Multi-Slab Multichannel Heat Exchanger for Uniform Airflow
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Solution Overview
Problem
Heat exchangers in HVAC&R systems face inefficiencies due to uneven airflow distribution, leading to variations in heat transfer rates across different tubes, particularly in multi-slab configurations where outer tubes may receive less airflow, affecting overall system performance.
Innovation Solution
A multi-slab heat exchanger design with subdivided groups of multichannel tubes and fluid connections between slabs to optimize refrigerant flow and airflow distribution, ensuring balanced heat transfer across all tubes by aligning tube groups and using manifolds to facilitate even airflow and refrigerant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multichannel tubes are arranged in horizontal rows with multiple slabs placed side-by-side to increase capacity within small footprint, then the heat exchanger capacity and compactness are improved, but the outer tubes receive more airflow resulting in uneven heat transfer distribution across tubes
Solution Approach 1:
The heat exchanger is divided into multiple slabs, each containing a specific arrangement of multichannel tubes. By segmenting the overall heat exchanger into discrete slabs with controlled configurations, the design achieves compactness while managing airflow distribution across different tube positions
Solution Approach 2:
Different tube groups within slabs are assigned different functions based on their airflow characteristics. Outer tube groups that receive more airflow are differentiated from inner tube groups, allowing each group to be optimized for its specific operating conditions and achieving uniform heat transfer distribution
2Productivity
If multichannel tubes are used to provide multiple flow channels within tubes, then the heat transfer surface area and capacity are improved, but the location of tubes within the heat exchanger causes uneven airflow reception and varying heat transfer rates
Solution Approach 1:
The tube arrangement is segmented into different groups (outer tube groups and inner tube groups) based on their airflow reception characteristics. This segmentation allows each group to be designed and configured to handle its specific airflow conditions, achieving uniform heat transfer across all tubes despite position differences
Solution Approach 2:
Each tube group is given local quality characteristics appropriate to its position. Outer tube groups receiving more airflow are configured differently from inner tube groups, with each group optimized for its local airflow conditions to achieve uniform overall 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 design enhances heat transfer efficiency and reduces frost growth by promoting even airflow and refrigerant distribution, improving the overall performance and capacity of HVAC&R systems, especially in outdoor applications.
Implementation Method 1
Heat exchangers transfer heat by circulating a refrigerant through a cycle of evaporation and condensation
Implementation Method 2
facilitate heat transfer between refrigerant contained within the tube flow channels and external air passing over the tubes
Implementation Method 3
circulating a refrigerant through a cycle of evaporation and condensation
Implementation Method 4
circulating a refrigerant through a cycle of evaporation and condensation
Data Source
AI summary
Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems and multi-slab heat exchangers are provided that include fluid connections for transmitting fluid between groups of tubes. The fluid connections may include generally tubular members fluidly connected to manifold sections. The fluid connections also may include partitioned manifolds containing tubes of different heights. Multichannel tubes are also provided that include a bent section configured to locate a flow path near a leading edge of a tube within one section and near a trailing edge of the tube within another section.