third setting in which a first portion of the cooling fluid is directed to the additional heat exchanger and a second portion of the cooling fluid is directed to the condenser.

Description

Technical Field

[0001] (Cross-Reference to Related Application) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 350,743, filed June 9, 2022, entitled "LOW CHARGE CHILLER AND FREE COOLING", which is incorporated herein by reference in its entirety for all purposes.

Background Art

[0002] This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the present disclosure described below. This discussion is believed to be helpful in providing 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 descriptions are to be read in this light, and not as admissions of prior art.

[0003] The present application generally relates to heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) systems employing a vapor compression assembly (or "chiller assembly") and a free cooling assembly.

[0004] Certain HVAC&R systems, such as chillers, employ vapor compression assemblies. A vapor compression system utilizes a working fluid (e.g., a refrigerant) that changes phases between vapor, liquid, and mixtures thereof in response to being exposed to different temperatures and pressures within the components of the vapor compression assembly. A vapor compression assembly may include an evaporator configured to place the working fluid in a heat exchange relationship with a process fluid (e.g., water), for example, by conditioning, so that the working fluid absorbs heat from the process fluid. The process fluid, cooled by the working fluid, may then be directed towards a conditioned environment, such as a data center, where information is provided by the HVAC&R system. The process fluid may pass through downstream equipment, such as an air handler, to condition other fluids, such as air, directed towards the conditioned environment. A condenser in the vapor compression assembly may be employed to receive the working fluid and condense it into the liquid phase. A compressor in the vapor compression assembly may be employed to energize the working fluid through the vapor compression assembly (e.g., by increasing the pressure of the working fluid).

[0005] In certain HVAC&R systems employing vapor compression assemblies, free cooling assemblies may also be employed. For example, a cooling fluid associated with a free cooling assembly (e.g., water, glycol, or a mixture thereof) may be used to cool various fluids associated with the HVAC&R system, such as the working fluid in the condenser of the vapor compression assembly. Furthermore, a cooling tower (or other cooling source) may be employed in the free cooling assembly to reduce the temperature of the process fluid via the ambient air. In this way, the free cooling assembly can leverage the relatively low ambient air temperature to provide cooling and reduce the load on the vapor compression assembly.

[0006] In conventional systems, the operation of the free cooling assembly may be activated during certain conditions, such as when the ambient air temperature is relatively low. When the ambient air temperature is relatively low, the HVAC&R system may be configured to operate with adequate cooling capacity via the free cooling assembly without supplying power to the compressor (e.g., by relying on a thermal siphon or natural convection for the movement of the working fluid), and / or while reducing the vapor compression assembly's reliance on the compressor (or other components). However, in conventional HVAC&R systems utilizing vapor compression and free cooling assemblies, technical constraints may necessitate a reliance on the vapor compression assembly over the reliance on the free cooling assembly. That is, in conventional HVAC&R systems, cooling may be heavily dependent on the vapor compression assembly, which requires a relatively large refrigerant charge in the vapor compression assembly and contributes to the energy inefficiency of the HVAC&R system. Therefore, it is recognized that an improved HVAC&R system employing vapor compression and free cooling assemblies is desired. [Overview of the project] [Means for solving the problem]

[0007] An overview of specific embodiments disclosed herein is provided below. It should be understood that these embodiments are presented solely to provide the reader with a brief overview of these specific embodiments and are not intended to limit the scope of this disclosure. In fact, this disclosure may encompass a variety of embodiments not described below.

[0008] In one embodiment, the HVAC&R system includes a vapor compression assembly and a free cooling assembly. The free cooling assembly corresponds to a cooling fluid (e.g., in an internal fluid cooling loop) and includes an air-cooled heat exchanger, one or more additional heat exchangers, a fluid pump, and valves. The HVAC&R system also includes at least one controller configured to receive data indicating the ambient condition, operating condition, or both of the HVAC&R system. The at least one controller is also configured to actuate valves between various settings based on the data. The various settings include a first setting in which the cooling fluid is directed to the additional heat exchanger and isolated from the condenser of the vapor compression assembly; a second setting in which the cooling fluid is directed to the condenser and isolated from the additional heat exchanger; and a third setting in which a first portion of the cooling fluid is directed to the additional heat exchanger and a second portion of the cooling fluid is directed to the condenser.

[0009] In another embodiment, a control assembly for a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes a sensor configured to detect ambient or operating conditions of the HVAC&R system, and at least one controller. The at least one controller is configured to receive feedback from the sensor indicating ambient or operating conditions. The at least one controller is also configured to actuate valves of a free cooling assembly between various settings based on the feedback. The various settings include a first setting in which the cooling fluid of the free cooling assembly is directed toward the heat exchanger of the free cooling assembly rather than toward the vapor compression assembly; a second setting in which the cooling fluid is directed toward the vapor compression assembly rather than toward the heat exchanger; and at least one third setting in which a first portion of the cooling fluid is directed toward the heat exchanger and a second portion of the cooling fluid is directed toward the vapor compression assembly.

[0010] In yet another embodiment, a method for operating a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system includes receiving first data, via at least one controller, indicating a first value of the ambient or operating state of the HVAC&R system; and, via at least one controller and based on the first data, controlling a valve to a first setting, such that the cooling fluid of a free cooling assembly is directed toward the heat exchanger of the free cooling assembly rather than the condenser of a vapor compression assembly. The method also includes receiving second data, via at least one controller, indicating a second value of the ambient or operating state of the HVAC&R system, wherein the second value is different from the first value; and, via at least one controller and based on the second data, controlling a valve to a second setting, such that the cooling fluid is directed toward the condenser rather than the heat exchanger. The method also includes receiving third data via at least one controller, which indicates a third value of the ambient or operating state of the HVAC&R system, wherein the third value is different from the first and second values; and controlling a valve via at least one controller and based on the third data to a third setting in which a first portion of the cooling fluid is directed toward the heat exchanger and a second portion of the cooling fluid is directed toward the condenser.

[0011] Various aspects of this disclosure can be better understood by reading the following detailed description and referring to the drawings. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of a heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) system employing a vapor compression assembly (or chiller assembly), a free cooling assembly, and a control mechanism configured to adjust the dependence on the vapor compression assembly and the free cooling assembly, according to one aspect of the present disclosure. [Figure 2]Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 85 degrees Fahrenheit and the operating load is 100% of the system's design load capacity. [Figure 3] Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 65 degrees Fahrenheit and the operating load is 100% of the system's design load capacity. [Figure 4] Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 60 degrees Fahrenheit and the operating load is 100% of the system's design load capacity. [Figure 5] Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 85 degrees Fahrenheit and the operating load is 50% of the system's design load capacity. [Figure 6] Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 65 degrees Fahrenheit and the operating load is 50% of the system's design load capacity. [Figure 7] Figure 1 is a schematic diagram of an HVAC&R system according to one aspect of the present disclosure, where the ambient temperature is 60 degrees Fahrenheit and the operating load is 50% of the system's design load capacity. [Figure 8] This is a process flow diagram illustrating a method for operating the HVAC&R system shown in Figure 1 according to one aspect of this disclosure. [Figure 9] This is a schematic diagram of a multi-temperature hot water HVAC&R system employing a vapor compression assembly (or chiller assembly), a free cooling assembly, and a control mechanism configured to adjust the dependence on the vapor compression assembly and the free cooling assembly, according to one aspect of the present disclosure. [Modes for carrying out the invention]

[0013] One or more specific embodiments are described below. Not all features of actual implementations are described herein in order to provide a concise description of these embodiments. In developing any such actual implementation, as with any engineering or design project, it should be understood that many implementation-specific decisions, which may differ from implementation to implementation, must be made to achieve the developer's specific goals, including compliance with system-related and industry-related constraints. Furthermore, it should be understood that while such development efforts may be complex and time-consuming, they nevertheless become routine design, fabrication, and manufacturing tasks for those skilled in the art who benefit from this disclosure.

