Dishwasher Heat Exchanger with Turbulent-Flow Surface Elements

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Solution Overview

Problem

Existing domestic dishwashers face inefficiencies in heat transfer between heat exchanger elements and washing liquor or air, as the heat transfer is not effectively enhanced by the conventional coiled metal heat exchanger elements.

Innovation Solution

A heat pump arrangement with heat exchanger elements featuring multiple surface elements connected via irregularly spaced connection points, creating a network of channel sections that deflect and mix the refrigerant flow, resulting in a turbulent flow that improves heat transfer between the refrigerant and the washing liquor or air.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional coiled metal heat exchanger elements are used, then the structure is simple and easy to manufacture, but the heat transfer efficiency between the heat exchanger and washing liquor or air is insufficient

Engineering Contradiction:
Improveease of manufactureVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The heat exchanger element is divided into multiple flat surface elements (first, second, third surface elements) connected at discrete connection points, creating a segmented structure. This segmentation increases the effective heat transfer surface area and creates turbulence-promoting features that enhance heat transfer efficiency while maintaining manufacturing simplicity through modular construction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a conventional coiled three-dimensional structure to a planar/flat surface element configuration. This dimensional change increases the heat transfer surface area within a compact footprint and creates unique flow patterns that enhance convective heat transfer between the heat exchanger and washing liquor or air

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

2Loss of energy

If the heat exchanger element uses multiple surface elements connected via connection points, then the heat transfer efficiency is improved through turbulent flow, but the device complexity increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

Multiple flat surface elements are merged into a single integrated heat exchanger element with continuous refrigerant flow paths. The connection points serve dual purposes: structural joining of surface elements and flow distribution nodes, reducing the need for additional components and simplifying the overall device complexity while maintaining enhanced heat transfer performance

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 configuration enhances heat transfer efficiency, allowing for better heating of washing liquor during cleaning and drying, improving the overall performance of the domestic dishwasher.

Implementation Method 1

at least one evaporator for evaporating a refrigerant

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a compressor for compressing the evaporated refrigerant. The gaseous refrigerant entering the compressor during operation of the heat pump arrangement is compressed with the aid of the compressor, during which it heats up

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

a heat exchanger element that acts as a condenser, in which the heated gaseous refrigerant condenses again and thereby emits heat

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

heat must be transferred from a heat source (e.g., a thermal or air heater) of the domestic dishwasher to the wash liquor or to air entering or circulating in the domestic dishwasher

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 5

The connection points are arranged in such a way that the refrigerant is deflected several times as it passes through the heat exchanger element and is mixed in the process, resulting in a turbulent flow that improves heat transfer

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3335616B1Domestic dishwasher with heat pump assembly
Publication Date: 2020.02.26 BSH HAUSGERATE GMBH
  • EP3335616B1 patent drawingFigure 1
  • EP3335616B1 patent drawingFigure 2
  • EP3335616B1 patent drawingFigure 3

AI summary

Proposed is a domestic dishwasher with a receiving space (1) for accommodating items to be washed (2), the domestic dishwasher having a heat pump arrangement with at least one evaporator (3) for evaporating a refrigerant (11) and a condenser (5) for condensing the refrigerant (11). comprises, wherein the evaporator (3) and / or the condenser (5) comprise one or more sheet-like heat exchanger elements (6). The household dishwasher is characterized in that at least one of the heat exchanger elements (6) comprises two surface elements (7) which are connected in places via connection points (26), the surface elements (7) and the connection points (26) forming a free space (10) limit over which the refrigerant (11) can pass the heat exchanger element (6), the connection points (26) being arranged in such a way that the refrigerant (11) is deflected several times when passing through the heat exchanger element (6) and is mixed in the process.