A method for controlling a laundry dryer with a variable drum rotation speed and a variable fan rotation speed

Solution Overview

Problem

Laundry dryers with constant drum rotation speed negatively affect drying performance and energy efficiency, particularly when variations in drum speed are necessary for different types of laundry, and these issues are exacerbated by the presence of a heat pump system.

Innovation Solution

A method for controlling a laundry dryer with a variable drum rotation speed and fan rotation speed, where the fan rotation speed and motor power are adjusted based on the drum rotation speed to maintain optimal drying performance while keeping energy consumption within predetermined limits, using a control unit to independently manage the drum and fan motors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the drum rotation speed is varied to meet different laundry drying requirements, then the adaptability is improved, but the drying performance and energy efficiency deteriorate

Engineering Contradiction:

Improveadaptability to different laundry typesVSAvoiddrying performance

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the fan rotation speed adjustable and variable during the drying cycle. The control unit dynamically adapts the fan speed based on the drum rotation speed to maintain optimal drying performance across different laundry types and drum speed settings, transforming a static system into a dynamic one that responds to changing conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the fan motor by adjusting its rotation speed according to the drum rotation speed. The control unit modifies the fan speed parameter in response to drum speed variations, allowing the system to maintain effective drying performance while adapting to different laundry requirements through parameter adjustment

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the drum rotation speed is decreased for delicate laundry, then the laundry protection is improved, but the drying performance deteriorates

Engineering Contradiction:

Improvelaundry damageVSAvoiddrying performance

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies the counterweight principle by using the fan rotation speed to compensate for the reduced drum rotation speed. When the drum speed is lowered to protect delicate laundry, the control unit increases the fan speed to maintain adequate air circulation and drying performance, effectively counterbalancing the negative impact of reduced drum speed

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The fan acts as an intermediary element that mediates between the drum rotation speed and the drying performance. By adjusting the fan speed, the system can decouple the relationship between drum speed and drying effectiveness, allowing low drum speeds for delicate laundry while maintaining drying performance through increased fan activity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the drum rotation speed is increased for bulky laundry, then the drying performance is improved, but the energy consumption increases

Engineering Contradiction:

Improvedrying performanceVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by adjusting the fan rotation speed to provide only the necessary air circulation needed for effective drying at each drum speed level. Rather than maintaining constant high fan speed regardless of drum speed, the control unit modulates fan speed to match actual drying needs, avoiding excessive energy consumption while maintaining adequate drying performance

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The control unit implements feedback by continuously monitoring the drum rotation speed and adjusting the fan rotation speed accordingly. This closed-loop control ensures that the fan provides adequate air circulation for the current drum speed and laundry conditions without wasting energy, optimizing the balance between drying performance and energy consumption

Inventive Principle:

Principle #23Feedback

4Productivity

If the fan rotation speed is increased to compensate for decreased drum speed, then the drying performance is maintained, but the energy consumption increases

Engineering Contradiction:

Improvedrying performanceVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operational parameters of the fan motor by adjusting its rotation speed according to the drum rotation speed. The control unit modifies the fan speed parameter in response to drum speed variations, allowing the system to maintain effective drying performance while adapting to different laundry requirements through parameter adjustment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies dynamics by making the fan rotation speed adjustable and variable during the drying cycle. The control unit dynamically adapts the fan speed based on the drum rotation speed to maintain optimal drying performance across different laundry types and drum speed settings, transforming a static system into a dynamic one that responds to changing conditions

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

This approach maintains high drying efficiency by compensating for decreased drum rotation speed with increased fan rotation speed, reducing overall energy consumption and optimizing heat exchange in the heat pump system, thus improving both energy performance and cycle time.

Implementation Method 1

laundry dryer with a heat pump system

Methodology Applied

Scientific EffectHeat pump: Heat Exchanger

Data Source

PatentEP2922993B1A method for controlling a laundry dryer with a variable drum rotation speed and a variable fan rotation speed

Publication Date: 2017.06.28 ELECTROLUX HOME PROD CORP NV

Figure 1
Figure 2
Figure 3~4

AI summary

A method for controlling a laundry dryer with a variable drum rotation speed and a variable fan rotation speed The present invention relates to a method for controlling a laundry dryer including a laundry drum (12) with a variable drum rotation speed (vd) and a drying air stream fan (18) with a variable fan rotation speed (vf). Said method comprising the steps of setting a course of the drum rotation speed (vd) or a course of a drum motor power (Pd) of the laundry drum (12), and setting a fan rotation speed (vf) and/or a fan motor power (Pf) of the drying air stream fan (18) on the basis of the drum rotation speed (vd) and/or the drum motor power (Pd) of the laundry drum (12). The fan rotation speed (vf) and/or the fan motor power (Pf) of the drying air stream fan (18) is decreased with an increasing drum rotation speed (vd) and/or increasing drum motor power (Pd) of the laundry drum (12). The fan rotation speed (vf) and/or the fan motor power (Pf) of the drying air stream fan (18) is increased with a decreasing drum rotation speed (vd) and/or decreasing drum motor power (Pd) of the laundry drum (12). Further, the present invention relates to a corresponding laundry dryer.