[0014] When introducing elements of the various embodiments of this disclosure, the articles “a,” “an,” and “the” are intended to indicate that one or more of the elements exist. The terms “comprising,” “including,” and “having” are intended to be comprehensive and mean that additional elements other than those enumerated may exist. Additionally, it should be understood that any reference in this disclosure to “one embodiment” or “an embodiment” is not intended to be construed as excluding the existence of additional embodiments that similarly incorporate the enumerated features.

[0015] Embodiments of the present disclosure relate to heating, ventilation, air conditioning, and / or refrigeration (HVAC&R) systems utilizing vapor compression assemblies and free cooling assemblies. Vapor compression assemblies may be employed, for example, in the context of chillers, used for conditioning or cooling process fluids during specific conditions. Generally, HVAC&R systems are configured to cool process fluids and route them toward loads. For example, process fluids may be cooled by an HVAC&R system and directed toward downstream equipment such as an air handling unit (AHU). The AHU may cool an airflow through the process fluid and distribute the airflow to various spaces (e.g., rooms, data centers) conditioned by the HVAC&R system. Alternatively, process fluids may be employed in immersion applications to directly cool loads, such as equipment in a data center.

[0016] A vapor compression assembly may include a vapor compression loop (referred to in specific examples of this disclosure as a working fluid loop) that circulates a working fluid (e.g., a refrigerant) through an evaporator, a condenser, and a compressor. The compressor may operate to compress the working fluid (e.g., increase its pressure) under specific conditions, thereby energizing the working fluid through the vapor compression loop. An evaporator may be employed to cool the process fluid by absorbing heat from the process fluid into the working fluid under specific conditions. A condenser may be employed to remove heat from the working fluid, for example, through the cooling fluid of an internal fluid cooling loop associated with a free cooling assembly under specific conditions. Thus, the condenser may be considered part of the internal fluid cooling loop while the cooling fluid of the internal fluid cooling loop is present in the condenser.

[0017] A free cooling assembly may include an air-cooled heat exchanger placed in the external environment, a valve, and a plate-frame heat exchanger that provides liquid-liquid cooling. For example, a plate-frame heat exchanger may be employed to cool a process fluid through the cooling fluid of a free cooling assembly under certain conditions. An air-cooled heat exchanger, which may include a single fan (e.g., a single fan working for a V-coil assembly), may be employed to reduce the temperature of the cooling fluid before it is directed toward the condenser of the plate-frame heat exchanger and / or vapor compression assembly.

[0018] Valves in a free cooling assembly (e.g., diversion valves) may be located in the internal fluid cooling loop associated with the free cooling assembly. Furthermore, the valves can be controlled to various valve settings that direct portions of the cooling fluid to the condenser, the plate-frame heat exchanger, or both. For example, in certain conditions, the valves may be controlled to a valve setting that directs the cooling fluid to the condenser and shuts it off from the plate-frame heat exchanger. In certain other conditions, the valves may be controlled to a valve setting that directs the cooling fluid to the plate-frame heat exchanger and shuts it off from the condenser. In certain other conditions, the valves may be controlled to a valve setting that directs a portion of the cooling fluid to the plate-frame heat exchanger and an additional portion of the cooling fluid to the condenser. According to this disclosure, a controller may receive various inputs indicating the ambient conditions of the HVAC&R system (e.g., ambient temperature, referred to in the specific examples of this disclosure as ambient dry-bulb temperature) and / or operating conditions (e.g., the return temperature or target return temperature of the process fluid from the load, the supply temperature or target supply temperature of the process fluid to the load, the operating load, etc.). Based on one or more of these inputs, the controller may actuate valves to preferred valve settings so that the cooling fluid is directed toward the appropriate components of the HVAC&R system, as described in detail above and below.

[0019] It should be noted that several valve settings of the valve may exist to direct a portion of the cooling fluid to the plate-frame heat exchanger and direct an additional portion of the cooling fluid to the condenser. Additionally or alternatively, only one valve setting of the valve may exist to direct a portion of the cooling fluid to the plate-frame heat exchanger and direct an additional portion of the cooling fluid to the condenser, and the pump may be controlled to adjust the amount or flow rate of the portion and the additional portion of the cooling fluid based on various conditions. In this way, the amount or flow rate of the portion of cooling fluid directed to the plate-frame heat exchanger and the additional amount or additional flow rate of the additional portion of cooling fluid directed to the condenser can be controlled, so as to provide appropriate cooling for the cooling fluid (and subsequently for the load) while minimizing dependence on the vapor compression assembly.

[0020] In addition to the above points, the setting of the compressor of the vapor compression system, which operates to increase the pressure of the working fluid in the vapor compression loop, may be controlled by the controller to correspond to the valve setting, to correspond to the pump setting, and / or based on the ambient and / or operating conditions described above. Further in addition to the above points, the fan of the air-cooled heat exchanger may be controlled to a setting to provide sufficient cooling for the cooling fluid of the free cooling assembly. Other control modes are also possible, and will be described in detail with reference to the drawings.

[0021] By adopting the features described above, the HVAC&R system can provide cooling to a conditioned space, such as a data center, through substantial reliance on the free cooling assembly and relatively low reliance on the vapor compression assembly, thereby providing adequate cooling while improving energy efficiency and reducing refrigerant charge of the vapor compression assembly compared to conventional embodiments. By way of example, for an HVAC&R system having a design load capacity of 500 refrigeration tons, where the operating load is 100% of the system's design load capacity, a process fluid supply temperature of 70 degrees Fahrenheit can be enabled at least when the ambient temperature is about 60 degrees Fahrenheit or below via full reliance on the free cooling assembly (e.g., with the compressors of the vapor compression assembly turned off). Further, when the operating load is reduced, a process fluid supply temperature of 70 degrees Fahrenheit can be enabled via full reliance on the free cooling assembly when the ambient temperature is substantially higher than 60 degrees Fahrenheit. By way of example, when the operating load is 50% of the system's design load capacity, the HVAC&R system, as described above, can provide adequate cooling when the ambient temperature is about 65 degrees Fahrenheit or below via full reliance on the free cooling assembly (e.g., with the compressors of the vapor compression assembly turned off). It will be appreciated that at even higher ambient temperatures, the HVAC&R system can still rely heavily on the free cooling assembly to provide process fluid at an appropriate temperature to cool the load. Other examples are provided with reference to the drawings.

[0022] In general, the systems and methods of the present disclosure enable cooling with greater reliance on free cooling and reduced reliance on vapor compression compared to conventional embodiments. In so doing, the required refrigerant charge of the vapor compression assembly is reduced compared to conventional embodiments, and the energy efficiency of the HVAC&R system is improved compared to conventional embodiments. These and other features are described in detail below with reference to the drawings.

[0023] Figure 1 is a schematic diagram of one embodiment of an HVAC&R system 10 employing a vapor compression assembly 12 (or chiller assembly), a free cooling assembly 14, and a control mechanism configured to adjust the dependence on the vapor compression assembly 12 and the free cooling assembly 14. Generally, the vapor compression assembly 12 and the free cooling assembly 14 are configured to cool a process fluid 16 (e.g., water, glycol, water-glycol mixture, dielectric fluid in immersion applications, etc.) corresponding to a process fluid loop 18, and the process fluid 16 is energized through the process fluid loop 18 via a pump 19. As shown in the figure, the process fluid loop 18 can direct the process fluid 16 to a load 20 (e.g., a conditioning space and / or data center) to cool the load 20. Depending on the ambient and / or operating conditions of the HVAC&R system 10, the reliance on the vapor compression assembly 12 and / or the free cooling assembly 14 for cooling the process fluid 16 can be adjusted to ensure adequate cooling and reduce the energy consumption of the HVAC&R system 10, compared to conventional embodiments. These and other features are described in detail below with reference to Figure 1.

