System and method for evaporative heat exhaust device fan speed control

Abstract

A thermal management system includes a heat rejection device configured to be fluidly coupled to a refrigeration system; a fan configured to provide an incoming airflow through the heat extraction device to cool a water flow within the heat extraction device; and a controller, a controller configured to control a speed of the fan to minimize a total utility operating cost of the thermal management system based on at least two of (i) a relative humidity of the incoming airflow, (ii) a percentage of capacity in which one or more components of the refrigeration system operate, (iii) a ratio of water cost to energy cost, and (iv) a controller configured to control a speed of the fan to minimize a total utility operating cost of the thermal management system based on at least two of (i) a relative humidity of the incoming airflow, (ii) a percentage of capacity in which one or more components of the refrigeration system operate, (iii) a ratio of water cost to energy cost, and (iv) A ratio of a design power of a compressor of the refrigeration system to a design power of the fan, the total utility operating cost including (i) an energy cost for operating the fan and the refrigeration system, and (ii) a water cost of the water flow.

Description

[0001] This application is a divisional application of a Chinese invention patent application with an international application date of August 29, 2017, an international application number of PCT / US2017 / 049136, a national application number of 2017800652971, and an invention name of “System and method for fan speed control of evaporative heat rejection equipment”.

[0002] Cross-references to related patent applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 383,375, filed on September 2, 2016, and U.S. Provisional Patent Application No. 62 / 426,205, filed on November 23, 2016, both of which are incorporated herein by reference in their entirety. Background Art

[0004] The operating cost of a thermal management system with an evaporative heat rejection device generally includes the energy cost for operating the components of the thermal management system and the water cost of the water used in the evaporative heat rejection device. Traditionally, such thermal management systems are controlled based only on energy cost, ignoring water cost, resulting in increased operating cost. Summary of the invention

[0005] One embodiment relates to a thermal management system. The thermal management system includes: a heat rejection device configured to be fluidly coupled to a refrigeration system; a fan configured to provide an incoming airflow through the heat rejection device to cool a water flow within the heat rejection device; and a controller configured to control the speed of the fan to minimize a total utility operating cost of the thermal management system based on at least two of the following: (i) relative humidity of the incoming airflow, (ii) a capacity percentage at which one or more components of the refrigeration system are operating, (iii) a ratio of water cost to energy cost, and (iv) a ratio of a design power of a compressor of the refrigeration system to a design power of the fan, the total utility operating cost comprising (i) energy cost for operating the fan and the refrigeration system, and (ii) water cost of the water flow.

[0006] Another embodiment is directed to a method for fan speed control of an evaporative heat rejection device. The method includes: receiving, by processing circuitry, humidity data from a humidity sensor, the humidity data indicating a relative humidity of an incoming airflow moved through an evaporative heat rejection device by a fan; receiving, by the processing circuitry, capacity data indicating a capacity percentage at which at least one component of a refrigeration system is operating, wherein the refrigeration system is fluidly coupled to the heat rejection device; and controlling, by the processing circuitry, a speed of the fan based on: the relative humidity of the incoming airflow, and the capacity percentage at which the at least one component of the refrigeration system is operating.

[0007] Yet another embodiment relates to a thermal management system. The thermal management system includes a refrigeration system, a cooling tower, a fan, and a controller. The refrigeration system has a compressor, an evaporator, a condenser, and an expansion valve. The cooling tower is fluidly coupled to the condenser. The fan is positioned to provide an airflow through the cooling tower to cool a water flow within the cooling tower. The controller is configured to control the speed of the fan based on a relative humidity of the airflow and a capacity ratio of the condenser.

[0008] Those skilled in the art will appreciate that the summary is illustrative only and is not intended to be limiting in any way. Other aspects, inventive features, and advantages of the apparatus and / or process described herein, as limited only by the claims, will become apparent in the detailed description set forth herein and taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a perspective view of a building served by a thermal management system according to an exemplary embodiment.

[0010] Figure 2A is a more detailed description of an exemplary embodiment. Figure 1 A block diagram of a portion of a thermal management system that includes a cooling tower.

[0011] Figure 2B is a more detailed description of an exemplary embodiment. Figure 1 A block diagram of a portion of a thermal management system that includes an evaporative condenser.

[0012] Figure 3 According to an exemplary embodiment, Figure 2A and Figure 2B Block diagram of the control system of the thermal management system.

[0013] Figure 4 is a graph illustrating the speed of a fan of an evaporative heat rejection device based on humidity, according to an exemplary embodiment.

[0014] Figure 5 is a block diagram illustrating a thermal management system according to another exemplary embodiment.

[0015] Figure 6 is a flow chart of a method for evaporative heat rejection device fan speed control according to an exemplary embodiment. DETAILED DESCRIPTION

[0016] Traditionally, in order to produce the lowest chiller kilowatt per ton (kW / ton) or the lowest compressor horsepower per ton (HP / ton), the cooling tower and evaporative condenser fans are run at full speed until the minimum condensing pressure allowed by the compressor system is reached. This control scheme may not provide efficient control of the system and reduce the overall system efficiency. This control strategy may not take into account the water usage in the evaporative cooling device and is therefore not intended to reduce water usage. In addition, it will be expected by those skilled in the art that reducing the fan speed may therefore increase the compressor condensing temperature and increase the compressor heat that must be discharged, thereby resulting in an increase in the load and water usage of the evaporative cooling device.

