Refrigeration system and control method therefor
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Solution Overview
Problem
Large-scale refrigeration equipment with two-stage or three-stage centrifugal compressors experiences severe flow separation, leading to significant pressure pulsation, noise, and vibration when operating below design load, affecting user experience.
Innovation Solution
A refrigeration system with a liquid injection branch connected from a high-pressure liquid-phase refrigerant section between the condenser and economizer to the intermediate stage gas inlet of the compressor, equipped with a liquid injection valve that turns on when vibration or noise exceeds preset values, introducing liquid-phase refrigerant in droplet form to absorb sound wave energy and reduce pulsation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inlet guide vane opening is reduced to operate below design load, then the refrigeration capacity is reduced, but severe flow separation occurs causing high pressure pulsation and noise
Solution Approach 1:
The patent introduces an intermediary substance (liquid refrigerant) into the compressor's intermediate stage to act as a mediator that absorbs pressure pulsations and reduces noise. The liquid refrigerant injection system serves as an intermediary mechanism between the harmful pressure pulsations and the compressor structure, converting the harmful acoustic energy into useful refrigeration effect through evaporation.
Solution Approach 2:
The patent changes the physical state parameter of the refrigerant by injecting liquid refrigerant into the intermediate stage. This parameter change (from gas phase to liquid phase) allows the refrigerant to absorb pressure pulsations more effectively and reduces noise while maintaining refrigeration capacity below design load.
2Object-affected harmful factors
If liquid injection branch is activated to reduce noise and vibration, then noise and vibration are reduced, but system complexity increases
Solution Approach 1:
The liquid injection branch serves multiple functions: it reduces noise and vibration while simultaneously providing additional refrigeration capacity. This multi-functionality reduces the need for separate noise control devices, thereby limiting the increase in system complexity.
Solution Approach 2:
The injected liquid refrigerant serves itself by evaporating in the intermediate stage, automatically absorbing pressure pulsations and reducing noise without requiring external control mechanisms. The system self-regulates the noise reduction effect through the natural evaporation process.
3Object-affected harmful factors
If liquid-phase refrigerant is injected into the intermediate stage, then sound wave energy is absorbed reducing noise, but energy efficiency may be affected
Solution Approach 1:
The patent converts the harmful sound wave energy and pressure pulsations into beneficial refrigeration effect. The liquid refrigerant absorbs the acoustic energy through evaporation, transforming the harmful noise into useful cooling, thereby improving overall energy efficiency while reducing noise.
Solution Approach 2:
The patent utilizes the phase transition of refrigerant from liquid to vapor in the intermediate stage. This phase transition process absorbs the sound wave energy and pressure pulsations while providing refrigeration, effectively converting noise into beneficial cooling effect.
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
Effectively reduces noise and vibration by absorbing sound wave energy, improving user experience and system operation while maintaining energy efficiency by only activating the liquid injection branch when necessary.
Implementation Method 1
The liquid-phase refrigerant in the form of droplets can effectively absorb the sound wave energy in the compressor pipeline, thereby reducing the overall discharge pulsation of the compressor and eventually reducing the noise and vibration of the condenser
Implementation Method 2
the liquid injection branch is configured such that the liquid-phase refrigerant enters the intermediate stage gas inlet of the multi-stage compressor in the form of droplets
Data Source
Figure 1
Figure 2
AI summary
The present application provides a refrigeration system (100) and a control method therefor. The refrigeration system includes: a main circuit (110) configured to connect, through a pipeline, to a multi-stage compressor (111), a condenser (112), an economizer (113), a main throttling element, and an evaporator (115); an air supply branch (120) configured to connect, through a pipeline, to the air outlet of the economizer (113) and the intermediate stage air inlet of the multi-stage compressor (111); and a liquid injection branch (130) configured to connect to the intermediate stage air inlet of the multi-stage compressor (111) from a section having a high-pressure liquid-phase refrigerant in the main circuit (110).