A method for controlling a heat pump system for a laundry drying machine and a corresponding laundry drying machine
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Solution Overview
Problem
Conventional laundry dryers with heat pump systems using fixed speed compressors are limited in adaptability to varying loads, leading to inefficient energy usage and inability to control operating parameters during the drying cycle.
Innovation Solution
A method for controlling a laundry drying machine with a heat pump system that includes a compressor with variable rotation speed, allowing the average speed or power to be adjusted based on the load, using sensors and parameters like weight, electrical measurements, and conductivity to determine the load and optimize compressor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed speed compressor is used in a heat pump system, then the device complexity is reduced and space constraints are satisfied, but the adaptability to different load conditions deteriorates and energy efficiency decreases
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed-speed compressor to a variable-speed compressor that can dynamically adjust its rotation speed based on detected load conditions. The control system modifies operational parameters including compressor speed, fan speed, and heating element power in real-time to match the actual drying needs, thereby resolving the contradiction between device complexity and adaptability.
2Device complexity
If a fixed speed compressor is used, then the device structure is simplified, but the energy consumption increases and drying efficiency decreases
Solution Approach 1:
The patent implements parameter changes by allowing the compressor rotation speed to vary continuously based on detected load conditions. The control system adjusts multiple parameters including compressor speed, fan speed, and heating element power to optimize energy consumption. This resolves the contradiction by maintaining simple compressor structure while enabling dynamic parameter adjustment to reduce energy waste.
3Adaptability or versatility
If a variable speed compressor is used, then the adaptability to different loads is improved, but the device complexity increases
Solution Approach 1:
The patent applies feedback by implementing a control system that continuously detects load conditions (such as drum weight or air temperature) and uses this information to adjust compressor speed and other operational parameters in real-time. This feedback mechanism enables high adaptability to varying loads while managing control system complexity through automated closed-loop control.
4Device complexity
If the compressor operates in on/off mode, then the control system is simplified, but the ability to control operating parameters during operation is lost
Solution Approach 1:
The patent resolves this contradiction by replacing the static on/off control mode with dynamic continuous speed control. The variable-speed compressor can operate at any rotation speed within its range, allowing precise control of heating capacity and energy consumption. This dynamic control capability is managed by a control system that adjusts parameters continuously rather than switching between fixed states.
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 enables energy savings by optimizing compressor speed according to the load, reducing drying time and energy consumption while maintaining drying efficiency.
Implementation Method 1
The refrigerant flows in the refrigerant circuit where it is compressed by the compressor
Implementation Method 2
The condenser heats up the drying air while the evaporator cools and dehumidifies the drying air leaving the drum
Implementation Method 3
The evaporator cools and dehumidifies the drying air leaving the drum
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a method for controlling a laundry drying machine of the type comprising a heat pump system having a refrigerant circuit (30) for a refrigerant and comprising an air stream circuit (10) including at least one laundry drum (9) for receiving laundry to be dried. The refrigerant circuit (30) comprises a compressor (24) with a variable rotation speed, a first heat exchanger for a thermal coupling between said air stream circuit (10) and said refrigerant circuit (30) and a second heat exchanger (23) for a further thermal coupling between said air stream circuit (10) and said refrigerant circuit (30). The method comprises the steps of: - determining the amount of load (W) in the laundry drum (9); and - controlling the average speed (V) or the average power (P) of the compressor (24) in a drying cycle according to the amount of load (W), so that in case of a first amount of load (W) the average speed (V) or the average power (P) of the compressor (24) is set to a first operational value (Vh) and in case of a second amount of load (W) the average speed (V) or the average power (P) of the compressor (24) is set to a second operational value (Vf). The first amount of load (W) is smaller than the second amount of load (W) and the first operational value (Vh) is higher than the second operational value (Vf).