Chiller / heater process fluid temperature coordination

Abstract

Runtime of heating, ventilation, air conditioning, and refrigeration (HVACR) is maintained, in part, by creating an operational limit and an improved staging scheme based on the evaporator water temperature in heating mode, or the condenser water temperature in cooling mode. If the water temperature becomes close to the operational limit setpoint the chiller will start unloading running compressors, and eventually shutdown compressors to manage the difference in load, while maintaining operation of the HVACR.

Description

FIELD

[0001] This disclosure relates generally to heating and cooling systems that are selectively operable in either a booster chiller configuration or in a cascade configuration. More specifically, the disclosure relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system in which process fluid temperature safety protection diagnostics are exploited to guard against system damage.BACKGROUND

[0002] A heating and cooling system may be used to heat and cool one or more process fluids for a variety of applications. For example, the heating and cooling system may be used to heat a heating load and / or cool a cooling load for industrial processes. Accordingly, an HVACR system may provide heating and / or provide cooling for the conditioned space. The HVACR system may include a heat exchanging circuit system that includes one or more of, at least, compressors, expanders, a condenser, an evaporator, fans, filters, dampers, circulation pumps, etc., in which the one or more compressors, condenser, expander, and evaporator are fluidly connected. Safe and efficient implementation of such a heat exchanging circuit system relies on adherence to physical limitations of the components thereof.SUMMARY

[0003] This disclosure relates generally to heating and cooling systems that are selectively operable in either a booster chiller configuration or in a cascade configuration. More specifically, the disclosure relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system in which water temperature safety protection diagnostics are exploited to guard against system damage.

[0004] In at least one non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other; a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and a controller. The controller operates the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to reject heat to a heating load via the first heat exchanging unit and unloads the first compressor when a fluid operation parameter for the first heat exchanging unit is determined to be less than an acceptable range.

[0005] In at least one other non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other; a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and a controller. The controller operates the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanging unit and unloads the second compressor when a fluid operation parameter for the second heat exchanging unit is determined to be higher than an acceptable range.

[0006] In yet another non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit operating in a heating mode that includes a first compressor, a first condenser, and a first evaporator in fluid communication with each other. The heating and cooling system also includes a second heat exchanging unit operating in a cooling mode that includes a second compressor, a second condenser, and a second evaporator in fluid communication with each other. The system includes, further, an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and a second heat exchanging unit, and at least one controller. The controller is configured to, at least, unload the first compressor when a cooling load of the second heat exchanging unit decreases causing a fluid operation parameter for the first heat exchanging unit to be less than an acceptable range.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the detailed description that follows, embodiments are described as illustrations only since various changes and modifications will become apparent to those skilled in the art from the following detailed description. The use of the same reference numbers in different figures indicates similar or identical items.

[0008] FIG. 1 illustrates a schematic diagram of a heating and / or cooling system, according to at least one non-limiting example embodiment of chiller / heater water temperature coordination.

[0009] FIG. 2 illustrates a schematic diagram of an HVACR system that includes a refrigerant circuit, arranged in accordance with at least one non-limiting example embodiment of chiller / heater water temperature coordination.

[0010] FIG. 3 is a flowchart of a control method of heating and / or cooling a system, according to an embodiment.

[0011] FIG. 4 is a graphical representation of the operation of heat exchanging units, configured in a booster or cascade configuration, according to an embodiment.DETAILED DESCRIPTION

[0012] In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current example embodiment. Still, the example embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0013] Particular embodiments of the present disclosure are described herein with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. In this description, as well as in the drawings, like-referenced numbers represent elements that may perform the same, similar, or equivalent functions.

[0014] Additionally, the present disclosure may be described herein in terms of functional block components and various processing steps. It should be appreciated that such functional blocks may be realized by any number of hardware and / or software components configured to perform the specified functions.

[0015] The scope of the disclosure should be determined by the appended claims and their legal equivalents, rather than by the examples given herein. For example, the steps recited in any method claims may be executed in any order and are not limited to the order presented in the claims. Moreover, no element is essential to the practice of the disclosure unless specifically described herein as “critical” or “essential.”

[0016] A heating and cooling system may be used to heat a heating load and / or cool a cooling load for a variety of applications including for industrial processes, e.g., heating and / or cooling gas or liquid flows to maintain reaction temperatures or temperature setpoints, cooling industrial waste, providing heat to replace gas boilers, providing refrigeration, etc. In some embodiments, the heating and cooling system may be implemented as an HVACR system that is used to provide comfort heating and provide comfort cooling.

[0017] In some embodiments of an HVACR, thermal energy in a heat exchanging circuit is exchanged with one or more process fluids, e.g., water, air, etc., which may then be used to condition a space, which may be within a structure, e.g., office building, commercial building, factory, laboratory, data center, a residential building, etc. When implemented to heat and / or cool a conditioned space, heat generated from compression of a working fluid in the heat exchanging circuit or heat exchanging unit may be rejected therefrom to heat the process fluid that circulates in a heating water circuit to condition the space. Similarly, when cooling to the conditioned space, the HVACR system may extract heat from a second process fluid that is circulated in a chilled water circuit of the hydronic system to cool the process fluid to condition the space.

[0018] The non-limiting example embodiments described and recited herein are directed towards implementing reliable performance parameters pertaining to a process fluid, that provide reliable diagnostics that allow the HVACR system operating by limit unit cycling and maintaining process fluid stability.

[0019] Thus, in accordance with at least some of the non-limiting example embodiments described and recited herein, one or more components, e.g., compressor, of a high temperature chiller running in heating mode unloads or shuts off when an evaporator leaving process fluid temperature falls below an evaporator limit; and / or when a low temperature chiller running in cooling mode unloads or shuts off when a condenser leaving process fluid temperature increases to exceed a condenser limit. That is, a high temperature chiller / heater operating in a heating mode is unable to produce sufficient heating capacity if the evaporator leaving process fluid temperature, e.g., evaporator leaving water temperature, drops to an unacceptable level; likewise, a low temperature chiller / heater operating in a cooling mode is unable to produce sufficient cooling capacity if the condenser leaving process fluid temperature, e.g., condenser leaving process fluid temperature, rises beyond an unacceptable level.

[0020] As described or otherwise referenced herein, unloading a chiller / heater refers to unloading the compressor corresponding to the respective chiller / heater. A chiller / heater is unloaded to reduce the compressor output without shutting down the motor and short cycling.

[0021] The embodiments described and recited herein reference and / or implement a process fluid, e.g., water, temperature control algorithm that adheres to adjustable temperature operational limits to ensure that safety cutouts are not triggered and further controls active setpoints, further preventing multiple chillers connected as tandem from cycling by handling uneven loads.

[0022] FIG. 1 shows a schematic diagram of HVACR system 100 for heating and / or cooling one or more process fluids, e.g., water, using a compression cycle of a working fluid. HVACR system 100 may include a hydronic system that includes a first process fluid loop 105 and a second process fluid loop 110 for conditioning a space, building, or structure. The working fluid may be any suitable working fluid, including a refrigerant or blend of two or more refrigerants. In the non-limiting example embodiment of FIG. 1, HVACR system 100 is configured to provide cooling in a chiller system; however it is understood that heating and cooling systems that include one or more compressors according to embodiments described and recited herein may also be arranged as heat pumps, reversible systems, or any other suitable system providing heating and / or cooling through a compression cycle of a working fluid.

[0023] HVACR system 100 includes first heat exchanging unit 115, second heat exchanging unit 120, process fluid loop 125, and controller (see FIG. 2). First heat exchanging unit 115 includes a working fluid circuit that includes a compressor (see FIG. 2); first heat exchanger 135, e.g., condenser; optional expander (see FIG. 2); and second heat exchanger 140, e.g., evaporator. Second heat exchanging unit 120 includes a working fluid circuit that includes a compressor (see FIG. 2); a first heat exchanger 145, e.g., condenser; optional expander (see FIG. 2); and second heat exchanger 150, e.g., evaporator.

[0024] In first heat exchanging unit 115, the compressor is configured to compress a working fluid. The compressor may be, e.g., a screw compressor, a scroll compressor, a centrifugal compressor, etc. Working fluid from the compressor may pass to first heat exchanger 135, which may be configured to selectively exchange heat with a first process fluid to facilitate the working fluid rejecting heat to the process fluid, thereby heating the first process fluid in first process fluid loop 105. Thus, the first process fluid may provide / exchange heat for heating load 175.

[0025] The rejection of heat to the heating load 175 may be directed to, e.g., an ambient environment, a heating load, or other suitable sink for the heat being rejected by the working fluid at first heat exchanger 135, e.g., for conditioning one or more spaces, buildings, or structures. The working fluid may pass from first heat exchanger 135 to the expander, which may be configured to expand the working fluid, then to the second heat exchanger 140 at which the working fluid may extract heat from a source for cooling a cooling load or process fluid, thereby evaporating the working fluid prior to the working fluid returning to the compressor. The sources may be, e.g., from a process fluid or a conditioned space to be cooled, from an ambient environment, etc., to evaporate the working fluid. Working fluid leaving second heat exchanger 140 may be returned to a suction of the compressor, and the working fluid may continue to be circulated in first heat exchanging unit 115.