[0017] The overall system operating cost is a function of both energy usage and water usage. Conventional control methods focus only on energy usage and ignore water costs in control decisions. In addition, these conventional control methods may not provide the lowest system energy cost (e.g., chiller / compressor energy cost and cooling tower / condenser energy cost) under all load and ambient temperature conditions. Current evaporative heat rejection fan control strategies fail to operate in the following ways: (i) to produce the lowest overall system operating cost under all load and ambient temperature conditions experienced by the system (e.g., during a year, etc.); (ii) to effectively produce the lowest evaporative heat rejection device water consumption under all load and ambient temperature conditions experienced by the system.

[0018] According to an exemplary embodiment, the evaporative heat rejection fan control scheme of the present disclosure dynamically (e.g., adaptively, etc.) adjusts the speed of the fan of the evaporative heat rejection device based on various factors to ensure that the system can do the following: (i) operate at the lowest operating cost; and (ii) reduce the water usage of the evaporative heat rejection device under all operating conditions experienced by the system (e.g., throughout the year). According to an exemplary embodiment, the dynamic evaporative cooling fan speed control scheme takes into account the following: (i) the ratio of the actual load of the condenser to the design load; and (ii) the relative humidity of the ambient air. As a result, the control scheme can reduce the total system operating cost (e.g., energy cost plus water cost) under all load and ambient temperature conditions. The control scheme can reduce the water usage of the evaporative heat rejection device by adjusting the fan speed to minimize the unprofitable sensed air cooling load imposed on the device. In some embodiments, the control scheme is further improved by combining the ratio of the chiller or compressor energy to the heat rejection device fan energy and the water cost to energy cost equivalent ratio (WECER ratio = (water $ / 1000 gallons) / ($ / kWh)).

[0019] The evaporation rate on the evaporative heat removal device can be related to the sum of the process load and the sensible air cooling load of the mass flow rate of the air as it passes through the device. If the air dry bulb temperature increases as the air passes through the evaporative heat removal device, the ratio of the evaporative rate to the process load can be reduced. Therefore, if the air dry bulb temperature decreases as the air passes through the device, the ratio of the evaporative rate to the process load can be increased. According to an exemplary embodiment, the fan speed control scheme is configured to identify temperature and load conditions that result in sensible cooling of the air as it passes through the evaporative heat removal device and then reduce the fan speed of the device to increase the process cycle temperature, thereby increasing the air outlet dry bulb temperature to minimize this unhelpful cooling of the air. The control scheme can not only save the amount of device makeup water, but also reduce the system's total utility (e.g., energy and water) operating costs by simultaneously balancing the associated increase in compressor kW with the reduction in evaporative cooling device fan energy and lower makeup water costs.

[0020] According to an exemplary embodiment, the control scheme is configured to reduce water and total utility costs by setting a maximum cooling tower fan speed based on (e.g., based on, etc.): (i) a ratio of actual condenser range to design condenser range; and (ii) relative humidity of ambient air. In some embodiments, the control scheme controls fan speed under design conditions based on additional parameters to further optimize the maximum fan speed of the heat rejection device over a wider range of equipment selections and utility rates, such as (iii) a ratio of water cost to energy cost; and (iv) a ratio of compressor to evaporative heat rejection energy.

[0021] Now refer to Figure 1 , showing a perspective view of a building 10. The building 10 is served by a thermal management system 20. The thermal management system 20 may be a refrigeration system, a heating, ventilation and air conditioning (HVAC) system, and / or another type of thermal management system 20 (e.g., a thermal management system with an evaporative heat rejection device, etc.). The thermal management system 20 is shown to include a chiller 22, a boiler 24, a cooling unit or cooling tower 26, and a plurality of air handling units (AHU) 36. The thermal management system 20 uses a fluid circulation system to provide heating and / or cooling for the building 10 and / or a desired space (e.g., a refrigerator, a freezer, etc.) within the building 10. The circulating fluid may be cooled in the chiller 22 or heated in the boiler 24, depending on whether cooling or heating is required. The boiler 24 may add heat to the circulating fluid by burning a flammable material (e.g., natural gas, etc.). The chiller 22 may place the circulating fluid in a heat exchange relationship with another fluid (e.g., a refrigerant, etc.) in a heat exchanger (e.g., an evaporator, etc.). The refrigerant may remove heat from the circulating fluid during the evaporation process, thereby cooling the circulating fluid.

[0022] The circulating fluid from the chiller 22 or boiler 24 may be delivered to the AHU 36 via a line 32. The AHU 36 may place the circulating fluid in a heat exchange relationship with an airflow passing through the AHU 36. For example, the airflow may pass through a line through which the circulating fluid flows in a fan coil unit or other air conditioning terminal unit. The AHU 36 may transfer heat between the airflow and the circulating fluid, thereby providing heating or cooling for the airflow. The heated or cooled air may be delivered to the building 10 and / or desired spaces via an air distribution system including an air supply duct 38, and may be returned to the AHU 36 via an air return duct 40. The thermal management system 20 is shown as including an independent AHU 36 on each floor of the building 10. In other embodiments, the AHU 36 is selectively positioned in a desired area (e.g., in a freezer, in a refrigerator, etc.). In other embodiments, a single AHU (e.g., a rooftop AHU) may supply air to multiple floors or areas. The circulating fluid from the AHU 36 may be returned to the chiller 22 or boiler 24 via a line 34.

[0023] In some embodiments, the refrigerant in the cooler 22 evaporates when absorbing heat from the circulating fluid. The vapor refrigerant can be provided to the compressor in the cooler 22, in which the temperature and pressure of the refrigerant are increased (e.g., using a rotary impeller, a screw compressor, a scroll compressor, a reciprocating compressor, a centrifugal compressor, etc.). The compressed refrigerant can be discharged into the condenser in the cooler 22. In some embodiments, water (or another fluid) flows through the tubes in the condenser of the cooler 22 to absorb heat from the refrigerant vapor, thereby condensing the refrigerant. The water flowing through the tubes in the condenser can be pumped from the cooler 22 to the cooling tower 26 via the pipeline 28. The cooling tower 26 can use fan-driven cooling or fan-driven evaporation to remove heat from the water. The cooling water from the cooling tower 26 can be delivered back to the cooler 22 via the pipeline 30, and the cycle repeats.

