Waste Water Tank Heat Pump Control to Prevent Complete Icing
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Solution Overview
Problem
Existing washing machines and dishwashers with heat pumps to recycle heat from waste water risk complete icing of the waste water tank, requiring complex temperature monitoring and potential equipment redundancy.
Innovation Solution
A controller determines the ambient temperature to set a maximum heat pump runtime, eliminating the need for direct temperature sensors on the waste water tank and optimizing heat extraction based on ambient conditions, thereby preventing complete icing and simplifying equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct temperature measurement at the waste water tank is used to prevent complete icing, then the reliability of preventing complete icing is improved, but the device complexity increases due to additional temperature sensors and monitoring equipment
Solution Approach 1:
The controller uses the ambient temperature sensor data and pre-stored calibration information to autonomously determine the maximum heat pump runtime without requiring additional temperature sensors on the waste water tank. The system serves itself by using existing sensor data and calculated parameters to prevent complete icing.
Solution Approach 2:
The calibration measurements are performed in advance to create a stored relationship between ambient temperature and maximum heat pump runtime. This preliminary action allows the controller to determine safe operating parameters before the washing process begins, eliminating the need for complex real-time temperature monitoring during operation.
2Use of energy by moving object
If the heat pump runs for extended periods to maximize heat extraction, then the energy efficiency is improved, but the risk of complete icing increases requiring complex control mechanisms
Solution Approach 1:
The controller adjusts the heat pump runtime parameter based on the ambient temperature. By changing the operational parameters (maximum runtime) according to environmental conditions, the system optimizes heat extraction while preventing complete icing in different ambient temperature conditions.
Solution Approach 2:
The controller uses feedback from the ambient temperature sensor to dynamically adjust the heat pump operation. The stored calibration data provides a feedback mechanism that links ambient temperature conditions to appropriate maximum runtime settings, ensuring optimal energy extraction without exceeding safe operating limits.
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 approach effectively prevents waste water tank icing while reducing equipment complexity by using ambient temperature to limit heat pump operation, ensuring efficient heat recycling and energy use.
Implementation Method 1
a heat pump to extract heat from the waste water tank and feed it to the process water in the tub
Implementation Method 2
The waste water tank is cooled to such an extent that part of the process water in the waste water tank freezes
Data Source
Figure 1
AI summary
In a washing machine or a dishwasher, the tub (1) is followed by a waste water tank (6) for temporarily holding process water. A heat pump (7 - 10) extracts heat from the waste water tank (6) until the waste water in the waste water tank (6) is partially frozen. In order to prevent the waste water tank (6) from completely icing up, the maximum runtime of the heat pump (7 - 10) is determined depending on the measured ambient temperature.