Patent Application
20250102172
This application claims the benefit of and priority to Singaporean patent application number 10202302705R, filed Sep. 25, 2023, the entire disclosure of which is incorporated by reference herein.
The present disclosure relates generally to building management systems. The present disclosure relates more particularly to determining the efficiency of a chiller and adjusting the operation of a chiller to improve overall performance. A building management system (BMS) is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BMS can include, for example, a HVAC system, a security system, a lighting system, a fire alerting system, any other system that is capable of managing building functions or devices, or any combination thereof.
One implementation of the present disclosure is a system. The system includes one or more processors and one or more non-transitory computer-readable media storing instructions that, when executed by the one or more processors, cause at least one of the processors to perform operations. The operations include determining whether a first sensor is available at a chiller, the first sensor comprising a temperature sensor or a pressure sensor of the chiller. Responsive to determining that the first sensor is available, the operations include determining a plurality of enthalpy points by executing first logic that uses a measurement from the first sensor. Responsive to determining that the first sensor is unavailable, the operations include automatically switching from the first logic to second logic to compensate for unavailability to the first sensor and determining the plurality of enthalpy points using the second logic. The operations include determining an efficiency of the chiller based on the plurality of enthalpy points and affecting an operation of the chiller based on the efficiency.
Another implementation of the present disclosure is a system. The system includes one or more processors and one or more non-transitory computer-readable media storing instructions that, when executed by the one or more processors, cause the processors to perform operations. The operations include determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller, in response to determining that a first sensor of the plurality of temperature sensors and the plurality of pressure sensors is unavailable, determining an estimated value for the first sensor based on measurements from available sensors of the plurality of temperature sensors and the plurality of pressure sensors, determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors, and determining an efficiency of the chiller based on the plurality of enthalpy points.
In some embodiments, determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller includes checking that a measurement from the first sensor was obtained from the plurality of temperature sensors and the plurality of pressure sensors. In some embodiments, the determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller further includes checking that the obtained measurement of the first sensor is within a preset threshold.
In some embodiments, determining an estimated value for the first sensor based on measurements from available sensors of the plurality of temperature sensors and the plurality of pressure sensors includes estimating the value for the first sensor based on a modelled relationship between the available sensors and the first sensor.
In some embodiments, determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors includes calculating the enthalpy points using a modelled relationship between temperature, pressure, and the enthalpy points.
In some embodiments, determining an efficiency of the chiller based on the plurality of enthalpy points includes calculating a coefficient of performance.
In some embodiments, the plurality of temperature sensors and the plurality of pressure sensors are preinstalled sensors located along a refrigeration circuit of the chiller.
In some embodiments, the operation further includes converting the measurement from the first sensor and the measurements from the available sensors into standard units. In some embodiments, the operation further includes obtaining an operation code from the chiller, wherein the operation code indicates that the chiller is operating. In some embodiments, the operation further includes obtaining a plurality of operation codes from the chiller at various time points.
Another implementation of the present disclosure is a method. The method includes determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller, in response to determining that a first sensor of the plurality of temperature sensors and the plurality of pressure sensors is unavailable, determining an estimated value for the first sensor based on measurements from available sensors of the plurality of temperature sensors and the plurality of pressure sensors, determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors, and determining an efficiency of the chiller based on the plurality of enthalpy points.
In some embodiments, determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller includes checking that a measurement from the first sensor was obtained from the plurality of temperature sensors and the plurality of pressure sensors. In some embodiments, the determining whether a plurality of temperature sensors and a plurality of pressure sensors are available at a chiller further includes checking that the obtained measurement of the first sensor is within a preset threshold.
In some embodiments, determining an estimated value for the first sensor based on measurements from available sensors of the plurality of temperature sensors and the plurality of pressure sensors includes estimating the value for the first sensor based on a modelled relationship between the available sensors and the first sensor.
In some embodiments, determining a plurality of enthalpy points using the estimated value for the first sensor and the measurements from the available sensors includes calculating the enthalpy points using a modelled relationship between temperature, pressure, and the enthalpy points.
In some embodiments, determining an efficiency of the chiller based on the plurality of enthalpy points includes calculating a coefficient of performance.
In some embodiments, the plurality of temperature sensors and the plurality of pressure sensors are preinstalled sensors located along a refrigeration circuit of the chiller.
In some embodiments, the operation further includes converting the measurement from the first sensor and the measurements from the available sensors into standard units. In some embodiments, the operation further includes obtaining an operation code from the chiller, wherein the operation code indicates that the chiller is operating. In some embodiments, the operation further includes obtaining a plurality of operation codes from the chiller at various time points.
Another implementation of the present disclosure is a method. The method includes determining available sensors and unavailable sensor types for a unit of building equipment, automatically selecting logic from a set of available logic based on the available sensors and the unavailable sensor types for the unit of building equipment, determining an efficiency of the unit of building equipment using the logic and measurements from the available sensors, and affecting an operation of the unit of building equipment based on the efficiency.
Other aspects, inventive features, and advantages of the devices and/or processes described herein, as defined solely by the claims, will become apparent in the detailed description set forth herein and taken in conjunction with the accompanying drawings.
Following below are detailed descriptions of various concepts related to, and implementations of systems, methods, and apparatuses for, a chiller efficiency monitoring system for connected equipment. The chiller efficiency monitoring system includes a system that allows for adjustments to chiller operation in response to the calculated chiller efficiency. Determining the chiller efficiency can be done by installing multiple meters at a chiller, but such meters add complexity, time, and costs to the chiller installation and manufacturing. Furthermore, existing chillers often do not have the necessary meters to determine chiller efficiency. Accordingly, technical limitations of chillers make it difficult to directly measure the consumption and output of a chiller to determine chiller efficiency. Meanwhile, energy consumption by building equipment such as chillers makes up a large fraction of energy consumption attributable to an enterprise, as well as to the world's energy consumption. As such, determination, monitoring, and management of chiller efficiency values according to the teachings herein addresses a technical challenge associated with lack of appropriate physical metering in support of technical goals relating to energy management and associated benefits (e.g., emissions reductions, waste reduction, etc.).
