Counter-Flow Heat Exchanger Layout for Refrigerant Subcooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-row heat exchangers face challenges in enhancing heat transfer performance due to refrigerant flow dynamics, particularly in systems incorporating both heat exchange and subcooling units, where the existing designs do not effectively optimize the refrigerant flow to maintain a sufficient temperature difference with air for efficient heat exchange.
Innovation Solution
A heat exchanger configuration featuring a main heat exchange unit and a subcooling heat exchange unit connected by a connection pipe, where the refrigerant flows counter to the air flow, ensuring a counter-flow arrangement that maintains a sufficient temperature difference for improved heat transfer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-row heat exchanger is formed with flat heat transfer tubes aligned in rows to improve heat transfer performance, then the heat transfer performance per unit size is improved, but the refrigerant flow distribution becomes complex and difficult to optimize for maintaining sufficient temperature difference with air
Solution Approach 1:
The heat exchanger is divided into multiple rows of heat transfer tubes, with each row functioning as an independent heat transfer channel. This segmentation allows the refrigerant to flow through multiple parallel paths, increasing the overall heat transfer area and performance while maintaining manageable flow distribution through strategic inlet/outlet positioning.
Solution Approach 2:
The patent transitions from a single-row to a multi-row configuration, adding a spatial dimension to the heat exchanger design. By aligning heat transfer tubes in multiple rows along the air flow direction, the design expands the heat transfer surface area without significantly increasing the device's footprint, thereby improving heat transfer performance per unit size.
2Productivity
If the heat exchanger includes both heat exchange unit and subcooling unit as disclosed in Patent Literature 1, then the refrigerant can be condensed and subcooled, but the flow of refrigerant needs improvement to maintain sufficient temperature difference with air for efficient heat exchange
Solution Approach 1:
The patent implements a counter-flow arrangement where the refrigerant flows in the opposite direction to the air flow. This inversion of flow directions maximizes the temperature difference between the refrigerant and air throughout the heat exchange process, maintaining efficient heat transfer potential even as the refrigerant temperature changes during condensation and subcooling.
Solution Approach 2:
The patent optimizes refrigeratet flow parameters by configuring inlet and outlet positions to establish counter-flow movement. This parameter change in flow direction and positioning ensures that the refrigerant maintains a sufficient temperature difference with the air across the entire heat exchange surface, improving heat exchange efficiency without requiring complex flow control mechanisms.
3Temperature
If refrigerant flows through the heat exchanger in a conventional arrangement, then the heat exchange process occurs, but the temperature difference between refrigerant and air decreases along the flow direction, reducing heat transfer performance
Solution Approach 1:
The patent employs counter-flow arrangement where refrigerant and air move in opposite directions. This inversion ensures that the coldest refrigerant (at the outlet) contacts the coldest air (at the outlet), while the warmest refrigerant (at the inlet) contacts the warmest air (at the inlet), maintaining a relatively constant and sufficient temperature difference throughout the heat exchanger length.
Solution Approach 2:
The patent combines multiple heat transfer tubes arranged in rows with corrugated fins to create a composite heat exchange structure. This composite design increases the effective heat transfer surface area and enhances the overall heat transfer coefficient, compensating for any temperature difference reductions and maintaining high 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 the overall heat transfer performance by maintaining a substantial temperature difference between refrigerant and air, even in subcooling processes, thereby improving the efficiency of the heat exchanger.
Implementation Method 1
a main heat exchange unit configured to exchange heat between air and refrigerant, and condense the refrigerant
Implementation Method 2
a subcooling heat exchange unit configured to exchange heat between air and the refrigerant passing through the main heat exchange unit, and subcool the refrigerant passing through the main heat exchange unit
Implementation Method 3
the connection pipe connects the main heat exchange unit on its refrigerant outflow side and the subcooling heat exchange unit on its refrigerant inflow side, such that when the heat exchanger functions as a condenser, a counter flow in which a flow of the refrigerant is opposite to a flow of the air is formed in the main heat exchange unit and the subcooling heat exchange unit
Data Source
AI summary
A heat exchanger according to the present disclosure includes a main heat exchange unit configured to exchange heat between air and refrigerant, and condense the refrigerant, a subcooling heat exchange unit configured to exchange heat between air and the refrigerant passing through the main heat exchange unit, and subcool the refrigerant passing through the main heat exchange unit, and a connection pipe configured to connect the main heat exchange unit and the subcooling heat exchange unit to allow the refrigerant to pass therethrough, wherein the connection pipe connects the main heat exchange unit on its outflow side to the refrigerant and the subcooling heat exchange unit on its inflow side to the refrigerant, such that when the main heat exchange unit condenses the refrigerant, the refrigerant from the outside flows into the downstream side of the main heat exchange unit and the subcooling heat exchange unit relative to a flow of the air, and flows out from the upstream side of the main heat exchange unit and the subcooling heat exchange unit relative to a flow of the air to form a counter flow in which a flow of the refrigerant is opposite to a flow of the air.