Transport Refrigeration Unit Side Suction Layout Against Frost Buildup
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Solution Overview
Problem
Existing transportation refrigeration units face issues with reduced air flow rate due to frost accumulation at the air suction port, leading to cooling failures and cargo damage from dripped water, while their thin structure limits cargo loading capacity.
Innovation Solution
A double-layer structured refrigeration unit with a large air suction port on the side surface and a blower fan between the air suction and blow passages, which reduces frost adhesion and allows for closer cargo loading, preventing water from dripping onto the cargo.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air suction port is provided with a fan guard to keep out foreign matters, then the safety and protection are improved, but the ice crystals impinge on the fan guard to be adhered and grow to accumulation of ice, reducing the opening of the air suction port and partially sealing it, which reduces the flow rate of air and deteriorates the performance
Solution Approach 1:
The fan guard is removed from the air suction port. Instead of having a guard that accumulates ice, the patent uses the evaporator surface itself as the suction port, eliminating the intermediate structure where ice accumulation occurs. This resolves the contradiction by removing the protective element that causes the problem.
Solution Approach 2:
Instead of protecting the fan with a guard at the suction port, the patent inverts the approach by making the evaporator surface the suction port itself. The protection function is achieved differently - through the evaporator's position and structure rather than a separate guard component.
2Productivity
If the refrigeration unit is formed into a thin structure to minimize reduction in cargo loading efficiency, then the cargo loading efficiency is improved, but the air flow passage between the lower surface of the refrigeration unit and the cargo must be formed, which limits the effective loading volumetric capacity
Solution Approach 1:
The air suction port is moved from the lower surface to the side surface of the refrigeration unit. This dimensional change allows air intake without requiring vertical clearance between the unit and cargo, enabling cargo to be loaded directly against the lower surface while maintaining adequate air flow through side surface ports.
3Productivity
If the air suction port is enlarged to reduce air suction resistance, then the air flow rate is improved, but the fan guard opening becomes larger, allowing more foreign matters, hands or fingers to enter
Solution Approach 1:
The fan guard is completely removed from the design. The large opening air suction port is achieved without any guard structure, eliminating the trade-off between opening size and protection. The evaporator surface serves as both the cooling element and the suction port boundary.
4Loss of substance
If the dew condensation water or water liquefied from frost drains down to the cargo, then the water removal function is achieved, but the cargo quality deteriorates or the cargo is damaged
Solution Approach 1:
An air blow passage with upward airflow is introduced as an intermediary mechanism. This airflow counteracts gravity's effect on water droplets, preventing them from falling onto the cargo. The upward air current serves as a mediator that transports water away from the cargo area without direct contact.
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 enhances air flow resistance, prevents frost-related cooling failures, and increases cargo loading capacity by minimizing water damage to the cargo.
Implementation Method 1
a blower fan (12) disposed between the air suction passage (19) and the air blow passage (20), for sucking air from the air suction passage so as to blow the air to the air blow passage
Implementation Method 2
an evaporator (11) disposed downstream of the air suction passage (19) and the air blow passage (20)
Implementation Method 3
dew condensation water which is generated inside the unit body
Implementation Method 4
a lower panel which forms an outermost case of the unit body is disposed on a lower surface of the unit body, the lower panel being formed to have a drain pan shape
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
The transportation refrigeration unit allows the opening area of the air suction port to be sufficiently large, prevents dropping of the dew condensation water or the water liquefied from the frost down to the cargo, and increases the effective loading volumetric capacity of the cargo. The unit body (10) including the evaporator (11) and the blower fan (12) is suspended from the ceiling surface of the cooling compartment (3). A portion of the inside of the unit body (10) is formed as the double-layer structure in the unit thickness direction, one layer of which is formed as the air suction passage (19), and the other is formed as the air blow passage (20). The blower fan (12) is disposed between the air suction passage (19 and the air blow passage (20) to suck air from the air suction passage (19) and to blow the air to the air blow passage (20). The air suction port (21) communicated with the air suction passage (19) is formed on one side surface (15) of the unit body (10).