US-20260126196-A1 - SYSTEM AND METHOD FOR PROVIDING COOLING DURING REFRIGERANT LEAK

US20260126196A1US 20260126196 A1US20260126196 A1US 20260126196A1US-20260126196-A1

Abstract

A refrigeration system to provide cooling during refrigerant leak is disclosed. The system detects a refrigerant leak by detecting that a refrigerant concentration is more than a threshold concentration on at least two occasions. The system executes a mitigation plan until the concentration of refrigerant is less than the threshold concentration. The system determines if it is operated in a safe mode, where in the safe mode, a blower of the system is set to operate continuously. When the system is in the safe mode, the system determines a number of times where the concentration of refrigerant exceeded the threshold concentration. In response to determining that the number of times where the concentration of refrigerant exceeded the threshold concentration is more than the threshold value, the system operate the HVAC system in the safe mode and communicate a first alert message.

Inventors

Rakesh Goel
Siddarth RAJAN
Vijay Kumar Sathyamurthi

Assignees

LENNOX INDUSTRIES INC.

Dates

Publication Date: 20260507
Application Date: 20251231

Claims (20)

1 . An environmental control system configured to regulate a condition of an environment, the system comprising: a blower configured to move airflow across a heat exchange component and into or out of the environment; a refrigerant detection sensor circuit configured to detect a concentration of a refrigerant in a region; and one or more processors operatively associated with the refrigerant detection sensor circuit and the air mover, the one or more processors configured to: on one or more occasions: obtain information related to the detected concentration of the refrigerant in the region; evaluate the detected concentration with respect to a threshold concentration; and determine that the detected concentration of the refrigerant satisfies a trigger condition relative to the threshold concentration; in response to the determination, execute a mitigation action until the detected concentration of the refrigerant no longer satisfies the trigger condition; determine whether the system is operating in a safe mode in which the air mover is commanded to operate continuously; determine, based at least in part on occurrences where the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration, a number of such occurrences and whether the number of such occurrences is more than a threshold value; and in response to determining that the number of such occurrences is more than the threshold value: operate the system in the safe mode; and communicate an alert indicating detection of a refrigerant leak.
2 . The system of claim 1 , wherein the one or more processors are further configured to communicate a second alert message indicating that a refrigerant leak is detected while the blower is operating.
3 . The system of claim 1 , wherein the one or more processors are further configured to: in response to determining that the system does not operate in the safe mode: increase a counter by one each time the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration; determine whether the counter has reached the threshold value; and in response to determining that the counter has reached the threshold value, operate the system in the safe mode.
4 . The system of claim 1 , further comprising a compressor configured to compress refrigerant and discharge the refrigerant at a higher pressure.
5 . The system of claim 4 , wherein the one or more processors are further configured to: while the system operates in the safe mode, receive a request to turn on the compressor; and in response to receiving the request, turn on the compressor.
6 . The system of claim 4 , wherein the mitigation action comprises: turning off the compressor if the compressor is energized; and turning on the blower.
7 . The system of claim 1 , wherein the one or more processors are integrated into the refrigerant detection sensor circuit or are external to the refrigerant detection sensor circuit.
8 . A method for operating an environmental control system configured to regulate a condition of an environment, the method comprising: on one or more occasions: obtaining information related to a detected concentration of a refrigerant in a region; evaluating the detected concentration with respect to a threshold concentration; and determining that the detected concentration of the refrigerant satisfies a trigger condition relative to the threshold concentration; in response to the determining, executing a mitigation action until the detected concentration of the refrigerant no longer satisfies the trigger condition; determining whether the system is operating in a safe mode in which a blower is commanded to operate continuously; determining, based at least in part on occurrences where the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration, a number of such occurrences and whether the number of such occurrences is more than a threshold value; and in response to determining that the number of such occurrences is more than the threshold value, operating the system in the safe mode and communicating an alert indicating detection of a refrigerant leak.
9 . The method of claim 8 , further comprising communicating a second alert message indicating that a refrigerant leak is detected while the blower is operating.
10 . The method of claim 8 , further comprising, in response to determining that the system does not operate in the safe mode: increasing a counter by one each time the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration; determining whether the counter has reached the threshold value; and in response to determining that the counter has reached the threshold value, operating the system in the safe mode.
11 . The method of claim 8 , further comprising operating a compressor to compress refrigerant and discharge the refrigerant at a higher pressure.
12 . The method of claim 11 , further comprising, while the system operates in the safe mode, receiving a request to turn on the compressor and, in response to receiving the request, turning on the compressor.
13 . The method of claim 11 , wherein the mitigation action comprises turning off the compressor if the compressor is energized and turning on the blower.
14 . The method of claim 8 , wherein obtaining the information related to the detected concentration of the refrigerant in the region comprises receiving signals from a refrigerant detection sensor circuit.
15 . The method of claim 8 , wherein evaluating the detected concentration with respect to the threshold concentration comprises comparing the detected concentration to a threshold concentration derived from a lower flammability limit or a predetermined safety threshold.
16 . A non-transitory computer-readable medium storing instructions that, when executed by one or more processors of an environmental control system configured to regulate a condition of an environment, cause the one or more processors to: on one or more occasions: obtain information related to a detected concentration of a refrigerant in a region; evaluate the detected concentration with respect to a threshold concentration; and determine that the detected concentration of the refrigerant satisfies a trigger condition relative to the threshold concentration; in response to the determining, execute a mitigation action until the detected concentration of the refrigerant no longer satisfies the trigger condition; determine whether the system is operating in a safe mode in which a blower is commanded to operate continuously; determine, based at least in part on occurrences where the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration, a number of such occurrences and whether the number of such occurrences is more than a threshold value; and in response to determining that the number of such occurrences is more than the threshold value, operate the system in the safe mode and communicating an alert indicating detection of a refrigerant leak.
17 . The non-transitory computer-readable medium of claim 16 , wherein the instructions further cause the one or more processors to communicate a second alert message indicating that a refrigerant leak is detected while the blower is operating.
18 . The non-transitory computer-readable medium of claim 16 , wherein the instructions further cause the one or more processors to, in response to determining that the system does not operate in the safe mode: increase a counter by one each time the detected concentration of the refrigerant satisfies the trigger condition relative to the threshold concentration; determine whether the counter has reached the threshold value; and, in response to determining that the counter has reached the threshold value, operate the system in the safe mode.
19 . The non-transitory computer-readable medium of claim 16 , wherein the instructions further cause the one or more processors to, while the system operates in the safe mode, receive a request to turn on a compressor and, in response to receiving the request, turn on the compressor.
20 . The non-transitory computer-readable medium of claim 16 , wherein the mitigation action comprises turning off the compressor if the compressor is energized and turning on the blower.

