Nested-Tube Header Assembly to Reduce Refrigerant Pressure Drop
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Solution Overview
Problem
Existing vapor compression refrigeration systems with multiple refrigerant circuits face significant pressure drops due to the distributor and distribution tubes, leading to performance degradation, especially during reverse flow operations.
Innovation Solution
The introduction of a header tube assembly with an outer tube, an inner tube, and a flow valve, which includes a plurality of apertures to direct refrigerant flow and reduce pressure drop, addresses the issue of refrigerant distribution in heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a distributor and distribution tubes are used to split refrigerant into multiple refrigerant circuits, then refrigerant distribution is achieved, but pressure drop increases significantly
Solution Approach 1:
The patent employs a nested tube structure where an inner tube is positioned within an outer tube. The inner tube contains multiple inner apertures for refrigerant distribution, while the outer tube provides additional outer apertures. This nested configuration allows refrigerant to flow through multiple pathways (inner tube apertures and outer tube apertures) simultaneously, distributing refrigerant to multiple circuits while maintaining lower pressure drop compared to traditional single-path distributor designs.
Solution Approach 2:
The distributor is segmented into multiple functional components: the outer tube with outer apertures, the inner tube with inner apertures, and a flow valve. This segmentation creates multiple independent refrigerant flow paths, allowing refrigerant to be distributed to different circuits through different aperture sets. The segmented structure reduces flow resistance by providing parallel pathways, thereby decreasing overall pressure drop while achieving effective refrigerant distribution.
2Adaptability or versatility
If traditional distributor designs are used, then refrigerant can be split into multiple circuits, but system performance degrades during reverse flow operation
Solution Approach 1:
The patent incorporates a flow valve that can dynamically adjust its position along the inner tube based on flow direction. During reverse flow operation, the flow valve moves to different positions to optimize refrigerant distribution pathways. This dynamic adjustment capability allows the distributor to adapt to bidirectional flow conditions, maintaining effective refrigerant splitting and system performance whether the refrigerant flows in the forward or reverse direction, unlike static traditional distributors.
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 proposed solution effectively reduces pressure drop and enhances refrigerant distribution, thereby improving the overall performance of vapor compression refrigeration systems, especially during reverse flow operations.
Implementation Method 1
The flow valve can be configured to move in a first direction extending from the open end of the outer tube to the closed end of the outer tube and a second direction extending from the closed end of the outer tube to the open end of the outer tube. The flow valve can be configured to move in the first direction to a semi-closed state in response to a flow of refrigerant flowing through the header tube assembly in the first direction.
Data Source
AI summary
A header tube assembly is disclosed and can include an outer tube, an inner tube, and a flow valve. Each of the outer and inner tubes can include an open end and a closed end, as well as a plurality of apertures extending through a sidewall of the outer tube and inner tube, respectively. The apertures of the inner tube can permit a flow of refrigerant between an internal volume of the inner tube and a gap between the inner and outer tubes, and the apertures of the outer tube can permit a flow of refrigerant between the internal volume of the outer tube and a plurality of refrigerant circuits in a heat exchanger. The flow valve can be configured to selectively prevent refrigerant from flowing between the gap and the open end of the outer tube, depending on a direction of refrigerant flow through the header tube assembly.