Roll-Bond Evaporator with Embedded Heating Tube for Rapid Defrosting
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Solution Overview
Problem
Direct cooling type refrigerators with roll-bond type evaporators face inefficiencies due to frost deposition on the evaporator surface, leading to reduced heat exchange efficiency and longer defrosting times, and existing defrosting methods using external heat tubes suffer from high contact resistance and increased volume, compromising freezing chamber capacity.
Innovation Solution
An evaporator design with a heating tube embedded within the evaporator case, where a heater is attached to the outer surface to heat a working fluid flowing through the heating tube, optimizing the flow path and attachment design to enhance defrosting efficiency and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tube for transmitting heat is formed to surround an evaporator case, then frost can be removed by heating, but contact resistance between the tube and evaporator case becomes too large to exhibit defrosting effect
Solution Approach 1:
The heating tube is merged with the evaporator case by forming it within the case structure itself, eliminating the interface between separate components. This integration removes the contact resistance problem that occurred when external tubes were used to surround the evaporator case, as the heating surface is now directly formed in the evaporator case wall.
Solution Approach 2:
The heating tube is nested within the evaporator case structure, with the heating channel formed inside the case wall thickness. This nesting approach allows the heating tube to be embedded in the evaporator case, ensuring intimate thermal contact without requiring external mounting, thereby eliminating contact resistance issues.
2Reliability
If a water storage tank and heater are provided separately from the evaporator, then defrosting can be performed, but total volume of the evaporator including defrosting device becomes large, making it difficult to secure capacity of freezing chamber
Solution Approach 1:
The heating tube and heater are merged into the evaporator case structure, eliminating the need for separate water storage tanks and external heating devices. The heating channel is formed within the case wall, and the heater is attached directly to the case outer surface, integrating all defrosting components into the evaporator assembly itself.
Solution Approach 2:
The evaporator case structure serves multiple functions: it provides the cooling surface for refrigerant evaporation, contains the heating channel for defrosting, and supports the heater attachment. This multi-functionality eliminates the need for separate dedicated defrosting components, reducing overall volume while maintaining both cooling and defrosting capabilities.
3Reliability
If heating tube is embedded in evaporator case, then defrosting performance varies depending on shape of heating tube and heater, but structural design is required to optimize it
Solution Approach 1:
The heating tube is designed with non-uniform distribution within the evaporator case, concentrating heating channels in areas where frost accumulation is most severe. The heater attachment position and shape are optimized locally to match the specific thermal and frost deposition characteristics of different evaporator surfaces, rather than using a uniform design throughout.
Solution Approach 2:
The heating tube configuration allows for flexible adaptation to different evaporator geometries and frost patterns. The heating channel can be shaped and positioned dynamically within the case wall to optimize heat distribution, and the heater attachment design can be adjusted based on specific application requirements, providing design flexibility without excessive complexity.
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 reduces defrosting time, maintains food freshness, increases cooling efficiency, and maximizes freezing chamber capacity by efficiently using defrost heat without the need for additional volume for the defrosting device.
Implementation Method 1
a heater attached to an outer surface of the evaporator case corresponding to the heating tube and heating the working fluid in the heating tube
Implementation Method 2
a working fluid contained in a water storage tank is heated by a heater and moves along the pipe, thereby melting frost deposited in the evaporator case to remove it
Data Source
AI summary
Disclosed is an evaporator, comprising: a heating tube left as an empty space between first and second case sheets, which form an evaporator case, so as not to be overlapped with a cooling tube, and forming a heating passage in which a working liquid for defrosting flows; and a heater attached to the outer surface, which corresponds to the heating tube, of the evaporator case so as to heat the working liquid inside the heating tube. The heating tube can have a structure which an inlet and an outlet are respectively formed at both sides of a heater attachment part in the longitudinal direction and both end portions of a passage part are respectively connected to the inlet and the outlet, or can have a structure in which an opening is formed at one side of the heater attachment part, the working liquid heated by the heater is discharged through the opening, and the cooled working liquid is returned. The structures can form the heating passage, enabling the working liquid to circulate therethrough, without forming the inlet and the outlet, which are respectively connected to both end portions of the passage part, to be parallel at one side of the heater attachment part.