Heat Pump Washing Machine With Regenerative Tank Cooling
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Solution Overview
Problem
Existing washing machines with heat pumps face inefficiencies due to uncontrolled heat exchange and ineffective regeneration of heat, leading to suboptimal performance and design constraints.
Innovation Solution
Incorporating an additional fluid-to-air heat exchanger between the evaporator and compressor, with a controllable fan and pressure lowering device, to enhance heat transfer and reduce the size of the evaporator, allowing for partial superheating and evaporation within the additional heat exchanger, and a liquid circulation system for efficient regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the heat pump evaporator is connected in parallel with the electronics unit evaporator, then heat exchange capacity is increased, but the performance of the heat pump evaporator becomes uncontrolled and less efficient
Solution Approach 1:
The patent divides the evaporation function into two separate evaporators: a heat pump evaporator for cooling the liquid tank and an electronics unit evaporator for heating process water. This segmentation allows each evaporator to operate independently with dedicated control, resolving the performance control issue while maintaining heat exchange capacity through the heat pump cycle.
Solution Approach 2:
The patent introduces a three-way valve as an intermediary component to control the distribution of refrigerant between the heat pump evaporator and the electronics unit evaporator. This mediator enables selective activation of either evaporator based on operational requirements, maintaining control over heat pump evaporator performance while utilizing both heat exchange surfaces when needed.
2Quantity of substance
If the liquid tank volume is increased to improve heat storage capacity, then heat availability for the next process cycle is improved, but the device size and complexity increase
Solution Approach 1:
The patent changes the operational parameters of the liquid tank by implementing a controlled freezing regime. Instead of merely storing heat, the system intentionally freezes part of the liquid during off-cycle periods, creating a phase change heat storage mechanism. This allows significant heat storage capacity to be achieved in a reduced tank volume by utilizing the latent heat of fusion.
Solution Approach 2:
The patent utilizes the phase transition of water (freezing and melting) as a heat storage and release mechanism. During the freezing phase, heat is removed from the liquid tank; during the subsequent melting phase, this stored heat is automatically released to preheat the incoming process water, providing efficient heat recovery without requiring large tank volumes.
3Device complexity
If the evaporator size is reduced to decrease device complexity, then manufacturing cost and space are reduced, but the heat transfer efficiency and compressor safety may be compromised
Solution Approach 1:
The patent adds a temporal dimension to the evaporator operation by implementing a periodic freezing-melting cycle. The evaporator operates in alternating modes: during freezing mode, it removes heat from the liquid tank; during melting mode, the stored heat is released. This temporal dimension allows a smaller evaporator to achieve the same overall heat transfer effectiveness that would require a much larger continuous heat exchange surface.
Solution Approach 2:
The system performs preliminary freezing of the liquid tank contents during off-cycle periods or low-demand periods. This preliminary action stores thermal energy in the form of ice, which then melts during the next process cycle to provide heat. This preliminary heat storage action allows the evaporator to be smaller since it doesn't need to continuously provide full heat output.
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 increases heat pump efficiency, reduces ice formation, and allows for a smaller tank design while maintaining compressor safety, improving overall performance and energy efficiency.
Implementation Method 1
a heat pump adapted to extract heat from the liquid contained in the tank and to heat water to be used in the chamber
Implementation Method 2
heat is extracted from the liquid in the tank and, via a heat transfer fluid in a heat pump, is supplied to the process water
Implementation Method 3
where liquefaction takes place accompanied by release of heat... where the medium evaporates whilst absorbing heat
Implementation Method 4
where liquefaction takes place accompanied by release of heat
Implementation Method 5
an additional heat exchanger can be connected into a portion of the heat pump circuit between the outlet of the evaporator and the inlet of the compressor to provide heat, Q, to the heat transfer fluid
Implementation Method 6
pressure lowering device, such as an expansion valve or a capillary tube
Data Source
Figure 1
Figure 2
AI summary
Washing machine (1) comprising - a chamber (10) for receiving goods to be washed, - a tank (30) adapted to contain a liquid, - a heat pump (20) comprising a first heat exchanger (22), a second heat exchanger (24), a compressor (26) and a pressure lowering device (28) forming a circuit comprising a heat transfer fluid, the first heat exchanger (22) being adapted to cool said heat transfer fluid and to heat water to be used in the chamber (10), the second heat exchanger (24) being adapted to heat said heat transfer fluid and to cool the liquid contained in the tank (30).The washing machine may further comprise an additional heat exchanger connected between the outlet of the second heat exchanger (24) and the inlet of the compressor (26) and configured to release heat to the heat transfer fluid thereat, and/or a liquid circulation conduit (62) associated to the tank (30) and provided with an additional, fluid to air heat exchanger (66) having a controllable fan (68) associated therewith. A method of operating a washing machine is also provided, wherein heat is supplied to the contents of liquid tank (30) during operation of the heat pump (20).