# US 9,521,780 B2 · Regulation of airflow and performance in information handling systems after fan failure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,521,780 B2 - Document ID: US9521780B2 - Status: Granted - Kind: B2 - Application number: 14/575,845 - Filed: 2014-12-18 - Published: 2016-06-23 - Granted: 2016-12-13 - Earliest claimed: 2014-12-18 - Assignees: Dell Products L.P. - Applicants: Dell Products L.P. - Inventors: Dinesh Kunnathur Ragupathi; Hasnain Shabbir - Web page: https://patentgrep.com/patent/US9521780B2 ## CPC - H05K 7/20209: {Thermal management, e.g. fan control} - G05B 15/02: electric - H05K 7/20836: {Thermal management, e.g. server temperature control} - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A fan control subsystem may control a plurality of fans in an information handling system to cool the information handling system. The fan control subsystem may determine a fan importance factor for each of the plurality of fans based on the presence and thermal priority ratings of one or more thermal components located in a respective thermal region associated with each of the plurality of fans. Upon detecting a failure of one of the plurality of fans, the fan control subsystem may regulate airflow within the information handling system based on the fan importance factors determined for the fans. ## Claims ### Claim 1 A method for regulating airflow in an information handling system, comprising: determining, by a fan control subsystem, a first fan importance factor of a first fan associated with a first thermal region of the information handling system, the first fan importance factor being based on a presence of a first thermal component in the first thermal region and on a first thermal priority rating indicative of a priority of cooling the first thermal component; determining, by the fan control subsystem, a second fan importance factor of a second fan associated with a second thermal region of the information handling system, the second fan importance factor being based on a presence of a second thermal component in the second thermal region and on a second thermal priority rating indicative of a priority of cooling the second thermal component; detecting, by the fan control subsystem, a failure of the first fan; and regulating, by the fan control subsystem in response to detecting the failure of the first fan, airflow in the information handling system based on at least one of the first fan importance factor and the second fan importance factor. ### Claim 2 (depends on 1) The method of claim 1, wherein regulating the airflow in the information handling system comprises directing a user to swap the first fan with the second fan based on the first fan importance factor and on the second fan importance factor. ### Claim 3 (depends on 2) The method of claim 2, further comprising: determining, by the fan control subsystem, a relative importance ranking associated with the first fan based on the first fan importance factor; determining, by the fan control subsystem, a relative importance ranking associated with the second fan based on the second fan importance factor; and directing the user to swap the first fan with the second fan based on the relative importance ranking associated with the first fan and the relative importance ranking associated with the second fan. ### Claim 4 (depends on 1) The method of claim 1, wherein regulating the airflow in the information handling system comprises automatically increasing a fan speed of the second fan by an amount based on the first fan importance factor. ### Claim 5 (depends on 1) The method of claim 1, further comprising determining, by the fan control subsystem, a nominal volumetric airflow associated with cooling the information handling system when the first fan and the second fan are operational; wherein regulating the airflow in the information handling system comprises: monitoring an actual volumetric airflow; and automatically increasing a fan speed of the second fan by an amount based on the second fan importance factor while the actual volumetric airflow is less than the nominal volumetric airflow. ### Claim 6 (depends on 1) The method of claim 1, wherein regulating the airflow in the information handling system comprises directing that a thermal characteristic of the first thermal region be altered by at least one of: directing a user to swap the first thermal component with the second thermal component based on the first fan importance factor and on the second fan importance factor, directing a user to remove the first thermal component from the first thermal region based on the first fan importance factor, and automatically decreasing a power consumption of the first thermal component based on the first fan importance factor. ### Claim 7 (depends on 1) The method of claim 1, wherein the information handling system comprises the fan control subsystem. ### Claim 8 An article of manufacture, comprising: a non-transitory machine-readable medium; and instructions on the non-transitory machine-readable medium, when read by a processor, are configured to cause the processor to: determine a first fan importance factor of a first fan associated with a first thermal region of an information handling system, the first fan importance factor being based on a presence of a first thermal component in the first thermal region and on a first thermal priority rating indicative of a priority of cooling the first thermal component; determine a second fan importance factor of a second fan associated with a second thermal region of the information handling system, the second fan importance factor being based on a presence of a second thermal component in the second thermal region and on a second thermal priority rating indicative of a priority of cooling the second thermal component; detect a failure of the first fan; and in response to detecting the failure of the first fan, regulate airflow in the information handling system based on at least