Refrigerator Fan Motion Feedback for Compressor Overheat Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Refrigeration devices with forced cooling face challenges in maintaining heat dissipation when a fan fails, leading to overheating risks and complex, costly repairs, especially since existing solutions like temperature sensors can be influenced by ambient temperatures and are not effective in single-fan systems.

Innovation Solution

A refrigeration device that uses a fan's movement signal to control the compressor, allowing for continued operation by reducing power or switching off the compressor if the fan's movement is insufficient, with a control circuit that interprets oscillating output signals from the fan's motor to manage energy supply based on fan speed, preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If forced cooling is implemented with a single fan, then device compactness and space utilization are improved, but reliability deteriorates due to overheating risk when the fan fails

Engineering Contradiction:
Improvedevice compactnessVSAvoidoverheating risk
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where a control circuit continuously monitors the fan's operation status and dynamically adjusts the compressor's operating state accordingly. When the fan is detected to be non-operational, the control circuit automatically reduces or stops the compressor operation to prevent overheating, thereby resolving the reliability issue while maintaining the compact single-fan design.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamic control by making the compressor's operating state variable rather than fixed. The compressor can switch between different operating modes (normal operation, reduced power, or shutdown) based on real-time fan status, allowing the system to adapt to changing conditions and prevent overheating without requiring redundant fans.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a temperature sensor is used to monitor machine room temperature, then overheating detection is improved, but measurement precision deteriorates due to ambient temperature influence

Engineering Contradiction:
Improveoverheating detectionVSAvoidtemperature detection accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent uses the fan's operation status as an intermediary indicator to infer thermal conditions in the machine room. Instead of directly measuring temperature (which is affected by ambient conditions), the control circuit monitors whether the fan is running, and uses this information to determine appropriate compressor operation, thereby avoiding the measurement precision issues of temperature sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the thermal measurement approach (temperature sensing) with a mechanical/electrical monitoring approach (fan status detection). By monitoring the fan's electrical operation or mechanical rotation rather than measuring temperature, the system avoids the problem of ambient temperature interference while still achieving effective overheating prevention.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If compressor power is reduced to prevent overheating, then reliability is improved, but productivity deteriorates due to limited cooling capacity

Engineering Contradiction:
Improveoverheating preventionVSAvoidcooling capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic power adjustment where the compressor operates at full power when the fan is functional (maintaining productivity) and automatically reduces or shuts down when the fan fails (ensuring reliability). This dynamic switching allows the system to maintain high cooling capacity during normal operation while preventing overheating during fan failure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control circuit periodically monitors fan status and adjusts compressor power accordingly, enabling the system to alternate between full-power cooling mode and reduced-power protection mode based on real-time conditions, thus optimizing both productivity and reliability.

Inventive Principle:
Principle #19Periodic action

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

Enables continued operation and prevents overheating even in the event of a fan failure, ensuring safe operation and reducing repair complexities by dynamically adjusting compressor power based on fan performance, thus maintaining cooling functionality.

Implementation Method 1

The output signal can oscillate at least when the movement state of the fan is sufficient. Such an oscillating output signal can be derived quite easily, for example inductively, from the movement of a motor of the fan. The frequency of such a derived signal is preferably proportional to a rotational frequency of the fan.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2154452B1Cooling device with forced cooling
Publication Date: 2016.04.06 BSH HAUSGERATE GMBH
  • EP2154452B1 patent drawingFigure 1~3

AI summary

In a refrigerator with a compressor (3) and a condenser, at least one of which is forced-cooled by a fan (6), the fan (6) has a signal output (13) for an output signal indicating its state of motion, and a control circuit (8 ) is connected to the signal output (13) in order to control the operation of the compressor (3) based on the output signal.