Refrigeration system for transportation
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Solution Overview
Problem
Existing sub-engine type refrigeration systems for transportation do not effectively maintain high generation efficiency and energy efficiency due to variations in power consumption on the chiller side, as they rely on battery charging and discharging without active control of secondary batteries.
Innovation Solution
A sub-engine type refrigeration system that includes an AC generator and a secondary battery, where a control unit manages the battery's state of charge to maintain a consistently high load factor for the AC generator, stopping the engine when the battery is fully charged and starting power generation when it is not, ensuring the AC generator operates at a rated load and drives the chiller's electric load efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the sub engine operates continuously to charge the battery, then the battery charge level is maintained, but the energy efficiency deteriorates due to unnecessary engine operation
Solution Approach 1:
The control unit continuously monitors the battery's state of charge and dynamically adjusts engine operation based on real-time feedback. When the battery charge level is sufficient, the engine is stopped; when the charge level drops below a threshold, the engine starts to recharge. This closed-loop feedback control eliminates unnecessary engine operation while maintaining reliable battery charge levels.
Solution Approach 2:
The system transitions from static engine operation (continuous running) to dynamic operation (on-demand starting and stopping). The engine operates in discrete states based on battery charge conditions, adapting its behavior to system needs rather than maintaining constant operation, thereby improving energy efficiency.
2Adaptability or versatility
If the AC generator operates at variable load to match chiller power consumption, then the adaptability to load variations is improved, but the generation efficiency deteriorates due to operation away from rated load
Solution Approach 1:
The battery serves as an intermediary energy storage device between the AC generator and the chiller load. The generator operates at constant rated load to produce power, and the battery absorbs or supplies power to match load variations. This mediator allows the generator to maintain optimal efficiency while the system adapts to varying power consumption requirements.
Solution Approach 2:
The system changes the operating parameter of the AC generator from variable load to constant rated load. By fixing the generator's operating point at its most efficient rated condition and using battery charge/discharge to handle load variations, the system maintains high generation efficiency while adapting to changing power demands.
3Loss of energy
If the engine is stopped to improve energy efficiency, then the energy consumption is reduced, but the reliability of power supply deteriorates when external power is unavailable
Solution Approach 1:
The battery is pre-charged by the AC generator during periods when external power is available or when the chiller load is low. This preliminary energy storage ensures that sufficient power is available when the engine is stopped, maintaining power supply reliability without requiring continuous engine operation.
Solution Approach 2:
The system uses its own AC generator and battery to provide power when external power is unavailable, rather than relying continuously on the engine. The battery serves the system's own power needs, enabling the engine to be stopped while maintaining reliable operation through self-sufficient power supply.
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 configuration significantly improves energy efficiency by minimizing engine and AC generator operation ratios, maintaining high generation efficiency, and allowing the system to operate efficiently even when the engine and AC generator are stopped, using external power when available, and switching to battery power when necessary.
Implementation Method 1
a secondary battery (8) which is capable of storing the power generated by the AC generator (3)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Sub-engine type refrigeration system for transportation 1 that drives all or part of a chiller's electric load 7 by power generated by an AC generator 3, including a secondary battery 8 which is capable of storing power generated by the AC generator 3, and a control unit 12 which controls so that, when a state of charge of the secondary battery 8 is at or above a control lower limit value, an engine 2 is stopped and a chiller's electric load 7 is driven by power of the secondary battery 8, and when the state of charge of the secondary battery 8 is below the control lower limit value while the chiller's electric load 7 is driven by the power of the secondary battery 8, the engine 2 is operated and the AC generator 3 starts power generation.