Laundry Dryer Heat Pump Control for High-Temperature Sterilization
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Solution Overview
Problem
Conventional laundry treatment apparatuses with heat pumps face difficulties in supplying high-temperature air for sterilization due to the limited heat generation, making it challenging to kill bacteria in laundry.
Innovation Solution
A control method and apparatus that utilizes a heat pump to dehumidify and heat air, with a temperature sensing unit to maintain air temperature at 60 °C to 70 °C for 50 to 60 minutes, ensuring effective sterilization by stopping the heat pump and maintaining fan operation to ensure thorough sterilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heat pump is used to cool and heat air in the circulation duct, then energy efficiency is improved, but the air temperature remains too low to perform sterilization
Solution Approach 1:
The patent combines two different heating approaches: the heat pump system for general drying (energy efficient) and the heating wire system for sterilization (high temperature). Both systems are integrated in the same air circulation duct, allowing the controller to switch between or combine them based on the required function.
Solution Approach 2:
The controller dynamically adjusts the operation mode by detecting the drying state of laundry. When sterilization is needed, it activates the heating wire; when general drying suffices, it uses the heat pump. This dynamic switching optimizes both energy efficiency and temperature output based on real-time conditions.
2Reliability
If a heating wire is used to supply high-temperature air for sterilization, then sterilization effectiveness is improved, but energy consumption increases compared to heat pump
Solution Approach 1:
Instead of continuously operating the high-energy heating wire, the system applies it partially only when sterilization is detected as necessary. The controller monitors drying progress and activates the heating wire only during specific phases when high temperature is needed, reducing overall energy consumption while maintaining sterilization effectiveness.
Solution Approach 2:
The controller uses feedback from sensors monitoring the drying state to determine when sterilization is needed. This feedback mechanism ensures the heating wire is activated only when necessary, optimizing the balance between sterilization effectiveness and energy consumption based on actual laundry conditions.
3Productivity
If the fan operates continuously to circulate air, then drying speed is improved, but energy consumption increases
Solution Approach 1:
The fan operates periodically rather than continuously. The controller adjusts fan operation based on the drying phase: higher speed during initial drying phases, reduced speed or intermittent operation during later phases when less air circulation is needed. This periodic adjustment maintains drying speed while reducing overall energy consumption.
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
The method achieves 99% or more bacterial kill rate for harmful bacteria like Pseudomonas aeruginosa and Staphylococcus aureus, regardless of the laundry amount, by maintaining high-temperature air supply for a specified duration.
Implementation Method 1
a heat pump for performing heat exchange between air introduced into the duct and a refrigerant to dehumidify and heat the air
Implementation Method 2
a temperature sensing unit for measuring the temperature of the air introduced into the duct
Data Source
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AI summary
Disclosed is a control method of a laundry treatment apparatus including a drum (3) for storing laundry, a duct provided outside the drum for guiding air discharged from the drum (3) to the drum (3), a fan (75) provided in the duct (71), a heat pump (73) for performing heat exchange between air introduced into the duct (71) and a refrigerant to dehumidify and heat the air, and a temperature sensing unit for measuring the temperature of the air introduced into the duct (71), the control method including operating the fan and the heat pump (73) to supply heated air to the drum (a hot air supply step), measuring the temperature of the air discharged from the drum (3) through the temperature sensing unit (a temperature measurement step), when the temperature of the air measured by the temperature sensing unit (9) is equal to or higher than a predetermined reference temperature, measuring the amount of time for which the temperature of the air remains equal to or higher than the reference temperature (a time measurement step), and when the amount of time for which the temperature of the air remains equal to or higher than the reference temperature is equal to or greater than a reference amount of time, stopping the operation of the fan (75) and the heat pump (a hot air supply completion step).