Hybrid refrigeration system, control method thereof and transportation refrigeration vehicle
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Solution Overview
Problem
Existing refrigeration systems in transportation vehicles require large mechanical refrigeration devices with high power requirements, making them heavy and costly, and liquid nitrogen systems are expensive and unsuitable for long-distance transportation.
Innovation Solution
A hybrid refrigeration system combining a liquid nitrogen-based refrigeration device and a mechanical refrigeration device, controlled by a system that determines the need for each based on temperature thresholds, allowing for efficient temperature regulation and reducing the capacity and weight of mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a mechanical refrigeration device with large refrigeration capacity is used to quickly reduce cargo box temperature, then the cooling speed is improved, but the device volume and weight increase
Solution Approach 1:
The refrigeration system is divided into two independent parts: a liquid nitrogen refrigeration device for rapid cooling and a mechanical refrigeration device for temperature maintenance. This segmentation allows each device to be optimized for its specific function, enabling the mechanical device to be smaller and lighter since it only needs to handle temperature maintenance rather than rapid cooling.
Solution Approach 2:
Liquid nitrogen is introduced as an intermediary substance to perform the rapid cooling function. The liquid nitrogen refrigeration device uses liquid nitrogen evaporation to quickly reduce cargo box temperature, allowing the mechanical refrigeration device to be downsized since it no longer needs to provide large refrigeration capacity for initial cooling.
2Speed
If a liquid nitrogen refrigeration system is used to achieve rapid cooling, then the cooling speed is improved, but the system cost increases
Solution Approach 1:
The system merges liquid nitrogen refrigeration and mechanical refrigeration into a hybrid system that leverages the advantages of both approaches. Liquid nitrogen provides rapid cooling when needed, while the mechanical refrigeration device handles routine temperature maintenance, reducing overall system cost compared to using liquid nitrogen exclusively for all cooling needs.
Solution Approach 2:
Instead of using liquid nitrogen continuously or for all cooling requirements, the system applies liquid nitrogen only when rapid cooling is needed (when temperature difference exceeds the threshold). This partial use of liquid nitrogen reduces cost while maintaining the rapid cooling capability when necessary.
3Power
If a mechanical refrigeration device with large capacity is used, then the refrigeration capacity is improved, but the energy consumption and vehicle range are reduced
Solution Approach 1:
The refrigeration function is segmented between liquid nitrogen evaporation (for rapid cooling) and mechanical refrigeration (for temperature maintenance). This allows the mechanical refrigeration device to operate at lower capacity, reducing energy consumption from combustion engines or lithium batteries while maintaining adequate refrigeration capability.
Solution Approach 2:
The liquid nitrogen refrigeration device replaces the need for a large-capacity mechanical refrigeration system. By using liquid nitrogen evaporation for rapid cooling, the mechanical refrigeration device can be smaller and consume less energy, thereby extending vehicle range.
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
The hybrid system enables rapid cooling with liquid nitrogen and reduces the weight and volume of mechanical refrigeration devices, optimizing energy use and extending vehicle range by minimizing the mechanical refrigeration system's capacity and weight.
Implementation Method 1
the first refrigeration device regulates the temperature of the cargo box by converting liquid nitrogen into nitrogen gas
Implementation Method 2
transporting it to the cargo box
Implementation Method 3
the second refrigeration device comprises a compressor
Implementation Method 4
the second refrigeration device comprises a condenser
Implementation Method 5
the second refrigeration device comprises a throttling device
Implementation Method 6
the second refrigeration device comprises a second cargo box heat exchanger
Data Source
AI summary
A hybrid refrigeration system comprises: a liquid nitrogen based first refrigeration device for regulating the temperature of a cargo box of a transportation refrigeration vehicle; a mechanical based second refrigeration device for regulating the temperature of the cargo box of the transportation refrigeration vehicle; and a controller connected to the first refrigeration device and the second refrigeration device; wherein, the controller is configured to determine whether the difference between the temperature of the cargo box and the set temperature is greater than or equal to a first threshold when receiving a refrigeration demand for the cargo box; if so, start the first refrigeration device alone or start both the first refrigeration device and the second refrigeration device simultaneously; and if not, start the second refrigeration device alone.