Cool-Storage Evaporator Inner Fin Layout for Quiet Cooling Holdover
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Solution Overview
Problem
Ordinary car air conditioners experience a significant drop in cooling capacity when the engine stops, as the compressor-driven refrigerant supply halts, leading to noise issues due to liquid-phase cool storage material movement within evaporators with existing cool storage functions.
Innovation Solution
An evaporator design featuring flat refrigerant flow tubes, outer fins, and inner fins with crest and trough portions within cool storage material containers, which restricts the movement of cool storage material and maintains efficient cool storage and release, even when the engine is stopped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cool storage material container is disposed in the evaporator, then the cooling capacity is maintained when the engine stops, but unnatural sounds are produced due to liquid-phase cool storage material movement within the container
Solution Approach 1:
The inner fin is designed with varying thickness along its length, with the thickness being greater at the base portion near the refrigerant flow tube and progressively thinner toward the tip. This non-uniform thickness distribution creates local structural variations that restrict liquid-phase cool storage material movement while maintaining overall container integrity, thereby reducing unnatural sounds without compromising cooling capacity
Solution Approach 2:
The inner fin incorporates a curved or bent configuration rather than a straight design, allowing it to effectively span and restrict movement across the container space. The curved structure provides better mechanical support to contain the liquid-phase cool storage material while minimizing movement-induced noises during engine stoppage
2Ease of manufacture
If the inner fin is made thin to reduce material usage, then manufacturing cost decreases, but the inner fin cannot effectively restrict cool storage material movement
Solution Approach 1:
The inner fin employs non-uniform thickness distribution, being thicker at the base where mechanical support is most needed to restrict cool storage material movement, and progressively thinner toward the tip where less structural support is required. This localized quality variation optimizes both material efficiency and movement restriction effectiveness
Solution Approach 2:
The inner fin extends not only in the air-passing direction but also has significant dimensions in the thickness direction of the refrigerant flow tube, creating a three-dimensional structural element that provides effective movement restriction with minimal material usage by utilizing spatial arrangement rather than simply increasing fin thickness
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
Prevents sharp drops in cooling capacity and reduces unnatural sounds caused by cool storage material movement, ensuring effective cool storage and release while preventing container breakage due to increased internal pressure.
Implementation Method 1
The inner fin is disposed within the cool storage material container and has crest portions extending along the longitudinal direction, trough portions extending along the longitudinal direction, and connection portions connecting the crest portions and the trough portions
Implementation Method 2
imparting a cool storage function to the evaporator has been considered, to thereby enable cooling of a vehicle compartment by releasing the cool stored in the evaporator, when the compressor stops
Implementation Method 3
The plurality of flat refrigerant flow tubes have a longitudinal direction and a width direction which is perpendicular to the longitudinal direction and along which air is to pass
Data Source
AI summary
An evaporator with a cool storage function includes a plurality of refrigerant flow tubes. The flow tubes are spaced apart from one another in a thickness direction to form spaces among the plurality of refrigerant flow tubes. Outer fins are disposed in a first part of the spaces and are joined to the plurality of refrigerant flow tubes. The cool storage material container contains a cool storage material and is disposed in a second part of the spaces other than the first part. An inner fin is disposed within the cool storage material container and has crest portions extending along a longitudinal direction of the flow tubes, trough portions extending along the longitudinal direction, and connection portions connecting the crest portions and the trough portions.