[0024] Now refer to Figure 2A , a block diagram illustrating a portion of thermal management system 20 in greater detail is shown according to an exemplary embodiment. Figure 2A , the chiller 22 is shown to include a refrigeration circuit 42. The refrigeration circuit 42 is shown to include an evaporator 46, a compressor 48, a condenser 50, and an expansion valve 52. The compressor 48 can be configured to circulate the refrigerant through the refrigeration circuit 42. In some embodiments, the compressor 48 is operated by the controller 100. The compressor 48 can compress the refrigerant to a high pressure, high temperature state and discharge the compressed refrigerant into a compressor discharge line 54 connecting the outlet of the compressor 48 to the inlet of the condenser 50. According to an exemplary embodiment, the compressor 48 is a screw compressor. In some embodiments, the compressor 48 is a screw compressor, a semi-hermetic screw compressor, a hermetic or open screw compressor, a scroll compressor, a reciprocating compressor, a centrifugal compressor, or another type of compressor.

[0025] The condenser 50 may receive a compressed refrigerant from a compressor discharge line 54. The condenser 50 may also receive a separate heat exchange fluid (e.g., water, a water-glycol mixture, another refrigerant, etc.) from a cooling circuit 56. The condenser 50 may be configured to transfer heat from the compressed refrigerant to the heat exchange fluid (e.g., water, etc.) so that the compressed refrigerant condenses from a gaseous refrigerant to a liquid or mixed fluid state. In some embodiments, the cooling circuit 56 is a heat recovery circuit configured to heat an application using heat absorbed from the refrigerant. In other embodiments, the cooling circuit 56 includes a pump 58 for circulating the heat exchange fluid between the condenser 50 and the cooling tower 26. The cooling tower 26 includes a fan 60 configured to facilitate heat transfer between the heat exchange fluid and other fluids (e.g., air) flowing through the cooling tower 26. According to an exemplary embodiment, the controller 100 is configured to control the operation of the fan 60 (e.g., its speed, etc.). The heat exchange fluid may discharge heat in the cooling tower 26 and flow back to the condenser 50 via the line 30.

[0026] Still refer to Figure 2A , the refrigeration circuit 42 is shown to include a line 62 connecting the outlet of the condenser 50 to the inlet of the expansion device 52. The expansion device 52 can be configured to expand the refrigerant in the refrigeration circuit 42 to a low temperature and low pressure state. The expansion device 52 can be a fixed position device or a variable position device (e.g., a valve). The expansion device 52 can be manually or automatically actuated (e.g., by a controller 100 via a valve actuator) to adjust the expansion of the refrigerant passing therethrough. The expansion device 52 can output the expanded refrigerant to a line 64 connecting the outlet of the expansion device 52 to the inlet of the evaporator 46.

[0027] The evaporator 46 may receive the expanded refrigerant from the line 64. The evaporator 46 may also receive a separate cooling fluid (e.g., water, a water-glycol mixture, another refrigerant, etc.) from the cooling fluid circuit 66. The evaporator 46 may be configured to transfer heat from the cooling fluid to the expanded refrigerant in the refrigeration circuit 42, thereby cooling the cooling fluid and evaporating the refrigerant. In some embodiments, the cooling fluid circuit 66 includes a pump 68 that circulates the cooling fluid between the evaporator 46 and the AHU 36. The AHU 36 may include a cooling coil 70 configured to facilitate heat transfer between the cooling fluid and other fluids (e.g., air) flowing through the AHU 36. The cooling fluid may absorb heat in the AHU 36 and flow back to the evaporator 46 via the line 34. The evaporator 46 may output the heated refrigerant to a compressor suction line 72 that connects the outlet of the evaporator 46 to the inlet of the compressor 48.

[0028] In other embodiments, a fan is used instead of the cooling fluid circuit 66 and / or an evaporative condenser (e.g., parallel flow, counterflow, crossflow, etc. evaporative condenser, etc.) is used instead of the cooling circuit 56, and the evaporative condenser has a fan and a fluid injection system (e.g., a water injection system, etc.). For example, the fan can be positioned to force airflow through or through the evaporator 46 and / or the condenser 50, respectively. The fan can be controlled by the controller 100 to adjust the heat transfer rate in the evaporator 46 and / or the condenser 50. In some embodiments, the fan is a variable speed fan capable of running at a variety of different speeds. The controller 100 can increase or decrease the speed of the fan in response to various inputs (e.g., temperature measurements, pressure measurements, etc.). As another example, the fluid injection system can be positioned to spray a fluid (e.g., water, etc.) on the condenser 50. Additionally or alternatively, a jet pump can be controlled by the controller 100 to adjust the heat transfer rate in the condenser 50. The fan, ejector pump, condenser 50 and / or evaporator 46 may thereby provide a thermally conditioned air flow (eg, cooled air, conditioned air at a temperature acceptable for refrigeration and / or freezing, etc.) directly to a desired space.