Referring now to
Referring particularly to
The BMS that serves building 10 includes an HVAC system 100. HVAC system 100 can include a plurality of HVAC devices (e.g., heaters, chillers, air handling units, pumps, fans, thermal energy storage, etc.) configured to provide heating, cooling, ventilation, or other services for building 10. For example, HVAC system 100 is shown to include a waterside system 120 and an airside system 130. Waterside system 120 may provide a heated or chilled fluid to an air handling unit of airside system 130. Airside system 130 may use the heated or chilled fluid to heat or cool an airflow provided to building 10. An exemplary waterside system and airside system which can be used in HVAC system 100 are described in greater detail with reference to
HVAC system 100 is shown to include a chiller 102, a boiler 104, and a rooftop air handling unit (AHU) 106. Waterside system 120 may use boiler 104 and chiller 102 to heat or cool a working fluid (e.g., water, glycol, etc.) and may circulate the working fluid to AHU 106. In various embodiments, the HVAC devices of waterside system 120 can be located in or around building 10 (as shown in
AHU 106 may place the working fluid in a heat exchange relationship with an airflow passing through AHU 106 (e.g., via one or more stages of cooling coils and/or heating coils). The airflow can be, for example, outside air, return air from within building 10, or a combination of both. AHU 106 may transfer heat between the airflow and the working fluid to provide heating or cooling for the airflow. For example, AHU 106 can include one or more fans or blowers configured to pass the airflow over or through a heat exchanger containing the working fluid. The working fluid may then return to chiller 102 or boiler 104 via piping 110.
Airside system 130 may deliver the airflow supplied by AHU 106 (i.e., the supply airflow) to building 10 via air supply ducts 112 and may provide return air from building 10 to AHU 106 via air return ducts 114. In some embodiments, airside system 130 includes multiple variable air volume (VAV) units 116. For example, airside system 130 is shown to include a separate VAV unit 116 on each floor or zone of building 10. VAV units 116 can include dampers or other flow control elements that can be operated to control an amount of the supply airflow provided to individual zones of building 10. In other embodiments, airside system 130 delivers the supply airflow into one or more zones of building 10 (e.g., via supply ducts 112) without using intermediate VAV units 116 or other flow control elements. AHU 106 can include various sensors (e.g., temperature sensors, pressure sensors, etc.) configured to measure attributes of the supply airflow. AHU 106 may receive input from sensors located within AHU 106 and/or within the building zone and may adjust the flow rate, temperature, or other attributes of the supply airflow through AHU 106 to achieve setpoint conditions for the building zone.
Referring now to
In
Hot water loop 214 and cold water loop 216 may deliver the heated and/or chilled water to air handlers located on the rooftop of building 10 (e.g., AHU 106) or to individual floors or zones of building 10 (e.g., VAV units 116). The air handlers push air past heat exchangers (e.g., heating coils or cooling coils) through which the water flows to provide heating or cooling for the air. The heated or cooled air can be delivered to individual zones of building 10 to serve thermal energy loads of building 10. The water then returns to subplants 202-212 to receive further heating or cooling.
Although subplants 202-212 are shown and described as heating and cooling water for circulation to a building, it is understood that any other type of working fluid (e.g., glycol, CO2, etc.) can be used in place of or in addition to water to serve thermal energy loads. In other embodiments, subplants 202-212 may provide heating and/or cooling directly to the building or campus without requiring an intermediate heat transfer fluid. These and other variations to waterside system 200 are within the teachings of the present invention.
Each of subplants 202-212 can include a variety of equipment configured to facilitate the functions of the subplant. For example, heater subplant 202 is shown to include a plurality of heating elements 220 (e.g., boilers, electric heaters, etc.) configured to add heat to the hot water in hot water loop 214. Heater subplant 202 is also shown to include several pumps 222 and 224 configured to circulate the hot water in hot water loop 214 and to control the flow rate of the hot water through individual heating elements 220. Chiller subplant 206 is shown to include a plurality of chillers 232 configured to remove heat from the cold water in cold water loop 216. Chiller subplant 206 is also shown to include several pumps 234 and 236 configured to circulate the cold water in cold water loop 216 and to control the flow rate of the cold water through individual chillers 232.
Heat recovery chiller subplant 204 is shown to include a plurality of heat recovery heat exchangers 226 (e.g., refrigeration circuits) configured to transfer heat from cold water loop 216 to hot water loop 214. Heat recovery chiller subplant 204 is also shown to include several pumps 228 and 230 configured to circulate the hot water and/or cold water through heat recovery heat exchangers 226 and to control the flow rate of the water through individual heat recovery heat exchangers 226. Cooling tower subplant 208 is shown to include a plurality of cooling towers 238 configured to remove heat from the condenser water in condenser water loop 218. Cooling tower subplant 208 is also shown to include several pumps 240 configured to circulate the condenser water in condenser water loop 218 and to control the flow rate of the condenser water through individual cooling towers 238.
Hot TES subplant 210 is shown to include a hot TES tank 242 configured to store the hot water for later use. Hot TES subplant 210 may also include one or more pumps or valves configured to control the flow rate of the hot water into or out of hot TES tank 242. Cold TES subplant 212 is shown to include cold TES tanks 244 configured to store the cold water for later use. Cold TES subplant 212 may also include one or more pumps or valves configured to control the flow rate of the cold water into or out of cold TES tanks 244.
In some embodiments, one or more of the pumps in waterside system 200 (e.g., pumps 222, 224, 228, 230, 234, 236, and/or 240) or pipelines in waterside system 200 include an isolation valve associated therewith. Isolation valves can be integrated with the pumps or positioned upstream or downstream of the pumps to control the fluid flows in waterside system 200. In various embodiments, waterside system 200 can include more, fewer, or different types of devices and/or subplants based on the particular configuration of waterside system 200 and the types of loads served by waterside system 200.
Referring now to
In
Each of dampers 316-320 can be operated by an actuator. For example, exhaust air damper 316 can be operated by actuator 324, mixing damper 318 can be operated by actuator 326, and outside air damper 320 can be operated by actuator 328. Actuators 324-328 may communicate with an AHU controller 330 via a communications link 332. Actuators 324-328 may receive control signals from AHU controller 330 and may provide feedback signals to AHU controller 330. Feedback signals can include, for example, an indication of a current actuator or damper position, an amount of torque or force exerted by the actuator, diagnostic information (e.g., results of diagnostic tests performed by actuators 324-328), status information, commissioning information, configuration settings, calibration data, and/or other types of information or data that can be collected, stored, or used by actuators 324-328. AHU controller 330 can be an economizer controller configured to use one or more control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control actuators 324-328.
