Drying Air Heater Control Using Adaptive Temperature Threshold Sets
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Solution Overview
Problem
Current laundry drying apparatuses lack an efficient method to dynamically adjust heating levels based on various operating parameters, leading to suboptimal energy consumption and drying times, and do not effectively handle abnormal heater unit states or laundry humidity variations.
Innovation Solution
A laundry drying apparatus with a control unit that selects from multiple temperature threshold sets and heating levels based on parameters like drying cycle time, motor parameters, and ambient temperature, using a hysteresis-controller to manage the heater unit, ensuring optimal heating power distribution and detecting abnormal heater states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a single temperature threshold is used for heater control, then the control system is simple, but energy consumption is suboptimal and drying times are extended
Solution Approach 1:
The patent implements multiple temperature thresholds (first threshold and second threshold) that dynamically adjust heating power based on operating conditions such as ambient temperature and drying cycle progress. This dynamic threshold system allows the heater to operate at different power levels (first heating power and second heating power) optimized for different stages of the drying cycle, thereby reducing overall energy consumption while maintaining effective drying performance.
2Productivity
If heating power is continuously high, then drying time is reduced, but energy consumption increases and fabric care deteriorates
Solution Approach 1:
The patent employs periodic adjustment of heating power through multiple thresholds, switching between first heating power and second heating power based on temperature measurements and cycle progress. This periodic modulation of heating intensity maintains high drying efficiency during critical phases while reducing energy consumption during later stages when less heating is needed, thus optimizing the balance between drying time and energy usage.
Solution Approach 2:
The system changes operating parameters (heating power level and temperature threshold) based on the drying cycle progress and ambient conditions. By adjusting these parameters dynamically rather than maintaining constant high power, the system achieves effective drying times while significantly reducing overall energy consumption and preventing fabric damage from excessive heat.
3Adaptability or versatility
If temperature thresholds are fixed, then the control system is simple, but it cannot handle varying laundry loads and humidity levels effectively
Solution Approach 1:
The patent implements dynamic temperature thresholds (first temperature threshold and second temperature threshold) that adjust based on ambient temperature and drying cycle progress. This dynamic adaptation allows the system to effectively handle varying laundry loads and humidity levels by modifying control parameters in real-time, thereby achieving versatility without requiring complex additional hardware.
4Measurement precision
If heater unit is frequently switched on and off, then temperature control is precise, but heater wear increases and reliability decreases
Solution Approach 1:
The patent uses periodic switching between different heating power levels (first heating power and second heating power) based on temperature threshold comparisons. This periodic action maintains precise temperature control by adjusting power levels at appropriate intervals rather than frequent on/off switching, thereby reducing mechanical stress on the heater unit and improving reliability while maintaining control precision.
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 solution enables more efficient energy use, improved drying times, and better handling of abnormal conditions, ensuring consistent drying performance across varying laundry loads and humidity levels.
Implementation Method 1
a heater unit (6) arranged at or in the drying air channel (20) and being adapted to heat the drying air
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a laundry drying apparatus, in particular dryer or washing machine having drying function, comprising: a cabinet, a control unit (4) adapted to control a laundry drying cycle according to at least one drying program, a drum (18) rotatably arranged within the cabinet for receiving laundry to be dried, a drying air channel (20) adapted at least to guide drying air into the drum (18), and a heater unit (6) arranged at or in the drying air channel (20) and being adapted to heat the drying air, wherein the heater unit (6) has two or more heating levels, and a temperature sensor unit adapted to detect the temperature of the drying air and to provide at least one temperature signal to the control unit (4), wherein the control unit (4) is adapted to control the heater unit (6) to heat the drying air at a selected one of the two or more heating levels, wherein the control unit (4) is adapted to select or determine and apply during the drying cycle one of two or more temperature threshold sets, wherein the two or more temperature threshold sets are used by the control unit (4) for determining the heating level to be applied by the heater unit (6) in dependency of the at least one temperature signal from the temperature sensor unit, wherein the control unit (4) is adapted to select or determine one of the two or more temperature threshold sets in dependency of one or more operating parameters of the apparatus, and wherein the temperature thresholds of the temperature threshold sets are mutually different or are not identical, wherein during execution of the laundry drying cycle the control unit (4) is adapted to select or determine one of the two or more temperature threshold sets in dependency of one or more of the following operation parameters: a) the time or temporal progress of the laundry drying cycle, b) one or more operation parameters of or for the heater unit (6), c) an electrical or mechanical parameter of the drum (18) motor, d) a temporal gradient of the drying air temperature during execution of the laundry drying cycle, and e) an ambient temperature indicative for the temperature outside the apparatus cabinet or a temperature indicative of an apparatus component temperature.