[0029] For example, as in Figure 2B As shown in FIG. 1 , a refrigeration circuit 90 may be used instead of the refrigeration circuit 42. The refrigeration circuit 90 may be used in conjunction with the refrigeration circuit 42 as shown in FIG. Figure 2A Refrigeration circuit 90 is the same or similar to the refrigeration circuit 42 described above. For example, refrigeration circuit 90 is shown to include evaporator 46, compressor 48, condenser 50, expansion device 52, compressor discharge line 54, line 62, line 64, and compressor suction line 72. Refrigeration circuit 90 may be implemented in a chiller (e.g., chiller 22) or used in various other refrigeration systems or devices, such as refrigerators, freezers, refrigerated display cases, refrigerated storage devices, product coolers, stand-alone air conditioners, or any other system or device that uses a vapor compression refrigeration cycle to provide cooling.

[0030] In the refrigeration circuit 90, the evaporator 46 is shown as absorbing heat from an airflow 92 that is forced through or across the evaporator 46 by a fan 96 (e.g., in place of the cooling fluid circuit 66, etc.). In other embodiments, the refrigeration circuit 90 does not include the fan 96, but instead includes Figure 2A of the cooling fluid circuit 66 .

[0031] As in Figure 2BAs shown in FIG. 1 , the condenser 50 is configured as an evaporative condenser having a fan 60 and a fluid injection system 130. The fluid injection system 130 includes a fluid source 132, a jet pump 134, and one or more outlets or nozzles 136. The fluid source 132 can be configured to provide and / or store fluid (e.g., water from a utility, from a collection pool below the condenser, etc.). The jet pump 134 can be configured to pump fluid from the fluid source 132 to the nozzle 136. The nozzle 136 can be positioned and / or configured to provide and / or pass the fluid injection 138 to the condenser 50. Similarly, the fan 60 can be positioned to move the airflow 94 through or through the condenser 50 (e.g., replacing the cooling circuit 56, etc.). The condenser 50 can thereby discharge heat to the airflow 94. The fluid injection 138 can further increase the heat discharged to the airflow 94 by the condenser 50. Fan 96 and / or fan 60 can be controlled by controller 100 to adjust the heat transfer rate in evaporator 46 and / or condenser 50, respectively. In some embodiments, fan 96 and / or fan 60 are variable speed fans capable of operating at a plurality of different speeds. Controller 100 can increase or decrease the speed of fan 96 and / or fan 60 in response to various inputs from refrigeration circuit 90 (e.g., temperature measurements, pressure measurements, energy costs, water costs, etc.).

[0032] like Figure 2A As shown in FIG. 1 , the cooling fluid circuit 66 includes an inlet temperature sensor 74 positioned upstream of the evaporator 46. The inlet temperature sensor 74 may be configured to measure the temperature of the fluid (e.g., cooling fluid, etc.) flowing between the pump 68 and the evaporator 46 (i.e., the temperature of the cooling fluid entering the compressor 46). Figure 2A As shown in FIG. 1 , the cooling fluid circuit 66 includes an outlet temperature sensor 76 positioned downstream of the evaporator 46. The outlet temperature sensor 76 may be configured to measure the temperature of the fluid (eg, cooling fluid, etc.) exiting the evaporator 46. Figure 2A As shown in FIG. 1 , the cooling circuit 56 includes an inlet temperature sensor 78 positioned along the pipe 30. The inlet temperature sensor 78 may be configured to measure the temperature of the fluid (e.g., water, cooling fluid, etc.) flowing in the pipe 30 between the cooling tower 26 and the condenser 50 (i.e., the temperature of the water entering the condenser 50). Figure 2A As shown in FIG. 1 , the cooling circuit 56 includes an outlet temperature sensor 80. The outlet temperature sensor 80 may be configured to measure the temperature of a fluid (eg, water, cooling fluid, etc.) exiting the condenser 50. Figure 2AAs shown in FIG. 1 , the thermal management system 20 includes a humidity sensor 82. The humidity sensor 82 may be positioned and / or configured to measure the relative humidity of the ambient air entering the cooling tower 26 (e.g., the air being moved through the cooling tower 26 by the fan 60, etc.). Figure 2B As shown in FIG. 8 , humidity sensor 82 is positioned and / or configured to measure the relative humidity of ambient air entering condenser 50 .

[0033] The controller 100 may be configured to control the operation of the fan 60 based at least in part on the measured input received from the humidity sensor 82. In addition, the controller 100 may receive measured input from at least one of the inlet temperature sensor 74, the outlet temperature sensor 76, the inlet temperature sensor 78, and / or the outlet temperature sensor 80. The controller 100 may be configured to control the operation of the compressor 48 and / or the fan 60 based at least in part on the measured input received from at least one of the following: the humidity sensor 82, the inlet temperature sensor 74, the outlet temperature sensor 76, the inlet temperature sensor 78, and the outlet temperature sensor 80. The controller may be an embedded controller for the fan 60 configured to control the operation of the fan 60. The controller 100 may be an embedded controller for the chiller 22 configured to control components of the refrigeration circuit 42. For example, the controller 100 may be configured to activate / deactivate the compressor 48 and open / close the expansion device 52. The controller 100 may be configured to determine the thermodynamic properties of the refrigerant at various locations within the refrigeration circuit 42. For example, the controller 100 may calculate non-measured thermodynamic properties (eg, enthalpy, entropy, etc.) of the refrigerant in the compressor suction line 72 , the compressor discharge line 54 , and / or other locations within the refrigeration circuit 42 .

[0034] Figure 5 2 shows a thermal management system 500 according to an exemplary embodiment. The thermal management system 500 may be similar to the thermal management system 20. Figure 5 As shown in FIG. 5 , the thermal management system 500 includes a cooling tower 510 as part of a cooling loop 530 fluidly coupled to a chiller 520. The thermal management system 500 also includes a delivery loop 540 fluidly coupled to the chiller 520 and configured for thermally conditioning a conditioned space (e.g., a room, a freezer, a refrigerator, etc.).

