Refrigerant Branch-Pipe Heat Exchanger Layout for Stable Superheating
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Solution Overview
Problem
Conventional refrigeration devices face challenges in imparting adequate subcooling to refrigerant after the first expansion valve and maintaining proper superheating of refrigerant sucked into the compressor, leading to risks of overheating and critical state conditions.
Innovation Solution
The refrigeration device incorporates a branch pipe system that connects the radiator to the second expansion mechanism, merging with the refrigerant pipe between the evaporator and compressor, and includes a second internal heat exchanger to manage heat exchange between refrigerant streams, ensuring proper subcooling and superheating through controlled expansion mechanisms and heat exchanger interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an internal heat exchanger is merely provided to the refrigerant inflow side of the first expansion valve, then the structure is simple, but it is difficult to impart an adequate degree of subcooling to the refrigerant that has passed through the first expansion valve
Solution Approach 1:
The internal heat exchanger is divided into two separate heat exchangers: a first internal heat exchanger connected to the refrigerant inflow side of the first expansion valve, and a second internal heat exchanger connected to the refrigerant outflow side of the first expansion valve. This segmentation allows each heat exchanger to perform its specific function effectively, with the second heat exchanger specifically addressing the subcooling requirement for refrigerant after the first expansion valve.
Solution Approach 2:
A branch pipe is introduced as an intermediary component, branching from the refrigerant pipe between the radiator and the first expansion valve, and merging with the refrigerant pipe between the evaporator and the compressor. This branch pipe serves as a conduit to transport refrigerant between the two internal heat exchangers, enabling the second heat exchanger to receive refrigerant from the first expansion valve and provide adequate subcooling before it enters the evaporator.
2Device complexity
If an internal heat exchanger is merely provided to the refrigerant inflow side of the first expansion valve, then the structure is simple, but there is a risk of the refrigerant sucked into the compressor becoming overly superheated
Solution Approach 1:
The internal heat exchange function is segmented into two separate heat exchangers positioned at different locations in the refrigerant circuit. The first internal heat exchanger is located at the refrigerant inflow side of the first expansion valve, while the second internal heat exchanger is located at the refrigerant outflow side of the first expansion valve. This segmentation allows precise control of temperature at different stages, preventing excessive superheating of refrigerant entering the compressor.
Solution Approach 2:
The configuration creates a feedback mechanism where the second internal heat exchanger receives refrigerant from the first expansion valve and adjusts its temperature before the refrigerant continues to the evaporator and returns to the compressor. This feedback loop ensures that the refrigerant temperature is properly regulated, preventing overly high superheating degrees that could harm the compressor.
3Reliability
If a branch pipe with a third expansion mechanism is added to connect the radiator to the second expansion mechanism, then adequate subcooling and superheating can be maintained, but the device complexity increases
Solution Approach 1:
The branch pipe with the third expansion mechanism serves multiple functions: it provides an additional refrigerant flow path, enables the second internal heat exchanger to receive refrigerant for subcooling, and allows the third expansion mechanism to regulate refrigerant flow to the second internal heat exchanger. This multi-functionality justifies the added complexity by achieving reliable temperature control for both subcooling and superheating.
Solution Approach 2:
The third expansion mechanism introduces dynamic control capability to the refrigerant circuit. By adjusting the expansion ratio of the third expansion mechanism, the system can dynamically regulate the amount of refrigerant flowing through the branch pipe to the second internal heat exchanger, enabling flexible control of subcooling and superheating degrees according to different operating conditions.
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 configuration effectively imparts adequate subcooling and maintains proper superheating of refrigerant, preventing overheating and critical state conditions, thus enhancing the refrigeration device's efficiency and reliability.
Implementation Method 1
a first internal heat exchanger causing heat to be exchanged between refrigerant that flows in a first refrigerant pipe for connecting an exit side of the radiator and a refrigerant inflow side of the first expansion mechanism, and refrigerant that flows in a second refrigerant pipe for connecting an exit side of the evaporator and a refrigerant inflow side of the compression mechanism
Implementation Method 2
a second internal heat exchanger causing heat to be exchanged between refrigerant that flows out from the first expansion mechanism and refrigerant that flows out from the third expansion mechanism
Implementation Method 3
a first expansion mechanism connected to an exit side of the radiator... a second expansion mechanism connected to a refrigerant outflow side of the first expansion mechanism... a third expansion mechanism provided to the branch pipe
Data Source
AI summary
A refrigeration device includes a compression mechanism, a radiator, a first expansion mechanism, a second expansion mechanism, an evaporator, a first internal heat exchanger, a branch pipe a third expansion mechanism, and a second internal heat exchanger. The first internal heat exchanger causes heat to be exchanged between refrigerant that flows from the radiator to the inflow side of the first expansion mechanism, and refrigerant that flows from the evaporator to the compression mechanism. The branch pipe branches from a third refrigerant pipe for connecting the radiator and the second expansion mechanism, and merges with the second refrigerant pipe. A third expansion mechanism is provided to the branch pipe. The second internal heat exchanger causes heat to be exchanged between refrigerant that flows out from the first expansion mechanism, and refrigerant that flows out from the third expansion mechanism.