Systems and methods for predicting HVAC filter change

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Solution Overview

Problem

Existing HVAC systems lack a simple and cost-effective method to accurately predict when air filters need replacement, especially in demand-operation systems, due to variable usage patterns and environmental factors, leading to premature or delayed filter changes.

Innovation Solution

A computer-implemented method that estimates air filter replacement status by correlating fan runtime with outdoor weather data, such as temperature, without requiring sensors or mechanical components, using a Total Runtime Value compared to a Baseline Value to provide accurate and credible filter usage predictions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fixed calendar period replacement is used, then ease of operation is improved, but reliability deteriorates due to variable usage patterns

Engineering Contradiction:
Improvefilter replacement schedulingVSAvoidfilter performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system continuously monitors HVAC runtime and compares it against baseline values to dynamically adjust filter replacement scheduling. This feedback mechanism ensures the filter is replaced based on actual usage conditions rather than fixed calendar intervals, resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The filter replacement schedule is made dynamic by adjusting replacement intervals based on actual HVAC runtime and environmental factors. Instead of a static calendar-based schedule, the system adapts the replacement timing to match actual filter loading conditions, improving reliability while maintaining operational simplicity.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If visual inspection methods are used, then device complexity is reduced, but measurement precision deteriorates due to inability to assess actual filter condition

Engineering Contradiction:
Improvefilter status monitoringVSAvoidfilter condition assessment
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system uses HVAC runtime data as an intermediary indicator of filter condition. Instead of directly inspecting the filter's physical state, the system monitors the cumulative runtime of the HVAC system, which correlates with filter loading. This indirect measurement approach maintains simplicity while improving assessment accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The manual visual inspection process is replaced with an automated electronic monitoring system that tracks HVAC runtime and calculates filter status based on accumulated operational data. This substitution eliminates the need for physical filter inspection while providing more precise condition assessment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If sensor-based runtime tracking is implemented, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveruntime measurementVSAvoidsystem configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the HVAC controller's existing runtime tracking capability to monitor filter status. Instead of adding separate sensors, the invention leverages the self-service function already built into the HVAC controller, eliminating the need for additional measurement devices and reducing overall system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The HVAC controller is made multi-functional by using its existing runtime monitoring capability for dual purposes: system control and filter status indication. This universal use of the controller's built-in functions eliminates the need for dedicated runtime sensors while maintaining measurement precision.

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

4Productivity

If fixed interval replacement is used, then productivity is maintained through consistent scheduling, but loss of substance increases due to premature filter disposal

Engineering Contradiction:
ImproveHVAC system operationVSAvoidfilter material
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The system calculates and tracks the accumulated runtime leading up to the filter replacement point, allowing proactive scheduling of replacement at the optimal moment. This preliminary tracking prevents both premature replacement and delayed maintenance, maximizing filter utilization while maintaining HVAC productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The filter replacement criterion changes from a fixed calendar parameter to a dynamic parameter based on accumulated runtime and environmental conditions. This parameter change allows the filter to be used until its actual capacity is reached, reducing premature disposal while ensuring replacement before performance degradation occurs.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10610818B2Systems and methods for predicting HVAC filter change
Publication Date: 2020.04.07 3M INNOVATIVE PROPERTIES CO
  • US10610818B2 patent drawing
  • US10610818B2 patent drawing
  • US10610818B2 patent drawing

AI summary

Computer-implemented systems and methods for estimating a replacement status of an HVAC air filter. Outdoor weather data (e.g., outdoor temperature information), is obtained. A Total Runtime Value of the HVAC system is determined based upon the obtained outdoor weather data. Finally, a replacement status of the air filter is estimated as a function of a comparison of the Total Runtime Value with a Baseline Value. By correlating air filter replacement status with an estimated runtime of the HVAC system, a credible predictor of air filter usage is provided. By estimating fan runtime based on easily-obtained outdoor weather data, the methods are readily implemented with any existing HVAC system and do not require installation of sensors or other mechanical or electrical components to the HVAC system.