Sorption Unit Heat Exchanger for Dishwasher Energy Recovery

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Solution Overview

Problem

Conventional dishwashers with sorption drying systems face inefficiencies in energy usage and sorption material cooling, leading to prolonged drying times and reduced absorption capacity, necessitating a solution to enhance energy efficiency and accelerate material readiness for the next cycle.

Innovation Solution

Incorporating a heat exchanger within the sorption unit to transfer heat from the zeolitic material to the rinsing water, allowing for efficient cooling of the sorption material and simultaneous heating of the rinsing water, thereby reducing energy consumption and increasing the absorption capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the zeolitic material is used to absorb water vapor from the humid air in the rinsing chamber, then the drying time of the crockery is significantly reduced, but the zeolite material heats up during adsorption and requires regeneration which consumes additional energy and time

Engineering Contradiction:
Improvedrying timeVSAvoidenergy consumption for regeneration
Core Design Contradiction:
Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent converts the heat generated during the adsorption process (which was previously a harmful effect requiring energy-intensive regeneration) into a beneficial resource. The heated zeolite material is used to pre-heat the rinsing water, and the heat exchanger recovers heat from the regenerating zeolite to pre-heat incoming water, thereby reducing the energy required for water heating during subsequent washing cycles.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If the zeolite material is heated up for regeneration, then the water vapor bound to the surface is desorbed, but the sorption material only cools down slowly by giving off heat to the environment after regeneration, reducing absorption capacity for the next cycle

Engineering Contradiction:
Improveadsorption capacityVSAvoidcooling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent introduces a heat exchanger as an intermediary between the hot zeolite material and the rinsing water. This heat exchanger enables efficient thermal energy transfer, allowing the zeolite to cool down rapidly by transferring its heat to the water rather than slowly dissipating heat to the environment. This mediator facilitates quick thermal equilibrium restoration, making the zeolite ready for the next adsorption cycle faster.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a heat exchanger is added to transfer heat from the sorption unit to rinsing water, then the sorption material cools down faster and the drying device is ready for use again earlier, but the device complexity increases

Engineering Contradiction:
Improvereadiness for next cycleVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The heat exchanger is designed to serve multiple functions: it cools the zeolite material after adsorption, pre-heats the rinsing water to reduce energy consumption, and can be integrated into the existing drying device structure. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component addition.

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

Solution Approach 2:

The patent integrates the heat exchanger into the existing drying device structure, merging it with the sorption unit and water circulation system. This integration approach minimizes the increase in device complexity by combining the heat exchanger with existing components rather than adding it as a completely separate system.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly enhances energy efficiency, reduces drying time, and ensures the sorption material is ready for use sooner, while maintaining a cost-effective and simple integration process.

Implementation Method 1

the drying device comprises at least one heat exchanger for heat transfer from the sorption unit to rinsing water and/or fresh water

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the zeolite material absorbs water vapor from the humid air in the rinsing chamber, which flows through the sorption unit

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

The zeolite material is heated up so that the water vapor bound to the surface is desorbed

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 4

The desorbed hot water vapor is conducted into the washing compartment and condenses there on the surface of the dishes and the walls of the washing compartment

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP2682041B1Dishwasher
Publication Date: 2019.07.31 FRITZ EICHENAUER GMBH & CO KG
  • EP2682041B1 patent drawingFigure 1
  • EP2682041B1 patent drawingFigure 2
  • EP2682041B1 patent drawingFigure 3

AI summary

The dishwasher has a rinsing chamber (1), and a conveying device (8) e.g. fan, for conveying moist air from the rinsing chamber to a drying device (2) i.e. sorption drying system. The drying device comprises a sorption unit (3) and a heat exchanger (11) for transferring heat from the sorption unit to rinsing water and/or fresh water. A heating element (4) is arranged in the sorption unit and designed as a wire heating element. The heating element and the heat exchanger are directly connected with one another in a heat-conducting manner. An independent claim is also included for a method for drying moist air from a rinsing chamber of a dishwasher.