Multiple stage refrigeration system
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Solution Overview
Problem
Multi-stage refrigeration systems face adaptability issues under severe working conditions with a small temperature difference and high cooling capacity demand, leading to evaporator over-drying and system shutdown.
Innovation Solution
A multi-stage refrigeration system with a refrigeration loop, economizer branch, and bypass branch that allows switching between multi-stage and single-stage refrigeration modes, using control valves to manage refrigerant flow and temperature, ensuring efficient operation across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-stage refrigeration system operates under full load for a long time, then refrigeration capacity is maintained, but evaporator becomes over-dry and system shuts down
Solution Approach 1:
The system dynamically switches between multi-stage refrigeration mode and single-stage refrigeration mode based on real-time detection of working conditions (temperature difference between condenser and evaporator, refrigerant flow rate). When the temperature difference falls below a threshold indicating severe working conditions, the system transitions from multi-stage to single-stage mode, adjusting refrigerant flow dynamically to prevent evaporator over-drying while maintaining refrigeration capacity.
2Productivity
If multi-stage refrigeration system operates with small temperature difference, then cooling capacity is maintained, but evaporator over-drying occurs
Solution Approach 1:
The refrigeration system is designed to perform multiple functions through a single integrated system that can operate in both multi-stage and single-stage modes. The same refrigeration loop, compressor, condenser, and evaporator serve dual purposes: high-efficiency multi-stage operation under normal conditions and adaptive single-stage operation under severe conditions with small temperature differences, enhancing the system's versatility and adaptability.
3Productivity
If refrigerant flow rate is increased to meet high cooling demand, then cooling capacity is improved, but pressure difference between condenser and evaporator decreases
Solution Approach 1:
The system dynamically adjusts refrigerant flow rate based on detected working conditions. When severe conditions are detected (small temperature difference between condenser and evaporator), the system reduces refrigerant flow rate by switching from multi-stage to single-stage mode, thereby maintaining adequate pressure difference across the evaporator while still meeting cooling demands through optimized single-stage operation.
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
Enhances adaptability and stability by maintaining operation under severe conditions, preventing system shutdown and ensuring continuous cooling capacity through mode switching based on temperature and pressure parameters.
Implementation Method 1
a refrigeration loop 110, an economizer branch 120 and a bypass branch 130 which are used for providing a multi-stage refrigeration working cycle
Implementation Method 2
an outflow water temperature of cooling water at the position of an evaporator is relatively high while an outflow water temperature of cooling water at the position of a condenser is relatively low
Data Source
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AI summary
A multi-stage refrigeration system (100) includes: a refrigeration loop (110), which includes a gas suction port of a multi-stage compressor (111), a condenser (112), a first throttling element (113), an evaporator (114) and an exhaust port of the multi-stage compressor which are sequentially connected through pipelines; an economizer branch (120), which includes an economizer (121), a second throttling element (122) and a first control valve (123), the economizer having an economizer liquid inlet connected to the condenser via the first throttling element, an economizer liquid outlet connected to the evaporator via the second throttling element, and an economizer exhaust port connected to an intermediate stage of the multi-stage compressor via a control valve; and a bypass branch (130), which is joined to the evaporator from the downstream of the second throttling element and connected to the condenser via the first throttling element, and on which a second control valve (131) is arranged.