Aircraft Trolley Refrigerator Unit for Even Dry Ice Cooling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Inflight service carts face challenges in maintaining food and beverage products at a servable temperature overnight due to the aircraft's electrical systems being shut down, leading to food spoilage and uneven chilling with carbon dioxide ice, which rapidly chills and evaporates, causing freezing and spoilage issues.

Innovation Solution

A detachable and modular refrigerator unit using carbon-dioxide ice with regulated cold air release, featuring a thermal conductor and insulating materials to extend storage and serving times, ensuring even chilling without freezing and reducing evaporation, designed for compatibility with various aircraft dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If carbon-dioxide ice is used for refrigeration, then cooling effectiveness is improved, but uneven chilling and product freezing occur

Engineering Contradiction:

Improvecooling effectivenessVSAvoidchilling uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

A thermal conductor plate is introduced as an intermediary between the carbon-dioxide ice and the food products. The plate receives heat from the products and transfers it to the dry ice, providing uniform cooling without direct contact. This mediator prevents uneven chilling and freezing while maintaining effective temperature reduction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If carbon-dioxide ice is used directly, then rapid cooling is achieved, but rapid evaporation and short storage time occur

Engineering Contradiction:

Improvecooling speedVSAvoidstorage time

Core Design Contradiction:

SpeedVSDuration of action of stationary object

Solution Approach 1:

The thermal conductor plate acts as a buffer that moderates the interaction between carbon-dioxide ice and the environment. By controlling the heat transfer rate, the plate prevents rapid evaporation of the dry ice while maintaining effective cooling, thereby extending the storage duration.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If a tight container is used for carbon-dioxide ice, then containment is improved, but evaporation pressure builds up

Engineering Contradiction:

Improvecontainer containmentVSAvoidevaporation pressure

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The thermal conductor plate serves as a flexible thermal interface that allows controlled heat transfer while accommodating the expansion and evaporation of carbon-dioxide ice. This flexible approach manages evaporation pressure while maintaining containment.

Inventive Principle:

Principle #30Flexible shells and thin films

4Reliability

If a permanent refrigeration system is installed in the aircraft, then refrigeration reliability is improved, but device complexity and certification costs increase

Engineering Contradiction:

Improverefrigeration reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The refrigeration system is divided into separate, modular components: a reusable thermal conductor plate and replaceable carbon-dioxide ice containers. This segmentation allows the system to be simple and easy to certify while maintaining reliability through proven individual components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses inexpensive, replaceable carbon-dioxide ice containers rather than expensive permanent refrigeration equipment. The disposable nature of the ice containers simplifies the overall system while maintaining effective refrigeration.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

The solution provides long-term, even refrigeration, reducing food spoilage and improving product quality, while offering cost savings and enhanced safety for cabin crew by minimizing the handling of carbon dioxide ice, and allowing flexible temperature control and distribution within the service cart.

Implementation Method 1

The refrigerator unit leads cold air evenly along the metal plate to the inside of the service cart

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Carbon-dioxide ice releases carbon dioxide very strongly and cannot be enclosed in an entirely tight container, due to the evaporation pressure

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

By regulating the release amount of the tightly insulated and evaporating cold air the evaporation rate of the carbon-dioxide ice is reduced by more than 70%

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9242732B2Cooling solution in a trolley of an aeroplane

Publication Date: 2016.01.26 ICEBRIDGE

AI summary

The invention relates to an independent refrigerator unit for an inflight service cart. According to the invention, it comprises an insulated casing part, inside which is a refrigerant chamber for a refrigerant, and a thermal conductor connected to the insulated casing, in which there is a first part and a second part, in which case the first part is in direct thermal contact with the refrigerant chamber and the second part with the external space of the casing.