Refrigeration device
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Solution Overview
Problem
Conventional refrigeration devices face challenges in imparting adequate subcooling to refrigerant after the first expansion mechanism and maintaining proper superheating of the refrigerant sucked into the compressor, leading to risks of overheating and refrigerant reaching a critical state.
Innovation Solution
The refrigeration device incorporates a branch pipe that merges with the second refrigerant pipe, featuring a third expansion mechanism and a second internal heat exchanger to facilitate heat exchange between refrigerant streams, allowing for controlled subcooling and superheating, along with control units to manage the degree of superheating and prevent refrigerant from reaching a critical state.
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 and there is a risk of the refrigerant sucked into the compressor becoming overly superheated
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 independently, enabling adequate subcooling while preventing excessive superheating.
Solution Approach 2:
A branch pipe is introduced as an intermediary component to connect the second internal heat exchanger to the refrigerant pipe between the first and second expansion valves. This branch pipe serves as a mediator to facilitate heat exchange between the high-temperature refrigerant from the radiator and the low-temperature refrigerant from the evaporator, enabling effective subcooling without directly modifying the main refrigerant flow path.
2Reliability
If the refrigerant is excessively superheated before entering the compressor, then the compressor is protected from liquid slugging, but the compression efficiency decreases and energy consumption increases
Solution Approach 1:
The second internal heat exchanger provides feedback control by using the high-temperature refrigerant from the radiator to heat the superheated refrigerant from the evaporator before it enters the compressor. This feedback mechanism automatically adjusts the superheating degree based on the actual refrigerant conditions, maintaining optimal superheating levels for compressor protection while minimizing energy loss.
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 enables effective subcooling of the refrigerant and maintains the proper degree of superheating, preventing overheating and critical state conditions, thus ensuring efficient operation and extending the lifespan of refrigerant circuit components.
Implementation Method 1
a first internal heat exchanger that causes heat to be exchanged between refrigerant that flows in a first refrigerant pipe for connecting the exit side of the radiator and an inflow side of the first expansion mechanism, and refrigerant that flows in a second refrigerant pipe for connecting the exit side of the evaporator and the refrigerant inflow side of the compression mechanism
Implementation Method 2
a second internal heat exchanger that 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
Implementation Method 3
a compression mechanism configured to compress a refrigerant
Implementation Method 4
a radiator connected to a refrigerant discharge side of the compression mechanism
Implementation Method 5
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, and a third expansion mechanism provided to the branch pipe
Data Source
Figure 1
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AI summary
An object of the present invention is to make it possible to impart an adequate degree of subcooling to the refrigerant that has passed through the first expansion mechanism, and to maintain the proper degree of superheating of the refrigerant sucked into the compressor in a refrigerant circuit that is provided with a two-stage expansion mechanism. The refrigeration device (1) of the present invention is provided with a compression mechanism (11), a radiator (14), a first expansion mechanism (16), a second expansion mechanism (20), an evaporator (31), a first internal heat exchanger (15), a branch pipe (4), a third expansion mechanism (19), and a second internal heat exchanger (18). The first internal heat exchanger causes heat to be exchanged between refrigerant that flows from the exit side of the radiator to the inflow side of the first expansion mechanism, and refrigerant that flows from the exit side of the evaporator to the refrigerant inflow side of the compression mechanism. The branch pipe branches from a third refrigerant pipe for connecting the exit side of the radiator and the refrigerant inflow side of 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.