[0035] Now refer to Figure 3, according to an exemplary embodiment, a block diagram of a control system including a controller 100 is shown. According to an exemplary embodiment, the controller 100 is configured to selectively control the speed of the fan 60 based on at least one of the following: (i) relative humidity of the air; (ii) a capacity percentage of one or more components of the thermal management system 20 being used (e.g., a ratio of actual condenser range to designed condenser range, a ratio of actual evaporator range to designed evaporator range, a ratio of actual compressor power to designed compressor power, etc.); (iii) a ratio of water cost to energy cost; and (iv) a ratio of compressor to evaporative heat rejection energy.

[0036] like Figure 3 As shown in , the controller 100 includes a communication interface 102 and a processing circuit 104. The communication interface 102 may include a wired or wireless interface (e.g., a socket, an antenna, a transmitter, a receiver, a transceiver, a wire terminal, etc.) for data communication with various systems, devices or networks. For example, the communication interface 102 may include an Ethernet card and / or a port for sending and receiving data via an Ethernet-based communication network. In some embodiments, the communication interface 102 includes a wireless transceiver (e.g., a WiFi transceiver, a Bluetooth transceiver, a NFC transceiver, ZigBee, etc.) for communicating via a wireless communication network. The communication interface 102 can be configured to communicate via a local area network (e.g., a building LAN, etc.) and / or a wide area network (e.g., the Internet, a cellular network, a radio communication network, etc.) and various communication protocols (e.g., BACnet, TCP / IP, point-to-point, etc.) can be used.

[0037] In some embodiments, the communication interface 102 is configured to facilitate receiving measurement inputs from various sensors. The sensor may include, for example, a humidity sensor 82, an inlet temperature sensor 74, an outlet temperature sensor 76, an inlet temperature sensor 78, and / or an outlet temperature sensor 80. The communication interface 102 may receive measurement inputs from sensors directly, via a local area network, and / or via a remote communication network. The communication interface 102 may enable communication between the controller 100 and the fan 60 (and / or the fan 96). In some embodiments, the communication interface 102 is configured to facilitate transmission of speed commands to the fan 60 (and / or the fan 96). The communication interface 102 may directly, via a local area network, and / or via a remote communication network to send speed commands. Additionally or alternatively, the communication interface 102 may enable communication between the controller 100 and the cooler 22 (e.g., compressor 48, expansion valve 52, etc.). In some embodiments, the communication interface 102 may be configured to facilitate transmission of load and unload commands to the compressor 48 of the cooler 22. The communication interface 102 can send load and / or unload commands directly, via a local area network, and / or via a remote communication network. Additionally or alternatively, the communication interface 102 can enable communication between the controller 100 and a utility 200 (e.g., an energy company, a water company, etc.). The communication interface 102 can receive information (e.g., current energy costs, current water costs, etc.) from the utility 200 directly, via a local area network, and / or a remote communication network.

[0038] like Figure 3 As shown, the processing circuit 104 includes a processor 106 and a memory 108. The processor 106 can be a general or special processor, an application-specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGA), a group of processing components, or other suitable processing components. The processor 106 can be configured to execute computer codes or instructions stored in the memory 108 (e.g., fuzzy logic, etc.) or received from other computer-readable media (e.g., CDROM, network storage device, remote server, etc.) to perform one or more processes described herein.

[0039] The memory 108 may include one or more data storage devices (e.g., memory cells, memory devices, computer-readable storage media, etc.) configured to store data, computer code, executable instructions, or other forms of computer-readable information. The memory 108 may include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical storage, or any other suitable memory for storing software objects and / or computer instructions. The memory 108 may include a database component, an object code component, a script component, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. The memory 108 may be communicatively connected to the processor 106 via the processing circuit 104 and may include computer code for executing (e.g., by the processor 106) one or more processes described herein.

[0040] The memory 108 may include various modules for completing the processes described herein. More specifically, as shown in Figure 3 As shown in , the memory 108 includes a temperature module 110, a humidity module 112, a fan module 114, a utility module 118, and / or a chiller / compressor module 120. It should be understood that the controller 100 and the memory 108 may include any number of modules for performing the functions described herein. For example, the activities of multiple modules may be combined into a single module, and additional modules with additional functions may be included. Further, it should be understood that the controller 100 may further control other processes beyond the scope of this disclosure.

[0041] The temperature module 110 can be configured to receive and / or interpret temperature data indicating the temperature of the cooling fluid (e.g., water, etc.) flowing from the temperature sensors 78 and 80 into the condenser 50 and / or the cooling tower 26 and / or out of the condenser and / or the cooling tower. Additionally or alternatively, the temperature module 110 can be configured to receive and / or interpret temperature data indicating the temperature of the cooling fluid flowing from the temperature sensors 74 and 76 into the evaporator 46 and / or out of the evaporator. The humidity module 112 can be configured to receive and / or interpret humidity data indicating the temperature of the cooling fluid (e.g., water, etc.) flowing from the humidity sensor 82 into the cooling tower 26 and / or the condenser 50 (e.g., Figure 2B The utility module 118 may be configured to receive and / or interpret utility data indicating the current cost of energy (eg, electricity, etc.) and / or water from the utility 200.

