Refrigerant leak detection

Abstract

A building refrigeration system comprising: a compressor module configured to, in response to a determination that an amount of refrigerant existing outside of the refrigeration system and within the building is greater than a first predetermined amount, keep a compressor continuously off for a predetermined period; and a fan module configured to, in response to the determination, keep a fan continuously on for at least the predetermined period, and wherein the compressor module is further configured to, without receiving an input indicating a reset of the refrigeration system, selectively turn on the compressor after the compressor has been off for the predetermined period and the amount of refrigerant existing outside of the refrigeration system and within the building is less than a second predetermined amount.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Patent Application No. 16 / 988,269, filed August 7, 2020. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0003] This disclosure relates to heating, ventilation and air conditioning (HVAC) and other types of refrigeration systems, and more specifically to systems and methods for detecting and mitigating refrigeration leaks in HVAC or refrigeration systems. Background Technology

[0004] This section provides background information relating to the contents of this disclosure, which is not necessarily prior art.

[0005] Refrigeration and air conditioning applications are facing increasing regulatory pressure to reduce the global warming potential of the refrigerants they use. In order to use refrigerants with lower global warming potential, the flammability of the refrigerants may need to be increased.

[0006] Several refrigerants have been developed as options with low global warming potential, and they have been classified as A2L by ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers), which means slightly flammable. UL (Underwriters Laboratories) standard 60335-2-40 and similar standards specify predetermined (M1) levels for A2L refrigerants and state that refrigerant charge levels below the predetermined level do not require leak detection and mitigation. Summary of the Invention

[0007] This section provides an overview of the contents of this disclosure and is not a full disclosure of its entire scope or all its features.

[0008] HVAC systems using A2L refrigerant may require leak detection and mitigation capabilities. Control systems can be used to ensure the proper functioning of the HVAC system while providing maximum comfort for building occupants and preventing nuisance issues.

[0009] A2L (slightly flammable) refrigerant can be used in refrigeration and HVAC systems. Due to its flammability, systems using A2L refrigerant may require measures to mitigate any potential leaks. This can be done by running the indoor fans in the air handling unit to disperse any leaked refrigerant, thereby reducing its concentration in the building. The system can automatically reset after a mitigation event.

[0010] This application allows the system (e.g., by the building owner) to be manually reset to put the system into a reduced capacity mode, so some cooling is available, but less than when running at full capacity.

[0011] This disclosure relates to a resettable algorithm for a refrigerant sensor or detection system used to sense refrigerant leaks (e.g., A2L). A control module controls the system, and a switch is used to manually reset the system. The system also automatically resets after the A2L leak has been mitigated, allowing the system to resume normal operation.

[0012] If more than three (or some other predetermined number) leakage incidents occur, the control module can lock the compressor (hold the compressor) and request the contractor to be contacted, or the building owner can request the contractor to be contacted.

[0013] If the refrigerant leak level exceeds a predetermined level of the lower flammability limit (LFL) of the refrigerant used in the system (e.g., 25% or other suitable level), the system can be manually or automatically reset. When the compressor is locked due to a refrigerant leak event, the control module can maintain the compressor locked until a contractor visits the system for repairs. The system also allows the sensor / control module to retain data for a predetermined period (e.g., the last 7 days or other timeframes), enabling the contractor to use this information for diagnostic purposes.

[0014] Therefore, this application controls and mitigates the problem while ensuring operation, providing maximum comfort for homeowners and avoiding nuisance issues.

[0015] A vapor compression system includes a refrigeration cycle comprising a compressor, a condenser, an expansion valve, and an evaporator. A refrigerant leak sensor is positioned adjacent to a component of the refrigeration cycle. A fan is associated with the vapor compression system. A control module controls the operation of the compressor and the fan, and receives signals from the refrigerant leak sensor, wherein, upon detecting a leak, the control module automatically resets the operation of the vapor compression system after the refrigerant leak has been mitigated by the fan, allowing the system to return to normal operation.

[0016] In one feature, the building's refrigeration system includes: a compressor module configured to keep the compressor of the refrigeration system continuously off for at least a predetermined period of time in response to a determination that the amount of refrigerant in a refrigeration system outside the building's refrigeration system is greater than a first predetermined amount; and a fan module configured to keep the fan continuously on for at least a predetermined period of time in response to a determination that the amount of refrigerant in a refrigeration system outside the building's refrigeration system is greater than a first predetermined amount, wherein when the fan is on, the fan moves air through the evaporator of the refrigeration system, wherein the compressor module is further configured to selectively turn on the compressor after the compressor has been off for the predetermined period of time and the amount of refrigerant in a refrigeration system outside the building's refrigeration system is less than a second predetermined amount, without receiving an input instructing the refrigeration system to reset.