Still referring to
Cooling coil 334 may receive a chilled fluid from waterside system 200 (e.g., from cold water loop 216) via piping 342 and may return the chilled fluid to waterside system 200 via piping 344. Valve 346 can be positioned along piping 342 or piping 344 to control a flow rate of the chilled fluid through cooling coil 334. In some embodiments, cooling coil 334 includes multiple stages of cooling coils that can be independently activated and deactivated (e.g., by AHU controller 330, by BMS controller 366, etc.) to modulate an amount of cooling applied to supply air 310.
Heating coil 336 may receive a heated fluid from waterside system 200 (e.g., from hot water loop 214) via piping 348 and may return the heated fluid to waterside system 200 via piping 350. Valve 352 can be positioned along piping 348 or piping 350 to control a flow rate of the heated fluid through heating coil 336. In some embodiments, heating coil 336 includes multiple stages of heating coils that can be independently activated and deactivated (e.g., by AHU controller 330, by BMS controller 366, etc.) to modulate an amount of heating applied to supply air 310.
Each of valves 346 and 352 can be controlled by an actuator. For example, valve 346 can be controlled by actuator 354 and valve 352 can be controlled by actuator 356. Actuators 354-356 may communicate with AHU controller 330 via communications links 358-360. Actuators 354-356 may receive control signals from AHU controller 330 and may provide feedback signals to controller 330. In some embodiments, AHU controller 330 receives a measurement of the supply air temperature from a temperature sensor 362 positioned in supply air duct 312 (e.g., downstream of cooling coil 334 and/or heating coil 336). AHU controller 330 may also receive a measurement of the temperature of building zone 306 from a temperature sensor 364 located in building zone 306.
In some embodiments, AHU controller 330 operates valves 346 and 352 via actuators 354-356 to modulate an amount of heating or cooling provided to supply air 310 (e.g., to achieve a setpoint temperature for supply air 310 or to maintain the temperature of supply air 310 within a setpoint temperature range). The positions of valves 346 and 352 affect the amount of heating or cooling provided to supply air 310 by cooling coil 334 or heating coil 336 and may correlate with the amount of energy consumed to achieve a desired supply air temperature. AHU 330 may control the temperature of supply air 310 and/or building zone 306 by activating or deactivating coils 334-336, adjusting a speed of fan 338, or a combination of both.
Still referring to
In some embodiments, AHU controller 330 receives information from BMS controller 366 (e.g., commands, setpoints, operating boundaries, etc.) and provides information to BMS controller 366 (e.g., temperature measurements, valve or actuator positions, operating statuses, diagnostics, etc.). For example, AHU controller 330 may provide BMS controller 366 with temperature measurements from temperature sensors 362-364, equipment on/off states, equipment operating capacities, and/or any other information that can be used by BMS controller 366 to monitor or control a variable state or condition within building zone 306.
Client device 368 can include one or more human-machine interfaces or client interfaces (e.g., graphical user interfaces, reporting interfaces, text-based computer interfaces, client-facing web services, web servers that provide pages to web clients, etc.) for controlling, viewing, or otherwise interacting with HVAC system 100, its subsystems, and/or devices. Client device 368 can be a computer workstation, a client terminal, a remote or local interface, or any other type of user interface device. Client device 368 can be a stationary terminal or a mobile device. For example, client device 368 can be a desktop computer, a computer server with a user interface, a laptop computer, a tablet, a smartphone, a PDA, or any other type of mobile or non-mobile device. Client device 368 may communicate with BMS controller 366 and/or AHU controller 330 via communications link 372.
Referring now to
Each of building subsystems 428 can include any number of devices, controllers, and connections for completing its individual functions and control activities. HVAC subsystem 440 can include many of the same components as HVAC system 100, as described with reference to
Still referring to
Communications interfaces 407 and/or BMS interface 409 can be or include wired or wireless communications interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications with building subsystems 428 or other external systems or devices. In various embodiments, communications via communications interfaces 407 and/or BMS interface 409 can be direct (e.g., local wired or wireless communications) or via a communications network 446 (e.g., a WAN, the Internet, a cellular network, etc.). For example, communications interfaces 407 and/or BMS interface 409 can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications link or network. In another example, communications interfaces 407 and/or
BMS interface 409 can include a Wi-Fi transceiver for communicating via a wireless communications network. In another example, one or both of communications interfaces 407 and BMS interface 409 can include cellular or mobile phone communications transceivers. In one embodiment, communications interface 407 is a power line communications interface and BMS interface 409 is an Ethernet interface. In other embodiments, both communications interface 407 and BMS interface 409 are Ethernet interfaces or are the same Ethernet interface.
Still referring to
Memory 408 (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. Memory 408 can be or include volatile memory or non-volatile memory. Memory 408 can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application. According to some embodiments, memory 408 is communicably connected to processor 406 via processing circuit 404 and includes computer code for executing (e.g., by processing circuit 404 and/or processor 406) one or more processes described herein.
In some embodiments, BMS controller 366 is implemented within a single computer (e.g., one server, one housing, etc.). In various other embodiments BMS controller 366 can be distributed across multiple servers or computers (e.g., that can exist in distributed locations). Further, while
Still referring to
Enterprise integration layer 410 can be configured to serve clients or local applications with information and services to support a variety of enterprise-level applications. For example, enterprise control applications 426 can be configured to provide subsystem-spanning control to a graphical user interface (GUI) or to any number of enterprise-level business applications (e.g., accounting systems, user identification systems, etc.). Enterprise control applications 426 may also or alternatively be configured to provide configuration GUIs for configuring BMS controller 366. In yet other embodiments, enterprise control applications 426 can work with layers 410-420 to optimize building performance (e.g., efficiency, energy use, comfort, or safety) based on inputs received at communications interface 407 and/or BMS interface 409.
Building subsystem integration layer 420 can be configured to manage communications between BMS controller 366 and building subsystems 428. For example, building subsystem integration layer 420 may receive sensor data and input signals from building subsystems 428 and provide output data and control signals to building subsystems 428. Building subsystem integration layer 420 may also be configured to manage communications between building subsystems 428. Building subsystem integration layer 420 translate communications (e.g., sensor data, input signals, output signals, etc.) across a plurality of multi-vendor/multi-protocol systems.