[0026] In the second heat exchanging unit 120, the compressor is configured to compress a working fluid. Working fluid from the compressor may pass to heat exchanger 145, which may be configured to selectively exchange heat with process fluid in process fluid loop 125 to allow the working fluid to reject heat to the process fluid, thereby heating the process fluid in the process fluid loop 125, e.g., to provide lift for refrigerant in the first heat exchanging circuit or heat exchanging unit 115. The working fluid may pass from heat exchanger 145 to the expander, which is configured to expand the working fluid. Working fluid may pass from the expander to second heat exchanger 150, at which the working fluid may extract heat from the second process fluid of second process fluid loop 110 for cooling load 180, thereby evaporating the working fluid prior to the working fluid returning to the compressor. Working fluid leaving second heat exchanger 150 may be returned to a suction of the compressor, and the working fluid may continue to be circulated in second heat exchanging unit 120.

[0027] In some embodiments first heat exchanger 135 of first heat exchanging unit 115 and / or heat exchanger 145 of second heat exchanging unit 120 may be a dual-bundled heat exchanger, such as, a dual-bundled shell and tube heat exchanger or dual-bundled plate heat exchanger. As such, the first heat exchanger 135 may be selectively configurable to reject heat to either a process fluid for heating load 175, while heat exchanger 145 may be selectively configurable to reject heat to a process fluid from the process fluid loop 125.

[0028] Process fluid loop 125 may include a process fluid and one or more of valves, pumps, filters, stainers, etc., to control fluid flow between first heat exchanger 140 of first heat exchanging unit 115 and heat exchanger 145 of second heat exchanging unit 120. The process fluid may be, but not limited to, water, air, etc. The one or more valves may include a three-way feed valve, e.g., two position valve, or a four-way feed valve, e.g., three position valve, to allow the selectable connection of fluid to be cooled by first heat exchanger 140, e.g., connection to either the process fluid in process fluid loop 125 or the second process fluid for cooling load 180.

[0029] The controller 225 (see FIG. 2) may be programmed, designed, or otherwise configured to control one or more components of HVACR system 100 and / or is a building automation system (BAS) controller for a computerized network of electronic devices that can be configured to control one or more systems (e.g., mechanical, electrical, lighting, security, HVACR, etc.). Controller 225 (see FIG. 2) may include one or more processors and one or more non-volatile storage memories having instructions, which when executed by the one or more processors, carry out control operations, as discussed herein. In some embodiments, the controller may include programmability to enable receiving and / or receiving a signal to heat or cool, e.g., from the BAS controller. For example, a building load may be determined based on seasonality, e.g., winter or summer, such that when there is no heating demand, e.g., in the summer, the first heat exchanging circuit or heat exchanging unit can be selectively operated in a cooling mode, whereas, when there is heating demand, e.g., in the winter, the first heat exchanging circuit or heat exchanging unit can be selectively operated in a heating mode, in which the controller is configured to selectively provide one or more of the process fluid, the second process fluid from the process fluid load, or cooling fluid from the cooling device 260 to one or more of the heat exchangers.

[0030] As such, the HVACR system 100 may be optimized for use for either heating or cooling, in either a booster chiller configuration or in the cascade configuration described above. In a booster chiller configuration, 115 may be implemented as a high temperature chiller / heater and 120 may be implemented as a low temperature chiller / heater.

[0031] As disclosed, recited, or otherwise referenced herein, a cascade configuration for a heat exchanger may refer to a heat exchanger that selectively exchanges heat with coolant in a coolant loop to allow working fluid flowing therethrough to (1) reject heat to the coolant to thereby heat the coolant in the coolant loop to provide lift for refrigerant in the corresponding heat exchanging circuit or heat exchanging unit or (2) exchange heat with the cooling fluid from a cooling device, e.g., cooling tower, to allow the working fluid to reject heat to the cooling fluid.

[0032] Further, as disclosed, recited, or otherwise referenced herein, a booster chiller may refer to a chiller configuration that pre-cools air prior to the air entering a condenser. In this regard, water droplets may be sprayed into the air stream, e.g., via nozzles. As the sprayed water droplets evaporate, the evaporating water absorbs heat from the surrounding air, thus lowering the air temperature. This pre-cooled air enters the condenser of the chiller to thereby improve condenser efficiency, e.g., by reducing energy consumption and improving equipment lifespan.

[0033] A high temperature chiller / heater, as disclosed, recited, or otherwise referenced herein, may refer to a chiller / heater that is configured to cool and heat fluids within a wide temperature range. A high temperature chiller / heater may switch between heating and cooling modes to maintain a desired temperature for different stages of a process.

[0034] A low temperature chiller / heater, as disclosed, recited, or otherwise referenced herein, may refer to a chiller / heater that is configured to operate at temperatures that are below standard cooling or heating ranges. A low temperature chiller / heater may operate at extreme low temperatures, e.g., −40 °F to 0 °F, and may be utilized in environments for maintaining, e.g., perishable goods, or for maintaining appropriate working conditions, e.g., laboratories.

[0035] FIG. 2 illustrates a schematic diagram of an HVACR system including refrigerant circuit 200, arranged in accordance with at least the embodiments of 115 and 120 described above regarding FIG. 1.

[0036] In an example embodiment, refrigerant circuit 200 may include compressor 205, condenser 210, expander 215, and evaporator 220. Refrigerant circuit 200 may also include a controller 225 configured to communicate with and / or control the operations of the compressor 205, the condenser 210, optional expander 215, the evaporator 220, and / or other components, e.g., flow control device, sensor(s), etc., of the HVACR system.

[0037] Regarding the example embodiment of FIG. 1, controller 225 may be a centralized controller that coordinates operation of both high temperature chiller / heater 115 and low temperature chiller / heater 120. However, other example embodiments of system 100 may include an embodiment of controller 225 disposed in high temperature chiller 115 to thereby implement hot water control modulation pertaining to the evaporator leaving water temperature as an operational limit, as described herein. In addition, or alternatively, system 100 may include an embodiment of controller disposed in low temperature chiller 120 to thereby implement chilled water control modulation pertaining to condenser leaving water temperature as an operational limit, as described herein. Thus, embodiments described and / or recited herein may include system control or unit control.

[0038] In an example embodiment, controller 225 may include or be connected to a memory such as RAM and ROM and execute software, e.g., processor-executed instructions or algorithms, that may be stored in the RAM, particularly during execution, the ROM on a generally permanent basis, or another non-transitory computer readable medium such as other memory, flash drive, or disc. In some embodiments, controller 225 may be so connected to read such software. A microprocessor or other programmable device with suitable memory and I / O devices may also be implemented as controller 225. It is to be understood that the processes and / or steps described in any of the figures may be conducted, implemented, and / or performed by one or more controllers including, e.g., controller 225 and / or any other suitable controller, unless otherwise specified.

[0039] In at least one non-limiting example embodiment, refrigerant circuit 200 may generally be applied in a variety of systems that are used to control an environmental condition, e.g., temperature, humidity, air quality, etc., in a conditioned space.

[0040] In an example embodiment, compressor 205, condenser 210, expander 215, and evaporator 220 may be fluidly connected. Expander 215 may alternatively be referenced as an expansion device, e.g., an expansion valve, expansion plate, expansion vessel, orifice, etc., or other such types of expansion mechanisms, so long as expander 215 is used for expanding a working fluid to cause the working fluid to decrease in pressure and temperature.

[0041] Refrigerant circuit 200 is a non-limiting example and may be configured to include additional or fewer components. For example, in an embodiment, refrigerant circuit 200 may include other components including but not limited to an economizer heat exchanger, one or more flow control devices, e.g., a valve such as a solenoid valve, a check valve, a butterfly valve, a ball valve, etc.; a damper, a pump, etc.; a lubricant separator, a receiver tank, a dryer, a suction-liquid heat exchanger, one or more sensors, e.g., temperature sensor, pressure sensor, etc.

[0042] As applicable to the non-limiting example embodiment of FIG. 1, refrigerant circuit 200 may operate according to generally known principles and therefore be configured to heat and / or cool a liquid process fluid. The liquid process fluid may be a heat transfer fluid or medium, e.g., liquid such as, but not limited to, water, glycol, mixtures thereof, etc. Refrigerant circuit 200 may be generally representative of a liquid chiller system or may alternatively be configured to heat and / or cool a gaseous process fluid, e.g., a heat transfer medium or fluid, e.g., a gas such as, but not limited to, air, in which case refrigerant circuit 200 may be generally representative of an air conditioner and / or heat pump.

[0043] Also in accordance with the non-limiting example embodiment of FIG. 1, refrigerant circuit 200 may operate as a vapor-compression circuit such that compressor 205 compresses a working fluid, e.g., a heat transfer fluid such as, but not limited to, refrigerant, fluorine, etc., from a relatively lower pressure gas to a relatively higher-pressure gas. The relatively higher-pressure gas is at a relatively higher temperature, being discharged from compressor 205 and flowing through condenser 210.

