Cooling system
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Solution Overview
Problem
Existing refrigeration systems for transportable containers are not energy-efficient, as they rely on internal combustion engines or direct electrical feeding from vehicle networks, leading to excessive energy consumption.
Innovation Solution
A control unit adjusts the speed of the internal combustion engine and compressor motor to match the required refrigeration capacity, using a three-phase generator and compressor motor with speed-proportional operation, and converter units to optimize energy usage within specific cooling capacity ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the combustion engine is operated at high speed to provide sufficient electrical power for the cooling system, then the power supply is adequate, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts the combustion engine speed based on actual cooling requirements. The control unit monitors the cooling demand and regulates the engine speed accordingly, allowing the system to transition from static high-speed operation to dynamic speed matching, thereby reducing energy consumption while maintaining adequate power supply.
Solution Approach 2:
The invention changes the operating parameter (engine speed) from a fixed high value to a variable value that adapts to cooling demands. By implementing continuous speed regulation through the control unit and motor controller, the system optimizes the balance between power supply and energy consumption.
2Ease of operation
If the compressor motor speed is fixed, then the system is simple to operate, but the cooling capacity cannot be continuously adjusted to match actual requirements
Solution Approach 1:
The system transforms the compressor motor from a fixed-speed device to a variable-speed device through the integration of an inverter and control unit. This allows continuous adjustment of cooling capacity while maintaining ease of operation through automated control, resolving the contradiction between operational simplicity and adaptability.
Solution Approach 2:
The control unit implements feedback control by monitoring cooling requirements and automatically adjusting the compressor motor speed via the inverter. This closed-loop control system maintains simplicity of operation while achieving continuous adaptability of cooling capacity.
3Device complexity
If the generator and compressor motor operate at the same speed, then the system configuration is simple, but the system cannot optimize performance across different cooling capacity ranges
Solution Approach 1:
The system introduces dynamic speed ratio adjustment between the generator and compressor motor through the inverter control. Instead of maintaining a fixed 1:1 speed relationship, the system can dynamically optimize the speed ratio according to different operating conditions and cooling capacity ranges, improving overall productivity while managing complexity through electronic control.
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 allows for continuous adjustment of refrigeration capacity, reducing energy consumption by operating the system only as needed, and maintaining efficiency across varying cooling demands.
Implementation Method 1
a three-phase generator and compressor motor with speed-proportional operation
Implementation Method 2
a refrigeration circuit in which a refrigerant compressor, a high-pressure side heat exchanger, an expansion unit and a low-pressure side heat exchanger are arranged
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A refrigeration system (20), in particular for transport refrigeration, comprising a refrigeration circuit in which a refrigerant compressor (24), a high-pressure-side heat exchanger (26), an expansion unit (30) and a low-pressure-side heat exchanger (32) are arranged, an electric compressor motor ( 82) for driving the refrigerant compressor (24) and a control unit (110) for controlling a refrigeration capacity of the refrigeration circuit in such a way that it works as energy-saving as possible, it is proposed that the refrigeration system have a generator (76) for feeding electrical power into an internal electrical network (80) of the cooling system, from which the compressor motor (82) is fed, and that an internal combustion engine (74) is provided for driving the generator (76).