[0042] The chiller / compressor module 120 can be configured to: determine the current or actual load and / or range of one or more components of the chiller 22 (e.g., condenser 50, evaporator 46, compressor 48, chiller 22 as a whole, etc.); determine the capacity percentage at which one or more components of the chiller 22 can currently operate. In some embodiments, the chiller / compressor module 120 is configured to determine the current load or range of the condenser 50 based on the temperature of the cooling fluid (e.g., water, etc.) flowing through the condenser 50. For example, the actual or current condenser load / range can be determined based on the temperature of the cooling fluid measured by the inlet temperature sensor 78 and / or the outlet temperature sensor 80, respectively. In other embodiments, the chiller / compressor module 120 is configured to determine the current load or range of the condenser 50 based on additional or alternative factors and / or measurements. The chiller / compressor module 120 can be further configured to receive and store the design load and / or range of the condenser 50. The chiller / compressor module 120 may compare the actual load / range to the design load / range to determine a ratio of the actual load / range to the design load / range of the condenser 50 (eg, a percentage of the design load / range, a percentage of capacity, etc.).

[0043] In other embodiments, in addition or alternatively, the chiller / compressor module 120 is configured to determine the current load or range of the evaporator 46 (e.g., based on the temperature of the cooling fluid flowing through the evaporator 46, etc.). For example, the actual or current evaporator load / range can be determined based on the temperature of the cooling fluid measured by the inlet temperature sensor 74 and / or the outlet temperature sensor 76 located at the inlet and outlet of the evaporator 46, respectively. The chiller / compressor module 120 can be further configured to receive and store the design load and / or range of the evaporator 46. The chiller / compressor module 120 can compare the actual load / range with the design load / range to determine the ratio of the actual load / range of the evaporator 46 to the design load / range (e.g., a percentage of the design load / range, a percentage of capacity, etc.).

[0044] In other embodiments, additionally or alternatively, the chiller / compressor module 120 is configured to determine the current load or range of the chiller 22 as a whole. The chiller / compressor module 120 may be further configured to receive and store the design load and / or range of the chiller 22. The chiller / compressor module 120 may compare the actual load / range with the design load / range to determine a ratio of the actual load / range of the chiller 22 to the design load / range (e.g., a percentage of the design load / range, a percentage of capacity, etc.).

[0045] The fan module 114 can be configured to control the operation of the fan 60 (e.g., its speed, etc.) based on: (i) the capacity percentage of one or more components of the cooler 22 (e.g., the ratio of the actual load / range of the evaporator 46, the condenser 50, the cooler 22 to the designed load / range, etc.); and / or (ii) the relative humidity of the air. For example, the more humid the air, the faster the fan 60 can run. As another example, the less humid the air, the slower the fan 60 can run. Now referring to Figure 4 , according to an exemplary embodiment, a graph 400 is shown showing the speed of the fan 60 based on relative humidity as a percentage of the design load / range of the condenser 50 (ie, the ratio of the actual load / range to the design load / range). Figure 4 As shown in , a conventional control scheme for fan 60 as indicated by curve 440 includes setting the speed of fan 60 at maximum speed (100%) until the desired conditions are met. However, this may result in very inefficient operation of thermal management system 20 .

[0046] Variable control of the speed of the fan 60 can significantly reduce the energy required for operation, since the energy consumed by the fan 60 is proportional to the cube of the speed. Figure 4 As shown in , the controller 100 is configured to vary the speed of the fan 60 based on the relative humidity and the percentage of the design load / range of the condenser 50, as indicated by curves 410, 420, and 430. Curve 410 depicts the speed of the fan 60 at various percentages of the design range of the condenser 50 at a relative humidity of 20%. Curve 420 depicts the speed of the fan 60 at various percentages of the design range of the condenser 50 at a relative humidity of 60%. Curve 430 depicts the speed of the fan 60 at various percentages of the design range of the condenser 50 at a relative humidity of 100%. As indicated by curves 410, 420, and 430, the controller 100 is configured to increase the speed of the fan 60 as the relative humidity increases for each corresponding percentage of the design range of the condenser 50. For example, when the condenser 50 is operating at 80% of its design range, the controller 100 can be configured to: operate the fan 60 at 60% of the maximum speed when the relative humidity is at 20%; operate the fan at 75% of the maximum speed when the relative humidity is at 60%; and operate the fan at 92% of the maximum speed when the relative humidity is 100%. Thus, under even extreme conditions, the speed of the fan 60 can be operated at less than 100% while still providing adequate cooling to the cooling tower 26 and / or the condenser 50 (e.g., Figure 2B The required cooling can be provided by an evaporative condenser, etc., thereby reducing the operating cost of the thermal management system 20.

[0047] Additionally or alternatively, the fan module 114 can be configured to control the operation of the fan 60 (e.g., its speed, etc.) based on a ratio of water cost to energy cost. For example, the fan module 114 can be configured to analyze the cost of water and energy provided by the utility 200 when controlling the speed of the fan 60. For example, in the event that the cost of water increases, the fan module 114 can be configured to speed up the fan 60 and / or reduce the amount of water supplied (e.g., supplied to the cooling tower 26 via the pump 58, supplied to the condenser 50 via the jet pump 134, etc.) to save more water (e.g., reduce the amount of water required for operation, etc.). In another example, in the event that the cost of water decreases, the fan module 114 can be configured to control the speed of the fan 60 (e.g., reduce the fan speed and increase the water supply, etc.) to optimize energy consumption. Thus, the controller 100 can be configured to control the operation of the fan 60 and the thermal management system 20 as a whole, not optimizing energy efficiency alone to reduce energy costs, but rather optimizing the total operating cost of the thermal management system 20, the total operating cost comprising both: (i) electricity costs (e.g., usage and efficiency of components of the thermal management system 20, etc.), and (ii) water costs (e.g., amount of water used, etc.), while operating the fan 60 at a speed capable of cooling the water within the cooling tower 26 to a temperature required to cool the refrigerant flowing through the condenser 50 (or operating the fan 60 and / or the jet pump 134 at a speed capable of cooling the refrigerant simultaneously) to meet the load conditions on the thermal management system 20.