[0044] In accordance with generally known principles, the working fluid flows through condenser 210 and rejects heat to the process fluid, e.g., water, solution, air, etc., thereby cooling the working fluid. The cooled working fluid, which is now in a liquid form, flows to the expander 215 that reduces the pressure of the working fluid. As a result, a portion of the working fluid is converted to a gaseous form. The working fluid, which is now in a mixed liquid and gaseous form flows to evaporator 220. The working fluid flows through evaporator 220 and absorbs heat from the process fluid, etc., a heat transfer medium such as, but not limited to, water, a solution, air, fluorine, etc., heating the working fluid, and converting it to a gaseous form. The gaseous working fluid then returns to compressor 205. The above-described process continues while the heat exchanging circuit or heat exchanging unit is operating, for example, in a cooling mode, etc., while compressor 205 is enabled.

[0045] In an example embodiment, compressor 205 may compress the working fluid. Lubricant may be supplied to the compressor to provide lubrication for its moving parts. A lubricant may include one or more types of lubricants. For example, a lubricant can be, but is not limited to, etc., polyolester oils, oil blends, etc. The lubricant may be discharged from the compressor with the working fluid. Thus, the working fluid discharged from the compressor may contain lubricant. In some refrigerant circuits, the lubricant may also be separated from the working fluid and the separated lubricant can be circulated back to the compressor. In other refrigerant circuits, the lubricant can be circulated with the working fluid and can then be supplied through a suction inlet of the compressor as part of the working fluid. In an example embodiment, the working fluid may also include one or more additional components other than lubricant(s) and / or refrigerant(s), such as for example additives.

[0046] In accordance with the non-limiting example embodiments discussed above regarding FIGS. 1 and 2, any one or more of compressor 205, condenser 210, expander 215, and evaporator 220 may have a temperature sensor embedded therein or attached thereto to sense and / or determine a temperature of a working or process fluid passing therethrough.

[0047] FIG. 3 shows a flowchart for implementing at least one process 300 chiller / heater process fluid temperature coordination.

[0048] Process 300 may pertain to coordinating process fluid, e.g., process fluid control by determining and / or appropriating an operational limit that is beyond appropriate levels, i.e., safety limits, at which operation of the system may be maintained. This control may be implemented when the unit is operating in heating mode and / or in cooling mode.

[0049] When the HVACR, e.g., system 100, runs in heating mode, process 300 may be implemented to ensure that a low evaporator temperature safety limit is not met by determining and / or implementing an adjustable low evaporator leaving process fluid temperature operational limit. Thus, if the determined / implemented evaporator leaving process fluid temperature of the high temperature chiller / heater falls below the low evaporator leaving process fluid temperature operational limit setpoint, system 100 rebalances by unloading the high temperature chiller / heater to provide as much heating capacity as possible. As a result, the high temperature chiller controls the evaporator leaving process fluid temperature to be the operational limit setpoint.

[0050] As set forth above, the embodiments described and / or recited herein may pertain to system control or unit control. Thus, when system 100 runs in heating mode, process 300 may be implemented by a controller 225 (see FIG. 2) that is disposed in high temperature chiller / heater 115; alternatively, the processes may be implemented by a controller.

[0051] When low temperature loading decreases to the point of the evaporator leaving process fluid temperature setpoint, the system enters into the low evaporator process fluid temperature limit mode in which the controller controls the evaporator leaving process fluid temperature to the active chilled water setpoint. At this time the high temperature unit is not able to make setpoint, but provides a subset of available heating energy. Also, when the low temperature loading increases, the controller starts controlling the condenser leaving process fluid temperature to the active hot water setpoint, as the controller stops limiting the evaporator leaving process fluid temperature.

[0052] In plainer terms, in a heating and cooling system having a first heat exchanger and a second heat exchanger, such as in FIG. 1, with both heat exchangers having a respective compressor, evaporator, and condenser fluidly connected to each to each other, one or more controllers are provided to implement the process shown in FIG. 3. That is, the one or more controllers operate the first heat exchanger and the second heat exchanger in a booster or cascade configuration to reject heat to a heating load via the first heat exchanger and unload the compressor of the first heat exchanger when a fluid operation parameter, i.e., evaporator leaving process fluid temperature, for the first heat exchanger is determined to be less than an acceptable range, i.e., less than a predetermined active chilled water setpoint. The controller unloads the compressor of the first heat exchanger until the fluid operation parameter for the first heat exchanger returns to the acceptable range without shutting down the heating and cooling system.

[0053] FIG. 4 is a graphical representation of the operation of a first heat exchanging unit and a second heat exchanging unit, configured in a booster or cascade configuration, in a heating mode. As shown in the graphical representation, at 410 the supply temperature for the condenser of the first heat exchanging unit is set to 180 °F, which is the predetermined boost condenser temperature setpoint. But when the cooling load of the second heat exchanging unit is reduced, shown as the evaporator entering water temperature 430 and evaporator leaving water temperature 435 descend towards the predetermined evaporator temperature setpoint 437 at point 440, the condenser of the first heat exchanging unit is unable to meet the target temperature of the heating load. As the supply temperature of the condenser of the first heat exchanging unit drops below a predetermined minimum setpoint, e.g., boost evaporator setpoint 415, the controller changes operation to maintain evaporator control, thus allowing the compressor of the first heat exchanging unit to unload at 412, i.e., have its motor run without compressing functionality, although temperature and capacity are reduced.

[0054] Returning to FIG. 3, when the HVACR, e.g., system 100, runs in cooling mode, process 300 may be implemented to ensure that a high condenser temperature operational limit is not abutted by determining and / or implementing an adjustable high condenser leaving process fluid, e.g., water, temperature operational limit. Thus, if the determined / implemented condenser leaving process fluid temperature of the low temperature chiller rises above the high condenser leaving process fluid temperature operational limit setpoint, system 100 rebalances by unloading the low temperature chiller / heater to provide as much cooling capacity as possible. As a result, the low temperature chiller / heater controls the leaving condenser process fluid temperature to the operational limit setpoint.

[0055] As set forth above, the embodiments described and / or recited herein may pertain to system control or unit control. Thus, when system 100 runs in cooling mode, process 300 may be implemented by a controller 225 (see FIG. 2) that is disposed in low temperature chiller / heater 120. Alternatively, the processes may be implemented by a controller.

[0056] In plainer terms regarding cooling mode, the one or more controller \ operate the first heat exchanger and the second heat exchanger in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanger, and unload the second compressor when a fluid operation parameter, i.e., condenser leaving process fluid temperature, for the second heat exchanger is determined to be higher than an acceptable range, i.e., a predetermined active hot water setpoint. The controller unloads the compressor of the second heat exchanger until the fluid operation parameter returns to the acceptable range without shutting down the heating and cooling system.

[0057] As referenced above, heating modulation control includes controller 225 controlling the evaporator leaving process fluid temperature by introducing, i.e., determining or implementing, an operational limit to unload the unit when a changeable target value is approached or abutted. In at least one non-limiting example embodiment, this target value is an active chilled water setpoint, which may refer to a desired temperature for chilled water leaving a chiller.

[0058] Control of hot water, or process fluid, includes modulation of the unit based on the heating low evaporator process fluid temperature operational limit, which utilizes an active chilled process fluid setpoint as a target, to limit the evaporator leaving process fluid temperature while running. This is an unloading limit that allows the unit to produce as much heating capacity as possible on the condenser side while not allowing evaporator leaving process fluid temperature to continue dropping. That is, the lower the evaporator leaving process fluid temperature drops, the less heat is rejected, leading to an inability for the unit to meet its desired heating capacity. Without limiting a drop of the evaporator leaving process fluid temperature, the unit eventually shuts down as a protection diagnostic as the temperature would continue to be driven lower by hot process fluid control. Thus, the present embodiment provides at least limited heating capacity, as opposed to none, which would be the case if the chiller / heater is shut down.

[0059] As also referenced above, a cooling modulation controller includes controller 225 controlling the condenser leaving process fluid temperature by introducing a corresponding operational limit to unload the unit when a corresponding changeable target value is approached or abutted. In at least one non-limiting example embodiment, this target value is an active hot water setpoint.

[0060] Control of chilled water, or process fluid, includes modulation of the unit based on the cooling high condenser water temperature operational limit, which utilizes an active hot process fluid setpoint as a target, to limit the condenser leaving process fluid temperature. This is an unloading limit that allows the unit to produce as much chilled process fluid as possible on the evaporator side while not allowing the condenser leaving process fluid temperature to continue rising. That is, the higher the condenser leaving process fluid temperature rises, the less heat can be rejected from the condenser side, leading to an inability for the unit to meet its desired cooling capacity. Without limiting the rise of the condenser leaving process fluid temperature, the unit eventually shuts down as a protection diagnostic as the temperature continued to be driven higher by chilled process fluid control. Thus, the present embodiment provides at least limited cooling capacity, as opposed to none, which would be the case if the chiller / heater is shut down.

