Heat-Pump Laundry Dryer With Selective Resistance Heating
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Solution Overview
Problem
Existing laundry dryers with heat pumps often have inefficient energy consumption due to systematic activation of additional resistance heating, which may not be necessary, and slow temperature control, leading to prolonged drying times and potential damage to laundry items.
Innovation Solution
A laundry drying appliance with a heat-pump system and a Joule-effect drying air heater, where the user can selectively activate the Joule-effect heater through a user interface, and a temperature sensor to automatically de-energize it when a predetermined temperature is reached, along with variable compressor and fan modes for optimized energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If systematic resistance heating is activated to speed up drying, then drying time is reduced, but energy consumption increases unnecessarily
Solution Approach 1:
The heating system transitions from static systematic heating to dynamic selective heating, where the Joule-effect heater is activated only when specifically selected by the user through the control unit, adapting the heating behavior to actual user needs and laundry conditions
Solution Approach 2:
The system changes the operational parameter of heating activation from always-on to conditionally-on based on user selection, allowing the drying process to adjust heating intensity and duration according to specific laundry requirements
2Productivity
If resistance heating is continuously activated to maintain temperature, then drying performance is improved, but temperature control precision deteriorates
Solution Approach 1:
The control unit continuously monitors the actual temperature through temperature sensors and compares it with the target temperature, automatically adjusting or deactivating the Joule-effect heater to maintain precise temperature control and prevent overheating
Solution Approach 2:
The heating system performs self-regulation through automatic temperature monitoring and control, where the control unit independently manages heater activation and deactivation based on real-time temperature feedback without requiring continuous user intervention
3Productivity
If high power heat pump is used to reduce drying time, then productivity increases, but device complexity and cost increase
Solution Approach 1:
The heating function is segmented into two independent components: the heat pump system and the Joule-effect heater, allowing flexible combination of these components to achieve different drying modes and performance levels without requiring a single high-power system
Solution Approach 2:
The heating system serves multiple functions through the combination of heat pump and Joule-effect heater, capable of operating in different modes (heat pump only, combined heating, or Joule-effect only) to meet various drying requirements
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 allows for flexible and efficient laundry drying cycles with reduced energy consumption and timely temperature control, preventing damage to laundry items and improving drying performance.
Implementation Method 1
a Joule-effect drying air heater energizable for contributing to the heating of the drying air
Implementation Method 2
for de-moisturizing the moisture-laden drying air by condensing moisture in the moisture-laden drying air returning from the laundry treatment chamber
Data Source
Figure 1
Figure 2
Figure 3~10
AI summary
An appliance for drying laundry (100) comprising an appliance cabinet (110), a laundry treatment chamber (105) inside the cabinet, a drying air recirculation path (245) for causing recirculation of the drying air into/out from the laundry treatment chamber, the drying air recirculation path being at least partly external to the laundry treatment chamber, a drying air moisture condensing and heating system (215,220,225) located in the drying air recirculation path for dehydrating the moisture-laden drying air leaving the laundry treatment chamber and heating the dehydrated drying air before it re-enters into the laundry treatment chamber, wherein said drying air moisture condensing and heating system comprises a first heat exchanger (215) and a second heat exchanger (220) of a heat pump (215,220,225,210), and further comprising a drying air propeller (250) inside the drying air recirculation path and a Joule-effect drying air heater (255), downstream the second heat exchanger, energizable for contributing to the heating of the drying air, wherein the appliance comprises a user interface (121) comprising a laundry treatment cycle selector (305) operable by a user for selecting a laundry treatment cycle, and a control unit (265) adapted to control the machine operation, characterized in that the user interface comprises a command input means (315) operable by the user for imparting to the appliance an energization command to energize the Joule-effect heater, and in that during the execution of the laundry treatment cycle selected by the user, said control unit causes the selective energization of said Joule-effect drying air heater based on said energization command imparted by the user.