Plate Fin Coil Heat Exchanger for Uniform Refrigerant Distribution
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Solution Overview
Problem
Current heat exchangers, such as plate-type, shell-and-plate, and shell-and-tube heat exchangers, face inefficiencies in heat transfer due to uneven refrigerant distribution and liquid return issues, leading to suboptimal operation and the need for increased superheat to prevent liquid return to the compressor.
Innovation Solution
A heat exchanger design featuring a shell with a plate fin coil body, where the primary heat medium flows through a coil passing through multiple plate fins, and a distributor divides the flow evenly across multiple circuits to minimize pressure loss and enhance heat transfer area, allowing for efficient heat exchange between the primary and secondary heat mediums.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plate-type heat exchanger with stacked flat plates is used, then heat exchange can be performed by alternately flowing high-temperature gas and low-temperature fluid, but uneven refrigerant distribution and liquid return issues occur leading to suboptimal operation
Solution Approach 1:
The heat exchanger is divided into multiple independent circuits with separate flow paths. Each circuit has its own inlet and outlet, allowing independent refrigerant flow control. This segmentation prevents uneven distribution by ensuring each circuit receives balanced refrigerant flow, eliminating the liquid return issues that occur in stacked plate designs where refrigerant flows freely between plates.
Solution Approach 2:
Different regions of the heat exchanger are designed with specific local characteristics. The coil structure is wrapped around the peripheral wall to create localized heat exchange zones, while the shell provides a contained environment for secondary heat medium flow. This local quality optimization ensures uniform temperature distribution in each region, preventing the uneven refrigerant distribution that plagues plate-type designs.
2Reliability
If increased superheat is applied to prevent liquid return to the compressor, then liquid return is prevented, but heat transfer efficiency decreases due to suboptimal operation
Solution Approach 1:
By segmenting the heat exchanger into multiple circuits with dedicated flow paths, each circuit operates independently with optimized refrigerant flow. This prevents liquid return to the compressor without requiring excessive superheat, as each circuit's refrigerant is properly distributed and controlled, maintaining optimal heat transfer efficiency while ensuring reliable liquid return prevention.
3Productivity
If a shell-and-plate or shell-and-tube heat exchanger is used, then condensing or reliquefying of refrigerant can be achieved, but the structure is complex and the refrigeration system size is large
Solution Approach 1:
The heat exchanger merges the shell structure with the coil assembly into a single integrated unit. The shell serves as both the containment structure for the secondary heat medium and the structural support for the coil. This merging eliminates the need for separate plate stacks or tube bundles, significantly simplifying the overall structure while maintaining full refrigerant condensing and reliquefying capabilities.
Solution Approach 2:
The coil is nested within the shell structure, with the coil wrapped around the peripheral wall inside the shell. This nesting arrangement allows the heat exchanger to achieve compact design with high heat transfer efficiency in a reduced space, eliminating the complexity of traditional shell-and-tube configurations while maintaining refrigerant condensing capability.
4Area of stationary object
If multiple plate fins are stacked to form gaps for flow paths, then heat transfer area is increased, but pressure loss increases and heat transfer efficiency decreases due to biased refrigerant flow
Solution Approach 1:
The heat exchanger segments the refrigerant flow into multiple independent circuits, each with controlled flow paths through the plate fins. This segmentation prevents biased refrigerant flow by ensuring each circuit receives balanced flow distribution, reducing pressure loss while maintaining large heat transfer area through the extended coil structure wrapped around the shell periphery.
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 ensures uniform temperature distribution and increased heat transfer efficiency, reducing pressure loss and eliminating liquid return issues, thereby improving the refrigeration effect and refrigerating capacity while simplifying the refrigeration system and reducing its size.
Implementation Method 1
a plate fin coil body provided in the shell. The plate fin coil body includes a plurality of plate fins and a coil which passes through the plurality of plate fins and through which a primary heat medium is configured to flow
Data Source
AI summary
A heat exchanger includes a shell to which a secondary heat medium is configured to be supplied and a plate fin coil body provided in the shell. The plate fin coil body includes a plurality of plate fins and a coil which passes through the plurality of plate fins and through which a primary heat medium is configured to flow.