Multi-compartment transport refrigeration system
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Solution Overview
Problem
Conventional transport refrigeration systems face challenges in maintaining precise temperature control and efficiency, particularly in multi-compartment refrigerated containers, where varying temperature demands and icing issues affect the performance of refrigeration units.
Innovation Solution
A multi-compartment transport refrigeration system incorporating a cooling circuit with a hot gas flow path and a proportional valve, allowing for controlled hot gas flow to manage temperature and defrosting across compartments, regulated by a controller to optimize energy usage and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional refrigeration system with main evaporator and remote evaporators is used in multi-compartment containers, then the system can provide cooling to multiple compartments, but the system cannot efficiently provide heating or defrosting capabilities
Solution Approach 1:
The evaporators are designed to perform multiple functions: cooling, heating, and defrosting. The hot gas flow path enables evaporators to provide heating by routing hot refrigerant gas through them, while the cooling function is achieved through normal refrigeration cycle operation. This multi-functionality eliminates the need for separate heating systems.
Solution Approach 2:
A hot gas flow path with proportional valves acts as an intermediary system to redirect hot refrigerant gas to evaporators when heating or defrosting is required. This intermediary mechanism allows the same evaporators to serve dual purposes without requiring separate heating equipment.
2Adaptability or versatility
If remote evaporators are operated independently with individual valves, then each compartment can be cooled according to its specific demand, but the system cannot efficiently manage simultaneous cooling and heating requirements
Solution Approach 1:
The system dynamically adjusts the operation of each evaporator based on real-time temperature demands. The controller monitors compartment temperatures and activates or deactivates evaporators as needed, allowing the system to adapt to varying cooling and heating requirements across different compartments.
Solution Approach 2:
The proportional valves in the hot gas flow path allow for continuous adjustment of hot gas flow distribution to different evaporators. This enables precise control over the amount of heating provided to each compartment, optimizing energy efficiency by matching heating output to actual demand.
3Stability of the object's composition
If evaporators operate continuously to maintain temperature, then temperature stability is achieved, but icing occurs on evaporators decreasing system efficiency
Solution Approach 1:
The system implements periodic defrosting cycles where hot gas is routed through evaporators to melt accumulated ice. This periodic action maintains temperature stability during normal operation while periodically removing ice buildup that would otherwise decrease heat transfer efficiency and increase energy consumption.
Solution Approach 2:
The hot gas flow path converts the waste heat from the refrigeration cycle into a useful defrosting function. By routing hot refrigerant gas through evaporators during defrost cycles, the system uses otherwise wasted thermal energy to remove ice buildup, improving overall system efficiency.
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 temperature control, allowing simultaneous cooling and heating of compartments, defrosting, and improved energy efficiency by regulating hot gas flow, thus addressing the inefficiencies and temperature variability challenges in conventional systems.
Implementation Method 1
a hot gas flow path having an inlet located on the cooling circuit between the compressor and the heat rejection heat exchanger valve
Implementation Method 2
a proportional valve downstream of the hot gas flow path inlet; a first evaporator valve located downstream of the proportional valve
Implementation Method 3
a heat rejection heat exchanger valve downstream of the compressor discharge port; a heat rejection heat exchanger downstream of the heat rejection heat exchanger valve
Implementation Method 4
a first evaporator having an inlet coupled to the first evaporator expansion device and an outlet coupled to a compressor inlet path
Implementation Method 5
a first evaporator expansion device downstream of the heat rejection heat exchanger; a second evaporator expansion device downstream of the heat rejection heat exchanger
Implementation Method 6
allowing for controlled hot gas flow to manage temperature and defrosting across compartments
Data Source
AI summary
A multi-compartment transport refrigeration system includes a cooling circuit and a hot gas flow path. The hot gas flow path includes an inlet located on the cooling circuit between the compressor and the heat rejection heat exchanger valve; a first outlet located between the first evaporator expansion device and the first evaporator inlet; a second outlet located between the second evaporator expansion device and the second evaporator inlet; a proportional valve downstream of the hot gas flow path inlet; a first evaporator valve located between the proportional valve and the first outlet; and a second evaporator valve located between the proportional valve and the second outlet.