Laundry Dryer Heat Pump Control With Selective Heater Boost
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Solution Overview
Problem
Existing laundry dryers and washers/dryers often consume unnecessary energy due to systematic activation of resistance heating, which may not be required in all drying cycles, and lack flexibility in user-selected laundry treatment options.
Innovation Solution
A laundry drying appliance equipped with a heat pump system, a variable-output compressor, and a Joule-effect heater, allowing for multiple drying modes that adjust compressor power consumption and fan speed based on user input, enabling energy-efficient operation and customizable drying cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If resistance heating is systematically activated in laundry dryers, then the heating of drying air is ensured, but unnecessary electric energy consumption occurs when the heating action is not required
Solution Approach 1:
The system dynamically adjusts the heating strategy by switching between heat pump heating and resistance heating based on real-time temperature requirements. The control unit activates resistance heating only when the heat pump cannot meet the drying air temperature demand, eliminating systematic activation and reducing unnecessary energy consumption while ensuring temperature requirements are met.
Solution Approach 2:
The invention changes the operational parameters of the heating system by introducing a dual-heating configuration where the heat pump operates as the primary heating source and resistance heating serves as a supplementary source activated only under specific conditions (when additional heating is required), optimizing the balance between temperature control and energy efficiency.
2Use of energy by moving object
If a heat pump system is used for moisture condensation and heating, then energy efficiency is improved, but the system lacks flexibility in providing multiple drying modes
Solution Approach 1:
The heating function is segmented into two independent subsystems: the heat pump system for efficient heating and moisture condensation, and the resistance heating system for supplementary heating. This segmentation allows the control unit to selectively activate either or both systems based on the selected drying mode, providing flexibility (quick dry, energy-saving, balanced modes) while maintaining energy efficiency through the heat pump's primary role.
3Productivity
If the compressor operates at high power to speed up drying, then productivity is improved, but energy consumption increases
Solution Approach 1:
The system employs periodic action by cycling the resistance heating and compressor operations based on the selected drying mode and real-time drying requirements. In quick dry mode, the compressor operates at high power with resistance heating activated periodically to maintain temperature. In energy-saving mode, the compressor operates at lower power with intermittent resistance heating, reducing overall energy consumption while maintaining acceptable drying productivity.
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 appliance reduces energy consumption by selectively activating the Joule-effect heater and varying compressor and fan speeds, providing users with flexible and efficient drying options while optimizing energy use.
Implementation Method 1
a first heat exchanger for cooling the drying air and cause condensation of the moisture contained therein
Implementation Method 2
at least one Joule-effect (electric) heater located downstream the heat pump heat exchangers for boosting the heating of the drying air
Implementation Method 3
a second heat exchanger for heating the de-moisturized drying air
Data Source
AI summary
An Appliance for drying laundry (100) includes a drying-air moisture-condensing system (215,220, 225) comprising a heat pump system with a first heat exchanger (215) for cooling the drying air and a second heat exchanger (220) for re-heating said drying air, and a variable-output compressor (210). At least one Joule-effect heater (255) is located downstream of the heat pump heat exchangers for boosting the heating of the drying air. The appliance can perform at least one drying cycle in: at least a first drying mode, wherein the heater is kept de-energized and the compressor is driven to a first compressor mode having a compressor power consumption course and/or a compressor rotational speed course and/or a frequency course of the supply current/voltage of the compressor motor, and at least a second drying mode, wherein the heater is kept energized for at least an initial portion of the drying cycle and thereafter it is kept de-energized, and the compressor is driven to a second compressor mode comprising a compressor power consumption course and/or a compressor rotational speed course and/or a frequency course of the supply current/voltage of the compressor motor. For at least a portion of the drying cycle after the electric heater has been de-energized, a compressor power consumption and/or a compressor rotational speed and/or a frequency of the supply current/voltage the compressor of the second compressor mode is/are higher than the one/s of the first compressor mode.