Microchannel Condenser Layout to Eliminate Partial-Load Dead Spots
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Solution Overview
Problem
HVAC systems face inefficiencies in heat exchange, particularly during partial load operations, due to the segregation of refrigerant circuits in traditional multistage microchannel condensers, leading to ineffective heat transfer across the exchange area.
Innovation Solution
A multistage microchannel condenser design with laterally or longitudinally displaced manifolds, where at least two closed refrigerant circuits are interspersed throughout the exchange area, allowing for continuous heat exchange without partitioned zones, maintaining the same footprint as conventional designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If refrigerant circuits are segregated in traditional multistage microchannel condensers, then device complexity is reduced and manufacturing is simplified, but heat exchange efficiency deteriorates during partial load operations due to thermal dead spots
Solution Approach 1:
The condenser is segmented into multiple stages with alternating refrigerant circuits (first circuit in odd stages, second circuit in even stages), allowing each circuit to utilize the entire exchange area while maintaining manufacturing simplicity through modular stage construction
Solution Approach 2:
The manifolds are displaced in the lateral dimension rather than being positioned at opposite ends, enabling refrigerant circuits to interleave throughout the exchange area and eliminate thermal dead spots while maintaining a compact footprint
2Device complexity
If manifolds are positioned at opposite ends of the condenser, then device complexity is reduced and assembly is simplified, but heat exchange efficiency worsens due to limited heat transfer area utilization
Solution Approach 1:
The manifolds are displaced laterally by approximately half the condenser width rather than being positioned at opposite ends, enabling refrigerant circuits to interleave and utilize the entire exchange area while maintaining manageable device complexity
Solution Approach 2:
Different regions of the condenser utilize different refrigerant circuits in an alternating pattern, ensuring that the entire exchange area is actively engaged in heat transfer at all times, with each local stage optimized for its assigned circuit
3Area of stationary object
If the condenser footprint is reduced, then space utilization is improved, but heat exchange efficiency deteriorates due to insufficient exchange area
Solution Approach 1:
The lateral displacement of manifolds enables a more compact arrangement of refrigerant circuits within the same footprint, increasing the effective exchange area utilization without expanding the overall condenser dimensions
Solution Approach 2:
The alternating circuit arrangement ensures continuous heat exchange across the entire exchange area without thermal dead spots, maintaining high efficiency while accommodating a reduced footprint through optimized space utilization
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
Enhances efficiency during both full and partial load operations by ensuring heat exchange occurs across the entire exchange area, reducing thermal dead spots and maintaining the same condenser footprint, allowing for potential operation at slower blower speeds.
Implementation Method 1
heat exchange occurs across the entire exchange area
Implementation Method 2
condenser airflow across the multistage microchannel condenser
Implementation Method 3
heat transfer across the exchange area
Data Source
AI summary
In one instance, a multistage microchannel condenser is provided for use as an aspect of a heating, ventilating, and air conditioning (HVAC) system. The multistage microchannel condenser includes at least two pluralities of flat tubes having microchannels, each associated with a different refrigeration circuit, that are interspersed so that when only one refrigeration circuit is operational, the multistage microchannel condenser still does not have any substantial thermal dead spots. Manifolds are used on each end of the multistage microchannel condenser to fluidly couple members of the at least two pluralities of flat tubes such that the refrigerant in each refrigeration circuit remains separated while still using a majority of the area of the face of the multistage microchannel condenser. Other aspects are presented.