Phase-Change Heat Sink Tubes for Refrigerated Box Temperature Control

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Solution Overview

Problem

Refrigeration units experience temperature rise during the heating phase due to heat intrusion, leading to unnecessary energy consumption from running evaporator fans to circulate air and remove humidity, which also causes thermal gradients and increased energy use.

Innovation Solution

A supplemental refrigeration heat sink with sealed tubes filled with a phase change compound having a melting point higher than the average box temperature, which absorbs heat during the heating phase, eliminating the need for evaporator fan operation and reducing temperature rise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If evaporator fans are operated during the heating phase to circulate air and remove humidity, then humidity control is improved, but energy consumption increases

Engineering Contradiction:

Improvehumidity controlVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The phase change material is pre-cooled during the cooling phase to store cold energy, which is then released during the heating phase to counteract temperature rise and reduce humidity, eliminating the need for fan operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention utilizes the phase change (freezing and melting) of a material to store and release thermal energy, creating a passive cooling effect during the heating phase that prevents temperature and humidity buildup without requiring active fan circulation

Inventive Principle:

Principle #36Phase transitions

2Use of energy by moving object

If evaporator fans are stopped during the heating phase, then energy consumption is reduced, but thermal gradients develop in the box

Engineering Contradiction:

Improveenergy consumptionVSAvoidthermal gradient

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The phase change material is strategically placed in sealed tubes positioned throughout the refrigeration box, creating localized cooling zones that collectively maintain uniform temperature distribution without requiring air circulation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The phase change material automatically activates during the heating phase based on temperature conditions, providing self-regulating thermal management that maintains temperature uniformity without external control or fan operation

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If evaporator fans continue operating during the heating phase, then temperature uniformity is maintained, but additional energy is consumed for fan operation and subsequent humidity removal

Engineering Contradiction:

Improvetemperature uniformityVSAvoidenergy consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

Cold energy is stored in the phase change material during the cooling phase before it is needed, allowing the system to passively maintain temperature uniformity during the heating phase without activating fans or consuming additional energy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces the mechanical air circulation system (fans) with a passive thermal energy storage and release mechanism, eliminating the need for mechanical motion while maintaining temperature uniformity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution reduces energy consumption by minimizing fan operation, slows temperature increase, and maintains humidity control without additional moving parts, extending the interval between cooling cycles and reducing maintenance needs.

Implementation Method 1

the compound is preferably a phase change compound with a melting point proximate to and higher than the average box temperature. During the cooling phase of the box, the supplemental heat sink tubes are cooled, with the phase change material freezing or nearly freezing. During the heating phase, the phase change material readily absorbs heat from the box

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

the phase change material readily absorbs heat from the box, slowing the temperature rise at the top of the box

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 3

A supplemental refrigeration heat sink includes a plurality of sealed tubes filled with a compound and arranged so as to extend across the top of a refrigerated box

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS10240850B1Supplemental refrigeration heat sink and related systems and methods

Publication Date: 2019.03.26 STINE JOSEPH P

AI summary

A supplemental refrigeration heat sink includes a plurality of sealed tubes filled with a compound and arranged so as to extend across the top inside a refrigerated box. The compound is preferably a phase change compound with a melting point proximate to and higher than the average return air temperature. During the cooling phase of the box, the supplemental heat sink tubes are cooled, with the phase change material freezing or nearly freezing. During the heating phase, cooling fans can be secured and the phase change material readily absorbs heat from the box, slowing the temperature rise in the box.