[0017] Among other features, the sensor is configured to measure the amount of refrigerant present outside the building's refrigeration system.

[0018] Among other features, the sensor is positioned near the evaporator.

[0019] Among the other features, the second predetermined amount is less than the first predetermined amount.

[0020] Among other characteristics, the refrigerant has an A2L classification by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE).

[0021] Among other features, the compressor module is configured to keep the compressor off until an input instructing the refrigeration system to reset is received when the number of events in which the amount of refrigerant outside the refrigeration system within the building exceeds a first predetermined amount is greater than a predetermined number of events.

[0022] Among the other features, the number of pre-defined events is an integer greater than 1.

[0023] Among other features, the compressor module is configured to keep the compressor off when the amount of refrigerant present outside the building's refrigeration system exceeds a third predetermined amount, until an input instructing the refrigeration system to reset is received.

[0024] Among the other features, the third predetermined quantity is greater than the second predetermined quantity.

[0025] Among other characteristics, the third predetermined amount is at least 20 percent of the lower flammability limit (LFL) of the refrigerant.

[0026] Among other features, the locking module is configured to prevent one or more ignition devices from igniting for at least a predetermined period of time in response to a determination that the amount of refrigerant present outside the building's refrigeration system is greater than a first predetermined amount.

[0027] In one feature, a method includes: in response to a determination that the amount of refrigerant in a refrigeration system outside the building's refrigeration system is greater than a first predetermined amount, keeping the compressor of the refrigeration system continuously off for at least a predetermined period of time; in response to the determination that the amount of refrigerant in a refrigeration system outside the building's refrigeration system is greater than the first predetermined amount, keeping a fan continuously on for at least a predetermined period of time, wherein when the fan is on, the fan moves air through the evaporator of the refrigeration system; and, in the absence of receiving an input instructing the refrigeration system to reset, selectively turning on the compressor after the compressor has been off for the predetermined period of time and the amount of refrigerant in a refrigeration system outside the building's refrigeration system is less than a second predetermined amount.

[0028] Among other features, the method also includes using sensors to measure the amount of refrigerant present outside the building's refrigeration system.

[0029] Among other features, the sensor is positioned near the evaporator.

[0030] Among the other features, the second predetermined amount is less than the first predetermined amount.

[0031] Among other features, maintaining compressor shutdown includes maintaining compressor shutdown until an input instructing the refrigeration system to reset is received when the number of events in which the amount of refrigerant present outside the refrigeration system within the building exceeds a first predetermined amount is greater than a predetermined number of events.

[0032] Among other features, keeping the compressor off includes keeping the compressor off when the amount of refrigerant present outside the refrigeration system within the building exceeds a third predetermined amount, until an input instructing the refrigeration system to reset is received.

[0033] Among the other features, the third predetermined quantity is greater than the second predetermined quantity.

[0034] Among other characteristics, the third predetermined amount is at least 20 percent of the lower flammability limit (LFL) of the refrigerant.

[0035] Among other features, the method further includes preventing one or more ignition devices from igniting for at least a predetermined period of time in response to a determination that the amount of refrigerant present outside the refrigeration system within the building is greater than a first predetermined amount.

[0036] Other application areas will become apparent from the descriptions provided herein. The descriptions and specific examples in this overview are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0037] The accompanying drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of this disclosure.

[0038] Figure 1 This is a schematic diagram of an example refrigeration system including a leak sensor;

[0039] Figure 2 It is a flowchart depicting an example method for automatically resetting the refrigeration system after a refrigerant leak has been mitigated, unless a predetermined number of leaks are detected, and allowing the system to return to normal operation;

[0040] Figure 3 It is a flowchart depicting an example method for automatically resetting the refrigeration system after the refrigerant leak is mitigated, unless the leaked A2L refrigerant level exceeds a predetermined level, and allowing the system to resume normal operation; and

[0041] Figure 4 This is a functional block diagram of an example control system.

[0042] In several views of the accompanying drawings, corresponding reference numerals indicate corresponding parts. Detailed Implementation

[0043] The exemplary implementation will now be described more fully with reference to the accompanying drawings.

