Heat Pump Dryer Compressor Control for Stable Startup
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Solution Overview
Problem
Dryers face challenges in stable compressor operation during initial driving, preventing liquid phase refrigerant introduction and overheating, as well as noise and vibration issues due to variable compressor speeds.
Innovation Solution
A control method for dryers with a heat pump and variable compressor, involving staged speed increase of the compressor and adjustment of the expansion valve's opening based on temperature information to prevent liquid phase refrigerant introduction and manage refrigerant quantity, while reducing noise and vibration by adjusting compressor speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor driving speed is rapidly increased during initial driving, then the productivity and drying efficiency are improved, but liquid phase refrigerant may be introduced into the compressor causing unstable operation
Solution Approach 1:
The control method performs preliminary action by gradually increasing the compressor driving speed during initial driving rather than immediately reaching target speed. This staged approach allows the refrigerant to properly evaporate and prevents liquid phase refrigerant from entering the compressor, ensuring stable operation before full productivity is achieved.
2Object-generated harmful factors
If the compressor driving speed is reduced to minimize noise and vibration, then the object-generated harmful factors are reduced, but the productivity and drying efficiency deteriorate
Solution Approach 1:
The control method applies dynamics by making the compressor driving speed adjustable and variable rather than fixed. The speed is dynamically changed based on operational phase: reduced during initial driving to minimize noise and vibration, then increased to target speed for optimal drying efficiency, allowing the system to adapt to different operational requirements.
3Productivity
If the expansion valve opening is increased to improve heat pump efficiency, then the productivity is improved, but the compressor may overheat due to excessive refrigerant quantity
Solution Approach 1:
The control method implements feedback by continuously monitoring compressor temperature and using this information to adjust the expansion valve opening. When compressor temperature exceeds a predetermined threshold, the expansion valve opening is reduced to decrease refrigerant quantity, thereby preventing overheating while maintaining optimal heat pump efficiency through adaptive control.
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
Ensures stable compressor operation, prevents overheating, and reduces noise and vibration by controlling refrigerant flow and compressor speed, enhancing overall dryer performance.
Implementation Method 1
a heat pump having a variable compressor
Implementation Method 2
preventing liquid phase refrigerant from being introduced into a compressor
Implementation Method 3
a heat pump having a variable compressor
Implementation Method 4
reducing noise and vibration generated from a variable compressor by adjusting the driving speed of the compressor
Implementation Method 5
adjusting the driving speed of the compressor
Implementation Method 6
adjusting the degree of opening of an expansion valve of the heat pump
Data Source
Figure 1
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Figure 4~5
AI summary
The present invention relates to a dryer. A method for controlling the operation of a dryer, comprising a heat pump having a variable compressor, comprises the following steps: selecting at least one dryer operating course for supplying air or drying air; raising the compressor driving speed to a target speed while the selected dryer operating course is proceeding; and adjusting the degree of opening of an expansion valve of the heat pump.