[0061] In addition or in the alternative, staging control controls multiple chillers / heaters by turning the chillers / heaters on or off in a staged manner in accordance with cooling / heating demand. Thus, as load demand increases, additional chillers / heaters are activated; and, conversely, as load demand decreases, chillers / heaters are deactivated incrementally to match a reduced load requirement.

[0062] Thus, FIG. 3 shows process fluid modulation control by determining and / or appropriating an operational limit that is beyond appropriate levels, i.e., safety limits, at which operation of the system may be maintained. This control may be implemented when the unit is operating in heating mode and / or in cooling mode. Process 300 includes block 305, 310, 315, for modulating temperature control using process fluid modulation limits for both heating and cooling control schemes.

[0063] Block 305 includes the controller setting or determining a changeable operational limit that is appropriate for heating and cooling, respectively. For the heating mode, the operational limit for the evaporator leaving process fluid temperature is an active chilled water setpoint. For the cooling mode, the operational limit for the condenser leaving process fluid temperature is an active hot water setpoint.

[0064] Block 310 includes the controller receiving either or both of the evaporator leaving process fluid temperature when operating in the heating mode or the cooling mode, the operational limit for the condenser leaving process fluid temperature when operating in the cooling mode. The temperature readings are received from any one or more of the sensors embedded in or attached to the evaporator and condenser, respectively. The operation at block 310 further includes the controller determining whether the respective set or determined operational limits are being approached or abutted.

[0065] Block 315 includes the high temperature unit continuing operation in the heating mode continuing operation when the controller determines that the evaporator leaving process fluid temperature is not dropping to approach or abut the set or determined operational level, e.g., active chilled water setpoint.

[0066] Block 315, in addition or in the alternative, includes the low temperature unit continuing operation in the cooling mode when the controller determines that the condenser leaving process fluid temperature is not rising to approach or abut the set or determined operational level, e.g., active hot water setpoint.

[0067] Block 320 includes the high temperature unit unloading when the controller determines that the evaporator leaving process fluid temperature is dropping to approach or abut the set or determined operational level, e.g., active chilled water setpoint, to provide as much heating capacity as possible by controlling the leaving evaporator process fluid temperature to be the operational limit setpoint.

[0068] Block 320, in addition or in the alternative, includes the low temperature unit determining that the condenser leaving process fluid temperature is rising to approach or abut the set or determined operational level, e.g., active hot water setpoint, to provide as much cooling capacity as possible by controlling the condenser leaving process fluid temperature to be the operational limit setpoint.

[0069] Thus, the logic for process fluid, e.g., water temperature control coordination refers to an active cooling differential and / or an active heating differential to start and stop.

[0070] That is, to run, both the evaporator leaving process fluid temperature is above the corresponding operational setpoint, e.g., active chilled water setpoint, in addition to an active cooling differential; and the condenser leaving process fluid temperature is below the corresponding operational setpoint, e.g., active hot water setpoint, less an active heating differential.

[0071] To stop operation, either the evaporator leaving process fluid temperature is below the corresponding operational setpoint, e.g., active chilled water setpoint, less the active cooling differential; or the condenser leaving process fluid temperature is above the corresponding operational setpoint, e.g., active hot water setpoint, in addition to the active heating differential.

[0072] Accordingly, when hot water, or process fluid, control is selected, operational start is inhibited by low evaporator water temperature, which occurs when the active cooling differential to start is not satisfied.

[0073] Further, when chilled water, or process fluid, control is selected, operational start is inhibited by a high condenser water temperature, which occurs when the active heating differential to start is not satisfied.Aspects

[0074] Aspect 1. A heating and cooling system, comprising:

[0075] a first heat exchanging unit having a first compressor, a first evaporator, and a first condenser fluidly connected to each other;

[0076] a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and

[0077] a controller configured to:

[0078] operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to reject heat to a heating load via the first heat exchanging unit; and

[0079] unload the first compressor when a fluid operation parameter for the first heat exchanging unit is determined to be less than an acceptable range.

[0080] Aspect 2. The heating and cooling system of Aspect 1, wherein the controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

[0081] Aspect 3. The heating and cooling system of either Aspect 1 or Aspect 2, further comprising:

[0082] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

[0083] Aspect 4. The heating and cooling system of any of Aspects 1 to 3, wherein the fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature.

[0084] Aspect 5. The heating and cooling system of any of Aspects 1 to 4, wherein being less than the acceptable range includes being less than an active chilled water setpoint.

[0085] Aspect 6. The heating and cooling system of any of Aspects 1 to 5, wherein the active chilled water setpoint is predetermined by a user.

[0086] Aspect 7. A heating and cooling system, comprising:

[0087] a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other;

[0088] a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and

[0089] a controller configured to:

[0090] operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanging unit; and

[0091] unload the second compressor when a fluid operation parameter for the second heat exchanging unit is determined to be higher than an acceptable range.

[0092] Aspect 8. The heating and cooling system of Aspect 7, wherein the controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system

[0093] Aspect 9. The heating and cooling system of either of Aspect 7 or Aspect 8, further comprising:

[0094] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

[0095] Aspect 10. The heating and cooling system of any of Aspects 7 to 9, wherein the fluid operation parameter is a condenser leaving process fluid temperature.

[0096] Aspect 11. The heating and cooling system of any of Aspects 7 to 10, wherein being higher than the acceptable range includes being greater than an active hot water setpoint.

[0097] Aspect 12. The heating and cooling system of any of Aspects 7 to 11, wherein the active hot water setpoint is predetermined by a user.

[0098] Aspect 13. A heating and cooling system, comprising:

[0099] a first heat exchanging unit operating in a heating mode, wherein the first heat exchanging unit comprises:

[0100] a first compressor, a first condenser, and a first evaporator in fluid communication with each other;

[0101] a second heat exchanging unit operating in a cooling mode, wherein the second heat exchanging unit comprises:

[0102] a second compressor, a second condenser, and a second evaporator in fluid communication with each other; and

[0103] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and a second heat exchanging unit; and

[0104] at least one controller configured to:

[0105] unload the first compressor when a cooling load of the second heat exchanging unit decreases causing a fluid operation parameter for the first heat exchanging unit to be less than an acceptable range.

[0106] Aspect 14. The heating and cooling system of Aspect 13, wherein the at least one controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

[0107] Aspect 15. The heating and cooling system of either Aspect 13 or Aspect 14, wherein

[0108] the fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature, and

[0109] the acceptable range for the evaporator leaving process fluid temperature is a predetermined active chilled water setpoint

[0110] Aspect 16. The heating and cooling system of either of any of Aspects 13 to Aspect 15, wherein the at least one controller is further configured to:

[0111] unload the second compressor when a heating load of the first heat exchanging unit increases causing a fluid operation parameter for the second heat exchanging unit to be higher than an acceptable range.

[0112] Aspect 17. The heating and cooling system of any of Aspects 13 to 16, wherein the at least one controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system

[0113] Aspect 18. The heating and cooling system of either Aspect 16 or Aspect 17, wherein

[0114] the fluid operation parameter for the second heat exchanging unit is a condenser leaving process fluid temperature, and

[0115] the acceptable range for the condenser leaving process fluid temperature is a predetermined active hot water setpoint.

[0116] The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms “a,”“an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and / or “comprising,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components.

[0117] With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. This specification and the embodiments described are exemplary only, with the true scope and spirit of the disclosure being indicated by the claims that follow.

Examples

Embodiment Construction

[0012]In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current example embodiment. Still, the example embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configuratio...

FIELD

[0001] This disclosure relates generally to heating and cooling systems that are selectively operable in either a booster chiller configuration or in a cascade configuration. More specifically, the disclosure relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system in which process fluid temperature safety protection diagnostics are exploited to guard against system damage.BACKGROUND

[0002] A heating and cooling system may be used to heat and cool one or more process fluids for a variety of applications. For example, the heating and cooling system may be used to heat a heating load and / or cool a cooling load for industrial processes. Accordingly, an HVACR system may provide heating and / or provide cooling for the conditioned space. The HVACR system may include a heat exchanging circuit system that includes one or more of, at least, compressors, expanders, a condenser, an evaporator, fans, filters, dampers, circulation pumps, etc., in which the one or more compressors, condenser, expander, and evaporator are fluidly connected. Safe and efficient implementation of such a heat exchanging circuit system relies on adherence to physical limitations of the components thereof.SUMMARY

[0003] This disclosure relates generally to heating and cooling systems that are selectively operable in either a booster chiller configuration or in a cascade configuration. More specifically, the disclosure relates to a heating, ventilation, air conditioning, and refrigeration (HVACR) system in which water temperature safety protection diagnostics are exploited to guard against system damage.

[0004] In at least one non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other; a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and a controller. The controller operates the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to reject heat to a heating load via the first heat exchanging unit and unloads the first compressor when a fluid operation parameter for the first heat exchanging unit is determined to be less than an acceptable range.