[0024] The vapor compression assembly 12 may include a vapor compression loop 22 (referred to in certain examples of this disclosure as a working fluid loop) which routes a working fluid 24 (e.g., a refrigerant such as R-123, R-514A, R-1224yd, R-1233zd, R-134a, R-1234ze, R-1234yf, R-1311, R-32, R-410A, or others) through various components of the vapor compression assembly 12. For example, the vapor compression loop 22 may route the working fluid 24 through the compressor 28, condenser 26, expansion valve 32, and evaporator 30 of the vapor compression assembly 12. The compressor 28 may, under certain conditions, operate to energize the working fluid 24 through the vapor compression loop 22 (e.g., by increasing the pressure of the working fluid 24). The evaporator 30 may, under certain conditions, operate to cool the process fluid 16 of the process fluid loop 18. The expansion valve 32 may operate to reduce the pressure of the working fluid 22 between the condenser 26 and the evaporator 30. The condenser 26 may, under certain conditions, operate to remove heat from the working fluid 24 via liquid-liquid cooling, where heat is transferred from the working fluid 24 to the cooling fluid 34 (e.g., water, glycol, water-glycol mixture, etc.) corresponding to the internal fluid cooling loop 36 of the free cooling assembly 14. In this way, the condenser 26 may be considered part of the internal fluid cooling loop 36 while the cooling fluid 34 of the internal fluid cooling loop 36 is present in the condenser 26.

[0025] As described above, under certain ambient and / or operating conditions of the HVAC&R system 10, the free cooling assembly 14 may be employed to reduce the reliance on the vapor compression assembly 12 for cooling the process fluid 16 in the process fluid loop 18. For example, as the reliance on the free cooling assembly 14 increases in response to certain conditions, the reliance on the compressor 28 of the vapor compression assembly 12 may be reduced. Under certain conditions, while the HVAC&R system 10 relies solely on the free cooling assembly 14 to provide cooling to the process fluid 16, the compressor 28 may be completely disconnected or otherwise turned off. The movement of the working fluid 24 through the vapor compression loop 22 may continue even after the compressor 28 is disconnected or otherwise turned off via natural convection (e.g., via a thermal siphon). Additionally or alternatively, the HVAC&R system 10 may rely on both the free cooling assembly 14 and the vapor compression assembly 12 in certain conditions where the compressor 28 is controlled to a relatively low setting, thereby improving energy efficiency while ensuring adequate cooling of the process fluid 16. The configurations of the free cooling assembly 14, and the controls of the HVAC&R system 10 for adjusting the reliance on the vapor compression assembly 12 and / or the free cooling assembly 14, are described in detail below.

[0026] In the illustrated embodiments, the free cooling assembly 14 includes an internal fluid cooling loop 36 configured to route a cooling fluid 34 through various components of the HVAC&R system 10, including the condenser 26 of the vapor compression assembly 12, the air-cooled heat exchanger 38 of the free cooling assembly 14 (e.g., having a fan 39), and the plate-frame heat exchanger 40 of the free cooling assembly 14. Generally, the air-cooled heat exchanger 38 is configured to cool the cooling fluid 34 (e.g., via a fan 39) before it is delivered to the condenser 26 of the vapor compression assembly 12 and / or the plate-frame heat exchanger 40 of the free cooling assembly 14. In some embodiments, the air-cooled heat exchanger 38 may include only an example of a fan 39 configured to cool the cooling fluid 34 before it is delivered to the condenser 26 and / or the plate-frame heat exchanger 40.

[0027] When the cooling fluid 34 is present in the condenser 26, the cooling fluid 34 absorbs heat from the working fluid 24 corresponding to the vapor compression assembly 12, condensing the working fluid 24 before it is delivered to the expansion valve 32. When the cooling fluid 34 is present in the plate-frame heat exchanger 40, the cooling fluid 34 absorbs heat from the process fluid 16 corresponding to the process fluid loop 18. The configuration of the free cooling assembly 14 can be controlled to allocate some, none, or all of the cooling fluid 34 to the condenser 26 and some, none, or all of the cooling fluid 34 to the plate-frame heat exchanger 40, as will be described in detail below.

[0028] The free cooling assembly 14 includes a valve 42 controlled to various settings for directing a portion of the cooling fluid 34 to the condenser 26 of the vapor compression assembly 12 and / or the plate-frame heat exchanger 40 of the free cooling assembly 14. Furthermore, the free cooling assembly 14 includes a pump 44 configured to energize the cooling fluid 34 through the internal fluid cooling 36. Depending on the ambient and / or operating conditions of the HVAC&R system 10, the valve 42 can be controlled to a first valve setting in which the cooling fluid 34 is directed to the plate-frame heat exchanger 40 and isolated from the condenser 26; a second valve setting in which the cooling fluid 34 is directed to the condenser 26 and isolated from the plate-frame heat exchanger 40; or a third setting (or one of several third settings) in which a portion of the cooling fluid 34 is directed to the plate-frame heat exchanger 40 and an additional portion of the cooling fluid 34 is directed to the condenser 26.

[0029] A controller 46 of the HVAC&R system 10 may be employed to control the various components described above. In the illustrated embodiment, the controller 46 includes a processing circuit 48 and a memory circuit 50 having instructions stored thereon, which, when executed by the processing circuit 48, cause the processing circuit 48 to perform various functions. Note that, for the sake of brevity, only one example of the controller 46 is shown in the illustrated embodiment. However, note that multiple controllers (including dedicated processing and / or memory circuits) may be employed to implement the control mechanisms described herein.

[0030] The controller 46 may receive one or more inputs indicating various ambient and / or operating conditions of the HVAC&R system 10. For example, the controller 46 may receive a first input from a first sensor 52 indicating the ambient temperature (e.g., near the air-cooled heat exchanger 38). Additionally or alternatively, the controller 46 may receive a second input from a second sensor 54 indicating the supply temperature of the process fluid 16 directed to the load 20. Additionally or alternatively, the controller 46 may receive a third input from a third sensor 56 indicating the return temperature of the process fluid 16 returned from the load 20. In some embodiments, the controller 46 may adopt a target supply temperature of the process fluid 16 directed to the load 20 and / or a target return temperature of the process fluid 16 returned from the load 20 (e.g., in addition to or instead of the detected temperature). Additionally or alternatively, the controller 46 may receive (or otherwise determine) a fourth input indicating an operating load or cooling demand corresponding to the HVAC&R system 10 and / or load 20. In fact, the HVAC&R system 10 may include the system's design load capacity, but the operating load may correspond to a cooling demand for load 20 at a particular operating interval that is less than the system's design load capacity. The fourth input indicating the operating load or cooling demand may, for example, be a certain percentage of the system's design load capacity. The fourth input may be received from a sensor or other feedback device that may be part of (or separate from) one or more controllers 46. The control assembly may include one or more controllers 46 according to this disclosure and, in some embodiments, may include a first sensor 52, a second sensor 54, a third sensor 56, and / or any combination of other sensors or feedback devices.

[0031] In response to at least one of the inputs described above (e.g., ambient temperature, supply temperature and / or target supply temperature of process fluid 16, return temperature and / or target return temperature of process fluid 16, operating load), the controller 46 may control various components of the HVAC&R system 10 to ensure adequate cooling of the load 20 while reducing energy consumption. Specifically, the controller 46 may control the valve 42 of the free cooling assembly 14 to direct some or all of the cooling fluid 34 to the condenser 26 of the vapor compression assembly 12 and some or all of the cooling fluid 34 to the plate frame heat exchanger 40.

