Switchable Heat Exchanger Flow Paths for Low-Loss Heat Pump Heating
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Solution Overview
Problem
Existing heat exchangers for heat pump systems face challenges in improving heating performance due to high pressure loss and reduced heat absorption during heating operations, and lack efficiency in defrosting processes, especially when used as both condensers and evaporators.
Innovation Solution
A heat exchanger design with a main core and sub-cool core portion, featuring a first and second flow path with flow-path switching means, allowing refrigerant to bypass the receiver tank during heating, ensuring consistent flow directions and efficient heat exchange, and facilitating defrosting by bypassing the receiver tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the refrigerant flows through both the main core portion and the sub-cool core portion during heating operation, then the heat absorption area is increased, but the pressure loss in refrigerant flowing becomes large
Solution Approach 1:
The patent applies dynamics by making the refrigerant flow path configurable through flow-path switching means. During heating operation, the system dynamically switches to the second flow path where refrigerant flows only through the main core portion, reducing pressure loss. During cooling operation, it switches to the first flow path where refrigerant flows through both main core and sub-cool core portions, maximizing heat exchange area. This dynamic path selection resolves the contradiction between heat absorption area and pressure loss.
Solution Approach 2:
The patent changes the flow path parameter based on operation mode. By using flow-path switching means, the system alters which flow path the refrigerant takes - either through both cores (first flow path) or only through main core (second flow path). This parameter change allows optimization of pressure loss during heating while maintaining heat exchange efficiency during cooling.
2Loss of energy
If the refrigerant bypasses the sub-cool core portion during heating operation, then the pressure loss is reduced, but the heat absorption area becomes zero
Solution Approach 1:
The system dynamically adjusts the refrigerant flow path based on operation mode. During heating, it switches to the second flow path that bypasses the sub-cool core portion, reducing pressure loss. During cooling, it switches to the first flow path that includes both core portions, maximizing heat absorption area. This dynamic switching resolves the apparent contradiction by optimizing for different parameters at different times.
3Device complexity
If the heat exchanger is used as both condenser and evaporator, then the device complexity is reduced, but the defrosting operation efficiency is poor
Solution Approach 1:
The patent applies dynamics by implementing flow-path switching means that enables different refrigerant flow configurations. During defrosting operation, the system switches to the second flow path, allowing refrigerant to flow only through the main core portion and bypass the receiver tank and sub-cool core portion. This dynamic path selection improves defrosting efficiency by directing refrigerant flow optimally, while maintaining a unified heat exchanger structure that reduces overall device complexity.
Solution Approach 2:
The system changes the flow path parameter during defrosting operation to optimize performance. By switching to the second flow path, the refrigerant flow configuration is altered to bypass certain components, improving defrosting efficiency. This parameter change allows the unified heat exchanger structure to perform multiple functions effectively.
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 design reduces pressure loss, maintains heat exchange efficiency, simplifies the heat exchanger and refrigerant circuit, and enhances heating performance while achieving high-energy-efficient defrosting operations.
Implementation Method 1
a main core portion for performing heat exchange between air and a refrigerant
Implementation Method 2
a sub-cool core portion for sub-cooling a liquid refrigerant having flowed through the receiver tank by heat exchange with the air
Implementation Method 3
evaporation of the refrigerant is possible by heat absorption in the main core portion
Data Source
AI summary
A main core portion (6) performing heat exchange between air and a refrigerant, a receiver tank (8) into which the refrigerant having flowed through the main core portion flows, a sub-cool core portion (10) for sub-cooling a liquid refrigerant having flowed through the receiver tank by heat exchange with air, a first flow path (36b, 68, 78) through which a refrigerant flows in order of the main core portion, the receiver tank, and the sub-cool core portion, a second flow path (36a, 36c, 68, 72) through which the refrigerant flows in order of the main core portion and the sub-cool core portion by bypassing the receiver tank, and flow-path switching means (82) for switching between the first flow path and the second flow path.