Multi-Zone Refrigeration Pressure Balancing for Transport Containers
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Solution Overview
Problem
Existing refrigeration systems for transport vehicles struggle to maintain multiple temperature zones within the same cargo space efficiently, often prioritizing higher temperature spaces and leading to warming in colder zones before adequate cooling can be applied.
Innovation Solution
A refrigeration system with a compressor, condenser, and evaporators for separate temperature-controlled spaces, along with an evaporator equalizer that balances suction pressures to ensure equal cooling capacity between the evaporators, allowing for simultaneous and balanced cooling of both spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single refrigeration system cools multiple temperature zones, then the system structure is simplified, but the cooling capacity distribution becomes unbalanced and colder zones warm up before adequate cooling is applied
Solution Approach 1:
The system divides the refrigeration circuit into separate circuits for different temperature zones, with dedicated evaporators and expansion devices for each zone, allowing independent control and balanced cooling capacity distribution
Solution Approach 2:
Each temperature zone is equipped with its own expansion device (thermoexpansion valve or electronic expansion valve) that can independently adjust refrigerant flow based on local cooling demands, ensuring appropriate cooling capacity for each zone's specific requirements
2Speed
If refrigerant flow is prioritized to higher temperature spaces, then those spaces cool faster, but colder spaces experience warming before adequate cooling is applied
Solution Approach 1:
Each temperature zone has its own expansion device that independently controls refrigerant flow based on local temperature and cooling demand, preventing preferential flow to higher temperature zones and ensuring colder zones receive adequate refrigerant to maintain temperature stability
Solution Approach 2:
Temperature sensors in each zone provide feedback to control systems that adjust expansion valve openings and refrigerant flow rates dynamically, ensuring that colder zones receive sufficient refrigerant flow to prevent warming while higher zones receive appropriate flow for their cooling needs
3Temperature
If separate evaporators are used for different temperature zones, then each zone can be cooled independently, but the system complexity and cost increase
Solution Approach 1:
The refrigeration system is segmented into separate circuits with dedicated evaporators for different temperature zones, allowing independent temperature control for each zone while maintaining manageable system complexity through modular circuit design
Solution Approach 2:
The system uses universal components such as electronic expansion valves and controller units that can manage multiple temperature zones through a single control system, reducing overall complexity despite having separate evaporator circuits
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 efficient and balanced cooling of multiple temperature zones, preventing warming in colder spaces and ensuring that both zones reach their set point temperatures simultaneously, thereby maintaining optimal conditions for transporting temperature-sensitive goods.
Implementation Method 1
an evaporator equalizer associated with the first evaporator to balance the suction pressures of the first and second evaporators thereby substantially equalizing the cooling capacity of the first and second evaporators
Implementation Method 2
a compressor, a condenser, a first evaporator disposed within the first temperature controlled space
Implementation Method 3
a condenser that receives the flow of refrigerant from the compressor
Data Source
AI summary
An environmentally controlled shipping container including a storage space, a first environmentally controlled space within the storage space, a second environmentally controlled space within the storage space, and a transport refrigeration unit. The transport refrigeration unit including a compressor that provides a flow of refrigerant, a condenser that receives the flow of refrigerant from the compressor, a first evaporator positioned within the first environmentally controlled space and in fluid communication with the condenser, a second evaporator positioned within the second environmentally controlled space and in fluid communication with the condenser, and a pressure regulator associated with the first evaporator. The pressure regulator selectively restricts the flow of refrigerant from the first evaporator to the compressor such that the flow of refrigerant from the first evaporator to the compressor is substantially equal to the flow of refrigerant from the second evaporator to the compressor.