Mold prevention method for air conditioner

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Solution Overview

Problem

Conventional air conditioner heat exchanger drying methods suppress but do not kill bacteria and fungus, allowing them to regrow when cooling resumes, as temperatures required for sterilization are not typically achieved.

Innovation Solution

An antifungal method involving wetting the heat exchanger with dew condensation water and heating it to a temperature range of 45°C to 60°C to achieve 'wet-heat sterilization' without evaporating the water, using a connecting body to ensure heat transfer and shield wind, and utilizing a drain pan for efficient heat transfer and sterilization of accumulated dew.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the heat exchanger is heated to high temperature (150°C or higher) to achieve sterilization and kill bacteria and fungus, then the sterilization effect is improved, but the energy consumption and risk of damaging the heat exchanger increase

Engineering Contradiction:
Improvesterilization effectVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the temperature parameter from conventional high-temperature sterilization (150°C or higher) to a lower temperature range (45-60°C), and combines it with the parameter of moisture content (dew condensation water) to achieve sterilization through wet heat rather than dry heat, thereby reducing energy consumption and avoiding damage to the heat exchanger

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by generating dew condensation water on the heat exchanger surface before heating, ensuring that the surface is sufficiently wetted. This preliminary wetting action enables the subsequent low-temperature heating to achieve sterilization效果, avoiding the need for high-temperature heating

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the heat exchanger is heated to 40°C for drying to suppress bacterial and fungal growth, then the growth suppression is improved, but the sterilization effect deteriorates as bacteria and fungus are not killed

Engineering Contradiction:
Improvebacterial and fungal growth suppressionVSAvoidsterilization effect
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent raises the temperature parameter from 40°C to 45-60°C and combines it with the parameter of moisture content (maintaining dew condensation water on the surface) to transform the function from mere growth suppression to actual sterilization, killing bacteria and fungus through wet heat

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful dew condensation water (which promotes fungal growth) into a beneficial element for sterilization. By controlling the temperature to prevent evaporation while maintaining moisture, the dew condensation water becomes the medium for wet-heat sterilization, turning a problem into a solution

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If the heat exchanger surface is kept dry to prevent fungal growth, then the growth prevention is improved, but the sterilization capability deteriorates as it cannot kill existing bacteria and fungus

Engineering Contradiction:
Improvefungal growth preventionVSAvoidsterilization capability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the moisture parameter from complete dryness to controlled moisture (maintaining dew condensation water), and combines it with temperature control (45-60°C) to achieve a state where moisture is present but evaporation is prevented, enabling sterilization while preventing regrowth

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by controlling the temperature within a specific range (45-60°C) to dynamically balance two opposing requirements: maintaining moisture for sterilization while preventing evaporation that would lead to dryness and potential regrowth. This dynamic temperature control enables the system to achieve both sterilization and prevention of regrowth

Inventive Principle:
Principle #15Dynamics

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

Effectively sterilizes bacteria and fungus, reducing their numbers and preventing odor generation, while alleviating compressor overload conditions and ensuring reliable heat transfer for efficient dew condensation water heating.

Implementation Method 1

heating the heat exchanger based on condensation of a refrigerant

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

heat is transferred from the heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

the connecting body shields wind at an air gap between the front body and the rear body of the heat exchanger... the dew condensation water hardly evaporates

Methodology Applied
Scientific EffectEvaporation prevention: Evaporation

Data Source

PatentEP3591305B1Mold prevention method for air conditioner
Publication Date: 2024.02.14 FUJITSU GENERAL LTD
  • EP3591305B1 patent drawingFigure 1
  • EP3591305B1 patent drawingFigure 2
  • EP3591305B1 patent drawingFigure 3

AI summary

An antifungal method for an air conditioner, includes: a step of wetting a surface of a heat exchanger with dew condensation water; and a step of heating an indoor heat exchanger based on condensation of a refrigerant to heat the indoor heat exchanger without evaporating the dew condensation water. Therefore, it is possible to provide an antifungal method for an air conditioner, which realizes sterilization more effectively than the related art.