Dishwasher Zeolite Drying Control for Timed Desorption

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Solution Overview

Problem

Existing sorption drying systems in dishwashers face inefficiencies in the desorption process of reversibly dehydratable materials, such as zeolite, due to suboptimal timing and temperature conditions, which affect the moisture absorption capacity and overall drying performance.

Innovation Solution

The method involves evaluating air and water inlet temperatures to determine the optimal time for the desorption process, ensuring it occurs when the air temperature is lowest, and using this information to adjust the desorption timing and heating processes across various program steps, including cleaning and rinsing, to enhance energy efficiency and drying effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If desorption is carried out at high temperatures continuously, then moisture is effectively removed from the drying material, but energy consumption increases and the system cannot utilize optimal moisture absorption conditions

Engineering Contradiction:
Improveenergy consumptionVSAvoiddrying performance
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent implements periodic alternation between sorption (moisture absorption) and desorption (moisture release) phases. During sorption phase, cold dry air passes through the drying material to absorb moisture. During desorption phase, heated air releases stored moisture. This periodic cycling allows the system to achieve effective drying while utilizing both low-temperature moisture absorption and controlled high-temperature moisture release, reducing overall energy consumption compared to continuous heating.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically changes temperature and air flow parameters between sorption and desorption phases. During sorption, cold air at lower temperature is used to maximize moisture absorption capacity. During desorption, temperature is increased to facilitate moisture release. This parameter variation allows optimal performance at each phase while reducing total energy input compared to maintaining constant high temperature.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If desorption is delayed until air temperature is lowest, then moisture absorption capacity of air is maximized, but the duration of the drying process increases

Engineering Contradiction:
Improvemoisture absorption capacityVSAvoiddrying process duration
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary sorption of moisture by cold air into the drying material before the main drying phase. This pre-absorption prepares the drying material to be ready for rapid desorption when heated, allowing the system to capture moisture during low-temperature periods and release it during controlled heating phases, thereby maximizing absorption capacity without significantly extending total process time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous operation by seamlessly transitioning between sorption and desorption phases without idle periods. The sorption phase continuously absorbs moisture from the environment into the drying material, and the desorption phase continuously releases this moisture when heated. This continuous cycling ensures both high moisture absorption capacity and efficient utilization of time, avoiding process interruptions.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If heating means are operated during desorption, then moisture release is enhanced, but energy consumption increases

Engineering Contradiction:
Improvedesorption efficiencyVSAvoidheating energy
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The drying material itself serves as both the moisture absorber and the medium for moisture release. During desorption, the material releases previously absorbed moisture when heated, and this released moisture is then absorbed again during the subsequent sorption phase. The system uses the drying material's own moisture storage capacity to drive the cycle, reducing the need for external energy input compared to continuous active heating for moisture removal.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system exploits phase transitions of moisture between absorbed state (during sorption) and vapor state (during desorption). By heating the drying material during desorption phase, stored moisture transitions from bound liquid state to vapor state and is released. During sorption phase, vapor moisture is absorbed back into the material. This phase transition cycling allows efficient moisture management with minimized heating requirements, as heating is applied only during desorption rather than continuously.

Inventive Principle:
Principle #36Phase transitions

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 ensures efficient desorption and improved drying performance by aligning the desorption process with optimal temperature conditions, leading to enhanced energy efficiency and reduced drying time, while also allowing for more intensive cleaning and better utilization of heating resources.

Implementation Method 1

moisture is extracted from the air guided through by the reversibly dehydratable drying material located in the sorption compartment

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

For regeneration, i.e. desorption of the drying material, the reversibly dehydratable drying material is heated to very high temperatures. As a result, water stored in this drying material emerges as hot water vapor

Methodology Applied
Scientific EffectDesorption: Desorption

Data Source

PatentEP2352413B1Method for operating a dishwasher
Publication Date: 2012.09.05 BSH HAUSGERATE GMBH
  • EP2352413B1 patent drawingFigure 1
  • EP2352413B1 patent drawingFigure 2
  • EP2352413B1 patent drawingFigure 3

AI summary

The invention relates to a method for operating a dishwasher (GS), especially a household dishwasher, wherein a desorption process for the desorption of a reversibly dehydrogenable dry material (ZEO), especially zeolite, of a sorption drying system is generated at least temporarily. According to the invention, parameters influencing the desorption process are evaluated in order to determine when to carry out the desorption process.