Refrigeration cycle apparatus
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses face inefficiencies in heat transfer and refrigerant distribution due to unequal flow velocities and pressure losses during cooling and heating operations, particularly when the number of unit flow paths are equal, leading to reduced performance and uneven refrigerant distribution.
Innovation Solution
A refrigeration cycle apparatus with a flow path switching mechanism that adjusts the order of refrigerant circulation between heat exchange apparatuses, using multiple distribution devices to ensure even refrigerant distribution and optimal flow paths for both cooling and heating, allowing for counterflow heat exchange in both modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of unit flow paths in the heat exchanger is increased to improve refrigerant distribution, then refrigerant distribution evenness is improved, but flow velocity decreases and heat transferability is lowered
Solution Approach 1:
The heat exchanger is divided into multiple independent unit flow paths (first unit flow paths and second unit flow paths). During cooling operation, refrigerant flows through multiple first unit flow paths in parallel, improving distribution evenness. During heating operation, refrigerant flows through multiple second unit flow paths in parallel, improving distribution evenness. This segmentation allows the system to maintain appropriate flow velocities while achieving even refrigerant distribution in both cooling and heating modes.
2Speed
If the number of unit flow paths is decreased to maintain high flow velocity and heat transferability, then heat transferability is improved, but refrigerant distribution becomes uneven
Solution Approach 1:
The system dynamically switches between different flow path configurations based on operating mode. During cooling operation, refrigerant flows through first unit flow paths with a specific number of parallel paths optimized for condensation heat transfer. During heating operation, refrigerant flows through second unit flow paths with a different number of parallel paths optimized for evaporation heat transfer. This dynamic adaptation allows the system to maintain optimal flow velocities and heat transferability in each mode while ensuring even refrigerant distribution through the use of multiple parallel paths.
3Device complexity
If a single distribution apparatus is used for both cooling and heating, then device complexity is reduced, but refrigerant distribution becomes uneven due to different flow characteristics
Solution Approach 1:
The system provides different distribution apparatus for different operating modes: a first distribution apparatus for cooling operation and a second distribution apparatus for heating operation. The first distribution apparatus is specifically designed to distribute refrigerant evenly during cooling when refrigerant flows through first unit flow paths. The second distribution apparatus is specifically designed to distribute refrigerant evenly during heating when refrigerant flows through second unit flow paths. This localized optimization ensures even refrigerant distribution in each mode without compromising device complexity.
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 enhances heat transferability and refrigerant distribution, improving the coefficient of performance (COP) and annual performance factor (APF) by optimizing flow velocities and pressure losses, leading to more efficient operation during both cooling and heating cycles.
Implementation Method 1
use the heat exchanger as a condenser with the number of branches being decreased and with a flow velocity being high
Implementation Method 2
use the heat exchanger as an evaporator with the number of branches being increased and with a flow velocity being low
Implementation Method 3
two-phase refrigerant at a low pressure flows in, and during cooling condensation, gas refrigerant at a high pressure flows in
Data Source
AI summary
A second flow path switching apparatus includes a first distribution apparatus configured to distribute refrigerant to a plurality of refrigerant paths in a first heat exchange portion, a second distribution apparatus configured to distribute refrigerant to the plurality of refrigerant paths in the first heat exchange portion and a second heat exchange portion, and a switch portion configured to switch connection of a refrigerant inlet of a first heat exchange apparatus to the first distribution apparatus or to the second distribution apparatus and switch whether refrigerant which flows out of a refrigerant outlet of the first heat exchange portion is allowed to pass through the second heat exchange portion or to merge with refrigerant which flows out of a refrigerant outlet of the second heat exchange portion in accordance with whether an order of circulation of the refrigerant is a first order (cooling) or a second order (heating).