[0032] Other embodiments of the HVAC&R system 10 may also be controlled to correspond to the valve settings of valve 42 (or based on the inputs described above). For example, the settings of the compressor 28 and / or the fan 39 of the air-cooled heat exchanger 38 may be controlled in a manner that provides adequate cooling to the process fluid 16 while reducing the energy consumption of the HVAC&R system 10. Generally, the systems and methods of the present disclosure are configured to enable the HVAC&R system 10 to provide adequate cooling to the process fluid 16, with a heavy reliance on the free cooling assembly 14, thereby improving the efficiency of the HVAC&R system 10 compared to conventional embodiments.

[0033] Figures 2 to 7 illustrate various embodiments of the HVAC&R system 10 with different ambient temperatures and operating loads. As seen in Figures 2 to 7 and described in detail below, the control is adjusted at least partially based on the ambient temperature and operating load. In Figures 2 to 4, the operating load is 100% of the system's design load capacity (for example, at ambient temperatures of 85°F, 65°F, and 60°F, respectively). In Figures 5 to 7, the operating load is 50% of the system's design load capacity (for example, at ambient temperatures of 85°F, 65°F, and 60°F, respectively). Generally, the lower the ambient temperature and / or operating load, the more the HVAC&R system 10 relies on the free cooling assembly 14 for energy saving. Each of Figures 2 to 7 is described individually and in detail below.

[0034] Figure 2 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 85 degrees Fahrenheit (for example, as shown in Legend 59), and the operating load is 100% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. In the embodiment illustrated, the controller 46 of the HVAC&R system 10 controls the valve 42 of the free cooling assembly 14 to a valve setting such that the cooling fluid 34 is directed toward the condenser 26 of the vapor compression assembly 12 and isolated from the plate-frame heat exchanger 40 of the free cooling assembly 14. Thus, the HVAC&R system 10 relies on the vapor compression assembly 12 (for example, with the compressor 28 turned on and controlled to a sufficient setting) to cool the process fluid 16 through the evaporator 30, and does not rely on the plate-frame heat exchanger 40. In other words, none of the cooling fluids 34 are directed toward the plate frame heat exchanger 40.

[0035] The illustrated control relies on the vapor compression assembly 12, as indicated by a relatively high ambient temperature (e.g., 85 degrees Fahrenheit) and operating load (e.g., 100% of the system's design load capacity). In fact, as shown in the illustrated embodiment, the valve 42 is controlled to a valve setting such that the cooling fluid 34 routed to the condenser 26 is at a flow rate of approximately 600 gallons / minute (GPM) and at approximately 93 degrees Fahrenheit, and none of the cooling fluid 34 is routed to the plate-frame heat exchanger 40.

[0036] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 2 and associated with the conditions described above, which include parameters associated with compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kilowatts (kW / ton) per refrigeration ton for the illustrated conditions and control mechanism is 0.690.

[0037] Figure 3 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 65 degrees Fahrenheit (for example, as shown in Legend 59), and the operating load is 100% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. In the embodiment illustrated, the controller 46 of the HVAC&R system 10 controls the valve 42 of the free cooling assembly 14 to a valve setting such that a first portion of the cooling fluid 34 is directed toward the condenser 26 of the vapor compression assembly 12 (for example, at a first flow rate), and a second portion of the free cooling fluid 34 is directed toward the plate-frame heat exchanger 40 of the free cooling assembly 14 (for example, at a second flow rate). Therefore, the HVAC&R system 10 relies on a vapor compression assembly 12 to cool the process fluid 16 via the evaporator 30 (for example, with the compressor 28 turned on and controlled to a sufficient setting), and on a free cooling assembly 14 to cool the process fluid 16 via the plate-frame heat exchanger 40.

[0038] The illustrated control relies on both the vapor compression assembly 12 (e.g., with the compressor 28 turned on and controlled to a sufficient setting) and the plate-frame heat exchanger 40 of the free cooling assembly 14, as indicated by a relatively moderate temperature (e.g., 65 degrees Fahrenheit) and a high operating load (e.g., 100% of the system's design load capacity). As shown in the illustrated embodiment, the valve 42 is controlled to a valve setting such that the portion of the cooling fluid 34 routed to the condenser 26 is at approximately 67 degrees Fahrenheit at a flow rate of approximately 200 GPM, and the portion of the cooling fluid 34 routed to the plate-frame heat exchanger 40 is at approximately 67 degrees Fahrenheit at a flow rate of approximately 400 GPM. Naturally, when the ambient temperature rises above 65 degrees Fahrenheit, the valves 42 and / or pumps 44 of the free cooling assembly 14 can be controlled so that the flow rate of the cooling fluid 34 directed toward the condenser 26 is greater than approximately 200 GPM, and the flow rate of the cooling fluid 34 directed toward the plate-frame heat exchanger 40 is less than approximately 400 GPM. Additionally, when the ambient temperature falls below 65 degrees Fahrenheit, the valves 42 and / or pumps 44 of the free cooling assembly 14 can be controlled so that the flow rate of the cooling fluid 34 directed toward the condenser 26 is less than approximately 200 GPM, and the flow rate of the cooling fluid 34 directed toward the plate-frame heat exchanger 40 is greater than approximately 400 GPM.

[0039] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 3, associated with the conditions described above, which include parameters associated with compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kW / ton for the illustrated conditions and control mechanism is 0.089, which is substantially lower than that of the embodiment illustrated in Figure 2.

[0040] Figure 4 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 60 degrees Fahrenheit (as shown, for example, in Legend 59), and the operating load is 100% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. In the embodiment illustrated, the controller 46 of the HVAC&R system 10 controls the valve 42 of the internal fluid cooling loop 36 to a valve setting so that the cooling fluid 34 is isolated from the condenser 26 of the vapor compression assembly 12 and directed toward the plate-frame heat exchanger 40 of the free cooling assembly 14. Thus, the HVAC&R system 10 relies on the plate-frame heat exchanger 40 of the free cooling assembly 14 to cool the process fluid 16 of the process fluid loop 18, and does not rely on the evaporator 30 of the vapor compression assembly 12 to cool the process fluid 16 of the process fluid loop 18. The illustrated control relies on the free cooling assembly 14 (and does not rely on the vapor compression assembly 12), as shown for a relatively low ambient temperature (e.g., 60 degrees Fahrenheit), despite a high operating load (e.g., 100% of the system's design load capacity).

[0041] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 4 and associated with the conditions described above, which include parameters associated with compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kW / ton for the illustrated state and control mechanism is 0.030, which is substantially lower than that of the embodiments illustrated in Figures 2 and 3.

[0042] Figure 5 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 85 degrees Fahrenheit (for example, as shown in Legend 59), and the operating load is 50% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. In the embodiment illustrated, the controller 46 of the HVAC&R system 10 controls the valve 42 of the free cooling assembly 14 to a valve setting such that a portion of the cooling fluid 34 is directed (for example, at a first flow rate) toward the condenser 26 of the vapor compression assembly 12, and a second portion of the free cooling fluid 34 is directed (for example, at a second flow rate) toward the plate-frame heat exchanger 40 of the free cooling assembly 14. Therefore, the HVAC&R system 10 relies on the vapor compression assembly 12 to cool the process fluid 16 via the evaporator 30 (for example, when the compressor 28 is turned on and controlled to a sufficient setting), and the HVAC&R system 10 relies on the plate-frame heat exchanger 40 of the free cooling assembly 14 to cool the process fluid 16.