[0044] Example implementations are provided so that this disclosure will be thorough and will more fully convey the scope to those skilled in the art. Numerous specific details, such as examples of particular components, apparatuses, and methods, are set forth to provide a thorough understanding of implementations of this disclosure. It will be apparent to those skilled in the art that specific details are not required, example implementations may be practiced in many different forms, and neither the specific details nor the example implementations should be construed as limiting the scope of this disclosure. In some example implementations, well-known processes, well-known apparatus structures, and well-known techniques have not been described in detail.

[0045] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may also be intended to include the plural forms unless the context clearly indicates otherwise. The terms “comprising,” “containing,” “including,” and “having” are inclusive and therefore specify the presence of the said feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The methods, steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. It should also be understood that additional or alternative steps may be employed.

[0046] Reference Figure 1 A schematic diagram of an example refrigeration (e.g., air conditioning) system 10 is shown, which includes a compressor 12 and a condenser 14 that can be located outside the building (i.e., outdoors) and an expansion valve 16 and an evaporator 18 that can be located inside the building (i.e., indoors).

[0047] Fan 24 is positioned adjacent to evaporator 18 and blows air across evaporator 18. Control module 26 controls the operation of fan 24 (e.g., on, off, speed). Fan 24 may be a house-wide fan (e.g., configured to blow air across evaporator 18 and through ducts of refrigeration system 10), or alternatively, a ventilation system fan or air exchange system fan. Control module 26 may also control the operation of compressor 12 (e.g., on, off, speed, capacity).

[0048] A refrigerant leak sensor 30 or other leak detection system is provided for detecting refrigerant leaks. The leak sensor 30 may be, for example, an infrared leak sensor, an optical leak sensor, a chemical leak sensor, a thermally conductive leak sensor, an acoustic leak sensor, an ultrasonic leak sensor, or other suitable type of leak sensor. Alternatively, the leak detection module may detect the amount of refrigerant within the refrigeration system and detect a leak when the amount of refrigerant decreases by a predetermined amount. The leak detection module may calculate the amount of refrigerant, for example, based on one or more measurements such as one or more refrigerant pressures, one or more refrigerant temperatures, etc.

[0049] In various implementations, control module 26 receives signals from leak sensor 30 and can communicate with a second control module if a leak is detected.

[0050] Leak sensor 30 and / or control module 26 may include (e.g., non-volatile) memory in case of power loss. Power loss could be due to a mains power outage, refrigeration system recirculation, etc. If the refrigeration system is locked due to an A2L refrigerant leak, control module 26 can remain locked until the contractor resets the refrigeration system.

[0051] Leak sensor 30 and / or control module 26 can store and retain data for a predetermined period (e.g., data from the most recent 7 days or another suitable period), allowing the contractor to use the information for diagnostic purposes. Leak sensor 30 can be located near or at evaporator 18, such as near or at the midpoint of evaporator 18.

[0052] The control module 26 communicates with the compressor 12, the fan 24, and the leak sensor 30. The control module 26 can communicate wirelessly or via a wired connection, and can communicate directly or indirectly with another device or control module.

[0053] Control module 26 may include a single module or multiple control modules and may be implemented as part of a control board, furnace board, thermostat, air processor board, contactor, or diagnostic system. Control module 26 may include a power regulation circuitry to supply power to electronic devices using 24 volts (V) alternating current (AC), 120V to 240V AC, 5V direct current (DC), or other suitable power.

[0054] The control module 26 may include a bidirectional communication port, which can be wired, wireless, or both. This port can be used for, for example, system debugging, programming, updates, monitoring, and parameter / status transmission.

[0055] The refrigeration system 10 can be used in residential houses or other types of residential, commercial or industrial buildings.

[0056] When a leak is detected by control module 26, control module 26 can activate fan 24 and / or one or more other mitigation devices to disperse any leaking refrigerant. Furthermore, control module 26 can disable / lock the operation of any ignition source.

[0057] According to this disclosure, control module 26 automatically resets refrigeration system 10 after the refrigeration leak has been mitigated, allowing refrigeration system 10 to resume normal operation. When a leak is detected, control module 26 can output a warning to the building owner or operator. This warning can be, for example, a visual warning, an audible warning, both visual and audible warnings, or other suitable types of warnings.

