Evaporation Tray Overflow Sensing in Refrigeration Appliances

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Solution Overview

Problem

Conventional refrigeration devices face challenges in accurately estimating the water level in the evaporation tray, especially when it is full, leading to inefficient use of electrical heating and potential overflow, due to the unfavorable ratio of condensation water to waste heat and the inaccuracy of water level estimation based on heating rate.

Innovation Solution

A refrigeration appliance design featuring a temperature sensor in the flooding zone that detects changes in temperature to assess the water level, allowing for reliable estimation of the residual capacity by differentiating between the main and flooding zones, with a heating device operated based on detected temperature changes to prevent overflow, and utilizing waste heat from the compressor for efficient evaporation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a temperature sensor is used to estimate water level based on heating rate, then the device can detect water level, but the accuracy deteriorates when the evaporation tray is full

Engineering Contradiction:
Improvewater level detection accuracyVSAvoiddetection reliability at high water levels
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The evaporation tray is divided into two distinct zones: a main evaporation zone and a flooding zone. The temperature sensor is specifically positioned in the flooding zone to detect water presence independently of the main zone water level. This segmentation allows accurate detection even when the main evaporation tray is full, as the sensor responds only to water in its immediate vicinity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If an electrical heating device is used to increase evaporation rate, then evaporation efficiency improves, but power consumption increases significantly

Engineering Contradiction:
Improveevaporation rateVSAvoidpower consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The control unit continuously monitors the temperature sensor signal and adjusts the heating device operation accordingly. Heating is activated only when the sensor detects water in the flooding zone (indicating high water level), and deactivated when the zone is dry. This feedback mechanism ensures heating is applied only when necessary to prevent overflow, minimizing energy consumption while maintaining effective water level control.

Inventive Principle:
Principle #23Feedback

3Quantity of substance

If the evaporation tray is designed to accommodate more condensation water, then overflow prevention capability improves, but the space for evaporation surface decreases

Engineering Contradiction:
Improvecondensation water capacityVSAvoidevaporation surface area
Core Design Contradiction:
Quantity of substanceVSArea of stationary object

Solution Approach 1:

The flooding zone is positioned at a different vertical level than the main evaporation zone, creating a two-level structure. This dimensional arrangement allows the system to accommodate additional water volume in the flooding zone without reducing the evaporation surface area of the main zone. The sensor in the lower flooding zone detects water presence independently, enabling accurate water level monitoring while maintaining adequate evaporation surface in the upper main zone.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution enables accurate detection of the water level just below the overflow point, allowing for timely heating to prevent overflow and optimizing energy usage by using low heat output and short measuring times, thus improving the reliability and efficiency of evaporation in the refrigeration device.

Implementation Method 1

an evaporation arrangement for evaporating condensation water drained from the storage chamber

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a heat source, an evaporation arrangement for evaporating condensation water

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

a temperature sensor arranged on the evaporation arrangement in thermal contact with the heat source

Methodology Applied
Scientific EffectThermal contact heat transfer: Conduction (thermal)

Data Source

PatentEP2769156B1Refrigeration appliance comprising an evaporation tray and a heating device for promoting evaporation
Publication Date: 2015.12.30 BSH HAUSGERATE GMBH
  • EP2769156B1 patent drawingFigure 1~5
  • EP2769156B1 patent drawingFigure 3~6
  • EP2769156B1 patent drawingFigure 7~9

AI summary

A refrigeration appliance, especially a domestic refrigeration appliance, comprises at least one storage chamber (3), a heat source (10), an evaporation arrangement (9) for evaporating condensed water carried off from the storage chamber (3), a temperature sensor (15) arranged on the evaporation arrangement (9) in thermal contact with the heat source (10), a control unit (13) connected to the temperature sensor (15) and a heating device (10) which can be operated by the control unit (13) to increase the evaporation rate in the evaporation tray (9). The control unit (13) is designed to decide, based on a change in the temperatures detected by the temperature sensor (15), whether operation of the heating device (10) is carried on or discontinued. The evaporation arrangement (9) comprises a main zone (16) and a flooding zone (18) in which the temperature sensor (15) is arranged. The flooding zone (18) contains water in contact with the temperature sensor (15) only if the water level in the main zone (18) has reached or exceeded an overflow level.