[0043] The illustrated control relies on both the vapor compression assembly 12 (e.g., with the compressor 28 turned on and controlled to a sufficient setting) and the plate-frame heat exchanger 40 of the free cooling assembly 14, as indicated by the relatively low operating load (e.g., 50% of the system's design load capacity) despite the relatively high ambient temperature (e.g., 85 degrees Fahrenheit). As shown in the illustrated embodiment, the valve 42 is controlled to a valve setting such that the portion of the cooling fluid 34 routed to the condenser 26 is at approximately 89 degrees Fahrenheit at a flow rate of approximately 137 GPM, and the portion of the cooling fluid 34 routed to the plate-frame heat exchanger 40 is at approximately 89 degrees Fahrenheit at a flow rate of approximately 163 GPM. Naturally, when the ambient temperature rises above 85 degrees Fahrenheit, the valves 42 and / or pumps 44 of the free cooling assembly 14 may be controlled so that the flow rate of the cooling fluid 34 directed toward the condenser 26 is greater than approximately 137 GPM, and the flow rate of the cooling fluid 34 directed toward the plate-frame heat exchanger 40 is less than approximately 163 GPM. Additionally, when the ambient temperature falls below 85 degrees Fahrenheit, the valves 42 and / or pumps 44 of the free cooling assembly 14 may be controlled so that the flow rate of the cooling fluid 34 directed toward the condenser 26 is less than approximately 137 GPM, and the flow rate of the cooling fluid 34 directed toward the plate-frame heat exchanger 40 is greater than approximately 163 GPM. Similar adjustments may be made based on changes in the operating load.

[0044] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 5 and associated with the conditions described above, which include parameters associated with the compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kW / ton for the illustrated conditions and control mechanism is 0.380, which is substantially lower than that of the embodiment illustrated in Figure 2. In fact, the ambient temperature is 85 degrees Fahrenheit in both Figure 2 and Figure 5, but the operating load in Figure 5 is lower than that in Figure 2, which allows for at least partial reliance on the free cooling assembly 14, thereby reducing the total chiller kW / ton.

[0045] Figure 6 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 65 degrees Fahrenheit (as shown, for example, in Legend 59), and the operating load is 50% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. In the embodiment illustrated, the controller 46 of the HVAC&R system 10 controls the valve 42 of the free cooling assembly 14 to a valve setting such that the cooling fluid 34 is directed toward the plate-frame heat exchanger 40 of the free cooling assembly 14 and isolated from the condenser 26 of the vapor compression assembly 12. Thus, the HVAC&R system 10 relies on the plate-frame heat exchanger 40 of the free cooling assembly 14 to cool the process fluid 16 of the process fluid loop 18, and does not rely on the evaporator 30 of the vapor compression assembly 12 to cool the process fluid 16 of the process fluid loop 18. The illustrated control relies on the free cooling assembly 14 (and does not rely on the vapor compression assembly 12, which may include a compressor 28 that is disconnected or otherwise turned off) as shown for a relatively moderate ambient temperature (e.g., 65 degrees Fahrenheit) and a relatively low operating load (e.g., 50% of the system's design load capacity).

[0046] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 6 and associated with the conditions described above, which include parameters associated with the compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kW / ton for the illustrated conditions and control mechanism is 0.008, which is substantially lower than the kW / ton in Figures 2-5.

[0047] Figure 7 is a schematic diagram of one embodiment of the HVAC&R system 10 of Figure 1, where the ambient temperature is 60 degrees Fahrenheit (as shown, for example, in Legend 59), and the operating load is 50% of the system's design load capacity. Furthermore, the supply temperature of the process fluid 16 to the load 20 is 70 degrees Fahrenheit, and the return temperature of the process fluid 16 from the load 20 is 100 degrees Fahrenheit. As described above with respect to Figure 6, in the embodiment illustrated in Figure 7, the controller 46 of the HVAC&R system 10 controls the valve 42 of the internal fluid cooling loop 36 to a valve setting such that the cooling fluid 34 is directed toward the plate-frame heat exchanger 40 of the free cooling assembly 14 and isolated from the condenser 26 of the vapor compression assembly 12. Therefore, the HVAC&R system 10 relies on the plate-frame heat exchanger 40 of the free cooling assembly 14 to cool the process fluid 16 in the process fluid loop 18, and does not rely on the evaporator 30 of the vapor compression assembly 12 to cool the process fluid 16 in the process fluid loop 18. The illustrated control relies on the free cooling assembly 14 (and does not rely on the vapor compression assembly 12, which includes the compressor 28, which is disconnected or otherwise turned off) as shown for a relatively low ambient temperature (e.g., 60 degrees Fahrenheit) and operating load (e.g., 50% of the system's design load capacity).

[0048] In addition to adjusting the valve settings of valve 42 as described above, the controller 46 may also adjust the pump settings of pump 44 associated with the internal fluid cooling loop 36 of the free cooling assembly 14, the compressor settings of compressor 28 associated with the vapor compression loop 22 of the vapor compression assembly 12, the pump settings of pump 19 associated with the process fluid loop 18, the fan settings of fan 39 of the air-cooled heat exchanger 38, or any combination thereof. Various performance and result data are illustrated in Figure 7 and associated with the conditions described above, which include parameters associated with compressor 28, condenser 26, evaporator 30, air-cooled heat exchanger 38 (or its fan 39), plate-frame heat exchanger 40, load 20, valve 42, pump 44, pump 19, various fluid temperatures, various fluid flow rates, power consumption of various components, etc. Furthermore, as shown in block 60, the total chiller kW / ton for the illustrated conditions and control mechanism is 0.005.

[0049] In both Figures 6 and 7, it should be noted that valve 42 is controlled (e.g., via controller 46) to either shut off the cooling fluid 34 to the condenser 26 of the vapor compression assembly 12 and direct the cooling fluid 24 to the plate-frame heat exchanger 40 of the free-cooling assembly 14. Despite this correspondence in the flow of the cooling fluid 34 in Figures 6 and 7, the total chiller kW / ton in Figure 7 is lower than that in Figure 6. The lower total chiller kW / ton in Figure 7 is based on lower ambient temperatures (e.g., 60 degrees in Figure 7 and 65 degrees in Figure 6), as well as corresponding control of other features of the HVAC&R system 10. In fact, because the ambient temperature is reduced, other components of the HVAC&R system 10, such as the fan 39 of the air-cooled heat exchanger 38, can operate in a manner that reduces energy consumption. For example, the fan 39 of the air-cooled heat exchanger 38 in Figure 6 operates at 1.4 kW, while the fan 39 of the air-cooled heat exchanger 38 in Figure 7 operates at 0.7 kW. In this way, the fan 39 can be a variable-speed fan, controlled to a setting based on, for example, a desired amount of cooling or a target amount of cooling of the cooling fluid 34 by the fan 39.

[0050] In general, the HVAC&R system 10 according to this disclosure is configured to depend more heavily on the free cooling assembly 14 than on the vapor compression assembly 12 compared to conventional embodiments, regardless of whether the HVAC&R system 10 operates to depend solely on the vapor compression assembly 12 for cooling the process fluid 16, solely on the free cooling assembly 14 for cooling the process fluid 16, or on both the vapor compression assembly 12 and the free cooling assembly 14 for cooling the process fluid 16.

[0051] Figure 8 is a process flow diagram illustrating an embodiment of method 100 for operating the HVAC&R system of Figure 1. In the embodiment illustrated, method 100 includes energizing the process fluid through a process fluid loop via a pump (block 102) so that the process fluid is routed through the evaporator, load, and plate-frame heat exchanger of the free cooling assembly. Depending on the ambient conditions, operating conditions, and / or specific corresponding control mechanisms of the HVAC&R system, the working fluid of the vapor compression assembly, the cooling fluid of the free cooling assembly, or both may be employed to cool the process fluid. For example, the evaporator of the vapor compression assembly may be employed to cool the process fluid via the working fluid of the vapor compression assembly under certain conditions. Additionally or alternatively, the plate-frame heat exchanger may be employed to cool the process fluid via the cooling fluid of the free cooling assembly under certain conditions.