Description

CROSS-REFERENCE TO RELATED APPLICATION The application is a continuation of U.S. patent application Ser. No. 18/453,015, filed Aug. 21, 2023, entitled “SYSTEM AND METHOD FOR PROVIDING COOLING DURING REFRIGERANT LEAK,” which is incorporated herein by reference. TECHNICAL FIELD The present disclosure relates generally to heating, ventilation, and air conditioning (HVAC) systems and methods of their use, and more specifically to a system and method for providing cooling during refrigerant leak. BACKGROUND Heating, ventilation, and air conditioning (HVAC) systems are used to regulate environmental conditions within an enclosed space. Air is cooled or heated via heat transfer with refrigerant flowing through the system and returned to the enclosed space as conditioned air. During operation, refrigerant may leak from the working-fluid conduit subsystem or from one or more components. SUMMARY The system described in the present application provides several practical applications and technical advantages that overcome the current technical problems described herein. The following disclosure is particularly integrated into a practical application of improving refrigeration techniques by providing cooling during a refrigerant leak. In general, the disclosed system improves refrigeration techniques by enabling cooling even when a refrigerant leak is detected. The refrigerant may be flammable or at least mildly flammable, such as A2L. Therefore, it is crucial to detect and address A2L refrigerant leaks in a timely manner. In one approach, when a refrigerant leak is detected at any component of an HVAC system, the cooling unit (e.g., compressor circuits) of the HVAC system is switched off and the blower is switched on to dilute the refrigerant concentration that is present within the HVAC system. However, this approach suffers from several drawbacks. For example, switching off the cooling unit of the HVAC system leads to a temperature rise in a room where the HVAC system is deployed, and therefore, discomfort for the people in the room. In another example, with this approach, after the blower is switched on, the blower causes airflow from within the HVAC system to the outside which reduces the refrigerant concentration. This operation may be referred to as a mitigation plan to dilute the refrigerant concentration. In response to detecting that the refrigerant concentration is diluted, the blower may be switched off and the compressor circuit (that is associated with the refrigerant leak) may be switched back on. However, this refrigerant dilution may be temporary if the refrigerant leak is consistent and/or the refrigerant leak rate is significant. In other words, if the refrigerant leak is consistent and/or the refrigerant leak rate is significant, the refrigerant concentration will increase over time. In some cases, the mitigation plan cycle may repeat multiple times when the refrigerant leak is consistent and/or the refrigerant leak rate is significant. Current technology does not provide a solution to address multiple repetitions of the mitigation plan cycles. As a result, the refrigerant leakage will persist, and the blower may continue to be switched on and off in the mitigation plan cycles. This leads to degradation of the blower, compressor circuit, and other components that are involved in the cooling operation and the mitigation plan. This disclosure contemplates an unconventional system and method configured to provide cooling with one or more compressor circuits HVAC system during A2L (or other classes of flammable or mildly flammable) refrigerant leak. The disclosed system is configured to detect a number of times that refrigerant leak has occurred with respect to compressor circuit(s) within the HVAC system. The number of times occurrence of the refrigerant leak may be one, two, three, four, or any suitable number. If it is determined that the number of times that refrigerant leak has occurred is more than a threshold value, the disclosed system may operate the HVAC system in safe mode. The safe mode may be a mode of operation of the HVAC system in which the blower operates continuously. The disclosed system may continue to monitor refrigerant leaks at the compressor circuit(s). If a subsequent refrigerant leak is detected while the HVAC system is operating in the safe mode, the disclosed system may determine that the leak is significant enough such that even if the blower is switched on, it is not enough to dilute the refrigerant concentration or accumulation. In response, the disclosed system may transmit an alert message, for example, to a user device associated with a technician to provide a service to the HVAC system. Accordingly, the disclosed system provides a practical application of improving refrigeration techniques by allowing cooling even if an A2L refrigerant leak is detected. For example, if the HVAC system is a multi-compressor system, the system may switch on the blower as well as provide c