Hybrid Laundry Drying Airflow for Lower Water and Energy Use

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Solution Overview

Problem

Laundry treatment apparatuses with circulation drying systems consume excessive cooling water due to low cooling efficiency, while those with exhaust drying systems face high energy consumption due to discharge of heated air.

Innovation Solution

A laundry treatment apparatus with a combined drying system that includes a controller to manage the rotation speed of the drum, water supply, and air flow paths, preventing cooling water from reaching the laundry and optimizing air circulation to reduce energy and water consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a circulation drying system is used, then drying efficiency is improved through heat recovery, but cooling water consumption increases excessively

Engineering Contradiction:
Improvedrying efficiencyVSAvoidcooling water consumption
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent extracts and separates the cooling function from the circulation drying system by introducing a dedicated cooling water supply structure that supplies water to the tub rather than using cooling water for condensation. This allows the circulation system to maintain its heat recovery efficiency while eliminating excessive cooling water consumption through direct water supply to the drying space for evaporative cooling effect

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the parameter of cooling method from using cooling water for condensation (circulation system approach) to using water supply to the tub for evaporative cooling. This parameter change resolves the contradiction by maintaining drying efficiency through evaporation while avoiding the excessive cooling water consumption associated with condensation-based cooling

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If an exhaust drying system is used, then cooling water consumption is reduced, but energy consumption increases due to discharge of heated air

Engineering Contradiction:
Improvecooling water consumptionVSAvoidenergy consumption
Core Design Contradiction:
Loss of substanceVSUse of energy by moving object

Solution Approach 1:

The patent merges the advantages of both circulation and exhaust systems by creating a hybrid approach: the circulation duct recovers heat from exhaust air to pre-heat incoming air (reducing energy consumption), while the water supply unit provides evaporative cooling (reducing cooling water consumption). This combination resolves the contradiction by achieving both energy and water efficiency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent recovers thermal energy from the exhaust air that would otherwise be discarded through the circulation duct, using it to pre-heat incoming fresh air. This recovery mechanism reduces the energy required to heat air for drying while maintaining the benefit of discharging moisture-laden air, thus resolving the energy consumption issue

Inventive Principle:
Principle #34Discarding and recovering

3Quantity of substance

If cooling water is supplied to condense air in a circulation drying system, then dehumidification is achieved, but the system complexity increases

Engineering Contradiction:
Improveair dehumidificationVSAvoidsystem complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical condensation system (requiring cooling water circulation, condensate drainage, and heat exchangers) with a simpler evaporative cooling approach where water is supplied directly to the tub. This substitution achieves dehumidification through evaporation control while dramatically reducing system complexity by eliminating the need for complex cooling water management infrastructure

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

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

The solution achieves enhanced drying efficiency by minimizing energy and water usage, preventing cooling water from reaching the laundry, and maintaining effective air circulation, thus addressing the inefficiencies of previous systems.

Implementation Method 1

the controller may rotate the drum at first Revolutions Per Minute (RPM) and second RPM during operation of the fan and the heater, the first RPM may be set to RPM at which the centrifugal force of laundry caused by rotation of the drum becomes greater than the weight of the laundry

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a heater configured to heat air, a first heat exchange flow path including a tub configured to provide a space in which the drum is received and a space in which air is condensed and a duct through which some of interior air of the tub is directed to the heater and then resupplied to the tub

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a circulation duct through which interior air of the tub is circulated, an exhaust duct through which some of the interior air of the tub is discharged from the tub, a suction duct through which outside air is supplied into the tub and a heating unit configured to supply heated air into the tub

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

a first heat exchange flow path including a tub configured to provide a space in which the drum is received and a space in which air is condensed

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP2843120B1Laundry treatment apparatus
Publication Date: 2017.08.09 LG ELECTRONICS INC
  • EP2843120B1 patent drawingFigure 1(a)~1(b)
  • EP2843120B1 patent drawingFigure 2
  • EP2843120B1 patent drawingFigure 3(a)~3(b)

AI summary

Disclosed is a laundry treatment apparatus including a circulation duct (7) configured to guide air discharged from a tub (2) so as to resupply the air to the tub (2), a fan (71) placed in the circulation duct (7) to circulate interior air of the tub(2), a heater (73) placed in the circulation duct (7) to heat the air, an exhaust duct (83) configured to discharge some of air introduced into the tub (2) from the tub (2), a suction duct (81) configured to introduce outside air of the tub (2) into the tub (2), and a water supply unit (4) configured to supply water into the tub (2) so as to cool the tub (2).