[0058] Following at least a predetermined number of refrigerant leak events (e.g., 3 or other suitable number), control module 26 may disable refrigeration system 10 until it is manually reset, for example, by receiving a reset input from the building owner, operator, or contractor. In various implementations, control module 26 may request a manual reset only if the refrigerant leak level (e.g., the amount of refrigerant that has leaked) exceeds a predetermined value for the refrigerant used (e.g., 25% of the lower flammability limit (LFL)). If the refrigeration system is already locked due to a refrigerant leak event, control module 26 may remain locked until, for example, the contractor resets refrigeration system 10. Control module 26 may receive a manual reset, for example, in response to a user input to the reset actuator, from the thermostat in response to a user input to the thermostat, from an external device (e.g., via a port), or in other suitable manner.

[0059] Control module 26 can store at least a predetermined amount of measurement results and other data from sensor 30 (e.g., the last 7 days or other suitable periods), allowing contractors to use the stored information, for example, for diagnostic purposes. Other data may include system uptime date, leak time / date, gas concentration level reached during each leak event, time taken to mitigate each leak event, and other suitable data.

[0060] Figure 2 This is a flowchart depicting an example method for automatically resetting the refrigeration system and allowing it to resume normal operation after a refrigerant leak has been mitigated. At S100, control begins and proceeds in parallel to S102. At S102, control module 26 measures or determines the amount of refrigerant in the refrigeration system (A2L refrigerant level).

[0061] At S104, control module 26 determines whether a mitigation event is occurring. If a mitigation event is occurring, control proceeds to S106. If a mitigation event is not occurring, control proceeds to S118, which will be discussed further below.

[0062] At S106, control module 26 determines whether the A2L refrigerant level (measured from sensor 30, e.g., concentration) is less than a predetermined stop-relief level. The predetermined stop-relief level can be a predetermined level (amount) where relief from the leak can be stopped and can be calibrated. For example, the predetermined stop-relief level could be 1% of the refrigerant LFL or another suitable value. If S106 is true, control proceeds to S108. If S106 is false, control returns to S100.

[0063] At S108, control module 26 turns on all the fans (e.g., fan 24) in the entire building and begins incrementing the fan run timer. Therefore, the fan run timer tracks the duration for which the fans in the entire building are on. At S110, control module 26 determines whether the fans in the entire building have been on for a predetermined period (e.g., whether the fan run timer exceeds a predetermined value). For example, the predetermined period could be approximately 5 minutes or other suitable timeframes. If S110 is true, control proceeds to S112. If S110 is false, control returns to S100.

[0064] At S112, control module 26 increments the relief on-counter. Therefore, the relief on-counter tracks the number of relief events performed to mitigate refrigerant leaks. At S112, control module 26 can also shut off all the fans in the house.

[0065] At S114, control module 26 determines whether the resuscitation on-counter is greater than or equal to a predetermined value. For example only, the predetermined value could be 3 or any other suitable integer greater than zero. If S114 is true, control module 26 may keep compressor 12 disabled and keep refrigeration system 10 locked until a manual reset is received at S116, for example, from the contractor or building owner or operator. If S114 is false, at S117, control module 26 automatically resets refrigeration system 10 and allows compressor 12 to be reactivated (e.g., as requested by the thermostat). Control returns to S100.

[0066] Returning to reference S118 (when S104 is false - mitigation event has not occurred), control module 26 determines whether the A2L refrigerant level (measured by sensor 30) is greater than a predetermined start mitigation level. The predetermined start mitigation level can be a predetermined level (e.g., concentration) where mitigation of the leak should begin, and can be calibrated. As an example only, the predetermined start mitigation level can be greater than or equal to a predetermined stop mitigation level (e.g., greater than or equal to 1% of the refrigerant LFL) or other suitable value.

[0067] If S118 is true, control continues to S120. If S118 is false, control continues to S124. At S120, control module 26 locks compressor 12, thereby preventing compressor 12 from being turned on (e.g., despite a request from the thermostat). At S122, control module 26 turns on all the fans in the house (e.g., fan 24). At S124, control module 26 allows the refrigeration system 10 to operate in normal operating mode (e.g., turning the compressor on and off based on a request from the thermostat, etc.).

[0068] Figure 3 It is a flowchart depicting an example method for automatically resetting the refrigeration system and allowing the refrigeration system 10 to resume normal operation after the refrigerant leak is mitigated, unless the A2L refrigerant level (measured from sensor 30) is greater than a predetermined locking level (e.g., 25% of refrigerant LFL).

