# US 12,595,924 B2 · System and method for providing cooling during refrigerant leak > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,595,924 B2 - Document ID: US12595924B2 - Status: Granted - Kind: B2 - Application number: 18/453,015 - Filed: 2023-08-21 - Published: 2025-02-27 - Granted: 2026-04-07 - Earliest claimed: 2023-08-21 - Assignees: Lennox Industries Inc. - Applicants: Lennox Industries Inc. - Inventors: Rakesh Goel; Siddarth Rajan; Vijay Kumar Sathyamurthi - Web page: https://patentgrep.com/patent/US12595924B2 ## CPC - F24F 11/36: to leakage of heat-exchange fluid - F24F 11/52: Indication arrangements, e.g. displays - F24F 11/65: for selecting an operating mode - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) ## 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. ## Claims ### Claim 1 A heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the HVAC system comprising: a blower positioned in a duct system, wherein the blower is configured to move airflow across an indoor coil and out of the duct system; a refrigerant detection sensor circuit configured to detect a concentration of refrigerant in a volume; and one or more processors associated with the refrigerant detection sensor, and configured to: for at least two occasions: obtain information related to the detected concentration of the refrigerant in the volume; compare the detected concentration of refrigerant with a threshold concentration; and determine that the detected concentration of refrigerant exceeds the threshold concentration; execute a mitigation plan until the detected concentration of refrigerant is less than the threshold concentration; in response to determining that the HVAC system does not operate in a safe mode, wherein, in the safe mode, the blower of the HVAC system is set to operate continuously: determine a number of times where the detected concentration of refrigerant exceeded the threshold concentration; determine whether the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than a threshold value; and in response to determining that the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than the threshold value: operate the HVAC system in the safe mode; and communicate a first alert message, wherein the first alert message indicates a refrigerant leak is detected. ### Claim 2 (depends on 1) The HVAC system of claim 1, wherein the processor is further configured to communicate a second alert message, wherein the second alert message indicates that a refrigerant leak is detected while the blower is turned on. ### Claim 3 (depends on 1) The HVAC system of claim 1, wherein the processor is further configured to: in response to determining that the HVAC system does not operate in the safe mode: increase a counter parameter by one each time the concentration of refrigerant exceeds the threshold concentration; determine whether the counter parameter has reached the threshold value; and in response to determining that the counter parameter has reached the threshold value, operate the HVAC system in the safe mode. ### Claim 4 (depends on 1) The HVAC system of claim 1, further comprising a compressor configured to receive flow of refrigerant from an evaporator coil and to discharge the flow of refrigerant at a higher pressure. ### Claim 5 (depends on 4) The HVAC system of claim 4, wherein the processor is further configured to: while the HVAC 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. ### Claim 6 (depends on 4) The HVAC system of claim 4, wherein the mitigation plan comprises: turning off the compressor if the compressor is energized; and turning on the blower. ### Claim 7 (depends on 1) The HVAC system of claim 1, wherein the one or more processors is integrated into the refrigerant detection sensor or external to the refrigerant detection sensor. ### Claim 8 A method for operating a heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the method comprising: for at least two occasions: obtaining information related to a detected concentration of a refrigerant in a volume; comparing the detected concentration of refrigerant with a threshold concentration; and determining that the detected concentration of refrigerant exceeds the threshold concentration; executing a mitigation plan until the detected concentration of refrigerant is less than the threshold concentration; in response to determining that the HVAC system does not operate in a safe mode, wherein, in the safe mode, a blower of the HVAC system is set to operate continuously: determining a number of times where the detected concentration of refrigerant exceeded the threshold concentration; determining whether the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than a threshold value; and in response to determining that the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than the threshold value: operating the HVAC system in the safe mode; and communicating a first alert message, wherein the first alert message indicates a refrigerant leak is detected. ### Claim 9 (depends on 8) The method of claim 8, further comprising communicating a second alert message, wherein the second alert message indicates that a refrigerant leak is detected while the blower is turned on. ### Claim 10 (depends on 8) The method of claim 8, further comprising: in response to determining that the HVAC system does not operate in the safe mode: increasing a counter parameter by one each time the concentration of refrigerant exceeds the threshold concentration; determining whether the counter parameter has reached the threshold value; and in response to determining that the counter parameter has reached the threshold value, operating the HVAC system in the safe mode. ### Claim 11 (depends on 8) The method of claim 8, further comprising receiving, at a compressor, flow of refrigerant from an evaporator coil and to discharge the flow of refrigerant at a higher pressure. ### Claim 12 (depends on 11) The method of claim 11, further comprising: while the HVAC 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. ### Claim 13 (depends on 11) The higher pressure of claim 11, wherein the mitigation plan comprises: turning off the compressor if the compressor is energized; and turning on the blower. ### Claim 14 (depends on 8) The method of claim 8, wherein the refrigerant is flammable, mildly flammable, or toxic. ### Claim 15 A non-transitory computer-readable medium storing instructions that when executed by a processor, cause the processor to: for at least two occasions: obtain information related to a detected concentration of a refrigerant in a volume; compare the detected concentration of refrigerant with a threshold concentration; and determine that the detected concentration of refrigerant exceeds the threshold concentration; execute a mitigation plan until the detected concentration of refrigerant is less than the threshold concentration; in response to determining that a heating, ventilation, and air conditioning (HVAC) system does not operate in a safe mode, wherein, in the safe mode, a blower of the HVAC system is set to operate continuously: determine a number of times where the detected concentration of refrigerant exceeded the threshold concentration; determine whether the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than a threshold value; and in response to determining that the number of times where the detected concentration of refrigerant exceeded the threshold concentration is more than the threshold value: operate the HVAC system in the safe mode; and communicate a first alert message, wherein the first alert message indicates a refrigerant leak is detected. ### Claim 16 (depends on 15) The non-transitory computer-readable medium of claim 15, wherein the instructions further cause the processor to communicate a second alert message, wherein the second alert message indicates that a refrigerant leak is detected while the blower is turned on. ### Claim 17 (depends on 15) The non-transitory computer-readable medium of claim 15, wherein the instructions further cause the processor to: in response to determining that the HVAC system does not operate in the safe mode: increase a counter parameter by one each time the concentration of refrigerant exceeds the threshold concentration; determine whether the counter parameter has reached the threshold value; and in response to determining that the counter parameter has reached the threshold value, operate the HVAC system in the safe mode. ### Claim 18 (depends on 15) The non-transitory computer-readable medium of claim 15, wherein the instructions further cause the processor to receive, at a compressor, flow of refrigerant from an evaporator coil and to discharge the flow of refrigerant at a higher pressure. ### Claim 19 (depends on 18) The non-transitory computer-readable medium of claim 18, wherein the instructions further cause the processor to: while the HVAC 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. ### Claim 20 (depends on 18) The non-transitory computer-readable medium of claim 18, wherein the processor is integrated into the refrigerant detection sensor or external to the refrigerant detection sensor.