Inside air control system

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Solution Overview

Problem

Existing inside air control systems face increased running costs due to unnecessary replacement of gas sensors that temporarily output abnormal values, often due to condensation issues, rather than actual damage.

Innovation Solution

The system includes a controller that determines the normalcy of gas sensors by supplying outdoor air and comparing measured values, allowing continued use without replacement unless absolutely necessary, and calibrates sensors based on outdoor air measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gas sensors are replaced whenever abnormal measured values are output, then measurement reliability is improved, but running cost increases due to unnecessary replacements

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidrunning cost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system performs preliminary diagnostic actions by supplying outdoor air to the gas sensor before replacement. The controller measures the concentration of target gas in outdoor air (which has known concentration) and compares it with the sensor's reading to determine whether the abnormal measurement is due to sensor failure or temporary condensation, thereby avoiding unnecessary replacements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the measured values from gas sensors and automatically initiating diagnostic procedures when abnormalities are detected. The controller uses the feedback from outdoor air measurement comparisons to determine whether sensor replacement is actually necessary, optimizing the balance between reliability and cost

Inventive Principle:
Principle #23Feedback

2Measurement precision

If gas sensors are replaced when condensation occurs, then measurement accuracy is improved, but device complexity increases due to unnecessary maintenance

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmaintenance complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system enables self-diagnosis by automatically detecting when a gas sensor outputs abnormal values and initiating the outdoor air supply procedure to determine the cause. This self-service capability distinguishes between temporary condensation issues (where the sensor can continue operating) and actual failures requiring replacement, reducing unnecessary maintenance complexity

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces unnecessary repairs and maintenance costs by accurately assessing sensor functionality and calibrating sensors, ensuring accurate air composition control within target ranges.

Implementation Method 1

a gas sensor (92) configured to measure a concentration of a target gas contained in inside air in a storage (1)

Methodology Applied
Scientific EffectGas detection:

Implementation Method 2

supply outdoor air through the outdoor air supply passage (255, 281) to the gas sensor (92)

Methodology Applied
Scientific EffectGas flow:

Implementation Method 3

the gas sensor on which condensation has occurred, for example, may output an abnormal measured value

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

evaporation of condensed water after a lapse of a certain period of time allows the gas sensor to again output the correct measured value

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3872428B1Inside air control system
Publication Date: 2022.12.21 DAIKIN INDUSTRIES LTD
  • EP3872428B1 patent drawingFigure 1
  • EP3872428B1 patent drawingFigure 2
  • EP3872428B1 patent drawingFigure 3

AI summary

A carbon dioxide sensor (92) measures the carbon dioxide concentration of inside air. An inside air control system (30) controls the carbon dioxide concentration of the inside air based on a measured value obtained by the carbon dioxide sensor (92). If the measured value obtained by the carbon dioxide sensor (92) returns to a predetermined normal range after falling outside the normal range, the controller (110) of the inside air control system (30) performs a determination operation. The determination operation is an operation for supplying outdoor air to the carbon dioxide sensor (92) to determine whether or not the carbon dioxide sensor (92) is normal.