Cooling system and methods for cooling interior volumes of cargo trailers
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Solution Overview
Problem
Cryogenic cooling systems for refrigerated cargo trailers pose safety risks to operators due to the direct introduction of liquid nitrogen, which can lead to hazardous nitrogen levels within the trailer, necessitating improved safety and monitoring measures.
Innovation Solution
A monitoring system that includes sensors to detect environmental parameters such as temperature, pressure, and nitrogen levels, coupled with a controller to adjust the cryogenic cooling fluid distribution and provide notifications to operators, ensuring safe operating conditions and restricting access to hazardous areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If liquid nitrogen is sprayed directly into the cargo compartment for cooling, then cooling efficiency is improved, but safety risks increase due to dangerous nitrogen levels
Solution Approach 1:
The system incorporates oxygen sensors that continuously monitor the cargo compartment atmosphere and provide feedback to the controller. When oxygen levels indicate dangerous nitrogen concentrations, the controller automatically adjusts or shuts off liquid nitrogen discharge, resolving the contradiction by enabling efficient cooling while preventing hazardous conditions through real-time monitoring and automatic control.
Solution Approach 2:
The patent introduces an intermediary safety system consisting of oxygen sensors and a control unit that mediates between the cooling function and safety requirements. This intermediary layer allows the direct nitrogen spraying method to be used for efficient cooling while the monitoring system prevents dangerous nitrogen accumulation, thus resolving the contradiction between cooling efficiency and safety.
2Productivity
If direct liquid nitrogen injection is used, then defrost cycles are eliminated and drying of food is reduced, but operator safety is compromised
Solution Approach 1:
Oxygen sensors provide continuous feedback on cargo compartment atmosphere safety, enabling the system to maintain high productivity through direct nitrogen injection while automatically preventing dangerous conditions. The feedback mechanism allows the system to operate at full efficiency during normal conditions and switch to safety mode when needed.
Solution Approach 2:
The monitoring system automatically detects and responds to hazardous nitrogen levels without requiring manual intervention. The system self-regulates by controlling the liquid nitrogen discharge based on sensor readings, thereby maintaining both high productivity and operator safety through autonomous operation.
3Object-generated harmful factors
If cryogenic cooling systems are implemented, then environmental impact is reduced compared to diesel TRUs, but monitoring and safety systems are required
Solution Approach 1:
The system uses oxygen sensors and controllers to automatically monitor and control the cryogenic cooling process, ensuring safe operation. This feedback-based approach enables the environmental benefits of cryogenic cooling to be realized while managing the complexity through automated safety monitoring rather than manual procedures.
Solution Approach 2:
The patent replaces complex manual safety monitoring procedures with automated electronic sensors and control systems. This substitution manages device complexity by using reliable electronic monitoring technology rather than mechanical or manual safety systems, enabling cryogenic cooling to be implemented with acceptable complexity levels.
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 system significantly reduces health risks to operators by monitoring and controlling the cryogenic cooling fluid distribution, maintaining safe nitrogen levels, and preventing entry into potentially hazardous environments, thereby reducing operational costs and enhancing safety.
Implementation Method 1
nearly all of the potential heat energy absorption of the cooling medium is realized through direct interaction between the LN2 and the cargo
Implementation Method 2
the liquid nitrogen is sprayed within the space, air is drawn into the space
Implementation Method 3
the LN2 flows through the evaporator arrangement and is converted to gaseous nitrogen
Data Source
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AI summary
A system for controlling a temperature a within an interior volume of a cargo trailer adapted to transport perishable goods is described herein. The system includes a fluid distribution assembly and a monitoring system operatively coupled to the fluid distribution assembly for selectively channeling a flow of cryogenic cooling fluid into the cargo trailer interior volume to facilitate adjusting a temperature within the interior volume. The monitoring system includes at least one sensor for sensing an environmental parameter of the cargo trailer, and a controller coupled to the sensor and to the fluid distribution assembly. The controller is configured to receive a monitoring signal indicative of the sensed environmental parameter, determine an environmental condition of the cargo trailer as a function of the environmental parameter, and provide a notification signal if the determined environmental condition is different than a predefined environmental condition.