Sublimation defrosting method, sublimation defrosting device, and cooling device

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Solution Overview

Problem

Conventional defrosting methods for cooling devices require stopping operations, consume high thermal energy, and are inefficient, especially when using sublimation methods that need dehumidifiers or heaters to remove frost layers, leading to prolonged downtime and potential clogging issues.

Innovation Solution

A sublimation defrosting method that heats the root-side region of the frost layer below its melting point using a localized heat source, creating a temperature gradient to facilitate sublimation without stopping the cooling process, reducing the need for extensive heat application and preventing clogging by targeting the root-side region for removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the frost layer is heated and melted using conventional methods, then the frost layer can be removed, but the operation of the cooler must be stopped and high thermal energy is required

Engineering Contradiction:

Improvefrost layer removalVSAvoidthermal energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by using a heater positioned specifically at the root-side region of the frost layer (adhesion portion side) rather than heating the entire frost layer uniformly. This localized heating approach concentrates thermal energy where it is most needed to break adhesion, reducing overall energy consumption while maintaining effective defrosting

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The defrosting process is segmented into two distinct phases: first, localized heating of the root-side region to induce sublimation and reduce adhesion; second, mechanical removal of the detached frost layer. This segmentation allows the cooling operation to continue during the heating phase, improving productivity

Inventive Principle:

Principle #1Segmentation

2Reliability

If the frost layer is melted by spraying water or using a heater, then the frost layer can be removed, but it takes time to dry or remove water resulting from the melted frost layer, which elongates the time for stopping the cooler

Engineering Contradiction:

Improvefrost layer removalVSAvoidcooler downtime

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent utilizes the phase transition of ice directly to water vapor through sublimation, bypassing the liquid water phase. By controlling the heater temperature to be below the melting point of ice (0°C) while providing sufficient heat for sublimation, the method eliminates melt water generation, thereby eliminating the drying time and allowing the cooler to resume operation immediately after frost removal

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The heater is positioned to act on the root-side region of the frost layer first, creating a temperature gradient that promotes sublimation from the base upward. This preliminary action at the adhesion portion detaches the frost layer before complete removal, preventing water accumulation and enabling continuous operation

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the frost layer is removed by jetting a strong air flow, then some frost can be removed, but strongly adhering frost remains on the surface of the cooling pipe which can grow and clog the cooler

Engineering Contradiction:

Improvefrost removal efficiencyVSAvoidcooler clogging prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heating action is concentrated specifically at the adhesion portion (root-side region) where frost attaches to the cooling pipe, creating a localized temperature gradient that promotes sublimation at the critical attachment point without affecting the entire frost layer uniformly

Inventive Principle:

Principle #3Local quality

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 method allows for efficient defrosting without stopping the cooling device, reduces heat consumption, and prevents frost clogging by focusing on the root-side region, thereby improving defrosting efficiency and maintaining continuous operation.

Implementation Method 1

a sublimation defrosting method for removing a frost layer adhering to a cooling surface for cooling a to-be-cooled gas; the method comprising a heating/temperature-rising step of heating an adhesion portion of the cooling surface, to which the frost layer adheres, to rise a temperature of the adhesion portion by a heat source located on an adhesion portion side with respect to the frost layer, under a temperature condition below a melting point of the frost layer

Methodology Applied

Scientific EffectSublimation: Sublimation

Implementation Method 2

heating an adhesion portion of the cooling surface, to which the frost layer adheres, to rise a temperature of the adhesion portion by a heat source located on an adhesion portion side

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11378326B2Sublimation defrosting method, sublimation defrosting device, and cooling device

Publication Date: 2022.07.05 MAYEKAWA MFG CO LTD

AI summary

There is provided a sublimation defrosting method for removing a frost layer adhering to a cooling surface for cooling a to-be-cooled gas, including a heating/temperature-rising step of heating an adhesion portion of the cooling surface, to which the frost layer adheres, to rise a temperature of the adhesion portion by a heat source located on an adhesion portion side with respect to the frost layer, under a temperature condition below a melting point of the frost layer.