Controlling method for drying machine with heat pump and heater

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Solution Overview

Problem

Conventional drying machines face inefficiencies in energy use and extended drying times due to limitations in heat pump system capacity and potential compressor overload, especially when using both heat pump systems and heaters as heat sources.

Innovation Solution

A control method for a hybrid drying machine that selectively uses a heat pump system and a heater, where the heater is activated when the compressor operates normally and deactivated when it does not, and the system determines the operational status of the compressor and filter blockages to optimize energy efficiency and prevent overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the heat pump system is used as the heating unit, then energy efficiency is improved, but drying time increases due to limited capacity

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddrying time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system dynamically switches between heat pump-only mode and hybrid mode (heat pump + heater) based on real-time compressor status. When the compressor operates normally, the system uses only the heat pump for maximum energy efficiency. When compressor overload is detected, the system transitions to hybrid mode or heater-only mode to maintain drying performance, thus adaptively resolving the contradiction between energy efficiency and drying time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system changes operational parameters by monitoring compressor current and temperature differential across the evaporator. Based on these parameter changes, the system adjusts the heating configuration - switching from heat pump-only to hybrid operation when parameters indicate approaching overload conditions, thereby balancing energy efficiency with drying time requirements.

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If the heater is used as the heating unit, then drying time is reduced, but thermal efficiency is lowered due to high energy consumption

Engineering Contradiction:
Improvedrying timeVSAvoidthermal efficiency
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the proportion of heater usage based on compressor status. The heater is not used as a primary heat source but rather as a supplemental or backup heat source activated only when the heat pump system approaches its capacity limits or experiences overload. This dynamic adjustment minimizes heater usage and preserves thermal efficiency while ensuring drying time requirements are met.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system treats the heater as a short-term, supplemental heat source rather than a primary continuous heat source. The heater is activated only temporarily when needed to prevent compressor overload or meet drying time requirements, rather than being used continuously. This approach minimizes the negative impact on thermal efficiency while providing necessary drying capacity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Loss of time

If both heat pump system and heater are used together, then drying time is reduced, but compressor overload may occur lowering reliability

Engineering Contradiction:
Improvedrying timeVSAvoidcompressor reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system implements feedback control by continuously monitoring compressor current, temperature differential across the evaporator, and heater power consumption. When parameters indicate approaching overload conditions, the control system automatically adjusts heater power or switches to heater-only mode to prevent compressor damage. This feedback mechanism resolves the contradiction by dynamically balancing drying time requirements with compressor protection.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically transitions between multiple operational modes (heat pump-only, hybrid, heater-only) based on real-time compressor status. This dynamic mode switching allows the system to utilize the heater to reduce drying time when the heat pump capacity is sufficient, while preventing compressor overload by reducing or eliminating heater usage when the heat pump is already operating near its limits.

Inventive Principle:
Principle #15Dynamics

4Loss of time

If the heat pump system capacity is increased, then drying time is reduced, but device complexity and cost increase

Engineering Contradiction:
Improvedrying timeVSAvoidsystem complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The system achieves multiple functions using the existing heat pump and heater components. The heat pump serves as the primary heat source for energy-efficient operation, while the heater provides supplemental heating capacity and backup functionality. This multi-functionality approach allows the system to achieve faster drying times without requiring a larger, more complex heat pump system, thereby resolving the contradiction between drying time and system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 efficiency and reduces drying time by effectively managing the heat sources and preventing compressor overload, thereby improving the reliability and performance of the heat pump system.

Implementation Method 1

The heat pump system includes two heat exchangers, a compressor and an expansion apparatus. Accordingly, a refrigerant circulating in a system adsorbs energy contained in hot air discharged and the adsorbed energy is used for heating air to be supplied into the drum.

Methodology Applied
Scientific EffectHeat pump system: Heat Exchanger

Implementation Method 2

a refrigerant circulating in a system adsorbs energy contained in hot air discharged and the adsorbed energy is used for heating air to be supplied into the drum

Methodology Applied
Scientific EffectThermal energy transfer: Conduction (thermal)

Implementation Method 3

a refrigerant circulating in a system adsorbs energy contained in hot air discharged and the adsorbed energy is used for heating air to be supplied into the drum

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2921587B1Controlling method for drying machine with heat pump and heater
Publication Date: 2023.09.06 LG ELECTRONICS INC
  • EP2921587B1 patent drawingFigure 1
  • EP2921587B1 patent drawingFigure 2
  • EP2921587B1 patent drawingFigure 3

AI summary

The present invention provides a control method for a drying machine (100) comprising a heat pump system (70) for heating air to be supplied into a drum (10), and a heater (40) having a smaller heat supply capacity than the heat pump system, the drying machine (100) having a plurality of drying modes using the heat pump system (70) and the heater (40) individually or together. Said control method is characterized by comprising a compressor temperature control step of controlling the temperature of a compressor (72) of the heat pump system (70), in a drying mode using both of the heat pump system (70) and the heater (40), after the heater (40) is activated, by repeating activation and deactivation of the heater (40) according to the temperature of a refrigerant flowed through the compressor (72).