Heat Pump Dryer Compressor and Airflow Control for Adaptive Efficiency

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Solution Overview

Problem

Conventional heat-pump laundry dryers lack optimized efficiency during the drying cycle, particularly when parameters change, leading to suboptimal energy usage and performance.

Innovation Solution

A method for controlling the laundry drying machine with a heat pump system by varying the compressor speed and adjusting the volume flow of drying air based on compressor speed or power, using a compressor with variable rotation speed and thermal couplings between the drying air and refrigerant circuits to optimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the volume flow of drying air is increased to improve drying performance, then the drying efficiency is improved, but the energy consumption increases

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

Solution Approach 1:

The patent applies dynamics by making the volume flow of drying air variable rather than constant. The control unit adjusts the volume flow dynamically based on the heat pump performance at different operating times. This allows the system to optimize the balance between drying efficiency and energy consumption by adapting the air flow to the actual heating capacity available at each moment during the drying cycle.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of volume flow based on changing heat pump performance. As the heat pump performance varies during operation (due to temperature changes, condensation, etc.), the control unit modifies the volume flow parameter accordingly. This ensures that the drying air volume is optimized for the current thermal conditions, improving overall system efficiency while avoiding excessive energy consumption.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the heat pump performance is increased to improve drying capability, then the drying speed is improved, but the system efficiency decreases when parameters change during the cycle

Engineering Contradiction:
Improvedrying speedVSAvoidsystem efficiency
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The patent implements feedback control where the control unit continuously monitors heat pump performance and uses this information to adjust the volume flow of drying air. This closed-loop control ensures that the system responds to changes in heat pump performance (such as those caused by temperature variations or condensation) and optimizes the air flow accordingly, maintaining high drying speed while minimizing energy loss through adaptive adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment by automatically modifying the volume flow based on its own performance characteristics. The control unit uses internal sensors and control algorithms to regulate the air flow without external intervention, allowing the heat pump system to self-optimize its operation throughout the drying cycle, thereby maintaining efficiency despite changing parameters.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the volume flow is controlled according to fixed parameters, then the control simplicity is maintained, but the efficiency optimization during parameter changes is lost

Engineering Contradiction:
Improvecontrol simplicityVSAvoiddrying cycle efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent replaces fixed mechanical control with electronic/control system adjustment. Instead of using fixed mechanical settings for volume flow, the invention employs a control unit that electronically regulates the volume flow based on real-time heat pump performance data. This substitution allows for dynamic optimization of drying efficiency while maintaining operational simplicity through automated control, eliminating the need for manual adjustments or complex mechanical mechanisms.

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

This approach enhances energy savings and adapts to changing conditions during the drying cycle, improving overall performance and efficiency by matching air volume flow with heat pump performance.

Implementation Method 1

a heat exchanger for a thermal coupling between the drying air circuit and the refrigerant circuit wherein the temperature of the drying air increases and the temperature of the refrigerant decreases

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a heat exchanger for a thermal coupling between the drying air circuit and the refrigerant circuit wherein the temperature of the drying air decreases and the temperature of the refrigerant increases

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

The refrigerant flows in the refrigerant circuit where it is compressed by the compressor

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2935687B1A method for controlling a laundry drying machine and a corresponding laundry drying machine
Publication Date: 2021.06.16 ELECTROLUX HOME PROD CORP NV
  • EP2935687B1 patent drawingFigure 1
  • EP2935687B1 patent drawingFigure 2
  • EP2935687B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for controlling a laundry drying machine (1) of the type comprising a heat pump system (20) having a refrigerant circuit (30) for a refrigerant and comprising a drying air circuit (10) for conveying a volume flow of drying air (A) in a laundry drum (9) suitable for receiving laundry. The refrigerant circuit (30) comprises a compressor (24) with a variable rotation speed (Cs), a first heat exchanger (21) for a thermal coupling between the drying air circuit (10) and the refrigerant circuit (30), a second heat exchanger (23) for a further thermal coupling between the drying air circuit (10) and the refrigerant circuit (30). The method comprises the steps of controlling the speed (Cs) or the power (Cp) of the compressor (24) and controlling the volume flow of the drying air (A) in response to the speed (Cs) or the power (Cp) of the compressor (24).