Method for operating a laundry drying apparatus and laundry drying apparatus

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Solution Overview

Problem

Existing laundry drying apparatuses are inefficient in terms of energy consumption, as they do not effectively adjust compressor output based on the laundry load during the drying cycle, leading to suboptimal energy usage and prolonged drying times.

Innovation Solution

A method and apparatus for a laundry drying apparatus that includes a variable speed compressor and a control unit to detect the laundry load and adjust the compressor output by setting threshold values based on the load, reducing energy consumption by modifying the drying program parameters such as compressor speed and cooling fan activation in response to monitored operation parameters like refrigerant temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the compressor operates at constant high output throughout the drying cycle, then the drying speed is maintained, but energy consumption increases unnecessarily

Engineering Contradiction:
Improvedrying speedVSAvoidcompressor energy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The compressor operates with variable output levels (first, second, and third outputs) that are dynamically adjusted based on the drying phase and laundry load detection, rather than maintaining constant high output throughout the cycle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit detects the laundry load at the beginning of the drying cycle and pre-determines the appropriate compressor output levels and threshold values before the drying process starts, enabling optimized energy consumption from the outset

Inventive Principle:
Principle #10Preliminary action

2Use of energy by moving object

If the compressor output is reduced early in the drying cycle, then energy consumption decreases, but the drying time is prolonged

Engineering Contradiction:
Improvecompressor energy consumptionVSAvoiddrying cycle duration
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The compressor operates in periodic phases with different output levels: high output (first compressor output) during initial drying phases, intermediate output (second compressor output) during medium phases, and low output (third compressor output) during final phases, with automatic transitions between phases based on monitored threshold values

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control unit pre-determines the drying phases and corresponding compressor output levels based on detected laundry load, optimizing the balance between energy consumption and drying time before the cycle begins

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the compressor output is adjusted based on laundry load detection, then energy efficiency is improved, but the system complexity increases

Engineering Contradiction:
Improveoverall energy consumptionVSAvoidcontrol system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The laundry load is detected at the beginning of the drying cycle, and all subsequent compressor output adjustments and threshold values are pre-determined based on this initial detection, simplifying the control logic compared to continuous complex adjustments

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system adjusts discrete parameters (compressor output levels and threshold values) based on laundry load detection, using predefined parameter sets for different load conditions rather than continuous complex calculations

Inventive Principle:
Principle #35Parameter changes

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 overall energy consumption and optimizes drying time by dynamically adjusting compressor output and fan performance based on the laundry load, leading to improved energy efficiency and shorter drying cycles.

Implementation Method 1

a first heat exchanger (condenser) adapted to heat the drying air

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a second heat exchanger (evaporator) adapted to cool the drying air for humidity condensation

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

a compressor adapted to circulate refrigerant through the first and second heat exchangers

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3239390B1Method for operating a laundry drying apparatus and laundry drying apparatus
Publication Date: 2019.11.06 ELECTROLUX APPLIANCES
  • EP3239390B1 patent drawingFigure 1
  • EP3239390B1 patent drawingFigure 2~3
  • EP3239390B1 patent drawingFigure 4

AI summary

The invention relates to a method for operating a laundry drying apparatus, in particular a laundry dryer or a washer-dryer, during a drying program, and a laundry drying apparatus. The laundry drying apparatus (2) comprises: a drum (18) adapted to receive laundry (19) for drying the laundry using drying air; a drying air fan (8) adapted to convey drying air through the drum (18); a motor (46) adapted to drive the drying air fan (8); a heat-pump system (4) comprising a first heat exchanger (10) adapted to heat the drying air, a second heat exchanger (12) adapted to cool the drying air for humidity condensation, and a compressor (16) adapted to circulate refrigerant through the first and second heat exchangers (10, 12); and a laundry load indicating or detecting unit adapted to determine or estimate a laundry amount of laundry loaded into the drum (18), wherein the compressor (16) is a variable speed and/or variable power compressor. The method comprises: starting a drying program for drying the laundry received in the drum (18); operating the compressor (16) at an initial compressor output; the laundry load indicating or detecting unit (52) determining or estimating a laundry amount at least once during the drying program; setting a threshold value in dependency of the laundry amount; monitoring an operation parameter of the laundry drying apparatus; and operating the compressor (16) at a reduced compressor output if the monitored operation parameter reaches or exceeds the set threshold value.