HVAC Filter Fault Detection Using Multi-Sensor Efficiency Trends

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Solution Overview

Problem

HVAC systems face inefficiencies due to neglected filter maintenance, leading to degraded performance, increased energy consumption, and comfort issues, as users often fail to recognize when filters need cleaning or replacement.

Innovation Solution

A method and system that utilize sensors, including optical, temperature, pressure, and acoustic sensors, to estimate HVAC system performance and filter status, incorporating external data and user input to identify faults and estimate system capacity, with integrated wireless communication and power harvesting for efficient data transmission and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If filter is used to clean air in HVAC system, then air quality is improved, but airflow restriction increases over time leading to system performance degradation

Engineering Contradiction:
Improveair qualityVSAvoidsystem performance
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system performs preliminary monitoring of filter status using multiple sensors (pressure differential, airflow, particle counters) to detect degradation trends before they cause significant system performance loss. This allows proactive filter replacement scheduling that prevents the contradiction from fully manifesting.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors airflow and pressure differential across the filter, providing real-time feedback on filter loading status. This feedback loop enables dynamic adjustment of maintenance schedules and alerts users when filter replacement is needed to maintain optimal system performance while ensuring air quality.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple sensors are deployed to monitor filter status, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvefilter status detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensor types (pressure differential sensors, airflow sensors, particle counters) into an integrated monitoring system with a single controller that processes all inputs. This merging approach maintains high measurement precision through multi-parameter monitoring while reducing operational complexity by providing unified data processing and a single user interface.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The controller serves multiple functions: it processes data from various sensor types, performs predictive analytics, generates maintenance alerts, and provides user notifications. This multi-functionality consolidates what would otherwise be separate systems into a single device, maintaining measurement precision while managing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of time

If filter replacement is delayed, then loss of time for maintenance is reduced, but energy consumption and system inefficiency increase

Engineering Contradiction:
Improvemaintenance timeVSAvoidenergy waste
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The system performs preliminary analysis of filter degradation trends using sensor data and predictive algorithms to determine the optimal replacement timing. This allows scheduling maintenance at the precise moment when it becomes necessary, avoiding both premature replacement (wasting time) and delayed replacement (wasting energy).

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transitions from fixed-schedule maintenance to condition-based maintenance by continuously monitoring parameters such as pressure differential, airflow rate, and particle concentration. This parameter-driven approach optimizes the replacement timing to balance maintenance time investment against energy efficiency, replacing filters based on actual condition rather than arbitrary time intervals.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9092040B2HVAC filter monitoring
Publication Date: 2015.07.28 GOOGLE LLC
  • US9092040B2 patent drawing
  • US9092040B2 patent drawing
  • US9092040B2 patent drawing

AI summary

A method is described for identifying faults relating to an HVAC system, such a clogged filter. Sensor data is used to estimate HVAC system efficiency. Trends in system efficiency are then used to identify faults such as clogged filters. The sensor(s) can include one or more of the following types: optical sensor, temperature sensor, pressure sensor, acoustic transducer, humidity sensor, resistive sensor, capacitive sensor, and infrared sensor. The efficiency estimation can also be based on conditions external to the building, such as data from exterior sensors and/or data gathered from third parties such as government or private weather stations. The efficiency estimation can also be based on performance metrics such as the time used to reach a set point temperature. The fault identification includes filtering out non-fault related events.