# US 10,309,677 B2 · HVAC system air filter diagnostics and monitoring > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,677 B2 - Document ID: US10309677B2 - Status: Granted - Kind: B2 - Application number: 14/712,049 - Filed: 2015-05-14 - Published: 2015-11-19 - Granted: 2019-06-04 - Earliest claimed: 2014-05-15 - Assignees: Emerson Climate Technolgoies, Inc. - Applicants: Emerson Electric Co. - Inventors: Priotomo Abiprojo; Fadi M. Alsaleem - Web page: https://patentgrep.com/patent/US10309677B2 ## CPC - F24F 11/39: Monitoring filter performance - F24F 11/30: for purposes related to the operation of the system, e.g. for safety or monitoring - F24F 11/38: Failure diagnosis - F24F 11/52: Indication arrangements, e.g. displays - F24F 11/58: using Internet communication - F24F 11/62: characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values - F24F 11/63: Electronic processing - G05B 15/02: electric - F24F 11/47: Responding to energy costs - F24F 2140/00: Control inputs relating to system states - Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating - 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) - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A system and method for monitoring a heating, ventilation, or air conditioning (HVAC) system of a building is provided. A monitoring server, located remotely from the building, receives operating parameter data from a monitoring device at the building that measures an operating parameter of the HVAC system. The monitoring server generates a plurality of data clusters from the operating parameter data, each data cluster corresponding to operating parameter data generated during steady-state operation of the HVAC system. The monitoring server calculates an average operating parameter value for each data cluster. The monitoring server calculates normalized operating parameter values based on normalizing the average operating parameter values for the data clusters over a predetermined normalization time period. The monitoring server compares the normalized operating parameter values with a threshold. The monitoring server determine whether an air filter of the HVAC system needs to be replaced based on the comparison and generates a notification based on the determination indicating that the air filter needs to be replaced. ## Claims ### Claim 1 A monitoring system for a heating, ventilation, or air conditioning (HVAC) system of a building, the monitoring system comprising: a monitoring device having a current sensor at the building that measures current draw of a circulator blower of the HVAC system, the circulator blower having a plurality of stages; a monitoring server, located remotely from the building, configured to (i) receive operating parameter data, including current draw data, from the monitoring device at the building, (ii) identify steady-state segments in the operating parameter data, each steady-state segment including only operating data generated during steady-state operation of the circulator blower at one of the plurality of stages and excluding operating data generated while the circulator blower is in a start-up state between when the circulator blower is initiated and when the circulator blower reaches steady-state operation at one of the stages and excluding operating data generated while the circulator blower transitions between steady-state operation at a first stage of the plurality of stages and steady-state operation at a second stage of the plurality of stages, (iii) generate a plurality of data clusters from the operating parameter data based on the identified steady-state segments, each data cluster of the plurality of data clusters including operating data from steady-state segments that correspond to operation of the circulator blower at the same stage of the plurality of stages, (iv) calculate an average operating parameter value for each data cluster, (v) calculate normalized operating parameter values based on normalizing the average operating parameter values for the data clusters over a predetermined normalization time period, (vi) compare the normalized operating parameter values with a threshold, (vii) determine whether an air filter of the HVAC system needs to be replaced based on the comparison, (viii) generate a notification based on the determination indicating that the air filter needs to be replaced, (ix) communicate the notification to a customer device associated with the HVAC system, and (x) adjust the threshold after the notification is communicated to the customer device. ### Claim 2 (depends on 1) The monitoring system of claim 1, wherein the monitoring server sets the threshold relative to a baseline operating parameter value for the HVAC system, the baseline operating parameter value corresponding to at least one of: a predetermined expected operating parameter value for the HVAC system; and an average operating parameter value for the HVAC system over an initialization time period. ### Claim 3 (depends on 1) The monitoring system of claim 1, wherein the monitoring server identifies the steady-state segments in the operating parameter data based on a determination that a variance of a data segment within the operating parameter data is within a predetermined range of a variance threshold. ### Claim 4 (depends on 1) The monitoring system of claim 1, wherein the monitoring server identifies the steady-state segments in the operating parameter data based on a determination that a rate of change of values within the operating parameter data is within a predetermined range of a rate threshold. ### Claim 5 A method for monitoring a heating, ventilation, or air conditioning (HVAC) system of a building, the method comprising: measuring, with a monitoring device having a current sensor at the building, current draw of a circulator blower of the HVAC system, the circulator blower having a plurality of stages; receiving, with a monitoring server located remotely from the building, operating parameter data, including current draw data, from the monitoring device at the building; identifying, with the monitoring server, steady-state segments in the operating parameter data, each steady-state segment including only operating data generated during steady-state operation of the circulator blower at one of the plurality of stages and excluding operating data generated while the circulator blower is in a start-up state between when the circulator blower is initiated and when the circulator blower reaches steady-state operation at one of the stages and excluding operating data generated while the circulator blower transitions between steady-state operation at a first stage of the plurality of stages and steady-state operation at a second stage of the plurality of stages; generating, with the monitoring server, a plurality of data clusters from the operating parameter data based on the identified steady-state segments, each data cluster of the plurality of data clusters including operating data from steady-state segments that correspond to operation of the circulator blower at the same stage of the plurality of stages; calculating, with the monitoring server, an average operating parameter value for each data cluster; calculating, with the monitoring server, normalized operating parameter values based on normalizing the average operating parameter values for the data clusters over a predetermined normalization time period; comparing, with the monitoring server, the normalized operating parameter values with a threshold; determining, with the monitoring server, whether an air filter of the HVAC system needs to be replaced based on the comparison; generating, with the monitoring server, a notification based on the determining indicating that the air filter needs to be replaced; communicating, with the monitoring