Parallel Heat Exchanger Flow Path Asymmetry to Reduce Pressure Loss
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Solution Overview
Problem
Conventional air conditioning apparatuses face challenges in enhancing heat transfer performance during cooling operations due to the equal number of flow paths in both heat exchangers, which limits the increase in flow velocity of liquid refrigerant, thereby hindering improved heat transfer efficiency.
Innovation Solution
A refrigerant cycle apparatus with an outdoor device featuring a heat exchanger group connected by pipes, where the refrigerant flows through a first number of heat exchangers in parallel during condensation and a sum of heat exchangers in parallel during evaporation, allowing for increased flow velocity and improved heat transfer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of flow paths in both heat exchangers is set to the same number, then the pressure loss is minimized in heating operation, but the flow velocity of liquid refrigerant cannot be increased sufficiently in cooling operation to improve heat transfer performance
Solution Approach 1:
The patent applies asymmetry by setting different numbers of flow paths for the first and second heat exchangers. Specifically, the first heat exchanger has a first number of flow paths while the second heat exchanger has a second number of flow paths that is different from the first number. This asymmetric configuration allows the system to optimize for heat transfer performance in cooling operation (by having fewer flow paths in the second heat exchanger to increase liquid refrigerant flow velocity) while still maintaining acceptable pressure loss characteristics.
2Stability of the object's composition
If the length of unit flow paths is set to the same length, then the refrigerant flow distribution is balanced, but the heat transfer performance in the second heat exchanger cannot be enhanced by increasing flow velocity
Solution Approach 1:
The patent applies local quality by making the unit flow path lengths different between the first and second heat exchangers. The first heat exchanger has unit flow paths of a first length while the second heat exchanger has unit flow paths of a second length that is different from the first length. This allows each heat exchanger to have locally optimized flow path characteristics suited to its specific function in the refrigeration cycle, enabling the second heat exchanger to achieve higher flow velocities and improved heat transfer performance.
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 enhances heat transfer performance by increasing the flow velocity of refrigerant during condensation and reducing pressure loss, thereby improving the overall efficiency of the air conditioning apparatus.
Implementation Method 1
the high-temperature, high-pressure gas refrigerant discharged from the compressor flows into the outdoor heat exchanger of the outdoor device, is subjected to heat exchange with outdoor air
Implementation Method 2
is subjected to heat exchange with outdoor air, and is condensed into high-pressure liquid refrigerant
Implementation Method 3
The two-phase refrigerant flows into the indoor heat exchanger of the indoor device, and is subjected to heat exchange with indoor air. Consequently, the liquid refrigerant evaporates into low-pressure gas refrigerant
Data Source
AI summary
A heat exchanger group includes a first heat exchanger, a second heat exchanger, and a third heat exchanger. In a cooling operation, refrigerant discharged from the compressor is divided into two. One refrigerant is delivered to the second heat exchanger, and the other refrigerant is delivered to the third heat exchanger. The second heat exchanger performs heat exchange to turn the refrigerant into two-phase refrigerant. The third heat exchanger performs heat exchange to turn the refrigerant into two-phase refrigerant. The refrigerant that has flowed through the second heat exchanger and the refrigerant that has flowed through the third heat exchanger meet, and the resultant refrigerant is delivered to the first heat exchanger. The first heat exchanger performs heat exchange, so that the two-phase refrigerant turns into liquid refrigerant and flows through the first heat exchanger.