Multiple stage refrigeration system and control method thereof
Find Innovative SolutionsGenerate Solutions
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 an economizer branch and bypass branch, allowing switching between multi-stage and single-stage refrigeration modes, utilizing control valves to manage refrigerant flow and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-stage refrigeration mode is used under severe working conditions with small temperature difference and high cooling capacity demand, then refrigeration efficiency is improved, but evaporator over-drying occurs and system reliability deteriorates
Solution Approach 1:
The system dynamically switches between multi-stage refrigeration mode and single-stage refrigeration mode based on working conditions. When severe working conditions are detected (small temperature difference and high cooling capacity demand), the system switches to single-stage mode to prevent evaporator over-drying, thereby maintaining system reliability while preserving the ability to achieve high refrigeration efficiency under normal conditions
Solution Approach 2:
The system changes operational parameters by switching between different refrigeration modes. The control method monitors working conditions and adjusts the refrigeration mode accordingly, changing the system's operational state from multi-stage to single-stage or vice versa, thereby adapting to different working conditions and preventing evaporator over-drying
2Productivity
If multi-stage refrigeration system operates under full load for long time, then cooling capacity is maintained, but temperature difference between condenser and evaporator decreases leading to evaporator over-drying
Solution Approach 1:
The system takes preliminary action by monitoring working conditions and switching to single-stage refrigeration mode before evaporator over-drying occurs. The control method detects severe working conditions (small temperature difference and high cooling capacity demand) and proactively switches modes to prevent the harmful effect of evaporator over-drying, rather than waiting for the problem to manifest
Solution Approach 2:
The system dynamically adjusts its operational mode based on real-time working conditions. When operating under full load for extended periods, the system can switch from multi-stage to single-stage mode to maintain adequate temperature difference and prevent evaporator over-drying, thereby sustaining cooling capacity without causing harmful effects
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 system adaptability and stability by efficiently operating in both conventional and severe conditions, preventing evaporator over-drying and maintaining high cooling capacity.
Implementation Method 1
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
Implementation Method 2
a condenser, a first throttling element, an evaporator and an exhaust port of the multi-stage compressor which are sequentially connected through pipelines
Implementation Method 3
an evaporator and an exhaust port of the multi-stage compressor which are sequentially connected through pipelines
Data Source
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.