Multi-Region Heat Exchanger Layout for Uniform Air Temperature
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Solution Overview
Problem
Existing heat exchangers face challenges in maintaining a favorable temperature distribution in the tube stacking direction while suppressing overall refrigerant pressure loss, particularly when used as a condenser in a refrigeration cycle.
Innovation Solution
The heat exchanger incorporates a primary header tank, primary and secondary tubes, primary and secondary turn tanks, and secondary header tank, with distinct pressure losses in different regions to manage refrigerant flow and temperature distribution, using communication holes to control refrigerant flow rates and maintain uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the longitudinal length of the refrigerant inlet chamber is increased to improve temperature distribution, then the temperature uniformity improves, but the pressure loss in the refrigerant inlet chamber increases
Solution Approach 1:
The heat exchanger is divided into multiple independent heat exchange sections (first row tubes and second row tubes) with separate inlet chambers. This segmentation allows each section to have optimized refrigerant flow paths, reducing the need for excessive longitudinal length while maintaining temperature distribution uniformity across all sections.
Solution Approach 2:
Different inlet chamber configurations are provided for different rows of tubes. The first header tank includes a first inlet chamber for the first row tubes and a second inlet chamber for the second row tubes, allowing each chamber to be optimized for its specific thermal and flow requirements, thereby achieving uniform temperature distribution without excessive pressure loss.
2Productivity
If the refrigerant flow rate through the tubes is increased to improve heat exchange efficiency, then the heat exchange performance improves, but the pressure loss in the tubes increases
Solution Approach 1:
The refrigerant flow path is segmented into multiple parallel channels through the first row tubes and second row tubes. This allows the total refrigerant flow to be distributed across multiple paths, maintaining adequate flow velocity for effective heat exchange while reducing the pressure loss in each individual channel compared to a single long path.
Solution Approach 2:
The heat exchanger utilizes a two-dimensional arrangement with tubes in both a first row and a second row, allowing refrigerant to flow through multiple parallel paths simultaneously. This dimensional expansion enables high heat exchange efficiency without requiring excessive flow rate through any single tube, thereby controlling pressure loss.
3Temperature
If the tubes in the first row and second row are arranged to overlap in the airflow direction to uniformize discharged air temperature, then the air temperature uniformity improves, but the device complexity increases
Solution Approach 1:
The heat exchanger is segmented into functionally distinct first row tubes and second row tubes with separate inlet chambers and outlet arrangements. This segmentation enables the overlapping arrangement that uniformizes discharged air temperature while keeping each segment's internal structure relatively simple and modular.
Solution Approach 2:
Both the first row tubes and second row tubes serve dual functions: they are individual heat exchange channels and collectively work together to uniformize the discharged air temperature through their overlapping arrangement. This multi-functionality achieves temperature uniformity without requiring additional dedicated components, thereby limiting the increase in 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 configuration achieves a more uniform temperature distribution of air discharged from the heat exchanger by forming subcooled liquid regions strategically, reducing pressure loss variations, and simplifying pipe routing, thereby enhancing overall performance.
Implementation Method 1
a heat exchanger that performs heat exchange between a refrigerant and air
Implementation Method 2
a superheated gas refrigerant flowing into the heat exchanger undergoes heat exchange, goes through a gas-liquid two-phase state, and flows out as a subcooled liquid refrigerant
Implementation Method 3
the superheated gas refrigerant flows into the refrigerant inlet chamber and is subjected to heat exchange while passing through the tubes in the first row, thereby becoming the refrigerant in the gas-liquid two-phase state
Data Source
Figure 1
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AI summary
A heat exchanger includes: a plurality of primary tubes (221) that receive a refrigerant distributed from a primary header tank (21); a primary turn tank (23) and a secondary turn tank (24) that receive the refrigerant from the plurality of primary tubes (221); and a plurality of secondary tubes (251) that receive the refrigerant distributed from the secondary turn tank (24). An internal flow passage, which extends from the plurality of primary tubes (221) to the plurality of secondary tubes (251) via the primary turn tank (23) and the secondary turn tank (24), has a primary region (Tc) and at least one secondary region (Tf, Tr) that are arranged one after another in a stacking direction (y). A pressure loss of the primary region (Tc) and a pressure loss of the at least one secondary region (Tf, Tr) are different from each other when a flow rate of the refrigerant in the primary region (Tc) is the same as a flow rate of the refrigerant in the at least one secondary region (Tf, Tr).