[0069] At S200, control begins and proceeds in parallel to S202. At S202, control module 26 determines the A2L refrigerant level (e.g., a measurement from sensor 30). The A2L refrigerant level can reflect the amount (e.g., concentration) of A2L refrigerant at sensor 30.

[0070] At S204, control module 26 determines whether a mitigation event is occurring. If a mitigation event is occurring, control proceeds to S206. If a mitigation event is not occurring, control proceeds to S216, which will be discussed further below.

[0071] At S206, control module 26 determines whether the A2L refrigerant level (measured by sensor 30) is less than a predetermined stop relief level. If S206 is false, control can return to S200. If S206 is true, control can continue to S208.

[0072] At S208, control module 26 turns on all the fans in the house (e.g., fan 24) and begins incrementing the fan operation timer. At S210, control module 26 determines whether all the fans in the house have been on for a predetermined period (e.g., whether the fan operation timer is greater than or equal to a predetermined value). This predetermined period could be, for example, about 5 minutes or other suitable time period. If S210 is false, control module 26 turns on all the fans in the house, and control returns to S200. If S210 is true, control continues to S212.

[0073] At S212, control module 26 determines whether the A2L refrigerant level is greater than (or equal to) a predetermined lockout level. The predetermined lockout level can be calibrated and can be, for example, 25% of the refrigerant LFL or other suitable value.

[0074] If S212 is true, control proceeds to S213, and control module 26 disables the compressor and keeps the refrigeration system 10 locked until a manual reset is received, for example, from the contractor or the building owner or operator. If S212 is false, at S224, control module 26 automatically resets the refrigeration system 10 and allows the compressor 12 to be reconnected (e.g., as requested by the thermostat). Control returns to S200.

[0075] Returning to S216 (when S204 is false and no mitigation event has occurred), control module 26 determines whether the A2L refrigerant level measured by sensor 30 is greater than the predetermined start-mitigation level. If S216 is true, control continues to S218. If S216 is false, control transfers to S222. Then, in S218, the compressor is locked to prevent operation.

[0076] At S218, control module 26 locks compressor 12, thereby preventing compressor 12 from being turned on (e.g., despite a request from the thermostat). At S220, control module 26 turns on all the fans in the house (e.g., fan 24). At S222, control module 26 allows the refrigeration system 10 to operate in normal operating mode (e.g., turning the compressor on and off based on a request from the thermostat, etc.).

[0077] Figure 4 This is a functional block diagram of an example control system. As described above, fan module 404 controls the operation of fan 24 (e.g., on / off, speed). As described above, compressor module 408 controls the operation of compressor 12 (e.g., on / off, speed, capacity, etc.). As described above, locking module 412 controls the actuation of the locking device. As described above, locking module 412 can also control the locking of compressor 12.

[0078] Leakage module 436 determines the presence of a leak (i.e., refrigerant leaking from the building's refrigeration system) based on (e.g., the A2L refrigerant level measured by leak sensor 30). Alternatively, the A2L refrigerant level can be determined based on one or more other measurement parameters. For example, leakage module 436 can determine the presence of a leak when the A2L refrigerant level is greater than a predetermined start-to-relief level. When the A2L refrigerant level is lower than a predetermined stop-to-relief level, leakage module 436 can determine that the leak has been relieved (and there is no leak).

[0079] The leakage module 436 generates a signal indicating whether a leakage exists. For example, the leakage module 436 can set the signal to a first state when a leakage exists, and to a second state when a leakage does not exist.

[0080] When a leak is present, one or more remedial actions can be taken. For example, as described above, when a leak is present, fan module 404 can turn on fan 24. Furthermore, as described above, compressor module 408 can turn off compressor 12 and remain off until the leak is remedyed. However, compressor module 408 can keep compressor 12 off when the mitigation on / off counter is greater than or equal to a predetermined value or the A2L refrigerant level is greater than or equal to a predetermined lockout level. Additionally, lockout module 412 can actuate lockout device 32 to prevent ignition by one or more ignition devices within the building. Lockout module 412 can maintain the state of lockout device 32 for a predetermined period of time, for example, to allow the refrigerant leak to dissipate.

[0081] Furthermore, when a leak is present, the alarm module 440 can generate one or more indications. For example, the alarm module 440 can send indications to one or more external devices 444, generate one or more visual indications 448 (e.g., turn on one or more lights, display information on one or more displays, etc.) and / or generate one or more auditory indications, for example, via one or more speakers 452.

