External Flat-Tube Tank Heating With Heat Distribution Plate
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Solution Overview
Problem
Conventional flat tube designs in stationary liquid tanks face challenges in achieving desired heat flow while adhering to refrigerant charge limits and structural requirements, particularly in domestic hot water heating systems, where the heat exchanger is externally mounted, leading to issues with contamination prevention and thermal resistance.
Innovation Solution
The design incorporates a heat distribution plate between or within the flat tubes to increase the heat transfer surface area without increasing refrigerant volume, using materials with higher thermal conductivity and robust webs to withstand higher burst pressures, and optimizing the geometric cross-sectional shape of the flat tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cross-sectional area of the flat tube is increased to reduce thermal resistance, then heat transfer efficiency improves, but the internal volume of the flat tube increases, which is not feasible given the refrigerant charge limits
Solution Approach 1:
The patent introduces a heat distribution plate that extends the heat transfer surface area in a new dimension (radially outward from the flat tube), rather than increasing the cross-sectional area of the flat tube itself. This allows thermal resistance to be reduced by providing additional heat distribution pathways without consuming additional refrigerant volume within the flat tube channels.
Solution Approach 2:
The heat distribution plate acts as an intermediary component between the flat tube and the liquid tank. It receives heat from the flat tube surface and distributes it over a larger area to the liquid tank, effectively reducing thermal resistance by creating additional heat transfer pathways without requiring the flat tube itself to have a larger cross-sectional area.
2Loss of energy
If the web width is increased to reduce thermal resistance, then heat transfer efficiency improves, but the burst pressure capacity increases beyond standard requirements, leading to material inefficiency
Solution Approach 1:
The patent applies local quality by making the web thickness non-uniform along the flat tube. The web thickness is increased in specific regions where heat transfer enhancement is needed, while maintaining standard thickness in other regions. This allows thermal resistance to be reduced locally without unnecessarily increasing the overall burst pressure capacity and material usage throughout the entire flat tube.
Solution Approach 2:
The patent changes the web thickness parameter from a uniform value to a variable value that varies along the length of the flat tube. By optimizing the web thickness distribution, the patent achieves reduced thermal resistance in critical areas while avoiding excessive burst pressure capacity and material usage that would result from uniformly increasing web thickness throughout.
3Loss of energy
If the heat exchanger is integrated inside the liquid tank, then heat transfer efficiency improves, but installation complexity and contamination risk increase
Solution Approach 1:
The patent segments the heat transfer system into two separate components: the flat tube heat exchanger and the liquid tank. The flat tube is wrapped around the exterior of the tank, allowing independent installation, maintenance, and replacement of each component. This segmentation reduces installation complexity and eliminates contamination risks associated with internal integration, while still achieving effective heat transfer through the optimized heat distribution plate.
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 approach enhances heat transfer efficiency, reduces material usage, and simplifies installation while maintaining the same internal volume, preventing refrigerant contamination and minimizing thermal resistance.
Implementation Method 1
the heat distribution plate has high thermal conductivity and is, for example, made of aluminum. It distributes the heat flow from the surface in contact with the flat tube to a larger area.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a stationary liquid tank (1) with a temperature control device (2) for temperature control of a liquid (3) in the liquid tank (1), which has at least one flat tube (5) externally connected to the liquid tank (1) in a heat-transferring manner, with channels (6) having a channel width bK and webs (7) having a web width bs, wherein the flat tube (5) is made of a material with a tensile strength Rm and has a burst pressure PBERST,IST, - wherein a heat distribution plate (10) is arranged between the flat tube (5) and the liquid tank (1), which is connected over a surface to the flat tube (5) and the liquid tank (1), or - wherein the flat tube (5) with the channels (6) and webs (7) is designed such that it satisfies the following equation, 1.2bK+Tolerance/bS−Tolerance≤Rm/PBERST,MIN with tolerance = manufacturing tolerance of the web thickness bs. This should enable increased heat transfer.