one of the first fan importance factor and the second fan importance factor. ### Claim 9 (depends on 8) The article of claim 8, wherein the processor is further configured to regulate the airflow by directing a user to swap the first fan with the second fan based on the first fan importance factor and on the second fan importance factor. ### Claim 10 (depends on 9) The article of claim 9, wherein the processor is further configured to: determine a relative importance ranking associated with the first fan based on the first fan importance factor; determine a relative importance ranking associated with the second fan based on the second fan importance factor; and direct the user to swap the first fan with the second fan based on the relative importance ranking associated with the first fan and the relative importance ranking associated with the second fan. ### Claim 11 (depends on 8) The article of claim 8, wherein the processor is further configured to regulate the airflow in the information handling system by automatically increasing a fan speed of the second fan by an amount determined based on the first fan importance factor. ### Claim 12 (depends on 8) The article of claim 8, wherein the processor is further configured to: determine a nominal volumetric airflow associated with cooling the information handling system when the first fan and the second fan are operational; and regulate the airflow in the information handling system by: monitoring an actual volumetric airflow, and automatically increasing a fan speed of the second fan by an amount based on the second fan importance factor while the actual volumetric airflow is less than the nominal volumetric airflow. ### Claim 13 (depends on 8) The article of claim 8, wherein the processor is further configured to regulate the airflow in the information handling system by directing that a thermal characteristic of the first thermal region be altered by at least one of: directing a user to swap the first thermal component with the second thermal component based on the first fan importance factor and on the second fan importance factor, directing a user to remove the first thermal component from the first thermal region based on the first fan importance factor, and automatically decreasing a power consumption of the first thermal component based on the first fan importance factor. ### Claim 14 (depends on 8) The article of claim 8, wherein the information handling system comprises the processor. ### Claim 15 An information handling system, comprising: a first fan associated with a first thermal region of the information handling system; a second fan associated with a second thermal region of the information handling system; a processor; and a non-transitory machine-readable medium comprising instructions that, when read and executed by the processor, are configured to cause the processor to: determine a first fan importance factor of the first fan based on a presence of a first thermal component in the first thermal region and on a first thermal priority rating indicative of a priority of cooling the first thermal component; determine a second fan importance factor of the second fan based on a presence of a second thermal component in the second thermal region and on a second thermal priority rating indicative of a priority of cooling the second thermal component; detect a failure of the first fan; and in response to detecting the failure of the first fan, regulate airflow in the information handling system based on at least one of the first fan importance factor and the second fan importance factor. ### Claim 16 (depends on 15) The information handling system of claim 15, wherein the processor is further configured to regulate the airflow by directing a user to swap the first fan with the second fan, based on the first fan importance factor and on the second fan importance factor. ### Claim 17 (depends on 16) The information handling system of claim 16, wherein the processor is further configured to: determine a relative importance ranking associated with the first fan based on the first fan importance factor; determine a relative importance ranking associated with the second fan based on the second fan importance factor; and direct the user to swap the first fan with the second fan based on the relative importance ranking associated with the first fan and the relative importance ranking associated with the second fan. ### Claim 18 (depends on 15) The information handling system of claim 15, wherein the processor is further configured to regulate the airflow in the information handling system by automatically increasing a fan speed of the second fan by an amount determined based on the first fan importance factor. ### Claim 19 (depends on 15) The information handling system of claim 15, wherein the processor is further configured to: determine a nominal volumetric airflow associated with cooling the information handling system when the first fan and the second fan are operational; and regulate the airflow in the information handling system by: monitoring an actual volumetric airflow, and automatically increasing a fan speed of the second fan by an amount based on the second fan importance factor while the actual volumetric airflow is less than the nominal volumetric airflow. ### Claim 20 (depends on 15) The information handling system of claim 15, wherein the processor is further configured to regulate the airflow in the information handling system by directing that a thermal characteristic of the first thermal region be altered by at least one of: directing a user to swap the first thermal component with the second thermal component based on the first fan importance factor and on the second fan importance factor, directing a user to remove the first thermal component from the first thermal region based on the first fan importance factor, and automatically decreasing a power consumption of the first thermal component based on the first fan importance factor.