[0052] Method 100 also includes detecting the ambient temperature via a sensor (e.g., a temperature sensor) (block 104). The sensor may be located, for example, adjacent to the air-cooled heat exchanger of the free cooling assembly. As can be understood with consideration of the following description, the ambient temperature detected by the sensor may be used to determine various control mechanisms associated with the HVAC&R system, such as a control mechanism employed to direct the cooling fluid of the free cooling assembly to the condenser of the vapor compression assembly (e.g., to remove heat from the working fluid of the vapor compression assembly), a plate-frame heat exchanger of the free cooling assembly (e.g., to cool the process fluid), or both.

[0053] Method 100 also includes controlling the valve settings of the valves of the free cooling assembly (block 106) to control the flow of cooling fluid of the free cooling assembly to one or more of the condenser of the vapor compression assembly, the plate-frame heat exchanger of the free cooling assembly, or both, via a controller and based at least on ambient temperature and the operating load (or cooling demand) associated with the load. Various control mechanisms associated with different ambient temperatures and / or operating loads are illustrated in Figures 2 to 7 and described in detail above. Generally, when the ambient temperature and / or operating load is relatively low, the system relies more heavily (or entirely) on the free cooling assembly than on the vapor compression assembly. The valve settings of the valves may also at least partially depend on the supply temperature (or target supply temperature) of the process fluid to the load and / or the return temperature (or target return temperature) of the process fluid from the load.

[0054] Method 100 also includes controlling other aspects of the HVAC&R system via a controller (block 108). For example, control of other aspects of the HVAC&R system may depend at least in part on the ambient and / or operating conditions of the HVAC&R system as described above. Additionally or alternatively, control of other aspects of the HVAC&R system may depend on the valve settings of valves. Aspects of the HVAC&R system that can be controlled according to the data mentioned above may include the compressor settings of a compressor, the pump settings of a pump corresponding to a free cooling assembly, the pump settings of a pump corresponding to a process fluid loop, the fan settings of an air-cooled heat exchanger in a free cooling assembly, and / or other aspects of the HVAC&R system. For example, if the system relies solely on a free cooling assembly to cool the process fluid, the compressor may be disconnected, turned off, or controlled to a otherwise reduced setting. Additionally or alternatively, if the system includes a relatively low reliance on a vapor compression assembly to cool the process fluid, the compressor setting may be reduced. Furthermore, the fan setting of the air-cooled heat exchanger fan may be reduced when the ambient temperature and / or operating load are relatively low. Based on these controls, valve setting controls, and other embodiments of the HVAC&R system of this disclosure, sufficient cooling to the process fluid (and subsequently the load) can be provided compared to conventional embodiments, while reducing energy consumption and reducing refrigerant charge in the vapor compression assembly.

[0055] The features illustrated in Figures 1-7 and described above in relation to Figures 1-7 are examples of HVAC&R systems employing a vapor compression assembly and a free cooling assembly, where the free cooling assembly is preferred for energy savings and reduced refrigerant charge in the vapor compression assembly. The components illustrated in Figures 1-7 and described in detail above can enable energy savings and reduced refrigerant charge compared to conventional embodiments. However, Figures 1-7 and the corresponding descriptions are merely illustrative, and other components are also possible that enable the technical effects described above and / or further improve energy savings and reduce refrigerant charge.

[0056] For example, Figure 9 is a schematic diagram of one embodiment of a multi-temperature hot water HVAC&R system 210 that employs a vapor compression assembly 212 (or chiller assembly), a free cooling assembly 214, and a control mechanism configured to adjust the dependence on the vapor compression assembly 212 and the free cooling assembly 214.

[0057] Generally, the vapor compression assembly 212 and the free cooling assembly 214 are configured to cool a process fluid 216 (e.g., water, glycol, water-glycol mixture, dielectric fluid in immersion applications, etc.) corresponding to a process fluid loop 218, and the process fluid 216 is energized through the process fluid loop 218 via one or more pumps 219a, 219b. As shown in the figure, the process fluid loop 218 can guide the process fluid 216 to one or more loads 220a, 220b. In the illustrated embodiment, load 220a is a high-temperature load and load 220b is a low-temperature load. Depending on the ambient and / or operating conditions of the HVAC&R system 210, the reliance on the vapor compression assembly 212 and / or the free cooling assembly 214 for cooling the process fluid 216 can be adjusted to ensure adequate cooling and reduce the energy consumption of the HVAC&R system 210 compared to conventional embodiments.

[0058] The vapor compression assembly 212 may include a vapor compression loop 222 (referred to in certain examples of this disclosure as a working fluid loop) which routes a working fluid 224 (e.g., a refrigerant such as R-123, R-514A, R-1224yd, R-1233zd, R-134a, R-1234ze, R-1234yf, R-1311, R-32, R-410A, or others) through various components of the vapor compression assembly 212. For example, the vapor compression loop 222 may route the working fluid 224 through the compressor 228, condenser 226, expansion valve 232, and evaporator 230 of the vapor compression assembly 212. The compressor 228 may, under certain conditions, operate to energize the working fluid 224 through the vapor compression loop 222 (e.g., by increasing the pressure of the working fluid 224). The evaporator 230 may, under certain conditions, operate to cool the process fluid 216 of the process fluid loop 218. The expansion valve 232 may operate to reduce the pressure of the working fluid 224 between the condenser 226 and the evaporator 230. The condenser 226 may, under certain conditions, operate to remove heat from the working fluid 224 via liquid-liquid cooling, where heat is transferred from the working fluid 224 to the cooling fluid 234 (e.g., water, glycol, water-glycol mixture, etc.) corresponding to the internal fluid cooling loop 236 of the free cooling assembly 214. In this way, the condenser 226 may be considered part of the internal fluid cooling loop 236 while the cooling fluid 234 of the internal fluid cooling loop 236 is present in the condenser 226.

[0059] In the illustrated embodiment, the vapor compression assembly 212 includes a mechanism configured to divert some or all of the flow path of the working fluid 224 under certain conditions. For example, a valve 237 may be controlled (e.g., via a controller 246) to cause a flow of refrigerant 224 through a heat exchanger 235 corresponding to a heat recapture path 241 employing a heat recapture fluid 243 (e.g., water, glycol, or a water-glycol mixture), based on certain ambient and / or operating conditions. In this way, the heat recapture fluid 243 can extract heat from the working fluid 224 in the heat exchanger 235. The heat exchanger 235 may be a plate-frame heat exchanger of a welded-brazed heat exchanger.

[0060] As described above, under certain ambient and / or operating conditions of the HVAC&R system 210, the free cooling assembly 214 may be employed to reduce the reliance on the vapor compression assembly 212 for cooling the process fluid 216 in the process fluid loop 218. For example, as the reliance on the free cooling assembly 214 increases in response to certain conditions, the reliance on the compressor 228 of the vapor compression assembly 212 may be reduced. Under certain conditions, while the HVAC&R system 210 relies solely on the free cooling assembly 214 to provide cooling to the process fluid 216, the compressor 228 may be completely disconnected or otherwise turned off. The movement of the working fluid 224 through the vapor compression loop 222 may continue even after the compressor 228 is disconnected or otherwise turned off via natural convection (e.g., via a thermal siphon). Additionally or alternatively, the HVAC&R system 210 may rely on both the free cooling assembly 214 and the vapor compression assembly 212 in certain conditions where the compressor 228 is controlled to a relatively low setting, thereby improving energy efficiency while ensuring adequate cooling of the process fluid 216. The embodiments of the free cooling assembly 214, and the controls of the HVAC&R system 210 for adjusting the reliance on the vapor compression assembly 212 and / or the free cooling assembly 214, are described in detail below.

