Evaporator Cold Storage Layout for Controlled Condensate Freezing
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Solution Overview
Problem
Evaporators in vehicle air conditioners for idle-stop vehicles face breakage due to freezing of condensed water, especially when the distance between refrigerant tubes is narrow, leading to deformation or damage.
Innovation Solution
The evaporator design includes refrigerant tubes extending vertically with parallel air passages, cold storage containers with distinct drainage regions, and a temperature detector to control compressor ON-OFF based on temperature, allowing freezing in a designated region while preventing it in another to avoid damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple grooves or recess portions are provided on the cold storage container surface to promote condensed water drainage, then condensed water drainage is improved, but when the distance between refrigerant tubes is narrow, condensed water retention still occurs leading to freezing and deformation
Solution Approach 1:
The cold storage container is divided into two distinct regions: a first region with multiple grooves for promoting condensed water drainage, and a second region without grooves that defines a smaller space. This segmentation allows different parts of the container to serve different functions - the grooved region handles drainage while the non-grooved region prevents freezing damage by maintaining a smaller space that avoids condensation accumulation.
Solution Approach 2:
Different regions of the cold storage container are given different structural qualities. The first region has grooves for drainage promotion, while the second region has a smooth surface and smaller defined space. This local differentiation allows the container to simultaneously achieve good drainage performance and prevent freezing damage in critical areas.
2Productivity
If the distance between refrigerant tubes is reduced to increase heat exchange efficiency, then heat exchange performance is improved, but condensed water retention occurs leading to freezing and breakage
Solution Approach 1:
The cold storage container is designed with different regions having different spatial relationships to the refrigerant tubes. The first region has a relatively large space with grooves for drainage, while the second region has a smaller space that is strategically positioned to prevent condensation accumulation. This allows narrow tube spacing for heat exchange efficiency while protecting against freezing damage in the smaller-space region.
3Reliability
If a temperature detector is installed to monitor temperature for preventing condensed water freezing, then freezing prevention control is improved, but the detector must be positioned in a specific region to accurately represent the heat exchange surface temperature
Solution Approach 1:
The temperature detector is installed in the first region (freezing allowable region) which has a relatively large space and grooves. This region serves as an intermediary location that accurately reflects the heat exchange surface temperature while being positioned where condensed water freezing does not cause damage. The detector readings from this region are used to control the compressor ON-OFF timing to prevent freezing in the second region.
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 prevents deformation or breakage by allowing controlled freezing in a specific region and preventing it in another, ensuring the evaporator functions effectively without damage from condensed water freezing.
Implementation Method 1
cold storage containers (14) disposed in a group of air passages (13) of the multiple air passages (13), and each of the cold storage containers (14) having a first region (14f) that defines a relatively large space with the refrigerant tubes (12) for promoting of drainage of the condensed water, and a second region (14g) that is positioned on an upper side of the first region (14f) and defines a smaller space with the refrigerant tubes (12) than the space defined by the first region (14f)
Implementation Method 2
a temperature detector (18) that is disposed within the freezing allowable region (19a)
Implementation Method 3
an evaporator (8) including multiple refrigerant tubes (12) that extend in a vertical direction and have a refrigerant passage, and multiple air passages (13) that are provided between the refrigerant tubes (12)
Data Source
AI summary
An evaporator includes multiple refrigerant tubes, multiple air passages provided between the refrigerant tubes, a cold storage container disposed in the multiple air passages, and a temperature detector. The evaporator further includes a freezing allowable region and a freezing unallowable region that is provided above the freezing allowable region. The cold storage container has a small thickness region and a large thickness region that is positioned above the small thickness region. The large thickness region demarcates a smaller space with the refrigerant tubes than the space demarcated between the small thickness region and the refrigerant tubes. The small thickness region of the cold storage container is positioned within the freezing allowable region, the large thickness region is positioned in the freezing unallowable region, and the temperature detector is disposed in the freezing allowable region.