COMPRESSOR PROTECTION FOR REFRIGERANT SYSTEMS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/692370, filed on Sep. 9, 2025. The entire disclosure of the application referenced above is incorporated herein by reference.

TECHNICAL FIELD

Apparatuses and methods consistent with example embodiments relate to refrigerant systems and mechanisms for protecting refrigerant systems in the advent of leaks and/or malfunctions.

BACKGROUND

Manufacturers of refrigerant systems are mandated by various regulations to adhere to certain safety standards. These standards may vary for different refrigerant systems. For example, larger refrigerant systems may be mandated to include safety shutoff valves to mitigate various safety concerns. Smaller refrigerant systems may not be subject to the same mandates. Accordingly, challenges for operating and maintaining refrigerant systems may vary at least partially on their respective sizes.

SUMMARY

The present disclosure is directed to a method and a system for controlling a refrigerant system. In some embodiments, a method includes monitoring a plurality of refrigerant system parameters using a plurality of sensors. A first warning may be generated by one of the plurality of sensors in response to a first parameter exceeding a first threshold. If the first parameter exceeds a second threshold, or all of the plurality of sensors generate warnings, a control system may shut down a compressor (e.g., one or more) of the refrigerant system for at least a first predetermined time period. The control system may further cause the operation of a plurality of fans for at least a second time period, wherein the second period may be greater than, less than, or equal to the first time period. The method also includes incrementing a variable value usable to determine a time at which normal operation of the refrigerant is to resume.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become apparent and more readily appreciated from the following description of example embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 generally illustrates a diagram illustrating one embodiment of a refrigerant system, according to the principles of the present disclosure; and

FIG. 2 generally illustrates a flow diagram illustrating a method for performing protection of a refrigerant system, according to the principles of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the example embodiments may have different forms and may not be construed as being limited to the descriptions set forth herein.

It will be understood that the terms “include,” “including,” “comprise,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be further understood that, although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections may not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section.

As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Various terms are used to refer to particular system components. Different companies may refer to a component by different names—this document does not intend to distinguish between components that differ in name but not function.

Matters of these example embodiments that are obvious to those of ordinary skill in the technical field to which these example embodiments pertain may not be described herein in detail.

It may be understood that the example embodiments described herein may be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each example embodiment may be considered as available for other similar features or aspects in other example embodiments.

Manufacturers and operators of refrigerant systems are mandated by various regulations to adhere to safety standards to ensure safe operation. For example, some refrigerants may be flammable, and thus various regulations may mandate that refrigerant leaks be kept below a predetermined lower flammability limit (LFL), with mitigations carried out in response to a sensor detecting a refrigerant leak exceeding such a limit. Large refrigerant systems may include safety shutoff values that can at least temporarily reduce or eliminate the safety hazards. However, smaller refrigerant systems may lack a safety shutoff value, e.g., due to cost reasons. Thus, in the presence of such leaks, compressors in smaller refrigerant systems may be subject to short-cycling in which they rapidly start and stop. This can in turn increase the wear on a compressor and reduce its useful life.

The present disclosure is directed to systems and methods for protection of a refrigerant system. In a refrigerant system, a plurality of sensors is configured to monitor various system parameters, such as pressures, in order to detect refrigerant leaks, such as in systems that use flammable refrigerants. A control system may determine, by comparison, whether refrigerant leaks in the system exceed a first threshold, such as an LFL threshold. If a given sensor exceeds a first threshold, a warning is issued. If any sensor detects that that the presence of leaked refrigerant exceeds a second threshold, or all sensors report a warning, various mitigation actions are performed. These actions include a shutdown of all compressors in the refrigerant system, and may also include the operating of fans to disburse the leaked refrigerant and thus reduce the hazards presented thereby. The compressors may remain turned off and the fans may run for respective time periods (which may be different from one another). Additionally, a variable value used in a later comparison to determine whether to restart the system may be incremented.