[0082] The foregoing description is illustrative in nature and is in no way intended to limit the scope of this disclosure, its application, or its uses. The broad teachings of this disclosure can be implemented in various forms. Therefore, although this disclosure includes specific examples, its true scope should not be limited thereto, as other modifications will become apparent upon examination of the drawings, specification, and appended claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without altering the principles of this disclosure. Furthermore, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of this disclosure may be implemented and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the substitution of one or more embodiments for each other remains within the scope of this disclosure.

[0083] Various terms are used to describe spatial and functional relationships between components (e.g., between modules, circuit elements, semiconductor layers, etc.), including “connection,” “joint,” “coupled,” “adjacent,” “right next to,” “on top,” “above,” “below,” and “set.” Unless explicitly stated as “direct,” when describing the relationship between the first and second components in the foregoing disclosure, the relationship can be a direct relationship where no other intervening components exist between the first and second components, or an indirect relationship (spatially or functionally) between the first and second components. As used herein, the phrases A, B, and C at least one should be interpreted as meaning the use of a non-exclusive logical OR (A or B or C) logic and should not be interpreted as meaning “at least one of A, at least one of B, and at least one of C.”

[0084] In the accompanying drawings, the direction of the arrows, as indicated by the arrows, typically indicates the flow of information important to the illustration (such as data or instructions). For example, when components A and B exchange various information, but the information transmitted from component A to component B is relevant to the illustration, the arrow can point from component A to component B. This unidirectional arrow does not imply that no other information is transmitted from component B to component A. Furthermore, for information sent from component A to component B, component B may send a request for the information or an acknowledgment of receipt of the information to component A.

[0085] In this application, which includes the definitions below, the term "module" or "control module" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include the following: application-specific integrated circuit (ASIC); digital, analog, or mixed-signal analog / digital discrete circuit; digital, analog, or mixed-signal analog / digital integrated circuit; combinational logic circuit; field-programmable gate array (FPGA); processor circuitry (shared, dedicated, or grouped) that executes code; memory circuitry (shared, dedicated, or grouped) that stores code executed by the processor circuitry; other suitable hardware components that provide the aforementioned functionality; or a combination of some or all of the above, such as in a system-on-a-chip.

[0086] A module may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functionality of any given module in this disclosure may be distributed across multiple modules connected via the interface circuits. For example, multiple modules may allow for load balancing. In another example, a server (also known as a remote or cloud) module may perform some functions on behalf of a client module.

[0087] The term "code," as used above, can include software, firmware, and / or microcode, and can refer to programs, routines, functions, categories, data structures, and / or objects. The term "shared processor circuitry" includes a single-processor circuitry that executes some or all of the code from multiple modules. The term "grouped processor circuitry" includes processor circuitry that is combined with other processor circuitry to execute some or all of the code from one or more modules. References to multiprocessor circuitry include multiprocessor circuitry on a discrete chip, multiprocessor circuitry on a single chip, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term "shared memory circuitry" includes a single memory circuitry that stores some or all of the code from multiple modules. The term "grouped memory circuitry" includes memory circuitry that is combined with other memory to store some or all of the code from one or more modules.

[0088] The term memory circuit is a subset of the term computer-readable medium. As used herein, the term computer-readable medium does not include transient electrical or electromagnetic signals propagating through a medium (e.g., on a carrier wave), and therefore the term computer-readable medium can be considered tangible and non-transient. Non-limiting examples of non-transient tangible computer-readable media are non-volatile memory circuits (e.g., flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (e.g., static random access memory circuits or dynamic random access memory circuits), magnetic storage media (e.g., analog magnetic tape or digital magnetic tape or hard disk drives), and optical storage media (e.g., CDs, DVDs, or Blu-ray discs).

[0089] The apparatus and methods described in this application can be implemented, partially or completely, by a special-purpose computer created by configuring a general-purpose computer to perform one or more specific functions embodied in a computer program. The aforementioned function blocks, flowchart components, and other elements serve as software specifications, which can be compiled into a computer program through the routine work of an experienced technician or programmer.

[0090] A computer program includes processor-executable instructions stored on at least one non-transitory, tangible, computer-readable medium. A computer program may also include or depend on stored data. A computer program may encompass a basic input / output system (BIOS) that interacts with the hardware of a special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0091] Computer programs can include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated by a compiler from source code; (iv) source code executed by an interpreter; (v) source code compiled and executed by a just-in-time (JIT) compiler, etc. As examples only, programs from languages ​​including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, and Lisp can be used. Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language 5th Edition), Ada, ASP (Dynamic Server-Side Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK and Use the syntax of the language to write source code.