[0048] Additionally or alternatively, the fan module 114 may be configured to control the operation of the fan 60 (e.g., its speed, etc.) based on a ratio of compressor energy and / or power (e.g., the design energy and / or power of the compressor 48, etc.) to evaporative heat rejection energy and / or power (e.g., the design energy and / or power of the fan 60, etc.). For example, the fan module 114 may be configured to receive information about the design energy and / or power of the compressor 48 and the design energy and / or power of the fan 60 (e.g., predefined within the controller 100, input by an operator of the thermal management system 20, etc.), and thereby be configured to determine a ratio between the design energy and / or power of the compressor 48 and the design energy and / or power of the fan 60. Based on the speed of the fan 60, a lower ratio between the design energy and / or power of the compressor 48 and the design energy and / or power of the fan 60 may have a greater impact on the overall energy usage of the thermal management system 20.

[0049] Now refer to Figure 6 , according to an exemplary embodiment, a method 600 for fan speed control of an evaporative heat rejection device is shown. In an exemplary embodiment, the method 600 may be used Figures 1 to 3 The thermal management system 20 and the controller 100 and / or Figure 5The thermal management system 500 is implemented. Figures 1 to 3 and / or Figure 5 Method 600 is described below.

[0050] At step 602, a controller (e.g., controller 100, etc.) of a thermal management system (e.g., thermal management system 20, etc.) is configured to receive humidity data (e.g., from humidity sensor 82, etc.) indicating the relative humidity of an airflow moved by a fan (e.g., fan 60, etc.) through an evaporative heat removal device (e.g., cooling tower 26, condenser 50, etc.). At step 604, the controller is configured to receive temperature data (e.g., from inlet temperature sensor 74, outlet temperature sensor 76, inlet temperature sensor 78, outlet temperature sensor 80, etc.) indicating the inlet temperature and outlet temperature of a cooling fluid (e.g., within cooling fluid circuit 66, etc.) and a cooling fluid (e.g., water within cooling circuit 56, etc.) flowing through an evaporator (e.g., evaporator 46, etc.) and / or a condenser (e.g., condenser 50, etc.) of a cooler (e.g., cooler 22, etc.), respectively. At step 606, the controller is configured to determine a current range of the evaporator and / or condenser based on the temperature data. In other embodiments, additionally or alternatively, the controller is configured to determine the current range and / or capacity of the chiller system (e.g., chiller 22, compressor 48, etc.). At step 608, the controller is configured to determine a condenser range ratio (e.g., percentage capacity, etc.) of the condenser based on the current range and design range of the condenser. In some embodiments, additionally or alternatively, the controller is configured to determine an evaporator range ratio (e.g., percentage capacity, etc.) of the evaporator based on the current range and design range of the evaporator. In some embodiments, additionally or alternatively, the controller is configured to determine a chiller range ratio (e.g., percentage capacity, etc.) of the chiller based on the current power and design power of the chiller.

[0051] At step 610, the controller is configured to receive utility data indicating the current cost of energy (e.g., electricity, etc.) and water. At step 612, the controller is configured to determine the water cost to energy cost ratio based on the utility data. In some embodiments, steps 610 and 612 are optional. At step 614, the controller may be configured to receive information about the design power of the compressor (e.g., compressor 48, etc.) of the cooler and the design power of the fan. At step 616, the controller is configured to determine the compressor design power to fan design power ratio based on the design power of the compressor and the design power of the fan. In some embodiments, steps 614 and 616 are optional. At step 618, the controller is configured to control the speed of the fan based on: (i) relative humidity of the airflow; (ii) percentage capacity of one or more components of the thermal management system (e.g., condenser range ratio, evaporator range ratio, cooler power ratio, etc.); (iii) water cost to energy cost ratio; and / or (iv) compressor design power to fan design power ratio.

[0052] The construction and arrangement of the system and method as shown in each exemplary embodiment are only illustrative. Although only several embodiments are described in detail in this disclosure, many modifications are possible (for example, the size, dimensions, structure, shape and ratio of various elements, the value of parameters, installation arrangement, the use of materials, color, orientation, etc. change). For example, the position of the element can be reversed or otherwise changed, and the property or quantity or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of this disclosure. The order or sequence of any process or method step can be changed or reordered according to alternative embodiments. Without departing from the scope of this disclosure, other substitutions, modifications, changes, and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments.

[0053] The present disclosure contemplates methods, systems, and program products on any machine-readable medium for performing various operations. Embodiments of the present disclosure may be implemented using an existing computer processor or by a dedicated computer processor in combination with an appropriate system for this or another purpose or by a hard-wired system. Embodiments within the scope of the present disclosure include program products, which include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media may be any available medium that can be accessed by a general-purpose or special-purpose computer or other machine with a processor. For example, such machine-readable media may include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, etc., or any other medium that can be used to carry or store desired program codes in the form of machine-executable instructions or data structures and can be accessed by a general-purpose or special-purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data that cause a general-purpose computer, a special-purpose computer, or a special-purpose processing machine to perform a certain function or group of functions.

[0054] Although the drawings show a specific order of method steps, the order of steps may be different from the order depicted. Two or more steps may also be performed simultaneously or partially simultaneously. Such variations will depend on the selected software and hardware systems and the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementation methods may be implemented with standard programming techniques having rule-based logic and other logic for implementing various connection steps, processing steps, comparison steps, and decision steps.