After a predetermined time has elapsed with the compressors remaining off, a comparison of the variable value and another threshold that may be input by a user. If the count of the variable value is less than the threshold, normal operation may resume. Otherwise, the operation of the refrigerant system may remain locked out until such time as additional interventions (e.g., by maintenance personnel) are carried out.

Various embodiments of systems and methods for protection of refrigerant systems and components thereof are now discussed in further detail below.

FIG. 1 is a block diagram of one embodiment of a refrigerant system that includes a system monitor and controller 105. The refrigerant system includes a condenser coil 126, a safety shutoff valve 122 (which may not be present in all embodiments), an expansion valve 118, an evaporation coil 116, a compressor 112, and a check valve 114. One or more evaporator fans 120 are located near evaporation coil 116, and are arranged to circulate cold air into a data center, particularly on to servers 150. Similarly, one or more condenser fans are located near condenser coil 126, and are arranged to expel warm air to an exterior of a facility i which the refrigerant system is implemented.

It is noted that embodiments having multiple compressors are possible and contemplated, and that the refrigerant system shown here is considered a non-limiting example. Similarly, the use case of a data center as shown here is also considered to be a non-limiting example, as refrigerant systems in accordance with the disclosure may be utilized in a wide variety of different applications.

The refrigerant system as shown here also includes a number of sensors 106. These sensors 106 are distributed throughout the system and are configured to sense one or more operating parameters of the refrigerant system. For example, sensors 106 may be present at various points in the system to detect nearby levels of refrigerant that have evaporated into the air, indicating the potential presence of leaks in the system. Various ones of sensors 106 may also be utilized to detect pressures at various points therein, which can also be indicative of the presence of leaks. Temperatures may also be monitored at various points of the system using one or more sensors 106.

The system in these embodiments is utilized in a data center to keep servers from overheating, and thus includes a number of evaporator fans 120 to blow cold air onto the servers. The system further includes a number of condenser fans 126 arranged to blow warmer air from the condenser to a location exterior to the facility.

The system monitor and controller 105 as shown here may carry out various monitoring and control functions using feedback provided from the sensors 106. Among the functions carried out by the system monitor and controller 105 is the comparing of sensor readings, received via the various sensor inputs, to various thresholds. Based on these comparisons, various warnings and alarms may be output, as well as various control outputs. For example, if a given sensor 106 detects a refrigerant leak (via detections of gas in the surrounding air), it may compare the level of refrigerant in the air to one or more LFL thresholds. If the level is greater than a first threshold, but less than a second, larger threshold, a warning may be generated by the given sensor 106 and displayed by the system monitor and controller 105. Since many systems may have multiple sensors, multiple warnings may be generated if corresponding sensors detect refrigerant leaks that exceed the first LFL threshold but are less than the second LFL threshold.

In this implementation, if a given sensor 106 detects a leak that exceeds a second LFL threshold, or if all sensors 106 detect leaks sufficient to generate warnings (even if none otherwise detect a leak exceeding the second LFL threshold), the system monitor and controller 105 may generate control outputs to cause the refrigerant system to shut down. In particular, the compressor (or compressors, in multi-compressor systems) may be shut down. In systems that include one, a safety shutoff valve may be closed.

After a shutdown, the system monitor and controller 105 may continue running the various fans of the system. In implementations that have additional fans, such fans may be activated as well. This may aid in clearing the air in which the refrigerant has leaked. The compressors of the refrigerant system may be shut down for at least a first predetermined period of time, while the fans may be allowed to run for a second predetermined period of time. These time periods may be different from one another.

When the system is shut down for the reasons noted above, the system monitor and controller 105 may increment a variable value that is used to determine when the system can be restarted. This value may be compared to a user input threshold value. If the variable value is less than the user input threshold value, the system may be automatically restarted by the system monitor and controller 105. However, if the variable value is equal to or greater than the user input threshold value, the system may remain in shutdown. While in shutdown, the fans may be allowed to continue running. Furthermore, the shutdown time may allow for technicians to locate and fix any leaks within the system using, e.g., the sensor data.