[0061] In the illustrated embodiments, the free cooling assembly 214 includes an internal fluid cooling loop 236 configured to route the cooling fluid 234 through various components of the HVAC&R system 210, including the condenser 226 of the vapor compression assembly 212, the air-cooled heat exchanger 238 of the free cooling assembly 214 (e.g., having a fan 239), and the plate-frame heat exchanger 240 of the free cooling assembly 214. Generally, the air-cooled heat exchanger 238 is configured to cool the cooling fluid 234 (e.g., via a fan 239) before it is delivered to the condenser 226 of the vapor compression assembly 226 and / or the plate-frame heat exchanger 240 of the free cooling assembly 214. In some embodiments, the air-cooled heat exchanger 238 may include only an example of a fan 239 configured to cool the cooling fluid 234 before it is delivered to the condenser 226 and / or the plate-frame heat exchanger 240.

[0062] When the cooling fluid 234 is present in the condenser 226, it absorbs heat from the working fluid 224 corresponding to the vapor compression assembly 212, condensing the working fluid 224 before it is delivered to the expansion valve 232. When the cooling fluid 234 is present in the plate-frame heat exchanger 240, it absorbs heat from the process fluid 216 corresponding to the process fluid loop 218. The configuration of the free cooling assembly 214 can be controlled to allocate some, none, or all of the cooling fluid 234 to the condenser 226 and some, none, or all of the cooling fluid 234 to the plate-frame heat exchanger 240, as will be described in detail below.

[0063] The free cooling assembly 214 includes a valve 242 controlled to various settings for directing a portion of the cooling fluid 234 to the condenser 226 of the vapor compression assembly 212 and / or the plate-frame heat exchanger 240 of the free cooling assembly 214. Furthermore, the free cooling assembly 214 includes a pump 244 configured to energize the cooling fluid 234 through an internal fluid cooling loop 236. Depending on the ambient and / or operating conditions of the HVAC&R system 210, the valve 242 may be controlled to a first valve setting in which the cooling fluid 234 is directed to the plate-frame heat exchanger 240 and isolated from the condenser 226; a second valve setting in which the cooling fluid 234 is directed to the condenser 226 and isolated from the plate-frame heat exchanger 240; or a third setting (or one of several third settings) in which a portion of the cooling fluid 234 is directed to the plate-frame heat exchanger 240 and an additional portion of the cooling fluid 234 is directed to the condenser 226.

[0064] A controller 246 of the HVAC&R system 210, including processing circuits 248 and memory circuits 250, may be employed to control the various components described above. For example, the controller 246 may receive one or more inputs indicating various ambient and / or operating conditions of the HVAC&R system 210. In fact, the controller 246 may receive a first input from a first sensor 252 indicating the ambient temperature (e.g., near the air-cooled heat exchanger 238). Additionally or alternatively, the controller 246 may receive a second input from second sensors 254a, 254b indicating the supply temperature of the process fluid 216 directed to loads 220a, 220b. Additionally or alternatively, the controller 46 may receive a third input from third sensors 256a, 256b indicating the return temperature of the process fluid 216 returned from loads 220a, 220b. In some embodiments, the controller 246 may employ (for example, in addition to or instead of the detected temperature) a target supply temperature for the process fluid 216 directed to loads 220a, 220b, and / or a target return temperature for the process fluid 216 returned from loads 220a, 220b. Additionally or alternatively, the controller 246 may receive (or otherwise determine) a fourth input indicating the operating load corresponding to the HVAC&R system 210 and / or loads 220a, 220b.

[0065] In response to at least one of the inputs described above (e.g., ambient temperature, supply temperature and / or target supply temperature of process fluid 216, return temperature and / or target return temperature of process fluid 216, operating load), the controller 246 may control various components of the HVAC&R system 210 to ensure proper cooling of loads 220a and 220b while reducing energy consumption. Specifically, the controller 246 may control the valve 242 of the free cooling assembly 214 to direct some or all of the cooling fluid 234 to the condenser 226 of the vapor compression assembly 212 and some or all of the cooling fluid 234 to the plate frame heat exchanger 240.

[0066] Other embodiments of the HVAC&R system 210 may also be controlled to correspond to the valve settings of valve 242 (or based on the inputs described above). For example, the settings of the compressor 228 and / or the fan 239 of the air-cooled heat exchanger 238 may be controlled in a manner that provides adequate cooling to the process fluid 216 while reducing the energy consumption of the HVAC&R system 210. Generally, the systems and methods of the present disclosure are configured to enable the HVAC&R system 210 to provide adequate cooling to the process fluid 216, with a heavy reliance on the free cooling assembly 214, thereby improving the efficiency of the HVAC&R system 210 compared to conventional embodiments.

[0067] As described above, the HVAC&R system 210 includes a heat recapture path 241 configured to carry a heat recapture fluid 243 to the heat exchanger 235. The heat recapture fluid 243 may also be supplied to an additional heat exchanger 260 upstream of the heat exchanger 235. The additional heat exchanger 260 may be used to receive a portion of the process fluid 216 (for example, to cool the process fluid 216).

[0068] As described above, the HVAC&R system 210 employs a working fluid 224, a cooling fluid 234, a process fluid 216, and a heat recapture fluid 243. In the illustrated embodiment, the HVAC&R system may employ a fifth fluid loop 262 through which a fifth fluid 264 (e.g., water, glycol, or a water-glycol mixture) flows for additional cooling purposes. The fifth fluid loop 262 may circulate the fifth fluid 264 through a cooling tower 266 and a wet economizer heat exchanger 267. A pump 268 may be employed to energize the fifth fluid 264 through the fifth fluid loop 262. In the wet economizer heat exchanger 267, the fifth fluid 264 may extract heat from the process fluid 216. Furthermore, the cooling tower 266 may include a fan 269 controlled to various fan settings (e.g., by the controller 246) based on the wet-bulb temperature detected by the sensor 271, the required cooling capacity, and / or the availability of water, so that the cooling tower 266 (e.g., the fan 269 of the cooling tower 266) provides sufficient cooling to the fifth fluid 264. In some embodiments, the pump settings of the pump 268 may also be controlled based on the wet-bulb temperature detected by the sensor 271, and / or other ambient and / or operating conditions of the HVAC&R system 210.

[0069] The process fluid loop 218 in Figure 9 also includes a series of diversion valves 270a, 270b, 270c, 270d, and 270e, which are controlled to various settings to cause various flows of process fluid 216 through various paths in the process fluid loop 218. Furthermore, the process fluid loop 218 includes a series of bypass valves 272a, 272b, and 272c, which are employed to open and close various paths within the process fluid loop 218. The controller 246 may control the diversion valves 270a, 270b, 270c, 270d, and bypass valves 272a, 272b, 272c, and 272d (for example, based on ambient conditions, operating conditions, etc. of the HVAC&R system) to control the flow of process fluid 216 through various components of the HVAC&R system 210 as described in detail above. An example of a multi-temperature hot water HVAC&R system with a flow control mechanism can be found in PCT / US22 / 19819, filed on March 20, 2022, entitled "MULTI-STAGE THERMAL MANAGEMENT SYSTEMS AND METHODS," which is incorporated herein by reference in its entirety.

[0070] Generally, the systems and methods of this disclosure are configured to provide adequate cooling to one or more loads associated with an HVAC&R system, but with improved energy efficiency and reduced refrigerant charge for vapor compression compared to conventional embodiments.

[0071] Although only specific features of this embodiment have been illustrated and described herein, many modifications and changes will be conceived by those skilled in the art. Therefore, it should be understood that the appended claims are intended to encompass all such modifications and changes that fall within the true spirit of this disclosure. Furthermore, it should be understood that certain elements of the disclosed embodiments are interchangeable or interchangeable.

