Double-Pipe Refrigerant Heat Exchanger for Higher Supercooling
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses fail to secure a sufficient supercooling degree for the main refrigerant, leading to inefficient energy utilization and reduced energy efficiency.
Innovation Solution
A refrigeration cycle apparatus with a double pipe-type refrigerant/refrigerant heat exchanger where high pressure refrigerant flowing through the outer pipe is cooled by air, increasing the supercooling degree of the refrigerant, and air is induced into the evaporator, enhancing the temperature difference and enthalpy difference, thereby reducing the compression ratio and compressor power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a double pipe-type refrigerant/refrigerant heat exchanger is used with bypass refrigerant flowing through the inner pipe and main refrigerant flowing through the outer pipe, then heat exchange between refrigerants can be achieved, but the supercooling degree of main refrigerant is insufficient
Solution Approach 1:
The heat exchanger is divided into two separate heat exchange paths: an inner pipe for bypass refrigerant and an outer pipe for main refrigerant. This segmentation allows independent optimization of each refrigerant's heat exchange process, enabling the main refrigerant to achieve sufficient supercooling by utilizing both bypass refrigerant and air as heat exchange media
Solution Approach 2:
Air is introduced as an intermediary heat exchange medium in the annular space between the inner and outer pipes. This intermediary allows the main refrigerant in the outer pipe to exchange heat not only with the bypass refrigerant but also with the air, thereby achieving the required supercooling degree that cannot be obtained with bypass refrigerant alone
2Loss of energy
If the supercooling degree of refrigerant is increased by cooling high pressure refrigerant with air, then energy efficiency is improved, but the device complexity increases due to additional air intake and flow path components
Solution Approach 1:
The air intake structure serves multiple functions: it provides cooling air to the outer pipe for supercooling the main refrigerant, supplies air to the evaporator for heat exchange, and can be integrated with the existing housing structure of the refrigeration device. This multi-functionality reduces the need for separate components and minimizes device complexity
Solution Approach 2:
The air flow path is merged such that air cooling the outer pipe is subsequently supplied to the evaporator. This combining of functions allows a single air intake and flow path to serve both the supercooling process and the evaporator cooling requirement, thereby reducing the number of separate air handling systems needed
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
The increased supercooling degree enhances energy efficiency by increasing the evaporating pressure, reducing the compression ratio, and saving energy, while also improving the freezing effect in the evaporator.
Implementation Method 1
a double pipe-type refrigerant/refrigerant heat exchanger where high pressure refrigerant flowing through the outer pipe is cooled by air
Implementation Method 2
high pressure refrigerant flowing through the outer pipe is cooled by air
Implementation Method 3
air is induced into the evaporator, enhancing the temperature difference and enthalpy difference
Implementation Method 4
enhancing the temperature difference and enthalpy difference, thereby reducing the compression ratio and compressor power
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
The refrigeration cycle apparatus includes a refrigerant circuit 2, a refrigerant/refrigerant heat exchanger 23 and a control device 4. The refrigerant/refrigerant heat exchanger 23 includes an outer pipe 23a through which high pressure refrigerant flows, and an inner pipe 23b which is disposed in the outer pipe 23a and through which low pressure refrigerant flows. At least a portion of air flowing through the evaporator 25 is induced by the refrigerant/refrigerant heat exchanger 23. Therefore, the high pressure refrigerant is cooled by the air, a supercooling degree of refrigerant is increased, temperature of air flowing into the evaporator 25 is made to rise, and a heat exchanging amount in the evaporator 25 is increased. Therefore, it is possible to enhance energy efficiency.