Cascade Refrigeration Control for Faster Storage Temperature Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dual refrigerating apparatuses face challenges in maintaining consistent cooling temperatures inside storage due to mismatched compressor specifications and performance variations, leading to longer times for the cascade condenser and storage temperature to reach a constant state.
Innovation Solution
A refrigerating apparatus with a first and second refrigerant circuit, each with a compressor, condenser, decompressor, and evaporator, along with sensors and controllers to adjust compressor operation based on detected temperatures, ensuring the cascade condenser and storage temperatures are maintained within predetermined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If control is made based on a single sensor detecting storage temperature, then the control system is simple, but the temperature of the cascade condenser and storage may not reach constant temperature quickly due to mismatched compressor operations
Solution Approach 1:
The patent introduces dual feedback loops: one feedback loop monitors the cascade condenser temperature and adjusts the high-temperature side compressor accordingly, while another feedback loop monitors the storage temperature and adjusts the low-temperature side compressor. This independent feedback mechanism ensures each compressor responds appropriately to its respective temperature conditions, resolving the timing mismatch problem while maintaining reasonable system complexity.
Solution Approach 2:
The control system is segmented into two independent control modules: one module controls the high-temperature side compressor based on cascade condenser temperature, and the other module controls the low-temperature side compressor based on storage temperature. This segmentation allows each compressor to be controlled independently according to its specific operational requirements, eliminating the timing mismatch that occurs with unified control.
2Ease of manufacture
If compressor specifications are made uniform, then manufacturing and maintenance are easier, but performance variations still cause mismatched operation timings
Solution Approach 1:
The patent applies local quality by implementing separate control strategies for each compressor based on their specific performance characteristics and operational conditions. Rather than requiring uniform compressor specifications, the system adapts the control parameters and response thresholds to match each compressor's actual performance, ensuring reliable temperature control despite manufacturing variations.
Solution Approach 2:
The control system dynamically adjusts compressor operations based on real-time temperature measurements and compressor performance feedback. The control parameters are not fixed but adapt to the actual operational state of each compressor, allowing the system to compensate for performance variations and maintain reliable temperature control without requiring identical compressor specifications.
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 improves controllability of storage temperatures, ensuring the cascade condenser and storage reach stable temperatures more quickly and efficiently, even with varying compressor specifications.
Implementation Method 1
an evaporator of the high-temperature side refrigerant circuit (hereinafter referred to as a high-temperature side evaporator) and a condenser of the low-temperature side refrigerant circuit (hereinafter referred to as a low-temperature side condenser) form a cascade condenser so as to mutually exchange heat
Implementation Method 2
an evaporator of the high-temperature side refrigerant circuit... form a cascade condenser so as to mutually exchange heat. As a result, the second refrigerant is condensed by a cooling effect of the high-temperature side refrigerant circuit
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A refrigerating apparatus for keeping an inside of a storage at a predetermined low-temperature state includes first and second refrigerant circuits including compressors, condensers, decompressors, and evaporators, connected circularly with pipings to form refrigerating cycles, the circuit having a first or second refrigerant sealed therein as a working refrigerant, a first sensor which detects a temperature of a cascade condenser constituted by integrating the evaporator of the first refrigerant circuit and the condenser of the second refrigerant circuit in a heat exchangeable manner, a first controller which controls an operation performance of the first compressor in a variable manner based on a first-sensor-detected temperature in order that the first-sensor-detected temperature is a first temperature, a second sensor which detects a temperature inside the storage, and a second controller which controls an operation performance of the second compressor in a variable manner based on a second-sensor-detected temperature in order that the second-sensor-detected temperature is a second temperature.