[0005] In at least one other non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other; a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and a controller. The controller operates the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanging unit and unloads the second compressor when a fluid operation parameter for the second heat exchanging unit is determined to be higher than an acceptable range.

[0006] In yet another non-limiting example embodiment, a heating and cooling system includes a first heat exchanging unit operating in a heating mode that includes a first compressor, a first condenser, and a first evaporator in fluid communication with each other. The heating and cooling system also includes a second heat exchanging unit operating in a cooling mode that includes a second compressor, a second condenser, and a second evaporator in fluid communication with each other. The system includes, further, an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and a second heat exchanging unit, and at least one controller. The controller is configured to, at least, unload the first compressor when a cooling load of the second heat exchanging unit decreases causing a fluid operation parameter for the first heat exchanging unit to be less than an acceptable range.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the detailed description that follows, embodiments are described as illustrations only since various changes and modifications will become apparent to those skilled in the art from the following detailed description. The use of the same reference numbers in different figures indicates similar or identical items.

[0008] FIG. 1 illustrates a schematic diagram of a heating and / or cooling system, according to at least one non-limiting example embodiment of chiller / heater water temperature coordination.

[0009] FIG. 2 illustrates a schematic diagram of an HVACR system that includes a refrigerant circuit, arranged in accordance with at least one non-limiting example embodiment of chiller / heater water temperature coordination.

[0010] FIG. 3 is a flowchart of a control method of heating and / or cooling a system, according to an embodiment.

[0011] FIG. 4 is a graphical representation of the operation of heat exchanging units, configured in a booster or cascade configuration, according to an embodiment.DETAILED DESCRIPTION

[0012] In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current example embodiment. Still, the example embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0013] Particular embodiments of the present disclosure are described herein with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. In this description, as well as in the drawings, like-referenced numbers represent elements that may perform the same, similar, or equivalent functions.

[0014] Additionally, the present disclosure may be described herein in terms of functional block components and various processing steps. It should be appreciated that such functional blocks may be realized by any number of hardware and / or software components configured to perform the specified functions.

[0015] The scope of the disclosure should be determined by the appended claims and their legal equivalents, rather than by the examples given herein. For example, the steps recited in any method claims may be executed in any order and are not limited to the order presented in the claims. Moreover, no element is essential to the practice of the disclosure unless specifically described herein as “critical” or “essential.”

[0016] A heating and cooling system may be used to heat a heating load and / or cool a cooling load for a variety of applications including for industrial processes, e.g., heating and / or cooling gas or liquid flows to maintain reaction temperatures or temperature setpoints, cooling industrial waste, providing heat to replace gas boilers, providing refrigeration, etc. In some embodiments, the heating and cooling system may be implemented as an HVACR system that is used to provide comfort heating and provide comfort cooling.

[0017] In some embodiments of an HVACR, thermal energy in a heat exchanging circuit is exchanged with one or more process fluids, e.g., water, air, etc., which may then be used to condition a space, which may be within a structure, e.g., office building, commercial building, factory, laboratory, data center, a residential building, etc. When implemented to heat and / or cool a conditioned space, heat generated from compression of a working fluid in the heat exchanging circuit or heat exchanging unit may be rejected therefrom to heat the process fluid that circulates in a heating water circuit to condition the space. Similarly, when cooling to the conditioned space, the HVACR system may extract heat from a second process fluid that is circulated in a chilled water circuit of the hydronic system to cool the process fluid to condition the space.

[0018] The non-limiting example embodiments described and recited herein are directed towards implementing reliable performance parameters pertaining to a process fluid, that provide reliable diagnostics that allow the HVACR system operating by limit unit cycling and maintaining process fluid stability.

[0019] Thus, in accordance with at least some of the non-limiting example embodiments described and recited herein, one or more components, e.g., compressor, of a high temperature chiller running in heating mode unloads or shuts off when an evaporator leaving process fluid temperature falls below an evaporator limit; and / or when a low temperature chiller running in cooling mode unloads or shuts off when a condenser leaving process fluid temperature increases to exceed a condenser limit. That is, a high temperature chiller / heater operating in a heating mode is unable to produce sufficient heating capacity if the evaporator leaving process fluid temperature, e.g., evaporator leaving water temperature, drops to an unacceptable level; likewise, a low temperature chiller / heater operating in a cooling mode is unable to produce sufficient cooling capacity if the condenser leaving process fluid temperature, e.g., condenser leaving process fluid temperature, rises beyond an unacceptable level.

[0020] As described or otherwise referenced herein, unloading a chiller / heater refers to unloading the compressor corresponding to the respective chiller / heater. A chiller / heater is unloaded to reduce the compressor output without shutting down the motor and short cycling.

[0021] The embodiments described and recited herein reference and / or implement a process fluid, e.g., water, temperature control algorithm that adheres to adjustable temperature operational limits to ensure that safety cutouts are not triggered and further controls active setpoints, further preventing multiple chillers connected as tandem from cycling by handling uneven loads.

[0022] FIG. 1 shows a schematic diagram of HVACR system 100 for heating and / or cooling one or more process fluids, e.g., water, using a compression cycle of a working fluid. HVACR system 100 may include a hydronic system that includes a first process fluid loop 105 and a second process fluid loop 110 for conditioning a space, building, or structure. The working fluid may be any suitable working fluid, including a refrigerant or blend of two or more refrigerants. In the non-limiting example embodiment of FIG. 1, HVACR system 100 is configured to provide cooling in a chiller system; however it is understood that heating and cooling systems that include one or more compressors according to embodiments described and recited herein may also be arranged as heat pumps, reversible systems, or any other suitable system providing heating and / or cooling through a compression cycle of a working fluid.

[0023] HVACR system 100 includes first heat exchanging unit 115, second heat exchanging unit 120, process fluid loop 125, and controller (see FIG. 2). First heat exchanging unit 115 includes a working fluid circuit that includes a compressor (see FIG. 2); first heat exchanger 135, e.g., condenser; optional expander (see FIG. 2); and second heat exchanger 140, e.g., evaporator. Second heat exchanging unit 120 includes a working fluid circuit that includes a compressor (see FIG. 2); a first heat exchanger 145, e.g., condenser; optional expander (see FIG. 2); and second heat exchanger 150, e.g., evaporator.

[0024] In first heat exchanging unit 115, the compressor is configured to compress a working fluid. The compressor may be, e.g., a screw compressor, a scroll compressor, a centrifugal compressor, etc. Working fluid from the compressor may pass to first heat exchanger 135, which may be configured to selectively exchange heat with a first process fluid to facilitate the working fluid rejecting heat to the process fluid, thereby heating the first process fluid in first process fluid loop 105. Thus, the first process fluid may provide / exchange heat for heating load 175.

[0025] The rejection of heat to the heating load 175 may be directed to, e.g., an ambient environment, a heating load, or other suitable sink for the heat being rejected by the working fluid at first heat exchanger 135, e.g., for conditioning one or more spaces, buildings, or structures. The working fluid may pass from first heat exchanger 135 to the expander, which may be configured to expand the working fluid, then to the second heat exchanger 140 at which the working fluid may extract heat from a source for cooling a cooling load or process fluid, thereby evaporating the working fluid prior to the working fluid returning to the compressor. The sources may be, e.g., from a process fluid or a conditioned space to be cooled, from an ambient environment, etc., to evaporate the working fluid. Working fluid leaving second heat exchanger 140 may be returned to a suction of the compressor, and the working fluid may continue to be circulated in first heat exchanging unit 115.

[0026] In the second heat exchanging unit 120, the compressor is configured to compress a working fluid. Working fluid from the compressor may pass to heat exchanger 145, which may be configured to selectively exchange heat with process fluid in process fluid loop 125 to allow the working fluid to reject heat to the process fluid, thereby heating the process fluid in the process fluid loop 125, e.g., to provide lift for refrigerant in the first heat exchanging circuit or heat exchanging unit 115. The working fluid may pass from heat exchanger 145 to the expander, which is configured to expand the working fluid. Working fluid may pass from the expander to second heat exchanger 150, at which the working fluid may extract heat from the second process fluid of second process fluid loop 110 for cooling load 180, thereby evaporating the working fluid prior to the working fluid returning to the compressor. Working fluid leaving second heat exchanger 150 may be returned to a suction of the compressor, and the working fluid may continue to be circulated in second heat exchanging unit 120.

[0027] In some embodiments first heat exchanger 135 of first heat exchanging unit 115 and / or heat exchanger 145 of second heat exchanging unit 120 may be a dual-bundled heat exchanger, such as, a dual-bundled shell and tube heat exchanger or dual-bundled plate heat exchanger. As such, the first heat exchanger 135 may be selectively configurable to reject heat to either a process fluid for heating load 175, while heat exchanger 145 may be selectively configurable to reject heat to a process fluid from the process fluid loop 125.

[0028] Process fluid loop 125 may include a process fluid and one or more of valves, pumps, filters, stainers, etc., to control fluid flow between first heat exchanger 140 of first heat exchanging unit 115 and heat exchanger 145 of second heat exchanging unit 120. The process fluid may be, but not limited to, water, air, etc. The one or more valves may include a three-way feed valve, e.g., two position valve, or a four-way feed valve, e.g., three position valve, to allow the selectable connection of fluid to be cooled by first heat exchanger 140, e.g., connection to either the process fluid in process fluid loop 125 or the second process fluid for cooling load 180.

