Basement Process-Air Routing in Laundry Dryer Heat Pumps

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Solution Overview

Problem

The existing heat pump systems in laundry dryers face inefficiencies due to suboptimal air flow within the basement, leading to increased energy consumption and noise, primarily caused by sharp turns and angles in the process air duct, which are detrimental to aerodynamics.

Innovation Solution

The arrangement of the evaporator and condenser within the basement, combined with a strategically positioned drum exhaust process air conduit, allows for a larger, more aerodynamic path for the air flow, reducing the need for sharp turns and maintaining efficient heat exchange and filtering capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the evaporator and condenser are arranged in parallel in a straight basement process air duct, then the heat exchange efficiency is maintained, but the air flow experiences sharp turns and angles causing pressure drops and turbulences

Engineering Contradiction:
Improveenergy consumptionVSAvoidduct configuration complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies curvature by replacing sharp 90° turns with gentle curved transitions in the basement process air duct. The duct is designed with smooth bends that allow air to flow from the evaporator and condenser to the main fan without abrupt directional changes, reducing turbulence and pressure drops while maintaining the parallel arrangement of heat exchangers for efficient heat exchange

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Loss of energy

If sharp turns and angles are avoided in the process air duct, then energy consumption and noise are reduced, but more space is required in the basement for the duct

Engineering Contradiction:
Improveenergy consumptionVSAvoidbasement space
Core Design Contradiction:
Loss of energyVSVolume of stationary object

Solution Approach 1:

The patent utilizes three-dimensional space optimization by arranging the evaporator and condenser in parallel configuration within the basement, allowing the air duct to flow between them and connect to the main fan through gentle curves. This spatial arrangement enables the duct to achieve aerodynamic smooth transitions without requiring excessive basement volume, as the heat exchangers themselves provide the necessary spatial framework

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

3Loss of energy

If the heat exchangers are re-positioned to allow gentle curves in the duct, then aerodynamic performance is improved, but the available space for heat exchange surface is reduced

Engineering Contradiction:
Improveair flow efficiencyVSAvoidheat exchange surface area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The patent merges the evaporator and condenser into a parallel arrangement within the basement, where both heat exchangers operate simultaneously in the same air flow path. This combined configuration allows the air to pass through both exchangers sequentially with minimal directional changes, maintaining adequate heat exchange surface area while achieving smooth aerodynamic transitions through the basement duct

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 reduces energy consumption and noise levels by optimizing air flow, ensuring efficient heat exchange and filtering while allowing for a more aerodynamic path within the basement, thus improving the overall performance of the heat pump system.

Implementation Method 1

the process air stream is cooled down and dehumidified in an evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

the refrigerant is compressed by a compressor, condensed in the condenser

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The condenser and the evaporator are heat exchangers between the process air stream circuit and the refrigerant circuit

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

The refrigerant is compressed by a compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 5

expanded in an expansion device

Methodology Applied
Scientific EffectExpansion:

Data Source

PatentEP2990520B1Laundry dryer including a heat pump system
Publication Date: 2020.03.11 ELECTROLUX APPLIANCES
  • EP2990520B1 patent drawingFigure 1~1a
  • EP2990520B1 patent drawingFigure 2~1b
  • EP2990520B1 patent drawingFigure 3

AI summary

The present invention relates to a laundry dryer (1) including: - a casing (2) rotatably supporting a drum (3) for receiving a load to be dried, said drum being apt to rotate around a drum axis (R), said casing (2) including o a rear wall (21) and a front wall (20) defining, respectively, a rear side and a front side of said casing (2), an aperture (4a) being realized on said front wall to access said drum (3); o a basement (24) defining a basement plane (X,Y); - A process air conduit (18) in fluid communication with the drum (3) where a process air stream is apt to flow, said process air conduit including a drum exhaust process air conduit (18a) having an inlet (17) in which process air exiting said drum (3) is conveyed; - A heat pump (30) having a heat pump circuit in which a refrigerant can flow, said heat pump circuit including a first heat exchanger (31) where the refrigerant is cooled off and the process air is heated up, and a second heat exchanger (32) where the refrigerant is heated up and the process air is cooled off; said first and/or second heat exchanger (31, 32) being arranged in the process air conduit (18) in order to perform heat exchange between said refrigerant flowing in said heat pump circuit and said process air; Wherein - Said drum exhaust process air conduit (18a) includes an inlet edge (17s) surrounding said inlet (17) and defining a front end and a rear end; and - A first portion (32b) of said second heat exchanger (32) is located below said rear end of said inlet edge (17s) and a second portion (32d) of said second heat exchanger (32) is located below said drum (3).