Heat Pump Dryer Refrigerant Control With Internal Heat Exchanger
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Solution Overview
Problem
Heat pump clothes treatment apparatuses face issues with refrigerant phase changes during sudden indoor load changes, leading to potential compressor damage, inefficient operation, and increased energy loss due to premature superheat and supercooling, which affect drying time and efficiency.
Innovation Solution
Incorporating an internal heat exchanger within the heat pump module to exchange heat between refrigerant discharged from the condenser and passing through the evaporator, maintaining optimal superheat and supercooling degrees, thereby preventing liquid refrigerant entry into the compressor and reducing energy loss by recycling heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the degree of superheat is increased to prevent liquid refrigerant from entering the compressor, then compressor reliability is improved, but the dehumidifying ability of the evaporator drops and drying time increases
Solution Approach 1:
A gas-liquid separator is introduced as an intermediary component between the evaporator and compressor. This separator acts as a mediator that removes liquid refrigerant from the refrigerant flow before it reaches the compressor, allowing the system to maintain lower superheat degrees (improving evaporator efficiency) while still protecting the compressor from liquid damage through the separator's liquid removal function.
2Stability of the object's composition
If the degree of supercooling is increased to prevent flash gas generation, then refrigerant circulation stability is improved, but energy loss increases due to excessive heat exchange requirements
Solution Approach 1:
A refrigerant temperature sensor is installed at the evaporator outlet to provide real-time feedback on refrigerant temperature. The controller uses this feedback information to dynamically adjust the expansion valve opening degree, maintaining optimal supercooling levels that prevent flash gas generation while minimizing excessive heat exchange and associated energy losses.
Solution Approach 2:
The expansion valve opening degree is made dynamic rather than fixed. The system continuously adjusts the expansion valve position based on real-time refrigerant temperature measurements and operational conditions, allowing the supercooling degree to be optimized dynamically for each operating scenario, thereby preventing flash gas while minimizing energy loss.
3Reliability
If the expansion valve opening degree is reduced to maintain superheat, then compressor protection is improved, but refrigerant flow rate decreases and drying efficiency drops
Solution Approach 1:
The gas-liquid separator serves as an intermediary that enables the expansion valve to maintain larger opening degrees without compromising compressor safety. By removing liquid refrigerant before compressor intake, the separator allows the expansion valve to operate with larger openings (increasing refrigerant flow rate and drying efficiency) while the compressor remains protected from liquid damage.
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 stabilizes the refrigerant phase, enhances compressor efficiency, reduces drying time, and maintains optimal heat pump performance by controlling superheat and supercooling degrees, thus improving the overall drying process.
Implementation Method 1
an internal heat exchanger configured to exchange heat between refrigerant discharged from the condenser and refrigerant passing through the evaporator
Implementation Method 2
Air discharged from a drum, which is a clothes accommodation portion, is cooled and dehumidified through heat exchange with the refrigerant of the evaporator
Implementation Method 3
heated by heat exchange with the refrigerant of the condenser
Data Source
AI summary
A clothes treatment apparatus, including a drum rotatably provided within a cabinet to accommodate washing and drying objects; and a heat pump including an evaporator, a compressor, a condenser, and an expansion valve, through which refrigerant is circulated, to provide heat to air discharged from the drum and circulated to the drum, wherein the heat pump further includes an internal heat exchanger configured to exchange heat between refrigerant discharged from the condenser and refrigerant passing through the evaporator.