[0029] The controller 225 (see FIG. 2) may be programmed, designed, or otherwise configured to control one or more components of HVACR system 100 and / or is a building automation system (BAS) controller for a computerized network of electronic devices that can be configured to control one or more systems (e.g., mechanical, electrical, lighting, security, HVACR, etc.). Controller 225 (see FIG. 2) may include one or more processors and one or more non-volatile storage memories having instructions, which when executed by the one or more processors, carry out control operations, as discussed herein. In some embodiments, the controller may include programmability to enable receiving and / or receiving a signal to heat or cool, e.g., from the BAS controller. For example, a building load may be determined based on seasonality, e.g., winter or summer, such that when there is no heating demand, e.g., in the summer, the first heat exchanging circuit or heat exchanging unit can be selectively operated in a cooling mode, whereas, when there is heating demand, e.g., in the winter, the first heat exchanging circuit or heat exchanging unit can be selectively operated in a heating mode, in which the controller is configured to selectively provide one or more of the process fluid, the second process fluid from the process fluid load, or cooling fluid from the cooling device 260 to one or more of the heat exchangers.

[0030] As such, the HVACR system 100 may be optimized for use for either heating or cooling, in either a booster chiller configuration or in the cascade configuration described above. In a booster chiller configuration, 115 may be implemented as a high temperature chiller / heater and 120 may be implemented as a low temperature chiller / heater.

[0031] As disclosed, recited, or otherwise referenced herein, a cascade configuration for a heat exchanger may refer to a heat exchanger that selectively exchanges heat with coolant in a coolant loop to allow working fluid flowing therethrough to (1) reject heat to the coolant to thereby heat the coolant in the coolant loop to provide lift for refrigerant in the corresponding heat exchanging circuit or heat exchanging unit or (2) exchange heat with the cooling fluid from a cooling device, e.g., cooling tower, to allow the working fluid to reject heat to the cooling fluid.

[0032] Further, as disclosed, recited, or otherwise referenced herein, a booster chiller may refer to a chiller configuration that pre-cools air prior to the air entering a condenser. In this regard, water droplets may be sprayed into the air stream, e.g., via nozzles. As the sprayed water droplets evaporate, the evaporating water absorbs heat from the surrounding air, thus lowering the air temperature. This pre-cooled air enters the condenser of the chiller to thereby improve condenser efficiency, e.g., by reducing energy consumption and improving equipment lifespan.

[0033] A high temperature chiller / heater, as disclosed, recited, or otherwise referenced herein, may refer to a chiller / heater that is configured to cool and heat fluids within a wide temperature range. A high temperature chiller / heater may switch between heating and cooling modes to maintain a desired temperature for different stages of a process.

[0034] A low temperature chiller / heater, as disclosed, recited, or otherwise referenced herein, may refer to a chiller / heater that is configured to operate at temperatures that are below standard cooling or heating ranges. A low temperature chiller / heater may operate at extreme low temperatures, e.g., −40 °F to 0 °F, and may be utilized in environments for maintaining, e.g., perishable goods, or for maintaining appropriate working conditions, e.g., laboratories.

[0035] FIG. 2 illustrates a schematic diagram of an HVACR system including refrigerant circuit 200, arranged in accordance with at least the embodiments of 115 and 120 described above regarding FIG. 1.

[0036] In an example embodiment, refrigerant circuit 200 may include compressor 205, condenser 210, expander 215, and evaporator 220. Refrigerant circuit 200 may also include a controller 225 configured to communicate with and / or control the operations of the compressor 205, the condenser 210, optional expander 215, the evaporator 220, and / or other components, e.g., flow control device, sensor(s), etc., of the HVACR system.

[0037] Regarding the example embodiment of FIG. 1, controller 225 may be a centralized controller that coordinates operation of both high temperature chiller / heater 115 and low temperature chiller / heater 120. However, other example embodiments of system 100 may include an embodiment of controller 225 disposed in high temperature chiller 115 to thereby implement hot water control modulation pertaining to the evaporator leaving water temperature as an operational limit, as described herein. In addition, or alternatively, system 100 may include an embodiment of controller disposed in low temperature chiller 120 to thereby implement chilled water control modulation pertaining to condenser leaving water temperature as an operational limit, as described herein. Thus, embodiments described and / or recited herein may include system control or unit control.

[0038] In an example embodiment, controller 225 may include or be connected to a memory such as RAM and ROM and execute software, e.g., processor-executed instructions or algorithms, that may be stored in the RAM, particularly during execution, the ROM on a generally permanent basis, or another non-transitory computer readable medium such as other memory, flash drive, or disc. In some embodiments, controller 225 may be so connected to read such software. A microprocessor or other programmable device with suitable memory and I / O devices may also be implemented as controller 225. It is to be understood that the processes and / or steps described in any of the figures may be conducted, implemented, and / or performed by one or more controllers including, e.g., controller 225 and / or any other suitable controller, unless otherwise specified.

[0039] In at least one non-limiting example embodiment, refrigerant circuit 200 may generally be applied in a variety of systems that are used to control an environmental condition, e.g., temperature, humidity, air quality, etc., in a conditioned space.

[0040] In an example embodiment, compressor 205, condenser 210, expander 215, and evaporator 220 may be fluidly connected. Expander 215 may alternatively be referenced as an expansion device, e.g., an expansion valve, expansion plate, expansion vessel, orifice, etc., or other such types of expansion mechanisms, so long as expander 215 is used for expanding a working fluid to cause the working fluid to decrease in pressure and temperature.

[0041] Refrigerant circuit 200 is a non-limiting example and may be configured to include additional or fewer components. For example, in an embodiment, refrigerant circuit 200 may include other components including but not limited to an economizer heat exchanger, one or more flow control devices, e.g., a valve such as a solenoid valve, a check valve, a butterfly valve, a ball valve, etc.; a damper, a pump, etc.; a lubricant separator, a receiver tank, a dryer, a suction-liquid heat exchanger, one or more sensors, e.g., temperature sensor, pressure sensor, etc.

[0042] As applicable to the non-limiting example embodiment of FIG. 1, refrigerant circuit 200 may operate according to generally known principles and therefore be configured to heat and / or cool a liquid process fluid. The liquid process fluid may be a heat transfer fluid or medium, e.g., liquid such as, but not limited to, water, glycol, mixtures thereof, etc. Refrigerant circuit 200 may be generally representative of a liquid chiller system or may alternatively be configured to heat and / or cool a gaseous process fluid, e.g., a heat transfer medium or fluid, e.g., a gas such as, but not limited to, air, in which case refrigerant circuit 200 may be generally representative of an air conditioner and / or heat pump.

[0043] Also in accordance with the non-limiting example embodiment of FIG. 1, refrigerant circuit 200 may operate as a vapor-compression circuit such that compressor 205 compresses a working fluid, e.g., a heat transfer fluid such as, but not limited to, refrigerant, fluorine, etc., from a relatively lower pressure gas to a relatively higher-pressure gas. The relatively higher-pressure gas is at a relatively higher temperature, being discharged from compressor 205 and flowing through condenser 210.

[0044] In accordance with generally known principles, the working fluid flows through condenser 210 and rejects heat to the process fluid, e.g., water, solution, air, etc., thereby cooling the working fluid. The cooled working fluid, which is now in a liquid form, flows to the expander 215 that reduces the pressure of the working fluid. As a result, a portion of the working fluid is converted to a gaseous form. The working fluid, which is now in a mixed liquid and gaseous form flows to evaporator 220. The working fluid flows through evaporator 220 and absorbs heat from the process fluid, etc., a heat transfer medium such as, but not limited to, water, a solution, air, fluorine, etc., heating the working fluid, and converting it to a gaseous form. The gaseous working fluid then returns to compressor 205. The above-described process continues while the heat exchanging circuit or heat exchanging unit is operating, for example, in a cooling mode, etc., while compressor 205 is enabled.

[0045] In an example embodiment, compressor 205 may compress the working fluid. Lubricant may be supplied to the compressor to provide lubrication for its moving parts. A lubricant may include one or more types of lubricants. For example, a lubricant can be, but is not limited to, etc., polyolester oils, oil blends, etc. The lubricant may be discharged from the compressor with the working fluid. Thus, the working fluid discharged from the compressor may contain lubricant. In some refrigerant circuits, the lubricant may also be separated from the working fluid and the separated lubricant can be circulated back to the compressor. In other refrigerant circuits, the lubricant can be circulated with the working fluid and can then be supplied through a suction inlet of the compressor as part of the working fluid. In an example embodiment, the working fluid may also include one or more additional components other than lubricant(s) and / or refrigerant(s), such as for example additives.