Claims

1. A refrigeration system for a building, comprising: a compressor module configured to keep a compressor of the refrigeration system continuously off for at least a predetermined period in response to a determination that an amount of refrigerant existing outside of the refrigeration system within a building is greater than a first predetermined amount; and a fan module configured to keep a fan continuously on for at least the predetermined period in response to a determination that the amount of refrigerant existing outside of the refrigeration system within the building is greater than the first predetermined amount, wherein, when the fan is on, the fan moves air across an evaporator of the refrigeration system, wherein the compressor module is further configured to selectively turn the compressor on after the compressor has been off for the predetermined period and the amount of refrigerant existing outside of the refrigeration system within the building is less than a second predetermined amount without receiving an input indicative of a reset of the refrigeration system, and wherein the compressor module is further configured to keep the compressor off when a number of occurrences of the amount of refrigerant existing outside of the refrigeration system within the building being greater than the first predetermined amount is greater than a predetermined number of occurrences until the input indicative of the reset of the refrigeration system is received.

2. The refrigeration system of claim 1, further comprising a sensor configured to measure the amount of refrigerant existing outside of the refrigeration system within the building. the sensor is disposed proximate the evaporator.

3. The refrigeration system of claim 2 wherein, the second predetermined amount is less than the first predetermined amount.

4. The refrigeration system of claim 1 wherein, the refrigerant has an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) classification of A2L.

5. The refrigeration system of claim 1 wherein, the predetermined number of occurrences is an integer greater than 1.

6. The refrigeration system of claim 1 wherein, the compressor module is configured to keep the compressor off when the amount of refrigerant existing outside of the refrigeration system within the building exceeds a third predetermined amount until the input indicative of the reset of the refrigeration system is received.

7. The refrigeration system of claim 1 wherein, the third predetermined amount is greater than the second predetermined amount.

8. The refrigeration system of claim 7 wherein, the third predetermined amount is at least 20 percent of a lower flammable limit (LFL) of the refrigerant.

9. The refrigeration system of claim 7 wherein, 10. The refrigeration system of claim 1, further comprising a lockout module configured to prevent one or more ignition devices from igniting for at least the predetermined period in response to a determination that the amount of refrigerant existing outside of the refrigeration system within the building is greater than the first predetermined amount.

11. A method of refrigeration control for a building, comprising: keeping a compressor of a refrigeration system continuously off for at least a predetermined period in response to a determination that an amount of refrigerant existing outside of the refrigeration system within a building is greater than a first predetermined amount; keeping a fan continuously on for at least the predetermined period in response to a determination that the amount of refrigerant existing outside of the refrigeration system within the building is greater than the first predetermined amount, wherein, when the fan is on, the fan moves air across an evaporator of the refrigeration system; and ​ selectively turning the compressor on after the compressor has been turned off for the predetermined period of time and the amount of refrigerant present within the building other than the refrigeration system is less than a second predetermined amount in the absence of receiving the input indicating a reset of the refrigeration system, wherein maintaining the compressor off includes maintaining the compressor off until the input indicating a reset of the refrigeration system is received when a number of occurrences of the amount of refrigerant present within the building other than the refrigeration system being greater than the first predetermined amount is greater than a predetermined number of occurrences.

12. The method of claim 11, further comprising measuring the amount of refrigerant present within the building other than the refrigeration system using a sensor.

13. The method of claim 12, wherein, the sensor is positioned proximate the evaporator.

14. The method of claim 11, wherein, the second predetermined amount is less than the first predetermined amount.

15. The method of claim 11, wherein, maintaining the compressor off includes maintaining the compressor off until the input indicating a reset of the refrigeration system is received when the amount of refrigerant present within the building other than the refrigeration system exceeds a third predetermined amount.

16. The method of claim 15, wherein, the third predetermined amount is greater than the second predetermined amount.

17. The method of claim 15, wherein, the third predetermined amount is at least 20 percent of a lower flammable limit (LFL) of the refrigerant.

18. The method of claim 11, further comprising preventing one or more ignition devices from igniting for at least the predetermined period of time in response to determining that the amount of refrigerant present within the building other than the refrigeration system is greater than the first predetermined amount.

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