Demand response layer 414 can be configured to optimize resource usage (e.g., electricity use, natural gas use, water use, etc.) and/or the monetary cost of such resource usage in response to satisfy the demand of building 10. The optimization can be based on time-of-use prices, curtailment signals, energy availability, or other data received from utility providers, distributed energy generation systems 424, from energy storage 427 (e.g., hot TES 242, cold TES 244, etc.), or from other sources. Demand response layer 414 may receive inputs from other layers of BMS controller 366 (e.g., building subsystem integration layer 420, integrated control layer 418, etc.). The inputs received from other layers can include environmental or sensor inputs (e.g., internal to building 10, external to building 10, etc.) such as temperature, carbon dioxide levels, relative humidity levels, air quality sensor outputs, occupancy sensor outputs, room schedules, weather conditions, and the like. The inputs may also include inputs such as electrical use (e.g., expressed in kWh), thermal load measurements, pricing information, projected pricing, smoothed pricing, curtailment signals from utilities, and the like.
According to some embodiments, demand response layer 414 includes control logic for responding to the data and signals it receives. These responses can include communicating with the control algorithms in integrated control layer 418, changing control strategies, changing setpoints, or activating/deactivating building equipment or subsystems in a controlled manner. Demand response layer 414 may also include control logic configured to determine when to utilize stored energy. For example, demand response layer 414 may determine to begin using energy from energy storage 427 just prior to the beginning of a peak use hour.
In some embodiments, demand response layer 414 includes a control module configured to actively initiate control actions (e.g., automatically changing setpoints, etc.) which minimize energy costs based on one or more inputs representative of or based on demand (e.g., price, a curtailment signal, a demand level, etc.). In some embodiments, demand response layer 414 uses equipment models to determine an optimal set of control actions. The equipment models can include, for example, thermodynamic models describing the inputs, outputs, and/or functions performed by various sets of building equipment. Equipment models may represent collections of building equipment (e.g., subplants, chiller arrays, etc.) or individual devices (e.g., individual chillers, heaters, pumps, etc.).
Demand response layer 414 may further include or draw upon one or more demand response policy definitions (e.g., databases, XML files, etc.). The policy definitions can be edited or adjusted by a user (e.g., via a graphical user interface, etc.) so that the control actions initiated in response to demand inputs can be tailored for the user's application, desired comfort level, particular building equipment, and/or based on other concerns. For example, the demand response policy definitions can specify which equipment can be turned on or off in response to particular demand inputs, how long a system or piece of equipment should be turned off, what setpoints can be changed, what the allowable set point adjustment range is, how long to hold a high demand setpoint before returning to a normally scheduled setpoint, how close to approach capacity limits, which equipment modes to utilize, the energy transfer rates (e.g., the maximum rate, an alarm rate, other rate boundary information, etc.) into and out of energy storage devices (e.g., thermal storage tanks, battery banks, etc.), and/or when to dispatch on-site generation of energy (e.g., via fuel cells, a motor generator set, etc.).
Integrated control layer 418 can be configured to use the data input or output of building subsystem integration layer 420 and/or demand response later 414 to make control decisions. Due to the subsystem integration provided by building subsystem integration layer 420, integrated control layer 418 can integrate control activities of the subsystems 428 such that the subsystems 428 behave as a single integrated supersystem. In some embodiments, integrated control layer 418 includes control logic that uses inputs and outputs from a plurality of building subsystems to provide greater comfort and energy savings relative to the comfort and energy savings that separate subsystems could provide alone. For example, integrated control layer 418 can be configured to use an input from a first subsystem to make an energy-saving control decision for a second subsystem. Results of these decisions can be communicated back to building subsystem integration layer 420.
Integrated control layer 418 is shown to be logically below demand response layer 414. Integrated control layer 418 can be configured to enhance the effectiveness of demand response layer 414 by enabling building subsystems 428 and their respective control loops to be controlled in coordination with demand response layer 414. This configuration may advantageously reduce disruptive demand response behavior relative to conventional systems. For example, integrated control layer 418 can be configured to assure that a demand response-driven upward adjustment to the setpoint for chilled water temperature (or another component that directly or indirectly affects temperature) does not result in an increase in fan energy (or other energy used to cool a space) that would result in greater total building energy use than was saved at the chiller.
Integrated control layer 418 can be configured to provide feedback to demand response layer 414 so that demand response layer 414 checks that constraints (e.g., temperature, lighting levels, etc.) are properly maintained even while demanded load shedding is in progress. The constraints may also include setpoint or sensed boundaries relating to safety, equipment operating limits and performance, comfort, fire codes, electrical codes, energy codes, and the like. Integrated control layer 418 is also logically below fault detection and diagnostics layer 416 and automated measurement and validation layer 412. Integrated control layer 418 can be configured to provide calculated inputs (e.g., aggregations) to these higher levels based on outputs from more than one building subsystem.
Automated measurement and validation (AM&V) layer 412 can be configured to verify that control strategies commanded by integrated control layer 418 or demand response layer 414 are working properly (e.g., using data aggregated by AM&V layer 412, integrated control layer 418, building subsystem integration layer 420, FDD layer 416, or otherwise). The calculations made by AM&V layer 412 can be based on building system energy models and/or equipment models for individual BMS devices or subsystems. For example, AM&V layer 412 may compare a model-predicted output with an actual output from building subsystems 428 to determine an accuracy of the model.
Fault detection and diagnostics (FDD) layer 416 can be configured to provide on-going fault detection for building subsystems 428, building subsystem devices (i.e., building equipment), and control algorithms used by demand response layer 414 and integrated control layer 418. FDD layer 416 may receive data inputs from integrated control layer 418, directly from one or more building subsystems or devices, and/or from another data source. FDD layer 416 may automatically diagnose and respond to detected faults. The responses to detected or diagnosed faults can include providing an alert message to a user, a maintenance scheduling system, or a control algorithm configured to attempt to repair the fault or to work-around the fault.
FDD layer 416 can be configured to output a specific identification of the faulty component or cause of the fault (e.g., loose damper linkage, etc.) using detailed subsystem inputs available at building subsystem integration layer 420. In other exemplary embodiments, FDD layer 416 is configured to provide “fault” events to integrated control layer 418 which executes control strategies and policies in response to the received fault events. According to some embodiments, FDD layer 416 (or a policy executed by an integrated control engine or business rules engine) may shut-down systems or direct control activities around faulty devices or systems to reduce energy waste, extend equipment life, or assure proper control response.