[0046] In accordance with the non-limiting example embodiments discussed above regarding FIGS. 1 and 2, any one or more of compressor 205, condenser 210, expander 215, and evaporator 220 may have a temperature sensor embedded therein or attached thereto to sense and / or determine a temperature of a working or process fluid passing therethrough.

[0047] FIG. 3 shows a flowchart for implementing at least one process 300 chiller / heater process fluid temperature coordination.

[0048] Process 300 may pertain to coordinating process fluid, e.g., process fluid control by determining and / or appropriating an operational limit that is beyond appropriate levels, i.e., safety limits, at which operation of the system may be maintained. This control may be implemented when the unit is operating in heating mode and / or in cooling mode.

[0049] When the HVACR, e.g., system 100, runs in heating mode, process 300 may be implemented to ensure that a low evaporator temperature safety limit is not met by determining and / or implementing an adjustable low evaporator leaving process fluid temperature operational limit. Thus, if the determined / implemented evaporator leaving process fluid temperature of the high temperature chiller / heater falls below the low evaporator leaving process fluid temperature operational limit setpoint, system 100 rebalances by unloading the high temperature chiller / heater to provide as much heating capacity as possible. As a result, the high temperature chiller controls the evaporator leaving process fluid temperature to be the operational limit setpoint.

[0050] As set forth above, the embodiments described and / or recited herein may pertain to system control or unit control. Thus, when system 100 runs in heating mode, process 300 may be implemented by a controller 225 (see FIG. 2) that is disposed in high temperature chiller / heater 115; alternatively, the processes may be implemented by a controller.

[0051] When low temperature loading decreases to the point of the evaporator leaving process fluid temperature setpoint, the system enters into the low evaporator process fluid temperature limit mode in which the controller controls the evaporator leaving process fluid temperature to the active chilled water setpoint. At this time the high temperature unit is not able to make setpoint, but provides a subset of available heating energy. Also, when the low temperature loading increases, the controller starts controlling the condenser leaving process fluid temperature to the active hot water setpoint, as the controller stops limiting the evaporator leaving process fluid temperature.

[0052] In plainer terms, in a heating and cooling system having a first heat exchanger and a second heat exchanger, such as in FIG. 1, with both heat exchangers having a respective compressor, evaporator, and condenser fluidly connected to each to each other, one or more controllers are provided to implement the process shown in FIG. 3. That is, the one or more controllers operate the first heat exchanger and the second heat exchanger in a booster or cascade configuration to reject heat to a heating load via the first heat exchanger and unload the compressor of the first heat exchanger when a fluid operation parameter, i.e., evaporator leaving process fluid temperature, for the first heat exchanger is determined to be less than an acceptable range, i.e., less than a predetermined active chilled water setpoint. The controller unloads the compressor of the first heat exchanger until the fluid operation parameter for the first heat exchanger returns to the acceptable range without shutting down the heating and cooling system.

[0053] FIG. 4 is a graphical representation of the operation of a first heat exchanging unit and a second heat exchanging unit, configured in a booster or cascade configuration, in a heating mode. As shown in the graphical representation, at 410 the supply temperature for the condenser of the first heat exchanging unit is set to 180 °F, which is the predetermined boost condenser temperature setpoint. But when the cooling load of the second heat exchanging unit is reduced, shown as the evaporator entering water temperature 430 and evaporator leaving water temperature 435 descend towards the predetermined evaporator temperature setpoint 437 at point 440, the condenser of the first heat exchanging unit is unable to meet the target temperature of the heating load. As the supply temperature of the condenser of the first heat exchanging unit drops below a predetermined minimum setpoint, e.g., boost evaporator setpoint 415, the controller changes operation to maintain evaporator control, thus allowing the compressor of the first heat exchanging unit to unload at 412, i.e., have its motor run without compressing functionality, although temperature and capacity are reduced.

[0054] Returning to FIG. 3, when the HVACR, e.g., system 100, runs in cooling mode, process 300 may be implemented to ensure that a high condenser temperature operational limit is not abutted by determining and / or implementing an adjustable high condenser leaving process fluid, e.g., water, temperature operational limit. Thus, if the determined / implemented condenser leaving process fluid temperature of the low temperature chiller rises above the high condenser leaving process fluid temperature operational limit setpoint, system 100 rebalances by unloading the low temperature chiller / heater to provide as much cooling capacity as possible. As a result, the low temperature chiller / heater controls the leaving condenser process fluid temperature to the operational limit setpoint.

[0055] As set forth above, the embodiments described and / or recited herein may pertain to system control or unit control. Thus, when system 100 runs in cooling mode, process 300 may be implemented by a controller 225 (see FIG. 2) that is disposed in low temperature chiller / heater 120. Alternatively, the processes may be implemented by a controller.

[0056] In plainer terms regarding cooling mode, the one or more controller \ operate the first heat exchanger and the second heat exchanger in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanger, and unload the second compressor when a fluid operation parameter, i.e., condenser leaving process fluid temperature, for the second heat exchanger is determined to be higher than an acceptable range, i.e., a predetermined active hot water setpoint. The controller unloads the compressor of the second heat exchanger until the fluid operation parameter returns to the acceptable range without shutting down the heating and cooling system.

[0057] As referenced above, heating modulation control includes controller 225 controlling the evaporator leaving process fluid temperature by introducing, i.e., determining or implementing, an operational limit to unload the unit when a changeable target value is approached or abutted. In at least one non-limiting example embodiment, this target value is an active chilled water setpoint, which may refer to a desired temperature for chilled water leaving a chiller.

[0058] Control of hot water, or process fluid, includes modulation of the unit based on the heating low evaporator process fluid temperature operational limit, which utilizes an active chilled process fluid setpoint as a target, to limit the evaporator leaving process fluid temperature while running. This is an unloading limit that allows the unit to produce as much heating capacity as possible on the condenser side while not allowing evaporator leaving process fluid temperature to continue dropping. That is, the lower the evaporator leaving process fluid temperature drops, the less heat is rejected, leading to an inability for the unit to meet its desired heating capacity. Without limiting a drop of the evaporator leaving process fluid temperature, the unit eventually shuts down as a protection diagnostic as the temperature would continue to be driven lower by hot process fluid control. Thus, the present embodiment provides at least limited heating capacity, as opposed to none, which would be the case if the chiller / heater is shut down.

[0059] As also referenced above, a cooling modulation controller includes controller 225 controlling the condenser leaving process fluid temperature by introducing a corresponding operational limit to unload the unit when a corresponding changeable target value is approached or abutted. In at least one non-limiting example embodiment, this target value is an active hot water setpoint.

[0060] Control of chilled water, or process fluid, includes modulation of the unit based on the cooling high condenser water temperature operational limit, which utilizes an active hot process fluid setpoint as a target, to limit the condenser leaving process fluid temperature. This is an unloading limit that allows the unit to produce as much chilled process fluid as possible on the evaporator side while not allowing the condenser leaving process fluid temperature to continue rising. That is, the higher the condenser leaving process fluid temperature rises, the less heat can be rejected from the condenser side, leading to an inability for the unit to meet its desired cooling capacity. Without limiting the rise of the condenser leaving process fluid temperature, the unit eventually shuts down as a protection diagnostic as the temperature continued to be driven higher by chilled process fluid control. Thus, the present embodiment provides at least limited cooling capacity, as opposed to none, which would be the case if the chiller / heater is shut down.

[0061] In addition or in the alternative, staging control controls multiple chillers / heaters by turning the chillers / heaters on or off in a staged manner in accordance with cooling / heating demand. Thus, as load demand increases, additional chillers / heaters are activated; and, conversely, as load demand decreases, chillers / heaters are deactivated incrementally to match a reduced load requirement.

[0062] Thus, FIG. 3 shows process fluid modulation control by determining and / or appropriating an operational limit that is beyond appropriate levels, i.e., safety limits, at which operation of the system may be maintained. This control may be implemented when the unit is operating in heating mode and / or in cooling mode. Process 300 includes block 305, 310, 315, for modulating temperature control using process fluid modulation limits for both heating and cooling control schemes.

[0063] Block 305 includes the controller setting or determining a changeable operational limit that is appropriate for heating and cooling, respectively. For the heating mode, the operational limit for the evaporator leaving process fluid temperature is an active chilled water setpoint. For the cooling mode, the operational limit for the condenser leaving process fluid temperature is an active hot water setpoint.

[0064] Block 310 includes the controller receiving either or both of the evaporator leaving process fluid temperature when operating in the heating mode or the cooling mode, the operational limit for the condenser leaving process fluid temperature when operating in the cooling mode. The temperature readings are received from any one or more of the sensors embedded in or attached to the evaporator and condenser, respectively. The operation at block 310 further includes the controller determining whether the respective set or determined operational limits are being approached or abutted.

[0065] Block 315 includes the high temperature unit continuing operation in the heating mode continuing operation when the controller determines that the evaporator leaving process fluid temperature is not dropping to approach or abut the set or determined operational level, e.g., active chilled water setpoint.

[0066] Block 315, in addition or in the alternative, includes the low temperature unit continuing operation in the cooling mode when the controller determines that the condenser leaving process fluid temperature is not rising to approach or abut the set or determined operational level, e.g., active hot water setpoint.

