Dishwasher Load Heat Capacity Detection for Drying Control
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Solution Overview
Problem
Existing methods for determining the load in water-bearing household appliances like dishwashers are complex and require significant control and regulation efforts, and are affected by variations in electrical mains voltage, making them inefficient for optimizing drying processes.
Innovation Solution
A method that records temperature profiles during cooling or mixing cycles using temperature sensors integrated into the flushing circuit or on condensation surfaces to indirectly determine the heat capacity of the load, allowing for automatic load detection without operator input and independent of rinsing solution and pump performance data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature profiles are recorded during cooling or mixing cycles to determine heat capacity, then load detection accuracy is improved, but device complexity increases due to additional temperature sensors and control logic
Solution Approach 1:
The temperature sensors and control logic are designed to serve multiple functions: they monitor temperature during normal operation, detect load heat capacity during cooling/mixing cycles, and provide data for both immediate drying optimization and historical load analysis. This multi-functionality justifies the added complexity by eliminating the need for separate dedicated measurement systems.
Solution Approach 2:
The system uses the appliance's own thermal energy and existing temperature monitoring infrastructure to automatically determine load heat capacity. The cooling and mixing cycles that naturally occur during operation are leveraged as measurement opportunities without requiring external testing equipment or additional energy input, making the system self-sufficient.
2Ease of manufacture
If temperature sensors are integrated into the flushing circuit or on condensation surfaces, then ease of manufacture is improved, but measurement precision may be affected by thermal lag or environmental factors
Solution Approach 1:
The patent uses the wash water and condensation surfaces as thermal intermediaries that naturally equilibrate with the load. Rather than placing sensors directly on the load (which would be complex), the sensors measure the temperature of these intermediaries, which indirectly reflect the load's thermal state. This approach simplifies installation while maintaining measurement accuracy through proper thermal coupling.
Solution Approach 2:
The system continuously monitors temperature profiles and uses feedback algorithms to compensate for thermal lag and environmental influences. By analyzing the dynamic temperature changes during cooling and mixing cycles rather than relying on single static measurements, the system corrects for sensor placement limitations and maintains high measurement precision despite the simplified sensor integration.
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 simplifies the operation of dishwashers by providing a technically simple and accurate method to estimate the heat capacity of the load, enabling optimized drying processes by correlating temperature profiles with heat capacity, thus improving the efficiency and accuracy of load detection.
Implementation Method 1
the temperature of the cooling liquor, which is in temperature equilibrium with the items to be washed, can be measured
Implementation Method 2
the temperature of the cooling liquor, which is in temperature equilibrium with the items to be washed
Implementation Method 3
The fresh water heats up through contact with the warm items to be washed
Implementation Method 4
the change in heat capacity due to the load is determined calorimetrically by measuring a mixture temperature
Data Source
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AI summary
The invention relates to a method for detecting the load-related change in thermal capacity of a water-bearing domestic appliance, especially of a dishwasher, in order to optimize the drying process. The method according to the invention is characterized by detecting a temperature gradient during the cooling of the items to be cleaned.