Reversible Airflow Refrigeration for Uniform Galley Cart Cooling
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Solution Overview
Problem
Current galley cooling systems for pre-prepared airline food struggle to maintain uniform temperatures, leading to unwanted freezing or warming, which can result in spoilage and require more powerful, heavier, and less efficient cooling systems.
Innovation Solution
An apparatus with an air chiller, storage enclosure, and duct system that includes a valve system to periodically reverse the direction of chilled air flow, ensuring uniform temperature distribution by switching between forward and reverse airflow modes based on temperature differences within the compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is forced into the galley carts to maintain temperature, then the maximum temperature is controlled, but the temperature distribution becomes non-uniform causing some food to be too cold or too warm
Solution Approach 1:
The system periodically reverses the direction of air flow through the galley carts using a reversible fan. The fan alternates between pushing air through the carts and pulling air through the carts, creating periodic flow direction changes that redistribute cold air and eliminate temperature stratification, ensuring uniform temperature distribution throughout the storage compartment.
Solution Approach 2:
The system inverts the normal air flow direction by periodically switching the fan rotation direction. Instead of always forcing air in one direction, the system reverses the flow to pull air through the carts, which redistributes the cold air more evenly and prevents localized over-cooling or under-cooling zones.
2Temperature
If a more powerful cooling system is used to maintain lower maximum temperatures, then temperature control is improved, but the system becomes heavier and consumes more electrical power
Solution Approach 1:
The reversible fan operates in periodic cycles, alternating between forward and reverse directions. This periodic operation allows the same cooling capacity to be distributed more effectively over time and space, maintaining temperature control with a smaller, more energy-efficient system rather than requiring continuous high-power cooling.
Solution Approach 2:
The system changes the flow direction parameter periodically, which optimizes the thermal distribution efficiency. This parameter change allows a smaller cooling system to achieve the same temperature control效果 as a larger system would provide with continuous unidirectional flow, reducing overall power consumption.
3Productivity
If continuous unidirectional air flow is used, then cooling efficiency is maintained, but frost buildup occurs more rapidly in the air chiller
Solution Approach 1:
The system implements periodic reversal of air flow direction through the galley carts. This periodic action prevents moisture and condensation from accumulating in the same location continuously, significantly reducing frost buildup rate in the air chiller and extending the time between defrosting cycles while maintaining cooling efficiency.
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 maintains a consistent temperature throughout the compartment, reduces the need for more powerful cooling systems, and slows down frost buildup in the air chiller, thereby improving efficiency and reducing defrosting frequency.
Implementation Method 1
an air chiller blows chilled air into the duct system
Implementation Method 2
a fan having forward and reverse settings... chilled air flows from the first chiller port into the duct system in a first airflow direction when the fan operates in the forward setting
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A refrigeration apparatus includes an air chiller including a fan, a storage enclosure defining a compartment, and a duct system. The air chiller blows chilled air into the duct system. The compartment has first and second openings, each of which is coupled to the duct system. Chilled air enters the first opening and exits the second opening, and vice versa. In one implementation, the first opening is at the top of the compartment and the second opening is at the bottom of the compartment. A control circuit may periodically cause the fan to change the direction of the chilled air flow. This effectively maintains a relatively uniform temperature throughout the compartment.