Multi-Zone Transport Refrigeration with Variable Airflow Control
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Solution Overview
Problem
Existing transport refrigeration systems struggle to efficiently control temperature in multiple zones of a refrigerated transport unit, leading to suboptimal air circulation and heat transfer.
Innovation Solution
A transport refrigeration system with a controller that determines a variable target flow rate for return air in each zone based on monitored parameters such as zone dimensions and operating status, using a motor to drive a variable speed air mover to maintain the target flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a refrigeration circuit with evaporators and air movers is used to control temperature in multiple zones, then temperature control capability is improved, but device complexity increases due to the need for multiple components and control systems
Solution Approach 1:
The interior space is divided into multiple zones, each with its own evaporator and air mover, allowing independent temperature control for different cargo requirements. This segmentation enables precise temperature management while maintaining modular system architecture.
Solution Approach 2:
Variable speed air movers are used instead of fixed speed units, allowing dynamic adjustment of airflow rates based on real-time temperature requirements and zone configurations. This dynamic control optimizes temperature maintenance while reducing energy consumption during steady-state operation.
2Productivity
If variable speed air movers are used to optimize airflow in each zone, then temperature maintenance efficiency is improved, but device complexity increases due to variable speed motors and control systems
Solution Approach 1:
Temperature sensors in each zone provide feedback to the controller, which adjusts air mover speeds to maintain target temperatures. This closed-loop control ensures optimal temperature maintenance while adapting to changing thermal loads and zone configurations.
Solution Approach 2:
The system varies operational parameters such as air mover speed and airflow rate based on temperature deviations, zone volume, and cargo thermal characteristics. These parameter adjustments optimize cooling efficiency without requiring complex mechanical modifications.
3Measurement precision
If airflow rate is increased to improve heat transfer and temperature control, then temperature control precision is improved, but energy consumption increases
Solution Approach 1:
Airflow rates are dynamically adjusted based on real-time temperature requirements, zone configurations, and thermal loads. High airflow is applied only when needed for temperature correction, while lower airflow maintains steady-state conditions, optimizing the balance between control precision and energy consumption.
Solution Approach 2:
The system uses periodic temperature monitoring and intermittent airflow adjustment rather than continuous high-speed operation. Air movers are cycled or modulated to provide temperature corrections only when deviations occur, reducing overall energy consumption while maintaining temperature precision.
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 enables precise control of airflow and heat transfer in each zone, optimizing temperature maintenance and reducing power consumption by ensuring suitable air circulation based on zone configurations and operating conditions.
Implementation Method 1
the refrigeration circuit comprises a respective evaporator and a variable speed air mover driven by a motor, the air mover being configured to circulate a flow of return air from the respective zone past the evaporator
Data Source
AI summary
The present disclosure provides a transport refrigeration system for a refrigerated transport unit having an interior space comprising two or more zones. The system includes: a refrigeration circuit configured for temperature control of the zones and a controller. For each of the zones: the refrigeration circuit comprises a respective evaporator and a variable speed air mover driven by a motor. The controller is configured to: determine a target flow rate for the return air in the respective zone; and operate the motor to maintain the target flow rate of return air in the respective zone. The target flow rate is variable, and the controller is configured to determine the target flow rate based on one or more variable parameters monitored or determined by the controller.