Reversible Heat Pump Washing Machine for Gentle Water Cooling

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Solution Overview

Problem

Existing washing machines with heat pumps do not effectively protect delicate laundry from shrinkage and discoloration during the washing process, as they lack a mechanism to control water temperature precisely, especially during the main wash cycle where laundry is most intensely treated.

Innovation Solution

A washing machine equipped with a heat pump that reverses the flow direction of the heat pump medium to switch between heating and cooling modes, using a reversing valve to control the condenser and evaporator, allowing for precise temperature adjustment of the process water in the tub, thereby minimizing stress on delicate items.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heat pump is used to heat the process water in the tub, then the water temperature increases, but delicate laundry is subjected to excessive thermal stress causing shrinkage and discoloration

Engineering Contradiction:
Improveprocess water temperatureVSAvoidthermal stress on laundry
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent applies heat pump reversal to switch between heating and cooling modes. By inverting the heat pump operation, the system can cool process water instead of heating it, providing a gentle washing option for delicate laundry that prevents thermal stress, shrinkage, and discoloration while maintaining effective stain removal at lower temperatures

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If the heat pump medium flow direction is reversed to switch between heating and cooling modes, then temperature control precision improves, but device complexity increases due to the reversing valve

Engineering Contradiction:
Improvetemperature control precisionVSAvoidheat pump system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The heat pump system is designed to perform multiple functions - both heating and cooling of process water - using the same hardware components. The reversing valve enables a single heat pump unit to switch between heating mode (for warm water washing) and cooling mode (for delicate garment washing), eliminating the need for separate heating and cooling systems and thereby reducing overall device complexity

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

3Use of energy by moving object

If waste heat from cooling operation is utilized for subsequent heating operation, then energy efficiency increases, but the system requires coordinated operation between cooling and heating cycles

Engineering Contradiction:
Improveenergy efficiencyVSAvoidoperational coordination complexity
Core Design Contradiction:
Use of energy by moving objectVSExtent of automation

Solution Approach 1:

The control unit monitors the thermal state of the process water and waste water, and automatically coordinates heat pump operations between cooling and heating modes. When waste water accumulates sufficient heat from a cooling cycle, the system automatically switches to heating mode to utilize this stored thermal energy, creating an efficient feedback loop that maximizes energy recovery without requiring manual intervention

Inventive Principle:
Principle #23Feedback

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

The solution enables gentle washing by heating or cooling the laundry as needed, reducing the risk of shrinkage and discoloration, and enhances efficiency by utilizing waste heat for subsequent operations, thus protecting delicate laundry while optimizing energy use.

Implementation Method 1

In the cooling module, evaporation takes place in the condenser and condensation in the evaporator

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

In the cooling module, evaporation takes place in the condenser and condensation in the evaporator

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

The evaporator is in thermal contact with the waste water tank. This allows the waste water in the waste water tank to be cooled in heating mode and heated in cooling mode

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3135799B1Washing machine with cooling cycle
Publication Date: 2018.11.07 V-ZUG AG
  • EP3135799B1 patent drawingFigure 1
  • EP3135799B1 patent drawingFigure 2~3

AI summary

A washing machine has a heat pump comprising a compressor (7), a condenser (8), a throttle (9) and an evaporator (10). The condenser (8) is in thermal contact with the process water in the tank (1) of the device. In a heating mode, the process water in the tub (1) is heated with the heat pump. Cooling operation is also provided, in which the process water in the tub (1) is cooled with the heat pump. For this purpose, the direction of flow of the heat pump medium through the condenser (8), the throttle (9) and the evaporator (10) can be reversed with a reversing valve (30). The use of cooled process water in the vat (1) enables particularly gentle treatment of the laundry.