Refrigeration device
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Solution Overview
Problem
Conventional refrigeration apparatuses face challenges in rapidly returning the internal temperature of a storage space to a target value when the temperature rises, leading to inefficiencies and energy waste due to heat transmission delays and unnecessary compressor speed fluctuations.
Innovation Solution
A refrigeration apparatus with a cascade cycle configuration, including a first and second cooling section, a storage section, and a control system that determines the rotation speeds of compressors based on temperature sensors to efficiently manage refrigerant flow and heat exchange, allowing for rapid temperature recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the internal temperature rises and the conventional control system activates the compressors, then the storage space temperature begins to decrease, but the temperature recovery is slow due to heat transmission delays and unnecessary compressor speed fluctuations
Solution Approach 1:
The patent implements dynamic control of compressor rotation speeds based on real-time temperature deviations. The control section adjusts the rotation speeds of the first and second compressors dynamically according to the magnitude of temperature rise, enabling faster temperature recovery while avoiding unnecessary fluctuations. This dynamic adjustment allows the system to respond aggressively to large deviations and smoothly to small deviations, resolving the contradiction between recovery speed and time loss.
Solution Approach 2:
The control section continuously monitors the internal temperature via the internal temperature sensor and uses this feedback to adjust compressor operations. When the internal temperature rises above the target value, the control section calculates appropriate rotation speeds for both compressors based on the temperature deviation magnitude and supplies power accordingly. This closed-loop feedback mechanism eliminates heat transmission delays by immediately responding to temperature changes, thereby improving temperature recovery speed while reducing the time to return to target temperature.
2Speed
If the compressors operate at high speed to rapidly cool the storage space, then the temperature recovery speed increases, but energy consumption increases
Solution Approach 1:
The control section dynamically adjusts compressor rotation speeds based on the magnitude of temperature deviation from the target value. When the internal temperature rises significantly, both compressors operate at higher rotation speeds to provide rapid cooling. As the temperature approaches the target value, the rotation speeds are reduced to maintain efficiency. This dynamic speed adjustment enables fast temperature recovery when needed while minimizing energy consumption during normal operation, resolving the contradiction between recovery speed and energy use.
Solution Approach 2:
The system changes the operating parameters (rotation speeds) of the compressors based on the temperature condition. The control section determines optimal rotation speeds for the first and second compressors according to the internal temperature deviation, and the power supply sections adjust the electrical parameters accordingly. This parameter change strategy allows the system to achieve high temperature recovery speed only when necessary, thereby reducing overall energy consumption while maintaining effective temperature control.
3Device complexity
If the conventional control system uses sequential compressor activation, then the system complexity is reduced, but the temperature control precision and recovery efficiency deteriorate
Solution Approach 1:
The control system is segmented into two coordinated control loops: one for the first compressor (high-temperature side) and one for the second compressor (low-temperature side). The control section independently determines the rotation speed of each compressor based on the internal temperature deviation, allowing precise control of both the evaporator and cascade condenser temperatures. This segmentation enables simultaneous optimization of both cooling stages, improving temperature control precision and recovery efficiency while maintaining manageable system complexity through modular control logic.
Solution Approach 2:
The control section performs multiple functions simultaneously: it monitors internal temperature, calculates required cooling capacity, determines rotation speeds for both compressors, and coordinates their operation. The first and second compressors work together in a unified control framework where both contribute to temperature recovery based on real-time conditions. This multi-functional control approach achieves superior temperature control precision compared to sequential activation while keeping the control system integrated and relatively simple.
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 apparatus effectively and efficiently returns the storage space temperature to the target value quickly, reducing energy waste by optimizing compressor operations and heat management.
Implementation Method 1
a first evaporator that evaporates the low-temperature and low-pressure first refrigerant discharged from the first expander
Implementation Method 2
a second rear stage condenser that constitutes a cascade condenser in cooperation with the first evaporator
Implementation Method 3
a second evaporator that evaporates the low-temperature and low-pressure second refrigerant discharged from the second expander, and a storage space for a cooling target cooled by the second evaporator
Implementation Method 4
a first compressor that compresses the sucked first refrigerant, and discharges high-temperature and high-pressure gas refrigerant
Data Source
AI summary
A refrigeration device equipped with: a cascade cycle; a storage unit having a storage space for an object to be cooled by a second evaporator; an internal temperature sensor that detects the temperature of the storage space; a control unit that determines a second rotational speed of a second compressor on the basis of a target temperature for the storage space and the detection result from the internal temperature sensor, and that determines a first rotational speed for a first compressor having a prescribed correspondence relationship with the second rotational speed; and a first power supply unit and a second power supply unit that supply power respectively to the first compressor and the second compressor on the basis of the first rotational speed and the second rotational speed determined by the control unit.