Claims

1. A thermal management system, comprising: a heat rejection device fluidly coupled to the refrigeration system; a fan configured to move airflow through the heat removal device to cool the water flow within the heat removal device; as well as A controller, the controller being configured to: determining a fan speed control curve based on the relative humidity of the airflow entering the heat rejection device, wherein the fan speed control curve depicts the speed of the fan at various percentages of a design range for the heat rejection device at the relative humidity; controlling the speed of the fan according to the fan speed control curve based on the capacity percentage of the heat removal device to control the performance of the heat removal device; as well as The speed of the fan is further controlled based on a ratio of water cost to energy cost or a ratio of a design power of the compressor of the refrigeration system to a design power of the fan to manage the overall utility operating cost of the thermal management system.

2. The thermal management system according to claim 1, wherein: The refrigeration system includes the compressor, an evaporator, a condenser, and an expansion valve.

3. The thermal management system according to claim 2, wherein: The heat rejection device is fluidly coupled to the condenser.

4. The thermal management system of claim 3, wherein: The heat removal device includes a cooling tower.

5. The thermal management system of claim 2, wherein: The heat rejection device is the condenser.

6. The thermal management system of claim 5, wherein: The condenser comprises an evaporative condenser.

7. The thermal management system of claim 2, comprising one or more temperature sensors configured to acquire temperature data indicative of an inlet temperature and an outlet temperature of a fluid flowing through the evaporator, the condenser, or both the evaporator and the condenser.

8. The thermal management system of claim 7, wherein: The controller is configured to: receiving the temperature data from the one or more temperature sensors; determining a current capacity of the condenser based on the temperature data; and A capacity percentage of the condenser is determined based on the current capacity and a corresponding design capacity of the condenser.

9. The thermal management system of claim 1, comprising a humidity sensor configured to acquire humidity data indicative of the relative humidity of the airflow entering the heat rejection device, wherein: The controller is configured to: receiving the humidity data from the humidity sensor; and The relative humidity of the airflow entering the heat rejection device is determined based on the humidity data.

10. The thermal management system of claim 1, wherein: The controller is configured to: receiving utility data indicating current costs of energy and water; and The ratio of water cost to energy cost is determined based on the utility data.

11. A method comprising: receiving, by the processing circuit, feedback from a humidity sensor indicating relative humidity of an airflow driven by the fan and entering a heat rejection device; determining, by the processing circuit, a fan speed control curve based on the relative humidity of the airflow entering the heat rejection device, wherein the fan speed control curve depicts the speed of the fan at various percentages of a design range of the heat rejection device at the relative humidity; receiving, by the processing circuit, capacity data indicating a capacity percentage of the heat rejection device of a refrigeration system, wherein the refrigeration system is fluidly coupled to the heat rejection device; as well as The speed of the fan is controlled by the processing circuit according to the fan speed control curve and based on the capacity percentage of the heat rejection device of the refrigeration system to control the performance of the heat rejection device.

12. The method of claim 11, wherein: The refrigeration system includes a compressor, an evaporator, a condenser, and an expansion valve.

13. The method of claim 12, wherein: The heat removal device is the condenser, and wherein the condenser comprises an evaporative condenser with the fan and fluid injection system.

14. The method of claim 12, wherein: The heat rejection device includes a cooling tower, and wherein the cooling tower is fluidly coupled to the condenser of the refrigeration system.

15. The method of claim 14, wherein: Receiving the capacity data includes: receiving, by the processing circuit, additional feedback from a temperature sensor, wherein the additional feedback is indicative of an inlet temperature and an outlet temperature of a cooling fluid flowing through the condenser; determining, by the processing circuit, a current temperature range of the condenser based on the additional feedback; determining, by the processing circuit, a condenser temperature range ratio of the condenser based on the current temperature range and a design temperature range of the condenser; and The speed of the fan is controlled by the processing circuit based on the condenser temperature range ratio.

16. The method of claim 12, further comprising: receiving, by the processing circuit, utility data indicative of current water costs and current energy costs; determining, by the processing circuitry, a ratio of water cost to energy cost based on the utility data; and The speed of the fan is controlled by the processing circuit based on the ratio of water cost to energy cost.

17. A thermal management system comprising: a refrigeration system having a compressor, an evaporator, a condenser, and an expansion valve fluidly coupled to one another by one or more conduits; a cooling tower fluidly coupled to the condenser; a fan configured to move an airflow through the cooling tower to cool a water flow within the cooling tower; as well as A controller, the controller being configured to: determining a fan speed control curve based on the relative humidity of the airflow entering the cooling tower, wherein the fan speed control curve depicts the speed of the fan at various percentages of a design range for the condenser at the relative humidity; and The speed of the fan is controlled according to the fan speed control curve and based on the capacity ratio of the condenser to control the performance of the cooling tower.

18. The thermal management system of claim 17, comprising one or more temperature sensors configured to acquire temperature data indicative of an inlet temperature and an outlet temperature of the water flowing from the cooling tower through the condenser, wherein The controller is configured to: receiving the temperature data from the one or more temperature sensors; determining a current capacity of the condenser based on the temperature data; and The capacity ratio of the condenser is determined based on the current capacity of the condenser and its design capacity.

19. The thermal management system of claim 17, comprising a humidity sensor configured to acquire humidity data indicative of the relative humidity of the airflow, wherein: The controller is configured to: receiving the humidity data from the humidity sensor; and The relative humidity of the airflow entering the cooling tower is determined based on the humidity data.

20. The thermal management system of claim 17, wherein: The controller is configured to: receiving utility data indicating current water costs and current energy costs; determining a water cost to energy cost ratio based on the utility data; and The speed of the fan is further controlled based on the water cost to energy cost ratio.

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