[0067] Block 320 includes the high temperature unit unloading when the controller determines that the evaporator leaving process fluid temperature is dropping to approach or abut the set or determined operational level, e.g., active chilled water setpoint, to provide as much heating capacity as possible by controlling the leaving evaporator process fluid temperature to be the operational limit setpoint.

[0068] Block 320, in addition or in the alternative, includes the low temperature unit determining that the condenser leaving process fluid temperature is rising to approach or abut the set or determined operational level, e.g., active hot water setpoint, to provide as much cooling capacity as possible by controlling the condenser leaving process fluid temperature to be the operational limit setpoint.

[0069] Thus, the logic for process fluid, e.g., water temperature control coordination refers to an active cooling differential and / or an active heating differential to start and stop.

[0070] That is, to run, both the evaporator leaving process fluid temperature is above the corresponding operational setpoint, e.g., active chilled water setpoint, in addition to an active cooling differential; and the condenser leaving process fluid temperature is below the corresponding operational setpoint, e.g., active hot water setpoint, less an active heating differential.

[0071] To stop operation, either the evaporator leaving process fluid temperature is below the corresponding operational setpoint, e.g., active chilled water setpoint, less the active cooling differential; or the condenser leaving process fluid temperature is above the corresponding operational setpoint, e.g., active hot water setpoint, in addition to the active heating differential.

[0072] Accordingly, when hot water, or process fluid, control is selected, operational start is inhibited by low evaporator water temperature, which occurs when the active cooling differential to start is not satisfied.

[0073] Further, when chilled water, or process fluid, control is selected, operational start is inhibited by a high condenser water temperature, which occurs when the active heating differential to start is not satisfied.Aspects

[0074] Aspect 1. A heating and cooling system, comprising:

[0075] a first heat exchanging unit having a first compressor, a first evaporator, and a first condenser fluidly connected to each other;

[0076] a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and

[0077] a controller configured to:

[0078] operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to reject heat to a heating load via the first heat exchanging unit; and

[0079] unload the first compressor when a fluid operation parameter for the first heat exchanging unit is determined to be less than an acceptable range.

[0080] Aspect 2. The heating and cooling system of Aspect 1, wherein the controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

[0081] Aspect 3. The heating and cooling system of either Aspect 1 or Aspect 2, further comprising:

[0082] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

[0083] Aspect 4. The heating and cooling system of any of Aspects 1 to 3, wherein the fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature.

[0084] Aspect 5. The heating and cooling system of any of Aspects 1 to 4, wherein being less than the acceptable range includes being less than an active chilled water setpoint.

[0085] Aspect 6. The heating and cooling system of any of Aspects 1 to 5, wherein the active chilled water setpoint is predetermined by a user.

[0086] Aspect 7. A heating and cooling system, comprising:

[0087] a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other;

[0088] a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other; and

[0089] a controller configured to:

[0090] operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanging unit; and

[0091] unload the second compressor when a fluid operation parameter for the second heat exchanging unit is determined to be higher than an acceptable range.

[0092] Aspect 8. The heating and cooling system of Aspect 7, wherein the controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system

[0093] Aspect 9. The heating and cooling system of either of Aspect 7 or Aspect 8, further comprising:

[0094] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

[0095] Aspect 10. The heating and cooling system of any of Aspects 7 to 9, wherein the fluid operation parameter is a condenser leaving process fluid temperature.

[0096] Aspect 11. The heating and cooling system of any of Aspects 7 to 10, wherein being higher than the acceptable range includes being greater than an active hot water setpoint.

[0097] Aspect 12. The heating and cooling system of any of Aspects 7 to 11, wherein the active hot water setpoint is predetermined by a user.

[0098] Aspect 13. A heating and cooling system, comprising:

[0099] a first heat exchanging unit operating in a heating mode, wherein the first heat exchanging unit comprises:

[0100] a first compressor, a first condenser, and a first evaporator in fluid communication with each other;

[0101] a second heat exchanging unit operating in a cooling mode, wherein the second heat exchanging unit comprises:

[0102] a second compressor, a second condenser, and a second evaporator in fluid communication with each other; and

[0103] an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and a second heat exchanging unit; and

[0104] at least one controller configured to:

[0105] unload the first compressor when a cooling load of the second heat exchanging unit decreases causing a fluid operation parameter for the first heat exchanging unit to be less than an acceptable range.

[0106] Aspect 14. The heating and cooling system of Aspect 13, wherein the at least one controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

[0107] Aspect 15. The heating and cooling system of either Aspect 13 or Aspect 14, wherein

[0108] the fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature, and

[0109] the acceptable range for the evaporator leaving process fluid temperature is a predetermined active chilled water setpoint

[0110] Aspect 16. The heating and cooling system of either of any of Aspects 13 to Aspect 15, wherein the at least one controller is further configured to:

[0111] unload the second compressor when a heating load of the first heat exchanging unit increases causing a fluid operation parameter for the second heat exchanging unit to be higher than an acceptable range.

[0112] Aspect 17. The heating and cooling system of any of Aspects 13 to 16, wherein the at least one controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system

[0113] Aspect 18. The heating and cooling system of either Aspect 16 or Aspect 17, wherein

[0114] the fluid operation parameter for the second heat exchanging unit is a condenser leaving process fluid temperature, and

[0115] the acceptable range for the condenser leaving process fluid temperature is a predetermined active hot water setpoint.

[0116] The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms “a,”“an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and / or “comprising,” when used in this specification, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and / or components.

[0117] With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure. This specification and the embodiments described are exemplary only, with the true scope and spirit of the disclosure being indicated by the claims that follow.

Examples

Embodiment Construction

[0012]In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current example embodiment. Still, the example embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configuratio...

Claims

1. A heating and cooling system, comprising:a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other;a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other;a controller configured to:operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to reject heat to a heating load via the first heat exchanging unit; andunload the first compressor when a fluid operation parameter for the first heat exchanging unit is determined to be less than an acceptable range.

2. The heating and cooling system of claim 1, wherein the controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

3. The heating and cooling system of claim 1, further comprising:an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

4. The heating and cooling system of claim 1, wherein the fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature.

5. The heating and cooling system of claim 1, wherein being less than the acceptable range includes being less than an active chilled water setpoint.

6. The heating and cooling system of claim 5, wherein the active chilled water setpoint is predetermined by a user.

7. A heating and cooling system, comprising:a first heat exchanging unit having a first compressor, first evaporator, and first condenser fluidly connected to each other;a second heat exchanging unit having a second compressor, a second evaporator, and a second condenser fluidly connected to each other;a controller configured to:operate the first heat exchanging unit and the second heat exchanging unit in a booster or cascade configuration to extract heat from a cooling load via the second heat exchanging unit; andunload the second compressor when a fluid operation parameter for the second heat exchanging unit is determined to be higher than an acceptable range.

8. The heating and cooling system of claim 7, wherein the controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

9. The heating and cooling system of claim 7, further comprising:an intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and the second heat exchanging unit.

10. The heating and cooling system of claim 7, wherein the fluid operation parameter is a condenser leaving process fluid temperature.

11. The heating and cooling system of claim 7, wherein being higher than the acceptable range includes being greater than an active hot water setpoint.

12. The heating and cooling system of claim 11, wherein the active hot water setpoint is predetermined by a user.

13. A heating and cooling system, comprising:a first heat exchanging unit operating in a heating mode, wherein the first heat exchanging unit comprises:a first compressor, a first condenser, and a first evaporator in fluid communication with each other;a second heat exchanging unit operating in a cooling mode, wherein the second heat exchanging unit comprises:a second compressor, a second condenser, and a second evaporator in fluid communication with each other; andan intermediate loop to thermally communicate thermal energy between the first heat exchanging unit and a second heat exchanging unit; andat least one controller configured to:unload the first compressor when a cooling load of the second heat exchanging unit decreases causing a fluid operation parameter for the first heat exchanging unit to be less than an acceptable range.

14. The heating and cooling system of claim 13, wherein the at least one controller is to unload the first compressor until the fluid operation parameter for the first heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

15. The heating and cooling system of claim 13, whereinthe fluid operation parameter for the first heat exchanging unit is an evaporator leaving process fluid temperature, andthe acceptable range for the evaporator leaving process fluid temperature is a predetermined active chilled water setpoint.

16. The heating and cooling system of claim 13, wherein the at least one controller is further configured to:unload the second compressor when a heating load of the first heat exchanging unit increases causing a fluid operation parameter for the second heat exchanging unit to be higher than an acceptable range.

17. The heating and cooling system of claim 16, wherein the at least one controller is to unload the second compressor until the fluid operation parameter for the second heat exchanging unit returns to the acceptable range without shutting down the heating and cooling system.

18. The heating and cooling system of claim 15, whereinthe fluid operation parameter for the second heat exchanging unit is a condenser leaving process fluid temperature, andthe acceptable range for the condenser leaving process fluid temperature is a predetermined active hot water setpoint.

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