Household appliance comprising a water/process air heat exchanger

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Solution Overview

Problem

Existing washer-dryers face inefficiencies in drying processes, including high energy consumption, water usage, and voluminous designs, particularly in condensation using ambient air, fresh water, and heat pumps.

Innovation Solution

A household appliance with a closed-loop system incorporating a process air circuit and a water circuit, utilizing a water/process air heat exchanger and a heat pump, featuring a capillary tube mat for efficient heat transfer and a compact design, allowing for flexible integration into existing platforms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a heat pump is used for condensation drying, then energy efficiency is improved, but the device volume increases significantly

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddevice volume
Core Design Contradiction:
Loss of energyVSVolume of stationary object

Solution Approach 1:

The patent combines the heat exchanger and water reservoir into a single integrated water condensation component. The heat exchanger is positioned within the water reservoir, allowing the reservoir to serve dual purposes: storing water and facilitating heat exchange for condensation drying. This merging eliminates the need for separate heat exchanger housing and reduces overall device volume while maintaining heat pump energy efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchanger is nested within the water reservoir space, with the heat exchanger channels formed inside or within the structural walls of the reservoir. This nesting arrangement allows the heat exchanger to utilize the water reservoir's internal volume, achieving compact integration without compromising the heat exchange surface area needed for effective condensation drying.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If ambient air is used for condensation, then device complexity is reduced, but energy efficiency deteriorates and room temperature increases

Engineering Contradiction:
Improvedevice complexityVSAvoidenergy efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent introduces water as an intermediary cooling medium between the humid process air and the heat exchanger. Instead of directly using ambient air for condensation, cool water circulates through the heat exchanger channels, absorbing heat from the humid air and condensing the moisture. This intermediary water cooling system prevents ambient air from being heated and maintains higher energy efficiency while keeping device complexity manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If fresh water is used for condensation, then condensation effectiveness is improved, but water consumption increases

Engineering Contradiction:
Improvecondensation effectivenessVSAvoidwater consumption
Core Design Contradiction:
Loss of energyVSLoss of substance

Solution Approach 1:

The patent implements a closed-loop water circulation system where water is continuously pumped from the reservoir through the heat exchanger, used for condensation cooling, and then returned to the reservoir. The water is not discarded after single use but recovered and reused multiple times, significantly reducing water consumption while maintaining effective condensation drying performance.

Inventive Principle:
Principle #34Discarding and recovering

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 enhances thermodynamic efficiency, reduces water consumption, and provides a compact design while enabling flexible drying modes, improving energy efficiency and adaptability.

Implementation Method 1

a water/process air heat exchanger adapted to cool down the process air flowing within the process air channel

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a heating device for heating the process air

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

featuring a capillary tube mat for efficient heat transfer

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3241943B1Household appliance comprising a water/process air heat exchanger
Publication Date: 2019.09.11 BSH HAUSGERATE GMBH
  • EP3241943B1 patent drawingFigure 1
  • EP3241943B1 patent drawingFigure 2
  • EP3241943B1 patent drawingFigure 3

AI summary

A household appliance 1, 31, in particular washer-dryer 1, 31, comprises a process air circuit 10 for circulating process air P comprising a treatment chamber 2, 3 having an air inlet opening 5 and an air outlet opening 6 and a process air channel 9 connecting the openings 5, 6, a heating device 19, 19' for heating the process air P, and a water circuit 13 comprising: a water/process air heat exchanger 11 adapted to cool process air P flowing within the process air circuit 10 and a water circulation device 16 for circulating the water W in the water circuit 13. The invention is particularly useful for a laundry care apparatus, in particular for a clothes washer/dryer combination or washing machine with drying function ("washer-dryer"), in particular having a heat pump.