The incrementing of the variable value as described above may prevent frequent starts and stops of the system and components thereof, such as the compressors. In particular, this mechanism may prevent what is known as short-cycling, in which the compressors frequently start and stop. Such frequent starts and stops can cause damage to compressors and lead to early failure. Thus, as system shutdowns occur due to, e.g., leaks, the increase of the variable is more likely to keep the system shut down for longer periods of time until the issues causing the shutdown are resolved.

In some cases, after a shutdown, the system monitor and controller 105 may be restarted. Upon a system restart, the variable value may be reset to zero. Furthermore, if, after a shutdown which incremented the value, the refrigerant system operates for at least a certain amount of time (e.g., 8 hours), the value may be reset to zero as a response to that condition as well.

Utilizing the dynamic variable in the system may thus safeguard compressor systems against the detrimental effects of short cycling. By automatically increasing the count of the variable with each leak-driven shutdown, our technology provides a proactive approach to identifying and addressing potential refrigerant leaks before they escalate into critical issues. Moreover, by implementing a user inputted threshold before initiating a system lockout, our software effectively prevents compressors from running, thereby minimizing the risk of further damage. This not only enhances the reliability and longevity of compressor systems but also significantly reduces maintenance costs and downtime associated with potential repairs. Our solution epitomizes efficiency, reliability, and safety, delivering tangible benefits to manufacturers, operators, and end-users alike.

FIG. 2 is a flow diagram illustrating a method for performing protection of a refrigerant system. Method 200 as depicted here may be executed by the system monitor and controller 105 discussed above with reference to FIG. 1. For example, the system monitor and controller 105 may include a processor and a computer readable medium storing instructions that, when executed by the processor, carry out the methodology. Other embodiments may be implemented using, e.g., hardwired circuitry, various types of microcontrollers, programmable devices such as FPGAs, and so forth.

It is noted that the various values used in the description of Method 200 (e.g., 3 seconds, 20%, etc.) are given here by way of example, but are not intended to be limiting in any way. Accordingly, the disclosure contemplates that these values may be different for other implementations, in accordance with the various design parameters and needs of such systems.

In the method shown here, if, during normal operation, no sensor reports any warnings, normal operations continue (block 202). If any sensor within the system detects a leak, as indicated by an LFL of greater than 15% for three seconds (block 208), a warning is issued. If any sensor detects a leak with an LFL of greater than 20% (block 204), or if all other sensors report warnings (block 206), or if there is a loss of communications, the method moves to the mitigation phase (block 220). Mitigation in this embodiment includes shutting down all compressors (block 232) in the refrigerant system and running supply fans (block 234) to reduce any gas build-up. Alarms may also be sounded (block 236) to indicate to technicians or maintenance personnel that a shutdown has occurred. Additionally, in response to the condition that caused the shutdown, a variable value is incremented (block 238).

The initial mitigation in this example continues for at least 10 minutes (block 222). If, after 10 minutes, no reported LFL is greater than 10% (block 222, true), the count of the variable value is compared to a user input threshold value (block 224). If the count is less than the user input threshold value (block 224, true), normal operation resumes. However, if the count is greater than or equal to the user input threshold value (block 224, false), the system remains shut down and is considered to be in lockout (block 228), with an alarm indicating the same invoked (block 226). At this point in the method, normal operation may resume after intervention by a technician or other personnel. The intervention may include performing repairs or other maintenance to minimize or eliminated the leaks. After the intervention is complete, a technician may restart the system, which may include resetting the variable value that is compared to the user input threshold.

If an individual sensor generates a value corresponding to a warning or error (block 212), a sensor warning is issued (block 213). If a sensor encounters a serious error or loss of communications (block 214), a serious sensor warning is issued (block 215). Similarly, if a sensor encounters a critical error (block 216), a critical sensor warning is issued (block 217).

While example embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims.