Heat Pump Laundry Dryer Control for Faster Low-Energy Cycles
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Solution Overview
Problem
Existing laundry dryers and washers/dryers with condensation systems often consume unnecessary energy due to the systematic activation of resistance heating, which may not be required for all drying cycles, and lack flexibility in user-selected laundry treatment options.
Innovation Solution
A laundry drying appliance equipped with a heat pump system, including a first heat exchanger for cooling and a second heat exchanger for heating, and a variable-output compressor, along with a Joule-effect heater. The appliance operates in multiple drying modes, adjusting compressor power consumption and fan speed based on user input and cycle requirements, allowing for energy-efficient operation by activating the electric heater only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resistance heating is systematically activated to heat the drying air, then the drying speed is improved, but energy consumption increases unnecessarily
Solution Approach 1:
The system dynamically adjusts the heating strategy based on real-time conditions. The control unit monitors the drying process and selectively activates the resistance heating element only when the heat pump alone is insufficient to maintain the required drying air temperature, rather than systematically activating it throughout the entire drying cycle.
Solution Approach 2:
The system changes the operational parameters of the heating system based on the drying phase and environmental conditions. By varying the activation state of the resistance heating element and adjusting the heat pump operation, the system optimizes the balance between drying speed and energy consumption for different drying scenarios.
2Ease of operation
If a fixed heating strategy is used for all drying cycles, then the system operation is simplified, but flexibility in user-selected laundry treatment options is reduced
Solution Approach 1:
The control system dynamically adapts the heating strategy based on the selected drying program and real-time monitoring of drying air temperature. Different drying modes (e.g., energy-efficient mode, rapid drying mode) can be selected by the user, and the system adjusts the heating element activation and heat pump operation accordingly, providing both simplicity and flexibility.
Solution Approach 2:
The heating system is designed to serve multiple functions across different drying scenarios. The resistance heating element can be activated in conjunction with the heat pump for rapid drying, or remain inactive for energy-efficient drying, allowing the same physical system to support multiple drying strategies and user preferences.
3Use of energy by moving object
If the heat pump alone is used to heat the drying air, then energy consumption is reduced, but the drying air temperature may be insufficient for efficient drying
Solution Approach 1:
The system merges the heating capabilities of the heat pump and the resistance heating element into a unified heating system. The control unit coordinates the operation of both heating sources, activating the resistance heating element only when the heat pump alone cannot provide sufficient drying air temperature, thereby combining the energy efficiency of the heat pump with the high-temperature capability of the resistance heater when needed.
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 provides a more energy-efficient and flexible laundry drying process by optimizing energy use based on the selected drying mode, reducing unnecessary energy consumption and enhancing user control over drying cycles.
Implementation Method 1
a first heat exchanger for cooling the drying air and cause condensation of the moisture contained therein
Implementation Method 2
a second heat exchanger for heating the de-moisturized drying air
Implementation Method 3
at least one Joule-effect (electric) heater located downstream the heat pump heat exchangers for boosting the heating of the drying air
Data Source
Figure 1
Figure 2
Figure 3~10
AI summary
An appliance for drying laundry (100), comprising a drying-air moisture-condensing system comprising a heat pump system (215,220,225) with a first heat exchanger (215) for cooling the drying air and cause condensation of the moisture contained therein, and a second heat exchanger (220) for heating the de-moisturized drying air, and a variable-output compressor (210), and at least one Joule-effect heater (255) located downstream the heat pump heat exchangers for boosting the heating of the drying air. The appliance is adapted to perform at least one laundry drying cycle in: at least a first drying mode, wherein the Joule-effect 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 Joule-effect 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, the 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, wherein 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 of the compressor of the second compressor mode is/are higher than the one/s of the first compressor mode.