Offset-Fin Heat Exchanger for Low-Gradient Cooling Efficiency
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Solution Overview
Problem
High efficiency heat exchange devices face challenges in minimizing unwanted heat conduction along the flow direction, particularly in low temperature gradient applications, and conventional dehumidification methods are energy-intensive and inefficient.
Innovation Solution
A heat exchanger design featuring fins with a water retaining surface in the secondary channel, where the fins are offset and arranged in repeating groups to enhance water uptake and reduce laminar flow, combined with a method of manufacturing using thermally insulating spacing elements to minimize parasitic heat conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat exchanger operates across low temperature gradient to achieve high efficiency heat recovery, then heat transfer efficiency is improved, but unwanted heat conduction along the flow direction increases
Solution Approach 1:
The heat exchanger is divided into multiple individual plates arranged in series, with each plate handling a portion of the heat transfer. This segmentation allows insertion of insulating spacers between plates to block longitudinal heat conduction paths while maintaining the overall heat exchange function across low temperature gradients
Solution Approach 2:
Thermally insulating spacers are introduced as intermediary elements between the heat conducting plates. These spacers act as mediators that block the unwanted longitudinal heat conduction while allowing the heat transfer function to continue through the plate structure itself, enabling efficient operation across low temperature gradients
2Productivity
If conventional dehumidification using desiccant wheel is used, then dehumidification is achieved, but energy consumption increases due to heat of absorption and regeneration requirements
Solution Approach 1:
The patent converts the harmful effect of heat conduction into a beneficial cooling effect by allowing controlled heat transfer from the primary air stream to the secondary air stream in the heat exchanger. This passive cooling eliminates the need for energy-intensive desiccant regeneration, achieving dehumidification through the heat exchange process itself rather than through active cooling or chemical absorption
Solution Approach 2:
The system achieves dehumidification through self-service by utilizing the heat exchange between air streams to naturally cool and condense moisture from the primary air stream. The heat exchanger structure itself provides the cooling function without requiring external energy input for desiccant regeneration or active cooling mechanisms
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 achieves improved heat transfer efficiency and water uptake, leading to more effective indirect evaporative cooling and dehumidification with a compact construction, enhancing the overall efficiency of cooling systems.
Implementation Method 1
heat is transmitted from one stream to the other through the conducting wall
Implementation Method 2
a water retaining surface on the fins in at least the second channel and a source of water for wetting the fins
Implementation Method 3
the heat exchanger can be used for indirect evaporative cooling
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A heat exchanger (20) comprising: a pair of generally planar, heat conducting plates (10) arranged in spaced, generally parallel relationship; spacing elements (22) separating the plates (10) from one another and defining first (26) and second (28) flow channels between the plates (10) for flow in a first direction and a second direction respectively; wherein the plates (10) in at least the first channel (26) are divided into fins (14), the fins being separated from each other in the first direction and being offset from the plate (10) perpendicular to the first direction to a plurality of offset positions.