Indoor AC Airflow Layout to Shield Infrared Sensor Readings

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Solution Overview

Problem

In air-conditioning-apparatus indoor units, conditioned air often incorrectly determines the temperature or position of a human body due to being applied to the infrared sensor or its casing, leading to inaccurate readings.

Innovation Solution

The air-conditioning-apparatus indoor unit incorporates a housing with an air inlet at the top and an air outlet at the bottom, featuring left-right and up-down deflectors and air flow control members between the infrared sensor and the deflectors, which redirect conditioned air away from the sensor, preventing it from being applied to the sensor's vicinity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the infrared sensor is disposed at the front surface of the housing, then the sensor can detect temperature and position of human body, but conditioned air from the air outlet may be applied to the sensor causing incorrect determination

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidconditioned air interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A partition wall is introduced as an intermediary structure between the air outlet and the infrared sensor. This partition wall physically separates the conditioned air flow path from the sensor area, allowing the sensor to remain at the front surface for detection purposes while preventing harmful conditioned air from reaching the sensor and causing measurement errors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The front surface of the housing is segmented into multiple regions: an air outlet region and a sensor region. The partition wall creates distinct zones that allow independent optimization - the air outlet can discharge conditioned air effectively while the sensor region remains protected from air flow interference, enabling both functions to operate without mutual interference.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the sensor is disposed at the ends of the front portion of the housing, then the sensor can detect human body conditions, but conditioned air may still reach the sensor area causing incorrect readings

Engineering Contradiction:
Improvesensor detection functionVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The partition wall serves as a protective intermediary that allows the sensor to maintain its optimal detection position at the front surface while blocking the harmful effect of conditioned air. This enables the sensor to perform its detection function reliably without requiring relocation that would compromise ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration effectively eliminates or reduces the application of conditioned air to the infrared sensor, ensuring accurate temperature and position detection by maintaining the sensor's casing at the same temperature as the indoor space, thereby preventing false readings.

Implementation Method 1

an infrared sensor disposed at one end in the left-right direction of the front surface of the housing

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

at least one air flow control member that is disposed between the infrared sensor and one end of the left-right deflector close to the infrared sensor and that controls the air flow from the air outlet

Methodology Applied
Scientific EffectAir flow control: Convection

Data Source

PatentEP3104092B1Indoor unit for air conditioner
Publication Date: 2019.02.06 MITSUBISHI ELECTRIC CORP
  • EP3104092B1 patent drawingFigure 1~2
  • EP3104092B1 patent drawingFigure 3~4
  • EP3104092B1 patent drawingFigure 5~6

AI summary

An air-conditioning-apparatus indoor unit 1 eliminates or reduces the application of conditioned air to an area in the vicinity of an infrared sensor 35. The air-conditioning-apparatus indoor unit 1 includes a main body 2 that has an air inlet 22 disposed in an upper part of the main body 2 and an air outlet 23 disposed in a lower part of a front surface of the main body 2 and that accommodates a heat exchanger and a fan, left-right deflectors 7a and 7b that are arranged in the air outlet 23 and are configured to change the direction of an air flow from the air outlet 23 in a left-right direction, up-down deflectors 8a and 8b that are arranged in the air outlet 23 and are configured to change the direction of the air flow from the air outlet 23 in an up-down direction, the infrared sensor 35 disposed at one end in the left-right direction of the front surface of the main body 2 so that the infrared sensor 35 is next to one end in the left-right direction of the air outlet 23 of the main body 2, and an large air flow control plate 41, a small air flow control plate 43, and an upper air flow control plate 42 that are arranged between the infrared sensor 35 and one end of the left-right deflector 7b close to the infrared sensor 35 and that control the air flow from the air outlet 23.