server, the notification to a customer device associated with the HVAC system; and adjusting the threshold after communicating the notification to the customer device. ### Claim 6 (depends on 5) The method of claim 5, further comprising setting, with the monitoring server, the threshold relative to a baseline operating parameter value for the HVAC system, the baseline operating parameter value corresponding to at least one of: a predetermined expected operating parameter value for the HVAC system; and an average operating parameter value for the HVAC system over an initialization time period. ### Claim 7 (depends on 5) The method of claim 5, wherein identifying the steady-state segments in the operating parameter data is based on a determination that a variance of a data segment within the operating parameter data is within a predetermined range of a variance threshold. ### Claim 8 (depends on 5) The method of claim 5, wherein identifying the steady-state segments in the operating parameter data is based on a determination that a rate of change of values within the operating parameter data is within a predetermined range of a rate threshold. ### Claim 9 A monitoring system for a heating, ventilation, or air conditioning (HVAC) system of a building, the monitoring system comprising: a monitoring device having a current sensor at the building that measures current draw of a circulator blower of the HVAC system, the circulator blower having a plurality of stages; a monitoring server, located remotely from the building, configured to (i) receive operating parameter data, including current draw data, from the monitoring device at the building, (ii) identify steady-state segments in the operating parameter data, each steady-state segment including only operating data generated during steady-state operation of the circulator blower at one of the plurality of stages and excluding operating data generated while the circulator blower is in a start-up state between when the circulator blower is initiated and when the circulator blower reaches steady-state operation at one of the stages and excluding operating data generated while the circulator blower transitions between steady-state operation at a first stage of the plurality of stages and steady-state operation at a second stage of the plurality of stages, (iii) generate a plurality of data clusters from the operating parameter data based on the identified steady-state segments, each data cluster of the plurality of data clusters including operating data from steady-state segments that correspond to operation of the circulator blower at the same stage of the plurality of stages, (iv) calculate an average operating parameter value for each data cluster, (v) calculate normalized operating parameter values based on normalizing the average operating parameter values for the data clusters over a predetermined normalization time period, (vi) perform a trend analysis of the normalized operating parameter values by comparing each normalized operating parameter value with previous normalized operating parameter values, (vii) determine a trend for the normalized operating parameter values associated with each normalized operating parameter value, (viii) associate a trend confidence level with each normalized operating parameter value, (ix) determine whether an air filter of the HVAC system needs to be replaced based on the trend analysis, (x) generate a notification based on the determination indicating that the air filter needs to be replaced, and (xi) communicate the notification to a customer device associated with the HVAC system. ### Claim 10 (depends on 9) The monitoring system of claim 9, wherein the trend analysis includes calculating a sum of the trend confidence levels for each normalized operating parameter value and wherein the monitoring server determines that the air filter needs to be replaced when the sum is greater than a threshold. ### Claim 11 (depends on 10) The monitoring system of claim 10, wherein the monitoring server resets the sum once the monitoring server determines that the air filter needs to be replaced. ### Claim 12 (depends on 10) The monitoring system of claim 10, wherein the monitoring server determines that the air filter has been replaced and resets the sum once the monitoring server determines that the air filter needs to be replaced. ### Claim 13 A method for monitoring a heating, ventilation, or air conditioning (HVAC) system of a building, the method comprising: measuring, with a monitoring device having a current sensor at the building, current draw of a circulator blower of the HVAC system, the circulator blower having a plurality of stages; receiving, with a monitoring server located remotely from the building, operating parameter data, including current draw data, from monitoring device at the building of the HVAC system; identifying, with the monitoring server, steady-state segments in the operating data, each steady-state segment including only operating data generated during steady-state operation of the circulator blower at one of the plurality of stages and excluding operating data generated while the circulator blower is in a start-up state between when the circulator blower is initiated and when the circulator blower reaches steady-state operation at one of the stages and excluding operating data generated while the circulator blower transitions between steady-state operation at a first stage of the plurality of stages and steady-state operation at a second stage of the plurality of stages; generating, with the monitoring server, a plurality of data clusters from the operating parameter data based on the identified steady-state segments, each data cluster of the plurality of data clusters including operating data from steady-state segments that correspond to operation of the circulator blower at the same stage of the plurality of stages; calculating, with the monitoring server, an average operating parameter value for each data cluster; calculating, with the monitoring server, normalized operating parameter values based on normalizing the average operating parameter values for the data clusters over a predetermined normalization time period; performing, with the monitoring server, a trend analysis of the normalized operating parameter values by comparing each normalized operating parameter value with previous normalized operating parameter values, determining a trend for the normalized operating parameter values associated with each normalized operating parameter value, and associating a trend confidence level with each normalized operating parameter value; determining, with the monitoring server, whether an air filter of the HVAC system needs to be replaced based on the trend analysis; generating, with the monitoring server, a notification based on the determination indicating that the air filter needs to be replaced; and communicating, with the monitoring server, the notification to a customer device associated with the HVAC system. ### Claim 14 (depends on 13) The method of claim 13, wherein performing the trend analysis includes calculating a sum of the trend confidence levels for each normalized operating parameter value and wherein the monitoring server determines that the air filter needs to be replaced when the sum is greater than a threshold. ### Claim 15 (depends on 13) The method of claim 13, further comprising resetting the sum, with the monitoring server, once the monitoring server determines that the air filter needs to be replaced. ### Claim 16 (depends on 13) The method of claim 13, further comprising determining, with the monitoring server, that the air filter has been replaced and resetting the sum, with the monitoring server, once the monitoring server determines that the air filter needs to be replaced.