FDD layer 416 can be configured to store or access a variety of different system data stores (or data points for live data). FDD layer 416 may use some content of the data stores to identify faults at the equipment level (e.g., specific chiller, specific AHU, specific terminal unit, etc.) and other content to identify faults at component or subsystem levels. For example, building subsystems 428 may generate temporal (i.e., time-series) data indicating the performance of BMS 400 and the various components thereof. The data generated by building subsystems 428 can include measured or calculated values that exhibit statistical characteristics and provide information about how the corresponding system or process (e.g., a temperature control process, a flow control process, etc.) is performing in terms of error from its setpoint. These processes can be examined by FDD layer 416 to expose when the system begins to degrade in performance and alert a user to repair the fault before it becomes more severe.
Referring now to
BMS 500 provides a system architecture that facilitates automatic equipment discovery and equipment model distribution. Equipment discovery can occur on multiple levels of BMS 500 across multiple different communications busses (e.g., a system bus 554, zone buses 556-560 and 564, sensor/actuator bus 566, etc.) and across multiple different communications protocols. In some embodiments, equipment discovery is accomplished using active node tables, which provide status information for devices connected to each communications bus. For example, each communications bus can be monitored for new devices by monitoring the corresponding active node table for new nodes. When a new device is detected, BMS 500 can begin interacting with the new device (e.g., sending control signals, using data from the device) without user interaction.
Some devices in BMS 500 present themselves to the network using equipment models. An equipment model defines equipment object attributes, view definitions, schedules, trends, and the associated BACnet value objects (e.g., analog value, binary value, multistate value, etc.) that are used for integration with other systems. Some devices in BMS 500 store their own equipment models. Other devices in BMS 500 have equipment models stored externally (e.g., within other devices). For example, a zone coordinator 508 can store the equipment model for a bypass damper 528. In some embodiments, zone coordinator 508 automatically creates the equipment model for bypass damper 528 or other devices on zone bus 558. Other zone coordinators can also create equipment models for devices connected to their zone busses. The equipment model for a device can be created automatically based on the types of data points exposed by the device on the zone bus, device type, and/or other device attributes. Several examples of automatic equipment discovery and equipment model distribution are discussed in greater detail below.
Still referring to
In some embodiments, system manager 503 is connected with zone coordinators 506-510 and 518 via a system bus 554. System manager 503 can be configured to communicate with zone coordinators 506-510 and 518 via system bus 554 using a master-slave token passing (MSTP) protocol or any other communications protocol. System bus 554 can also connect system manager 503 with other devices such as a constant volume (CV) rooftop unit (RTU) 512, an input/output module (IOM) 514, a thermostat controller 516 (e.g., a TEC5000 series thermostat controller), and a network automation engine (NAE) or third-party controller 520. RTU 512 can be configured to communicate directly with system manager 503 and can be connected directly to system bus 554. Other RTUs can communicate with system manager 503 via an intermediate device. For example, a wired input 562 can connect a third-party RTU 542 to thermostat controller 516, which connects to system bus 554.
System manager 503 can provide a user interface for any device containing an equipment model. Devices such as zone coordinators 506-510 and 518 and thermostat controller 516 can provide their equipment models to system manager 503 via system bus 554. In some embodiments, system manager 503 automatically creates equipment models for connected devices that do not contain an equipment model (e.g., IOM 514, third party controller 520, etc.). For example, system manager 503 can create an equipment model for any device that responds to a device tree request. The equipment models created by system manager 503 can be stored within system manager 503. System manager 503 can then provide a user interface for devices that do not contain their own equipment models using the equipment models created by system manager 503. In some embodiments, system manager 503 stores a view definition for each type of equipment connected via system bus 554 and uses the stored view definition to generate a user interface for the equipment.
Each zone coordinator 506-510 and 518 can be connected with one or more of zone controllers 524, 530-532, 536, and 548-550 via zone buses 556, 558, 560, and 564. Zone coordinators 506-510 and 518 can communicate with zone controllers 524, 530-532, 536, and 548-550 via zone busses 556-560 and 564 using a MSTP protocol or any other communications protocol. Zone busses 556-560 and 564 can also connect zone coordinators 506-510 and 518 with other types of devices such as variable air volume (VAV) RTUs 522 and 540, changeover bypass (COBP) RTUs 526 and 552, bypass dampers 528 and 546, and PEAK controllers 534 and 544.
Zone coordinators 506-510 and 518 can be configured to monitor and command various zoning systems. In some embodiments, each zone coordinator 506-510 and 518 monitors and commands a separate zoning system and is connected to the zoning system via a separate zone bus. For example, zone coordinator 506 can be connected to VAV RTU 522 and zone controller 524 via zone bus 556. Zone coordinator 508 can be connected to COBP RTU 526, bypass damper 528, COBP zone controller 530, and VAV zone controller 532 via zone bus 558. Zone coordinator 510 can be connected to PEAK controller 534 and VAV zone controller 536 via zone bus 560. Zone coordinator 518 can be connected to PEAK controller 544, bypass damper 546, COBP zone controller 548, and VAV zone controller 550 via zone bus 564.
A single model of zone coordinator 506-510 and 518 can be configured to handle multiple different types of zoning systems (e.g., a VAV zoning system, a COBP zoning system, etc.). Each zoning system can include a RTU, one or more zone controllers, and/or a bypass damper. For example, zone coordinators 506 and 510 are shown as Verasys VAV engines (VVEs) connected to VAV RTUs 522 and 540, respectively. Zone coordinator 506 is connected directly to VAV RTU 522 via zone bus 556, whereas zone coordinator 510 is connected to a third-party VAV RTU 540 via a wired input 568 provided to PEAK controller 534. Zone coordinators 508 and 518 are shown as Verasys COBP engines (VCEs) connected to COBP RTUs 526 and 552, respectively. Zone coordinator 508 is connected directly to COBP RTU 526 via zone bus 558, whereas zone coordinator 518 is connected to a third-party COBP RTU 552 via a wired input 570 provided to PEAK controller 544.
Zone controllers 524, 530-532, 536, and 548-550 can communicate with individual BMS devices (e.g., sensors, actuators, etc.) via sensor/actuator (SA) busses. For example, VAV zone controller 536 is shown connected to networked sensors 538 via SA bus 566. Zone controller 536 can communicate with networked sensors 538 using a MSTP protocol or any other communications protocol. Although only one SA bus 566 is shown in
Each zone controller 524, 530-532, 536, and 548-550 can be configured to monitor and control a different building zone. Zone controllers 524, 530-532, 536, and 548-550 can use the inputs and outputs provided via their SA busses to monitor and control various building zones. For example, a zone controller 536 can use a temperature input received from networked sensors 538 via SA bus 566 (e.g., a measured temperature of a building zone) as feedback in a temperature control algorithm. Zone controllers 524, 530-532, 536, and 548-550 can use various types of control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control a variable state or condition (e.g., temperature, humidity, airflow, lighting, etc.) in or around building 10.
