Control method for laundry treating apparatus

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Solution Overview

Problem

The efficiency of heat exchange in condensation type laundry treating apparatuses deteriorates as the temperature of the refrigerant consistently rises during the drying process, leading to a decrease in the temperature difference between the refrigerant and air, which reduces the effectiveness of the drying process.

Innovation Solution

A control method for a laundry treating apparatus that measures the temperatures of the refrigerant and air passing through the evaporator, compares these temperatures to a reference temperature, and adjusts the opening degree of the expansion valve to maintain optimal heat exchange efficiency by decreasing the opening degree when the temperature difference is less than the reference, thereby increasing the superheat degree.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the drying cycle progresses in a condensation type laundry treating apparatus, then the refrigerant temperature consistently rises, but the temperature difference between refrigerant and air decreases leading to deteriorated heat exchange efficiency

Engineering Contradiction:
Improverefrigerant temperatureVSAvoidheat exchange efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The expansion valve opening degree is dynamically adjusted during the drying cycle based on real-time temperature measurements. The control unit continuously monitors refrigerant and air temperatures and modifies the expansion valve opening to maintain optimal heat exchange efficiency despite rising refrigerant temperatures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the opening degree parameter of the expansion valve in response to temperature changes. By adjusting this parameter, the system maintains an appropriate temperature difference between refrigerant and air, preventing heat exchange efficiency deterioration as the drying cycle progresses.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the temperature difference between refrigerant and air decreases, then the refrigerant and air approach thermal equilibrium, but the heat exchange efficiency deteriorates

Engineering Contradiction:
Improvethermal equilibriumVSAvoidheat exchange efficiency
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The control unit implements a feedback mechanism by continuously measuring the temperatures of refrigerant and air, comparing the temperature difference against a reference value, and adjusting the expansion valve opening degree accordingly. This closed-loop control prevents thermal equilibrium while maintaining optimal heat exchange efficiency.

Inventive Principle:
Principle #23Feedback

3Loss of energy

If the expansion valve opening degree is decreased to increase superheat degree, then heat exchange efficiency improves, but the refrigerant flow rate decreases

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidrefrigerant flow rate
Core Design Contradiction:
Loss of energyVSQuantity of substance

Solution Approach 1:

The expansion valve opening degree is dynamically adjusted during the drying cycle based on real-time temperature measurements. The control unit continuously monitors refrigerant and air temperatures and modifies the expansion valve opening to maintain optimal heat exchange efficiency despite rising refrigerant temperatures.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the opening degree parameter of the expansion valve in response to temperature changes. By adjusting this parameter, the system maintains an appropriate temperature difference between refrigerant and air, preventing heat exchange efficiency deterioration as the drying cycle progresses.

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 method enhances the efficiency of heat exchange in the heat pump, reducing the time and energy consumed in drying by maintaining a higher temperature difference between the refrigerant and air, thus improving the overall drying performance.

Implementation Method 1

an evaporator fixed to the refrigerant pipe in the duct and configured to vaporize the refrigerant by exchanging heat with the air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

vaporize the refrigerant by exchanging heat with the air

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a condenser fixed to the refrigerant pipe in the duct and configured to condense the refrigerant by exchanging heat with the air having passed the evaporator

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

condense the refrigerant by exchanging heat with the air

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3378986B1Control method for laundry treating apparatus
Publication Date: 2020.01.22 LG ELECTRONICS INC
  • EP3378986B1 patent drawingFigure 1
  • EP3378986B1 patent drawingFigure 2
  • EP3378986B1 patent drawingFigure 3

AI summary

There is disclosed a control method for laundry treating apparatus (100) configured to perform a dry cycle for clothes by operating a heat pump (9) comprising an expansion valve (97), the control method comprising:a measuring step (S420) for measuring the temperatures of a refrigerant and air which pass through an evaporator (91) to exchange heat; a comparing step (S430) for comparing a difference between the measured temperatures of the refrigerant and air with a preset reference temperature (Tref); and an adjusting step (440) for adjusting an opening degree of the expansion valve (97) according to the result of the comparing step (S430).