Heat Pump Laundry Dryer Compressor Control for Lower Energy and Noise
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Solution Overview
Problem
Current home tumble laundry dryers face challenges in reducing electric energy consumption and compressor noise levels, with existing solutions falling short in achieving efficient and cost-effective results.
Innovation Solution
The implementation of a variable-speed electric motor for the refrigerant compressor and a controlled ventilation system that adjusts fan operation based on refrigerant temperature, allowing for a dynamic energy-saving drying cycle with reduced motor speed and strategic heat removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electric motor rotates the output shaft at constant maximum speed to maintain constant refrigerant flow, then the drying efficiency is improved, but the energy consumption and noise level increase
Solution Approach 1:
The patent applies dynamics by transitioning from constant speed motor operation to variable speed operation. The motor speed is dynamically adjusted based on drying conditions, allowing the system to maintain high productivity when needed while reducing energy consumption during periods when maximum cooling capacity is not required. This resolves the contradiction by making the system adaptable to varying operational demands.
Solution Approach 2:
The patent changes the operational parameters of the electric motor from fixed constant speed to variable speed. By adjusting the rotation speed parameter according to actual drying needs and refrigerant temperature conditions, the system achieves both energy savings and maintained drying efficiency, resolving the contradiction between constant high productivity and reduced energy use.
2Temperature
If the electric motor operates at constant maximum speed to maintain constant refrigerant flow, then the cooling capacity is improved, but the noise level increases
Solution Approach 1:
The system dynamically adjusts motor speed based on actual cooling requirements. When refrigerant temperature indicates sufficient cooling capacity, the motor speed is reduced, thereby lowering noise levels while maintaining adequate cooling performance. This dynamic adaptation resolves the contradiction between maintaining high cooling capacity and reducing noise generation.
Solution Approach 2:
The patent implements feedback control by monitoring refrigerant temperature and using this information to adjust motor speed. The feedback mechanism ensures that cooling capacity is maintained at appropriate levels without excessive motor operation, thereby reducing noise while preserving necessary thermal management functionality.
3Device complexity
If the on/off control system is used to manage the electric motor, then the device complexity is reduced, but the energy consumption cannot be optimized
Solution Approach 1:
The patent replaces the simple on/off control with a dynamic variable speed control system. This allows the motor to operate at optimized speeds rather than simply being on or off, significantly improving energy consumption optimization while adding manageable complexity to the control system.
Solution Approach 2:
The control system now adjusts the motor speed parameter continuously rather than merely switching between on and off states. This parameter change enables fine-tuned energy optimization while maintaining reasonable control system complexity through the use of temperature-based control logic.
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 approach results in a 40% reduction in energy consumption and lower compressor noise levels, enhancing the efficiency and cost-effectiveness of the laundry drying process.
Implementation Method 1
the compressor comprises a reciprocating or rotary mechanical compressor assembly to compress the intermediate gaseous refrigerant
Implementation Method 2
the hot-air generator operates in the same way as a heat pump, circulates the same air inside the drying drum, and continually extracts the surplus moisture from the hot air issuing from the drying drum
Implementation Method 3
which transfers heat from one fluid to another by means of an intermediate refrigerant subjected to a closed thermodynamic cycle, so as to rapidly cool and so reduce the moisture content of the air issuing from the drying drum
Implementation Method 4
an electric motor, the output shaft of which is connected to the mechanical compression member to rotate or produce reciprocating movement of the compression members
Data Source
Figure 1
Figure 2
AI summary
An electric household appliance (1) having a hot-air generator (7) for feeding/drawing hot air to/from a drying drum (3) along an air-circulating pipe (8); a number of heat exchangers (10, 11) located along the air-circulating pipe (8) to allow a refrigerant to absorb/release heat from/to the airflow circulating in the air-circulating pipe (8); a compression device (9) having movable compression members (9a), and an electric motor (9b) for operating the movable compression members (9a); a fan (14a) for removing heat from the compression device (9); and an electronic central control unit (15), which controls the speed of the electric motor (9b) to achieve an intermediate speed (vint) lower than a maximum speed (vMAX) of the electric motor (9b), and activates/deactivates the fan (14a) to maintain the temperature (T) of the refrigerant within a predetermined range of a target temperature (To).