D-Shaped Collector Micro-Channel Condenser for Low Refrigerant Charge
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Solution Overview
Problem
Current thermodynamic heating devices face challenges in reducing refrigerant charge due to regulatory constraints, with existing condenser technologies either requiring high refrigerant volumes, suffering from scaling issues, or inducing destratification and thermal performance reduction.
Innovation Solution
A thermodynamic heating device featuring a D-shaped cross-section for the collectors, which reduces internal volume and refrigerant usage, enhances mechanical resistance, and improves thermal contact with the tank, minimizing pressure drops and mechanical stresses, while maintaining efficient heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a coiled tube condenser is used, then the refrigerant charge is reduced compared to traditional designs, but the internal volume remains too high and regulatory constraints are not fully met
Solution Approach 1:
The condenser is segmented into multiple parallel micro-channel strips instead of a single coiled tube. This segmentation reduces the internal volume while maintaining heat exchange surface area, allowing refrigerant charge to be reduced to comply with regulatory constraints (below 150g for R134a).
Solution Approach 2:
The invention transitions from a two-dimensional coiled tube arrangement to a three-dimensional micro-channel structure with multiple parallel strips wrapped around the tank. This dimensional change allows more efficient space utilization and reduced internal volume while maintaining effective heat transfer.
2Quantity of substance
If micro-channel strips are arranged in parallel, then the refrigerant charge is reduced, but the linear pressure drop increases requiring short channel lengths
Solution Approach 1:
The refrigerant flow path is segmented into multiple parallel micro-channel strips, each with optimized length. This segmentation allows the pressure drop in each individual strip to remain low while the total heat exchange surface area is sufficient, resolving the contradiction between reduced refrigerant charge and acceptable pressure drop.
Solution Approach 2:
Multiple parallel micro-channel strips are combined into a single condenser assembly wrapped around the tank. The parallel arrangement merges the heat exchange capability of multiple short channels while maintaining low pressure drop in each channel, achieving both reduced refrigerant charge and acceptable pressure characteristics.
3Strength
If the collector cross-section is circular, then the mechanical resistance is sufficient, but the internal volume is unnecessarily large
Solution Approach 1:
The collector cross-section is changed from a symmetric circular shape to an asymmetric D-shape. This asymmetric geometry reduces the internal volume of the collector while maintaining sufficient mechanical strength through optimized wall thickness distribution, directly resolving the contradiction between mechanical resistance and volume reduction.
4Temperature
If the D-shaped collector contacts the tank with its convex part, then thermal contact is improved, but mechanical stresses increase at connection points
Solution Approach 1:
The D-shaped collector applies local quality optimization by concentrating thermal contact at the convex portion that contacts the tank surface, while the flat portion serves as a stable mounting base. This local optimization improves thermal contact efficiency without distributing mechanical stresses across the entire structure, managing the stress concentration at specific connection points.
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
The D-shaped collector design effectively reduces refrigerant volume by up to 45% compared to circular sections, enhances heat transfer, and maintains mechanical integrity, addressing regulatory constraints and thermal performance issues.
Implementation Method 1
a condenser wound around a tank intended to contain liquid to be heated by the refrigerant circulating in this circuit through the various components
Implementation Method 2
The refrigerant circulates in this circuit through the various components of the circuit (compressor, condenser, expander and evaporator) and following the classic thermodynamic cycle
Implementation Method 3
compression, condensation, expansion and evaporation
Implementation Method 4
following the classic thermodynamic cycle: compression, condensation, expansion and evaporation
Data Source
Figure 1~5
Figure 6a~7
Figure 8~10
AI summary
The invention relates to a thermodynamic heating apparatus comprising a substantially cylindrical tank (10) containing liquid, characterized in that it comprises a condenser (14) which is wound around the tank in the manner of a belt, the condenser comprising two parallel collectors which frame a plurality of parallel bands which are perpendicular to the collectors, each band comprising a plurality of parallel channels which each have two opposite ends, the two opposite ends of the channels of each band each opening into one of the two collectors, each collector (16) having in cross-section a general shape of D which extends over the entire longitudinal dimension of the collector, the bar of the D being oriented opposite the tank (10).