[0072] The technologies presented and claimed herein are applied by reference to and in concrete examples of materials, objects, and specific examples of a practical nature that clearly improves the art, and are therefore not abstract, intangible, or purely theoretical. Furthermore, if any of the claims appended to the end of this specification include one or more elements designated as “means for performing [a function]” or “steps for performing [a function],” such elements are intended to be construed under Section 112(f) of the United States Patent Act. However, for any claims that include elements designated in any other manner, such elements are not intended to be construed under Section 112(f) of the United States Patent Act.

Claims

1. An HVAC&R system which is a heating, ventilation, air conditioning, and / or refrigeration system, The vapor compression assembly and A free cooling assembly that is compatible with the cooling fluid and includes an air-cooled heat exchanger, additional heat exchangers, pumps, and valves, It comprises at least one controller, and the at least one controller is Receiving data indicating the ambient conditions, operating conditions, or both of the HVAC&R system, Based on the aforementioned data, A first setting in which the cooling fluid is directed to the additional heat exchanger and isolated from the condenser of the vapor compression assembly, A second setting in which the cooling fluid is directed towards the condenser and isolated from the additional heat exchanger, An HVAC&R system configured to operate the valve between a third setting, in which a first portion of the cooling fluid is directed towards the additional heat exchanger and a second portion of the cooling fluid is directed towards the condenser.

2. The HVAC&R system according to claim 1, comprising a process fluid loop configured to guide the process fluid through the evaporator, load, and additional heat exchanger of the vapor compression assembly.

3. The HVAC&R system according to claim 1, comprising a sensor configured to detect an ambient temperature corresponding to the ambient conditions, wherein at least one controller is configured to receive data from the sensor indicating the ambient temperature corresponding to the ambient conditions.

4. The HVAC&R system according to claim 1, wherein the at least one controller is configured to control the fan settings of the fan of the air-cooled heat exchanger based on the data.

5. The HVAC&R system according to claim 1, wherein the at least one controller is configured to control the compressor settings of the compressor of the steam compression assembly based on the data.

6. The HVAC&R system according to claim 1, wherein the at least one controller is configured to control the pump settings of the pump based on the data, and the pump is configured to bias the cooling fluid through the free cooling assembly.

7. The HVAC&R system according to claim 1, wherein the additional heat exchanger comprises a plate frame heat exchanger.

8. The HVAC&R system according to claim 1, wherein at least one controller is configured to receive an input indicating an operating load or cooling demand for a load corresponding to the HVAC&R system, and the input corresponds to the data indicating the operating state of the HVAC&R system.

9. The HVAC&R system according to claim 1, wherein the at least one controller is configured to receive one or more inputs indicating the return temperature of the process fluid from a load corresponding to the HVAC&R system, the supply temperature of the process fluid to the load, or both, and the one or more inputs correspond to the data indicating the operating state of the HVAC&R system.

10. The HVAC&R system according to claim 1, wherein the at least one controller is configured to receive one or more inputs indicating a target return temperature of the cooling fluid from a load corresponding to the HVAC&R system, a target supply temperature of the cooling fluid to the load, or both, and the one or more inputs correspond to the data indicating the operating state of the HVAC&R system.

11. It is equipped with a heat recapture path, and the heat recapture path is A first heat recapture heat exchanger configured to receive the cooling fluid and the heat recapture fluid, The HVAC&R system according to claim 1, comprising: a second heat recapture heat exchanger located downstream of the first heat recapture heat exchanger on the heat recapture path and configured to receive the heat recapture fluid and the working fluid of the vapor compression assembly.

12. An additional cooling loop that accommodates additional cooling fluid, The HVAC&R system according to claim 1, comprising a wet economizer heat exchanger configured to receive a process fluid and the additional cooling fluid.

13. The additional cooling loop comprises a cooling tower and a pump configured to bias the additional cooling fluid between the wet economizer heat exchanger and the cooling tower. The HVAC&R system according to claim 12, wherein the at least one controller is configured to control the fan settings of the cooling tower's fans based on the required cooling capacity.

14. A process fluid loop configured to guide the process fluid through the evaporator of the vapor compression assembly, the additional heat exchanger, the high-temperature load, and the low-temperature load, A plurality of valves are arranged within the process fluid loop, The HVAC&R system according to claim 1, further comprising: a controller configured to actuate a plurality of valves in order to control the flow of the process fluid to the high-temperature load and the low-temperature load.

15. The HVAC&R system according to claim 14, wherein the controller is configured to operate the plurality of valves based on the data.

16. A control assembly for an HVAC&R system which is a heating, ventilation, air conditioning, and / or refrigeration system, wherein the control assembly is A sensor configured to detect the ambient conditions or operating conditions of the HVAC&R system, It comprises at least one controller, and the at least one controller is The sensor receives feedback indicating the ambient state or operating state, A control assembly configured to operate a valve of a free cooling assembly between a plurality of settings based on the aforementioned feedback, wherein the plurality of settings include: a first setting in which the cooling fluid of the free cooling assembly is directed toward the heat exchanger of the free cooling assembly rather than toward the vapor compression assembly; a second setting in which the cooling fluid is directed toward the vapor compression assembly rather than toward the heat exchanger; and at least one third setting in which a first portion of the cooling fluid is directed toward the heat exchanger and a second portion of the cooling fluid is directed toward the vapor compression assembly.

17. The control assembly according to claim 16, wherein the at least one controller is configured to control the fan setting of the fan of the air-cooled heat exchanger of the free cooling assembly based on the feedback, and the air-cooled heat exchanger is separate from the heat exchanger.

18. The control assembly according to claim 16, wherein the at least one controller is configured to control the compressor settings of the compressor of the steam compression assembly based on the feedback.

19. The control assembly according to claim 16, wherein the at least one controller is configured to control the pump setting of the pump of the free cooling assembly based on the feedback, and the pump is configured to bias the cooling fluid through the free cooling assembly.

20. The control assembly according to claim 16, wherein the at least one controller is configured to actuate the valve between the plurality of settings based on additional feedback, which is separate from the feedback and indicates an operating load or cooling demand.

21. The control assembly according to claim 16, wherein the at least one controller is configured to control a plurality of valves corresponding to a process fluid loop configured to guide process fluid through the evaporator of the vapor compression assembly, the heat exchanger of the free cooling assembly, and the load, based on the feedback.

22. A method for operating an HVAC&R system, which is a heating, ventilation, air conditioning, and / or refrigeration system, Receiving first data, which indicates a first value of the ambient or operating state of the HVAC&R system, via at least one controller, Controlling a valve to a first setting via at least one controller and based on the first data such that the cooling fluid of the free cooling assembly is directed toward the heat exchanger of the free cooling assembly rather than toward the condenser of the vapor compression assembly, Receiving second data via at least one controller that indicates a second value of the ambient state or operating state of the HVAC&R system, wherein the second value is different from the first value. Controlling the valve to a second setting via at least one controller and based on the second data such that the cooling fluid is directed toward the condenser rather than the heat exchanger, Receiving third data via at least one controller that indicates a third value of the ambient state or operating state of the HVAC&R system, wherein the third value is different from the first value and the second value. A method comprising controlling the valve to a third setting via at least one controller and based on the third data, such that a first portion of the cooling fluid is directed toward the heat exchanger and a second portion of the cooling fluid is directed toward the condenser.

23. When the cooling fluid is present in the condenser, heat is sunk from the working fluid of the vapor compression assembly to the cooling fluid, The method according to claim 22, comprising sinking heat from the process fluid in the process fluid loop to the cooling fluid when the cooling fluid is present in the heat exchanger.

24. The method according to claim 23, comprising directing the process fluid of a process fluid loop between the load and the evaporator of the vapor compression assembly, to the heat exchanger of the free cooling assembly, or both.

25. The method according to claim 22, comprising cooling the cooling fluid via an air-cooled heat exchanger of the free cooling assembly.

26. The method according to claim 22, comprising controlling the valve via at least one controller based on the operating load or cooling demand of the HVAC&R system.

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