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Connected equipment 610 can be outfitted with sensors to monitor particular conditions of the connected equipment 610. For example, chillers 612 can include sensors configured to monitor chiller variables such as chilled water return temperature, chilled water supply temperature, chilled water flow status (e.g., mass flow rate, volume flow rate, etc.), condensing water return temperature, condensing water supply temperature, motor amperage (e.g., of a compressor, etc.), variable speed drive (VSD) output frequency, and refrigerant properties (e.g., refrigerant pressure, refrigerant temperature, condenser pressure, evaporator pressure, etc.) at various locations in the refrigeration circuit. In some embodiments, chillers 612 can include sensors configured to monitor evaporator pressure, sub-cool temperature, suction temperature, evaporator temperature, condenser pressure, or discharge temperature at various locations in the refrigeration circuit. An example of a chiller 700 which can be used as one of chillers 612 is described in greater detail with reference to
Monitored variables can include any measured or calculated values indicating the performance of connected equipment 610 and/or the components thereof. For example, monitored variables can include one or more measured or calculated temperatures (e.g., refrigerant temperatures, cold water supply temperatures, hot water supply temperatures, supply air temperatures, zone temperatures, sub-cool temperature, suction temperature, evaporator temperature, discharge temperature, etc.), pressures (e.g., evaporator pressure, condenser pressure, supply air pressure, etc.), flow rates (e.g., cold water flow rates, hot water flow rates, refrigerant flow rates, supply air flow rates, etc.), valve positions, resource consumptions (e.g., power consumption, water consumption, electricity consumption, etc.), control setpoints, model parameters (e.g., regression model coefficients, etc.), and/or any other time-series values that provide information about how the corresponding system, device, and/or process is performing. Monitored variables can be received from connected equipment 610 and/or from various components thereof. For example, monitored variables can be received from one or more controllers (e.g., BMS controllers, subsystem controllers, HVAC controllers, subplant controllers, AHU controllers, device controllers, etc.), BMS devices (e.g., chillers, cooling towers, pumps, heating elements, etc.), and/or collections of BMS devices.
Connected equipment 610 can also report equipment status information. Equipment status information can include, for example, the operational status of the equipment, an operating mode (e.g., low load, medium load, high load, etc.), an indication of whether the equipment is running under normal or abnormal conditions, a safety fault code, and/or any other information that indicates the current status of connected equipment 610. In some embodiments, equipment status information reported by the connected equipment 610 is in the form of status codes. For example, four types of status codes can be reported by a connected equipment (e.g., chiller), including safety shutdown codes (safety codes), warning codes, cycling codes, and operation codes. The status codes are described in greater detail herein below in this disclosure.
In some embodiments, each device of connected equipment 610 includes a control panel (e.g., control panel 710 shown in
Connected equipment 610 can provide monitored variables and equipment status information to a network control engine 608. Network control engine 608 can include a building controller (e.g., BMS controller 366), a system manager (e.g., system manager 503), a network automation engine (e.g., NAE 520), or any other system or device of building 10 configured to communicate with connected equipment 610. In some embodiments, the monitored variables and the equipment status information are provided to network control engine 608 as data points. Each data point can include a point ID and/or a point value. The point ID can identify the type of data point and/or a variable measured by the data point (e.g., condenser pressure, refrigerant temperature, fault code, etc.). Monitored variables can be identified by name or by an alphanumeric code (e.g., Chilled_Water_Temp, 7694, etc.). The point value can include an alphanumeric value indicating the current value of the data point (e.g., 44° F., fault code 4, etc.).
Network control engine 608 can broadcast the monitored variables and the equipment status information to a remote operations center (ROC) 602. ROC 602 can provide remote monitoring services and can send an alert to building 10 in the event of a critical alarm. ROC 602 can push the monitored variables and equipment status information to a reporting database 604, where the data is stored for reporting and analysis. Chiller efficiency monitoring system 502 can access database 604 to retrieve the monitored variables and the equipment status information.
In some embodiments, chiller efficiency monitoring system 502 is a component of BMS controller 366 (e.g., within FDD layer 416). For example, chiller efficiency monitoring system 502 can be implemented as part of a METASYS® brand building automation system, as sold by Johnson Controls Inc. In other embodiments, chiller efficiency monitoring system 502 can be a component of a remote computing system or cloud-based computing system configured to receive and process data from one or more building management systems. For example, chiller efficiency monitoring system 502 can connect the connected equipment 610 (e.g., chillers 612) to the cloud and collect real-time data for over a number of points (e.g., 50 points) on those equipment. In other embodiments, chiller efficiency monitoring system 502 can be a component of a subsystem level controller (e.g., a HVAC controller, etc.), a subplant controller, a device controller (e.g., AHU controller 330, a chiller controller, etc.), a field controller, a computer workstation, a client device, and/or any other system and/or device that receives and processes monitored variables from connected equipment 610.
Chiller efficiency monitoring system 502 may use the monitored variables to determine the efficiency of a chiller 612. The chiller efficiency can be estimated by a chiller efficiency monitoring system 502 to expose when chillers 612 begin to degrade in efficiency and/or to predict when degradation will occur. In some embodiments, chiller efficiency monitoring system 502 determines whether the chiller is currently operating efficiently or calculates a chiller efficiency value such as a coefficient of performance (COP) or Kilo Watt/Ton of refrigeration (KW/TR). Chiller efficiency monitoring system 502 may report the current chiller efficiency or chiller efficiency estimations to client devices 448, service technicians 606, building 10, and/or any other system and/or device. Communications between chiller efficiency monitoring system 502 and other systems and/or devices can be direct and/or via an intermediate communications network, such as network 446. If the current chiller efficiency is identified as inefficient or moving toward an efficient state, chiller efficiency monitoring system 502 may generate an alert or notification for service technicians 606 to make repairs or adjustments to the chiller or other building equipment that affect the chiller operation. In some embodiments, chiller efficiency monitoring system 502 uses the current chiller efficiency to determine an appropriate control action for chillers 612 or connected equipment 610. In some embodiments, the chiller efficiency monitoring system 502 may transmit an alert of inefficient operation to the BMS, and the BMS may automatically control various connected equipment to conduct the appropriate control action.
