Counter-Flow Evaporative Heat Exchanger With Periodic Core Wetting
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Solution Overview
Problem
Existing indirect evaporative coolers face challenges in size and shape compatibility for domestic use, with issues related to space constraints, water distribution, and thermal performance, particularly in maintaining cooling efficiency and flushing salts from the heat exchanger core.
Innovation Solution
A counter flow indirect evaporative heat exchanger design featuring alternately stacked horizontal wet and dry passages constructed from corrugated sheets with a wettable and impermeable surface, utilizing a traversing water distribution mechanism to periodically wet the core efficiently, allowing for compact dimensions and effective cooling while minimizing water flow impact on cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heat exchanger height is increased to increase cooling capacity, then the cooling performance is improved, but the device depth from the wall increases beyond acceptable limits
Solution Approach 1:
The patent reorients the heat exchanger passages from vertical stacking to horizontal stacking arrangement. The wet and dry passages are stacked alternately in a horizontal configuration, allowing the cooling capacity to be increased by extending the device horizontally rather than vertically, thus maintaining a compact depth from the wall while achieving high cooling performance
2Object-generated harmful factors
If water flow through the wet passages is increased to flush salts, then salt removal is improved, but the cooling efficiency deteriorates due to excessive water flow
Solution Approach 1:
The patent implements a periodic wetting cycle where water is introduced to the wet passages at intervals to flush out accumulated salts, followed by periods where water flow is stopped or minimized to allow evaporation and restore cooling efficiency. This cyclic operation between wetting and drying phases enables salt removal while maintaining high cooling performance during the drying periods
Solution Approach 2:
The patent incorporates a water distribution mechanism that pre-wets the wet passages before the flushing cycle begins, ensuring that salt deposits are adequately saturated and loosened for effective removal during the subsequent flushing phase, thereby maximizing salt removal efficiency while minimizing the duration of reduced cooling performance
3Productivity
If the heat exchanger core is made taller to increase capacity, then the cooling capacity is improved, but the water distribution and flushing capability deteriorates
Solution Approach 1:
The patent transitions from vertical to horizontal stacking of heat exchanger passages, enabling the core to be extended in the horizontal dimension to increase capacity while maintaining effective water distribution. The horizontal configuration allows water to be distributed more uniformly across the wet passages through gravity and capillary action, improving water distribution effectiveness alongside increased cooling capacity
4Productivity
If the heat exchanger width is increased to increase capacity, then the cooling capacity is improved, but the device width exceeds handling and installation limits
Solution Approach 1:
The patent utilizes horizontal stacking of passages arranged in alternating wet and dry configurations, allowing the cooling capacity to be increased by extending the device in a controlled horizontal direction while maintaining a compact width suitable for handling and installation. The alternating passage arrangement optimizes the use of available space, achieving high capacity within manageable dimensional constraints
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 enables a compact, efficient, and practical indirect evaporative cooler that meets size and shape requirements, maintaining high cooling performance and allowing for periodic flushing of salts without compromising thermal efficiency, even in taller configurations.
Implementation Method 1
corrugated sheets with one side comprising a wettable and absorbent medium and the other side comprising a water impermeable surface
Implementation Method 2
Heat transferring from the wet passage side to the dry passage side has to travel through relatively long distances of heat exchanger material, necessitating the use of high conductivity materials such as metals to achieve reasonable performance
Implementation Method 3
evaporation still takes place from water held in the wetted surfaces and full thermal performance of the cooler is achieved
Data Source
AI summary
A counter flow indirect evaporative heat exchanger (10) having vertically stacked alternate counter flow wet (14) and dry (12) passages where the wet passages are wetted during operation of the heat exchanger by wetting means (50, 52, 53, 54, 70, 72, 74, 76) travelling vertically of the stack. Elongately wetting of a small plurality of the total number of passages (14, 12) of the heat exchanger (10) occurs at a time during vertical travel of the wetting means.