Turbo Refrigeration Bypass Control for Low-Refrigerant Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional turbo refrigeration units require a large amount of refrigerant, leading to inefficiencies and potential damage when liquid refrigerant is suctioned into the centrifugal compressor, causing unstable operation and refrigerant leakage.
Innovation Solution
A control device that manages the expansion valve, bypass-circuit control valve, and non-refrigerant pumps to regulate the temperature difference between the suction saturation temperature and the outlet temperature of the second non-refrigerant, reducing the amount of liquid refrigerant in the evaporator and ensuring stable operation by injecting high-pressure gas refrigerant into the suction port of the centrifugal compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large amount of refrigerant is used in the turbo refrigeration unit, then the refrigeration capacity is improved, but the device volume and refrigerant circulation amount increase
Solution Approach 1:
The patent applies parameter changes by controlling the degree of opening of the bypass-circuit control valve to regulate the flow rate of high-pressure gas refrigerant. This dynamic adjustment of flow parameters allows the system to achieve optimal refrigeration capacity with reduced refrigerant volume, resolving the contradiction between productivity and device volume.
2Duration of action of moving object
If liquid refrigerant is suctioned into the centrifugal compressor, then the refrigeration cycle continues, but the compressor is damaged and operation becomes unstable
Solution Approach 1:
The patent implements preliminary action by controlling the bypass circuit to inject high-pressure gas refrigerant into the suction port before liquid refrigerant can enter the compressor. This preventive measure ensures that only gas-phase refrigerant is suctioned, protecting the compressor from liquid damage while maintaining continuous operation.
Solution Approach 2:
The bypass circuit acts as an intermediary mechanism that introduces high-pressure gas refrigerant as a mediator between the condenser and the compressor suction port. This intermediary flow prevents liquid refrigerant from reaching the compressor, thereby protecting the compressor while allowing the refrigeration cycle to continue uninterrupted.
3Ease of operation
If the temperature difference between suction saturation temperature and outlet temperature of second non-refrigerant is not controlled, then the evaporator can operate freely, but liquid refrigerant accumulates in the evaporator
Solution Approach 1:
The patent applies feedback control by monitoring the temperature difference between the suction saturation temperature and the outlet temperature of the second non-refrigerant. Based on this feedback, the bypass-circuit control valve adjusts the flow rate of high-pressure gas refrigerant to maintain the temperature difference within an optimal range, preventing liquid refrigerant accumulation while allowing free evaporator 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
The solution reduces the amount of liquid refrigerant in the evaporator, preventing compressor damage and achieving stable operation while minimizing refrigerant leakage, thereby reducing the overall volume of the turbo refrigeration unit and the amount of circulating refrigerant.
Implementation Method 1
a bypass-circuit control valve that is provided in a bypass circuit used to inject part of the high-pressure gas refrigerant compressed by the centrifugal compressor into a suction port of the centrifugal compressor and that controls the flow rate of the high-pressure gas refrigerant
Implementation Method 2
a centrifugal compressor that compresses a refrigerant
Implementation Method 3
a condenser that condenses a high-pressure gas refrigerant through heat exchange with a first non-refrigerant supplied by a first-non-refrigerant pump
Implementation Method 4
an evaporator in which the expanded liquid refrigerant evaporates through heat exchange with a second non-refrigerant supplied by a second-non-refrigerant pump
Data Source
AI summary
An object is to provide a turbo-refrigeration-unit control device capable of achieving stable operation and reducing the amount of refrigerant. Provided is a control device for controlling a turbo refrigeration unit that includes a centrifugal compressor, a first-non-refrigerant pump for supplying a first non-refrigerant, a condenser that performs heat exchange between the first non-refrigerant and a refrigerant, an expansion valve that expands the refrigerant, a second-non-refrigerant pump for supplying a second non-refrigerant, an evaporator that performs heat exchange between the second non-refrigerant and the refrigerant, a bypass circuit that is used to inject part of the refrigerant from a discharge port of the centrifugal compressor into a suction port of the centrifugal compressor, and a bypass-circuit control valve that controls the flow rate of the refrigerant.