In some embodiments, chiller efficiency monitoring system 502 provides a web interface which can be accessed by service technicians 606, client devices 448, and other systems or devices. The web interface can be used to access the raw data in reporting database 604, view the results produced by the chiller efficiency monitoring system 502, identify which equipment is in need of preventative maintenance or adjustments, and otherwise interact with chiller efficiency monitoring system 502. Service technicians 606 can access the web interface to view a list of equipment for which inefficient operation are predicted by chiller efficiency monitoring system 502. Service technicians 606 can use the predicted inefficiency to proactively repair or adjust connected equipment 610 before chiller inefficiency or energy wastage occurs. These and other features of chiller efficiency monitoring system 502 are described in greater detail below.
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Chiller 700 can be configured to operate in multiple different operating states. For example, chiller 700 can be operated in a low load state, a medium load state, a high load state, and/or various states therebetween. The operating states may represent the normal operating states or conditions of chiller 700. Faults or changing conditions in in chiller 700 may cause the operation of chiller 700 to operate inefficiently. For example, various types of faults may occur in each of the normal operating states. For example, faults can be caused by stalling or surging in the compressor or other mechanical effects that can occur during operation. In some embodiments, chiller efficiency monitoring system 502 can collect or receive samples of the monitored variables. For example, chiller efficiency monitoring system 502 may collect or receive 1000 samples of the monitored variables at a rate of one sample per second.
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Communications interface 810 can include any number and/or type of wired or wireless communications interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.). For example, communications interface 810 can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications link or network. As another example, communications interface 810 can include a Wi-Fi transceiver, a NFC transceiver, a cellular transceiver, a mobile phone transceiver, or the like for communicating via a wireless communications network. In some embodiments, communications interface 810 includes RS232 and/or RS485 circuitry for communicating with BMS devices (e.g., chillers, controllers, etc.). Communications interface 810 can be configured to use any of a variety of communications protocols (e.g., BACNet, Modbus, N2, MSTP, Zigbee, etc.). Communications via interface 810 can be direct (e.g., local wired or wireless communications) or via an intermediate communications network 446 (e.g., a WAN, the Internet, a cellular network, etc.). Communications interface 810 can be communicably connected with processing circuit 812, and the various components thereof can send and receive data via communications interface 810.
Processing circuit 812 is shown to include a processor 814 and memory 816. Processor 814 can be implemented as a general purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. Memory 816 (e.g., memory, memory unit, storage device, etc.) can include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage, etc.) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present application. Memory 816 can be or include volatile memory or non-volatile memory. Memory 816 can include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present application. According to some embodiments, memory 816 is communicably connected to processor 814 via processing circuit 812 and includes computer code for executing (e.g., by processing circuit 812 and/or processor 814) one or more processes described herein.
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At stage 910, the availability of chiller sensors is determined. For example, the chiller efficiency monitoring system 502 is configured to determine the availability of chiller sensors 818 that are configured to measure or monitor evaporator pressure, sub-cool temperature, suction temperature, evaporator temperature, condenser pressure, or discharge temperature respectively. In such embodiment, the chiller efficiency monitoring system 502 determines that a sensor is unavailable. Determining the availability of chiller sensors can include the telemetry data check circuit 830 being configured to obtain telemetry data from a chiller 612 and to identify whether the data has been measured by a chiller sensor and that the data is within range as determined by a telemetry data threshold 832. In such example, the telemetry data includes evaporator pressure, sub-cool temperature, suction temperature, evaporator temperature, condenser pressure, or discharge temperature of a chiller 612. Units for temperature can include Celsius, Fahrenheit, or Kelvin. Units for pressure can include pascal, bar, or atmosphere. In some embodiments, the telemetry data include data points of a plurality of monitored variables from the connected equipment 610 or chillers 612.
In some embodiments, the connected equipment 610 can be configured to measure a plurality of monitored variables. As discussed herein above in relation to
In some embodiments, safety shutdown codes are generated when safety shutdowns occur. Safety shutdowns can be triggered when certain conditions that are deemed dangerous to a chiller occur. These conditions may cause physical damage to the evaporator, condenser, compressor, variable speed drive (VSD), motor, or other components of the chiller. By the time a safety shutdown occurs, the chiller may have already sustained some damage. In some embodiments, depending on what causes the safety shutdown, it may require time and money to do a shutdown and machine servicing, or it could just require a reset of a chiller panel or building control strategy. In some embodiments, knowing the type of safety shutdown may not be sufficient to determine the root cause and solution. In some embodiments, warning codes do not shut down the chiller but give alerts that the chiller is not operating under a good condition. In some embodiments, cycling codes generally shut down a chiller due to specific conditions that occur in the chiller. For example, if a pump that feeds the condenser fails, the chiller may shut down due to loss of condenser flow. In some embodiments, operation codes indicate if the chiller is running, not running, or in alarm or shutdown states. In some embodiments, there are a number of different safety codes, warning codes, and cycling codes that can occur. In some embodiments, the operation codes are limited to a maximum number (e.g., 15) and a subset (e.g., 3) represents states when the chiller is running.
In some embodiments, the telemetry data check circuit 830 of the chiller efficiency monitoring system 502 can receive or obtain time telemetry data (e.g., data points of the plurality of monitored variables) from the connect equipment 610 or chillers 612 through the communication interface 810 via the network 446. In some embodiments, the communication interface 810 can obtain the time series data from the reporting database 604. Table 2 shows an example of the telemetry data that can be used as inputs to the operations performed by the chiller efficiency monitoring system 502. In some embodiments, the data is collected from sensors and is related to physical quantities in the chiller. For example, for legacy chillers, points may be sampled every 1, 5, or 15 minutes, in some embodiments. For other chillers (e.g., SCC chillers), points may be change-of-value, in some embodiments.
As illustrated in Table 2 above, each input data or telemetry data can include a value and a timestamp indicating the time that the data is collected. For example, chilled water flow status (varname or ID: CHWP-STS) for this particular chiller has a value of 0.0 at the time 2018 Jul. 9 00:45:00. It should be understood that the example input data as shown in Table 2 are for illustrative purposes only and should not be regarded as limiting in any way.
In some embodiments, the telemetry data check circuit 830 of the chiller efficiency monitoring system 502 obtains or receives telemetry data threshold 832. The telemetry data threshold 832 are parameters specific to the connected equipment (e.g., chiller 612, 700). In some embodiments, the telemetry data threshold 832 are obtained from the reporting database 604 via the communication interface 810. In some embodiments, the telemetry data threshold 832 are obtained from another system or storage via the network 446 through the communication interface 810. In some embodiments, the telemetry data threshold 832 are stored in a memory or local storage of the chiller efficiency monitoring system 502.
