A heat pump dishwasher
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Solution Overview
Problem
In dishwashers using heat pumps, condensate water collected in drip trays under the heat exchanger often causes bad odors and can lead to electrical failures if not discharged properly, and the frequent reversal of refrigerant flow for heating and cooling complicates the heating process, prolonging the dishwashing duration.
Innovation Solution
A dishwasher design featuring a duct with a valve and control unit that allows bidirectional refrigerant flow, enabling the first heat exchanger to evaporate condensate water by reversing the refrigerant direction and utilizing waste water and drying heat to reduce energy consumption and prevent overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the refrigerant flow direction is frequently reversed for heating and cooling on the same heat exchanger, then both heating and cooling functions are achieved, but the heating/cooling process takes longer time and efficiency is reduced
Solution Approach 1:
The heat exchanger system is divided into two separate heat exchangers: a first heat exchanger dedicated to cooling (drawing heat from environment) and a second heat exchanger dedicated to heating (transferring heat to wash water). This segmentation eliminates the need for frequent flow direction reversals, allowing each heat exchanger to operate continuously in its optimal mode, thereby resolving the contradiction between versatility and process time efficiency.
2Reliability
If the first heat exchanger continues to draw heat from the environment during the drying step, then cooling function is maintained, but the condensate water in the drip tray is not evaporated, causing odors and potential electrical failures
Solution Approach 1:
The operational mode of the first heat exchanger is inverted during the drying step: instead of drawing heat from the environment (cooling mode), it is configured to give off heat to the environment (heating mode). This inversion allows the first heat exchanger to evaporate the condensate water in the drip tray, eliminating odors and preventing electrical failures while maintaining system reliability.
3Loss of energy
If waste water heat is utilized by passing it over the second heat exchanger during evaporation, then energy consumption is reduced, but the system complexity increases
Solution Approach 1:
The waste water circulation system is merged with the existing heat pump system by integrating a water circulation pump and routing waste water through the second heat exchanger. This combination allows the waste water to transfer its residual heat to the evaporating condensate, significantly reducing energy consumption for evaporation while adding minimal complexity to the overall system architecture.
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
Efficient evaporation of condensate water reduces odor issues and electrical risks, recycles energy, and shortens the dishwashing cycle by using waste water and drying heat, enhancing the overall efficiency and reliability of the dishwasher.
Implementation Method 1
Since the surface of the heat exchanger that draws heat from the environment is cold, the moisture in the ambient air condenses on the heat exchanger
Implementation Method 2
The heat pumps are operated with the principle that the refrigerant is compressed and expanded between at least two heat exchangers, thus providing heat transfer
Implementation Method 3
with the circulation of the refrigerant in the reverse direction, further providing that the first heat exchanger drawing heat from the environment during the heating of the wash water gives off heat and the water collected in the drip tray is evaporated by this heat
Implementation Method 4
the refrigerant is compressed and expanded between at least two heat exchangers
Data Source
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AI summary
The present invention relates to a dishwasher (1) comprising a body (2); a heat pump (3) that is disposed inside the body (2), that provides the heating of the water to be used in the washing step and that has a first heat exchanger (4) drawing heat from the ambient air, a second heat exchanger (5) transferring the heat received from the first heat exchanger (4) to the wash water and a compressor (6) fluidly connected to the first heat exchanger (4) and the second heat exchanger (5), realizing the refrigerant cycle by compressing and directing the refrigerant leaving the first heat exchanger (4) to the second heat exchanger (5), and a drip tray (7) that is disposed immediately under the first heat exchanger (4), wherein the water condensing on the first heat exchanger (4) is collected.