Evaporation Tray Heating Using a Refrigerator Compressor Motor

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Modern refrigeration appliances face an unfavorable ratio of condensation water to waste heat, risking overflow in the evaporation tray due to insufficient heat for evaporation, especially when there is no cooling requirement in the storage chamber, leading to inefficiency and potential damage.

Innovation Solution

A refrigeration appliance with a compressor motor in thermal contact with the evaporation tray and a control unit that switches between drive and heating modes by energizing different windings of the compressor motor, generating heat without rotation to evaporate condensation water, using a converter to distribute thermal load and estimate heat requirements based on sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the compressor operates in high-efficiency mode to meet cooling requirements, then energy consumption is optimized, but waste heat generation is insufficient to evaporate condensation water in the evaporation tray

Engineering Contradiction:
Improveenergy consumptionVSAvoidwaste heat generation
Core Design Contradiction:
Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The control unit dynamically switches the compressor motor between drive mode and heating mode based on real-time detection of water level in the evaporation tray. When condensation water accumulates to a critical level, the system transitions from high-efficiency cooling operation to heating operation, adjusting the operating mode to match the immediate thermal needs of the evaporation tray.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the electrical parameters supplied to the compressor motor windings. In heating mode, the control unit energizes windings with a current sequence that generates Joule heat without producing rotational motion, effectively converting the motor into a heating element. This parameter change allows the same motor to serve dual purposes: driving the compressor for cooling and generating heat for evaporation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the compressor operates in less efficient mode to generate more waste heat for evaporation, then condensation water evaporates faster, but energy efficiency deteriorates and cooling performance decreases

Engineering Contradiction:
Improvewaste heat generationVSAvoidenergy efficiency
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the compressor motor's operating mode based on real-time water level detection. The control unit monitors the evaporation tray and only switches to heating mode when condensation water accumulation reaches a critical level, ensuring that the compressor operates in high-efficiency cooling mode during normal conditions and only transitions to heating mode when thermal intervention is actually needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The compressor motor serves itself by generating the heat needed for evaporation through its own windings. The control unit energizes the motor windings in a sequence that produces Joule heat without rotation, allowing the motor to provide both cooling (during normal operation) and heating (when water evaporation is needed) functions without requiring external heating devices.

Inventive Principle:
Principle #25Self-service

3Reliability

If a separate electrical heating device is attached to the evaporation tray to ensure sufficient evaporation, then evaporation reliability is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:
Improveevaporation reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compressor motor is designed to perform multiple functions: it drives the compressor for cooling during normal operation and generates Joule heat for evaporating condensation water when needed. The control unit switches between drive mode and heating mode by energizing the motor windings differently, eliminating the need for a separate heating device and reducing overall system complexity.

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

Solution Approach 2:

The compressor motor provides its own heating capability by generating Joule heat through its windings when energized in heating mode. This self-service approach eliminates the need for external heating devices, water level sensors, and associated control systems, thereby reducing device complexity and manufacturing costs while maintaining evaporation reliability.

Inventive Principle:
Principle #25Self-service

4Quantity of substance

If the compressor is operated without cooling requirement solely to generate heat for evaporation, then sufficient heat is available to evaporate condensation water, but energy wastage increases

Engineering Contradiction:
Improveheat availabilityVSAvoidenergy wastage
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The control unit dynamically switches the compressor motor between drive mode and heating mode based on real-time water level detection in the evaporation tray. The system only operates in heating mode when condensation water accumulation reaches a critical level, avoiding unnecessary energy consumption by maintaining high-efficiency cooling mode during normal operation and transitioning to heating mode only when thermal intervention is actually needed.

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

Ensures efficient evaporation of condensation water without a separate heating device, preventing overflow and maintaining appliance efficiency even when there is no cooling requirement in the storage chamber, thereby reducing energy wastage and preventing frost damage.

Implementation Method 1

supplies current unsuitable for driving the rotation, i.e. a current which flows through the compressor motor and releases Joule heat there

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an evaporation tray for evaporating condensation water drained from a storage chamber of the appliance

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2880385B1Refrigerator having an evaporation tray
Publication Date: 2018.08.15 BSH HAUSGERATE GMBH
  • EP2880385B1 patent drawingFigure 1~2
  • EP2880385B1 patent drawingFigure 3

AI summary

A refrigerator, in particular a domestic refrigerator, comprises at least a storage chamber (3), an evaporation tray (9) for evaporating condensation water which drains from the storage chamber (3), a compressor motor (13) which is arranged in thermal contact with the evaporation tray (9), and a control unit (10) which can be switched over between a driving operating mode, in which it supplies a current which is suitable for driving a rotation of the compressor motor (13), and a heating operating mode, in which it supplies a current which is not suitable for driving the rotation.