Cargo Thermal Mass Modeling for Refrigeration Unit Control
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Solution Overview
Problem
Current air temperature sensors in cold chain distribution systems fail to accurately monitor cargo temperatures at the surface or within the cargo, leading to inefficient control of refrigeration systems and potential damage to temperature-sensitive goods.
Innovation Solution
A refrigeration system with temperature sensors associated with the cargo, either adjacent or embedded, that provides temperature data to a controller to model the thermal mass characteristics, allowing for optimized control of the refrigeration unit based on user-set temperature points and feedback from additional sensors like air temperature, fuel level, and sun load sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air temperature sensors are used to monitor conditions in cold chain distribution systems, then the system can detect air temperature, but the sensor readings do not accurately reflect actual cargo temperatures at the surface or within the cargo
Solution Approach 1:
The patent divides the temperature monitoring function into multiple segments: air temperature sensors monitor ambient conditions, while cargo surface and embedded sensors directly measure cargo temperature. This segmentation allows each sensor type to perform its specialized function, with the controller integrating data from all sources to achieve accurate cargo temperature measurement.
Solution Approach 2:
The controller acts as an intermediary that receives temperature data from air temperature sensors, cargo surface sensors, and embedded sensors. It processes this information and uses thermal mass modeling to estimate cargo core temperature, thereby mediating between direct measurements and inferred temperature values to provide comprehensive temperature information.
2Productivity
If refrigeration systems operate without accurate cargo temperature data, then the system structure remains simple, but the control efficiency and cargo protection are compromised
Solution Approach 1:
The system implements feedback control by continuously monitoring cargo temperature through embedded sensors and comparing actual temperatures with desired setpoints. The controller adjusts refrigeration unit operation based on this feedback, ensuring reliable temperature control while optimizing energy consumption and preventing cargo damage.
Solution Approach 2:
The controller uses thermal mass modeling to predict future cargo temperature trends based on current conditions and refrigeration unit operation. This preliminary action allows the system to anticipate temperature changes and adjust refrigeration capacity in advance, improving control efficiency and reliability without excessive refrigeration cycling.
3Measurement precision
If temperature sensors are embedded in the cargo, then accurate cargo temperature measurement is achieved, but the system complexity and sensor installation requirements increase
Solution Approach 1:
The patent applies local quality by placing temperature sensors at specific locations within the cargo based on its thermal characteristics. Rather than uniformly distributing sensors throughout, the system strategically positions embedded sensors in locations that provide the most informative data about cargo core temperature, reducing the overall number of sensors needed while maintaining measurement accuracy.
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 temperature control within cargo containers, optimizing refrigeration operations, conserving fuel, and preventing damage to perishable goods by accurately measuring and responding to cargo temperatures, thereby enhancing the efficiency and reliability of cold chain distribution.
Implementation Method 1
at least one temperature sensor associated with the cargo to provide at least one temperature associated with the thermal mass
Implementation Method 2
the controller models a temperature characteristic of the thermal mass
Implementation Method 3
a refrigeration unit associated with the volume... controlling the refrigeration unit in response to the at least one temperature associated with the thermal mass and a temperature set point
Data Source
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AI summary
A method and system for use with a volume containing a cargo (30) having a thernal mass includes, at least one temperature sensor (50) associated with the cargo to provide at least one temperature associated with the thermal mass, a refrigeration unit (40) associated with the volume, and a controller (60) to control the refrigeration unit (40) in response to the at least one temperature associated with the thermal mass and a temperature set point, wherein the controller (60) models a temperature characteristic of the thermal mass.