Transport refrigeration unit and control method
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air-cargo transport refrigeration units with simple non-adaptive control systems often result in sub-optimal performance due to inefficient or ineffective cooling, as they maintain constant speed operation of refrigeration components regardless of changing conditions.
Innovation Solution
A method involving a control loop that regulates compressor and condenser fan speeds based on temperature and discharge pressure monitoring, adjusting speeds to maintain a threshold temperature decrease rate and optimize refrigeration cycle performance, including adaptive adjustments during in-flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If constant speed operation of refrigeration components is used, then device complexity is reduced and ease of operation is improved, but cooling efficiency and effectiveness deteriorate
Solution Approach 1:
The patent applies dynamics by transitioning from constant speed operation to variable speed operation of the compressor and condenser fan. The compressor speed is regulated based on the rate of temperature decrease in the cargo hold, and the condenser fan speed is regulated based on discharge pressure, allowing the system to adapt to changing thermal conditions and optimize cooling efficiency.
Solution Approach 2:
The patent changes the operating parameters of the refrigeration components by regulating compressor speed according to temperature decrease rate and condenser fan speed according to discharge pressure. This parameter adjustment enables the system to maintain optimal performance across varying operational conditions rather than operating at fixed speeds.
2Device complexity
If constant speed operation of refrigeration components is used, then device complexity is reduced, but cooling effectiveness deteriorates
Solution Approach 1:
The patent implements feedback control by continuously monitoring the temperature in the cargo hold and discharge pressure, then using this information to regulate compressor and condenser fan speeds. This closed-loop feedback ensures the system responds to actual thermal conditions, maintaining reliable and effective cooling performance.
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 approach enhances the efficiency and effectiveness of the refrigeration process by dynamically adjusting compressor and condenser fan speeds, improving cooling capacity and reducing wear on components, while maintaining stability and reliability.
Implementation Method 1
a refrigeration cycle comprising a compressor
Implementation Method 2
a condenser for rejecting heat to ambient air
Implementation Method 3
a condenser for rejecting heat to ambient air
Implementation Method 4
an evaporator for cooling the internal cargo space
Implementation Method 5
an evaporator for cooling the internal cargo space
Data Source
AI summary
A method of controlling an air-cargo transport refrigeration unit to regulate a compressor speed and a condenser fan speed is provided. Also, a method of controlling an air-cargo transport refrigeration unit based on determining an in-flight condition of the refrigeration unit is provided.