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In some embodiments, the telemetry data check circuit 830 can check a set of predetermined rules to determine if there is a violation of any of the rules. Responsive to a violation of one or more rules, the telemetry data check circuit 830 can generate alerts to determine on the availability of a telemetry data point. For example, the telemetry data check circuit 830 may consider a plurality of telemetry data thresholds for the obtained telemetry data such as evaporator pressure, sub-cool temperature, suction temperature, condenser pressure, and discharge temperature. In some embodiments, for example, using the telemetry data thresholds 832, the telemetry data check circuit 830 applies the following predetermined rules to perform the telemetry data checks:
In some embodiments, the telemetry data check results in the telemetry data check circuit 830 determining that a chiller sensor is unavailable in response to the telemetry data failing the data check (e.g., in response to telemetry data not meeting the telemetry data threshold 832 or otherwise being determined as missing). A chiller sensor can be determined as available in response to satisfying (passing) the data check (e.g., in response to telemetry data being within the telemetry data threshold 832). Sensor availability can thereby be determined in step 910.
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To elaborate, in some embodiments, step 920 can include determine, based on which sensor is unavailable, one or more assumptions that should be made in order to estimate a value for the corresponding sensor (e.g., which of the evaporator pressure sensor, sub-cool temperature sensor, suction temperature sensor, condenser pressure sensor, or discharge temperature sensor is unavailable). For instance, if a discharge pressure sensor is determined to be unavailable, step 920 can include determining that an assumption should be made that the chiller performs an isentropic compression (i.e., constant entropy), such that discharge pressure can be estimated based on entropy prior to compression and discharge temperature using a physics-based model (e.g., Mollier chart). As another example, if a suction temperature sensor is determined to be unavailable, step 920 can include determining that an assumption should be made that a refrigerant phase change within an evaporator of the chiller occurs under constant pressure such that pressure measured elsewhere in the chiller can be used with an idealized refrigerant phase change to select suction temperature using a physics-based model (e.g., Mollier chart). Various such assumptions can be made to treat certain dynamics of the refrigerant cycle as idealized or otherwise according to predefined models depending which sensor(s) are determined to be unavailable in a given scenario, enabling use of a model, chart, look-up table (e.g., Mollier chart) to determine an estimated value for any missing sensor given the selected assumptions. Stage 920 thereby provides adaptability in scenarios with unreliable or faulty sensors which may prevent estimation of chiller efficiency in embodiments lacking such features.
At stage 930, the enthalpy points at different points in the refrigeration cycle of the chiller are determined. In some embodiments, the chiller efficiency monitoring system 502 can be configured to determine or calculate the enthalpy points based on measurements from available sensors and estimated values for any unavailable sensors (e.g., as determined in stage 920). For example, the enthalpy calculation circuit 840 may determine enthalpy between evaporation and compression (referred to as enthalpy point h1), between compression and condensation (referred to as enthalpy point h2), and between expansion and evaporation (referred to as enthalpy point h4) (enthalpy point h3 being the corner of the refrigeration cycle between condensation and expansion which goes unused in at least some embodiments of stage 930).
At stage 940, the chiller efficiency is determined based on the determined enthalpy points. For example, the chiller efficiency monitoring system 502 can be configured to determine or calculate the chiller efficiency, for example using a formula:
As such, the chiller efficiency can be calculated as a coefficient of performance. Such a formula reflects the efficiency of the refrigeration cycle provided by the chiller, i.e., reflecting a ratio of actual cooling power output from the refrigeration cycle to an amount of work done by a compression stage of the refrigeration cycle. This coefficient of performance can also be estimated to be reflective of a ratio of electricity consumption of a chiller to the cooling capacity of the chiller (e.g., kW/TR). Once the chiller efficiency is determined, various steps can be taken to affect operations of the chiller and/or other equipment based on the chiller efficiency, for example as explained below with reference to stage 1090 of process 1000.
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For example, stage 1050 can employ logic as in the following paragraphs to account for various scenarios in which three of the set of data points including evaporator pressure, sub-cool temperature, suction temperature, condenser pressure, and discharge temperature are unavailable (with the other two being available).
If evaporator pressure and discharge temperature are available (with the other points unavailable), stage 1050 can adjust the logic used for enthalpy point calculation to (i) determine h1 as the intersection between evaporator pressure as measured and the liquid-vapor compression line (shown as line 1102 in
If sub-cool temperature and suction temperature are available (with other points unavailable), step 1050 can adjust the logic used for enthalpy point calculation to (i) determine h1 as being at the intersection between suction temperature as measured and the liquid-vapor line (line 1102 in
If suction temperature and discharge temperature are available (with other points unavailable), step 1050 can adjust the logic used for enthalpy point calculation to (i) determine h1 as being at the intersection between suction temperature as measured and the liquid-vapor line (line 1102 in
If evaporator pressure and condenser pressure are available (with other points unavailable), step 1050 can adjust the logic used for enthalpy point calculation to (i) determine h1 at the intersection between evaporator pressure as measured and the liquid-vapor line (line 1102 in
Various other adjustments can be made to the logic used for enthalpy point calculation depending on the available and unavailability of various telemetry points.
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The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements can be reversed or otherwise varied and the nature or number of discrete elements or positions can be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps can be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.
As used herein, the term “circuit” may include hardware structured to execute the functions described herein. In some embodiments, each respective “circuit” may include machine-readable media for configuring the hardware to execute the functions described herein. The circuit may be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc. In some embodiments, a circuit may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, etc.), telecommunication circuits, hybrid circuits, and any other type of “circuit.” In this regard, the “circuit” may include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on).
The “circuit” may also include one or more processors communicatively coupled to one or more memory or memory devices. In this regard, the one or more processors may execute instructions stored in the memory or may execute instructions otherwise accessible to the one or more processors. In some embodiments, the one or more processors may be embodied in various ways. The one or more processors may be constructed in a manner sufficient to perform at least the operations described herein. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., circuit A and circuit B may include or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. Each processor may be implemented as one or more general-purpose processors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc.), microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example the one or more processors may be a remote processor (e.g., a cloud based processor). Alternatively or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc.) or remotely (e.g., as part of a remote server such as a cloud-based server). To that end, a “circuit” as described herein may include components that are distributed across one or more locations.
The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure can be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which 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 which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.
Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps can be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10202302705R | Sep 2023 | SG | national |
