Ejector refrigeration system and control method thereof
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Solution Overview
Problem
Ejector refrigeration systems face challenges in mode switching due to large pressure differences across throttling elements and complex control logic requiring multiple valves, which complicates operation and reduces reliability.
Innovation Solution
The system incorporates a three-way valve and second throttling element to control flow paths, allowing for simplified mode switching by alternating between two flow paths and utilizing the ejector as an additional throttling element, thereby reducing pressure differences and simplifying control logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple solenoid valves or three-way valves are adopted to control on/off or switching of flow paths, then the ejector can be turned on/off in different operating modes, but the control logic becomes extremely complex, thus reducing the reliability of the whole system
Solution Approach 1:
The patent extracts the complex control logic and multiple valve requirements by utilizing the inherent flow path characteristics of the ejector itself. The ejector's internal structure naturally provides the necessary flow path switching between standard mode and ejector mode, eliminating the need for multiple external solenoid valves or three-way valves, thereby simplifying the control system and improving reliability.
Solution Approach 2:
The ejector is designed to perform multiple functions: it serves as both a refrigerant flow control device and a mode switching mechanism. By adjusting the ejector's operation, the system can switch between standard refrigeration mode and ejector-enhanced mode without requiring separate control valves for each mode, thus reducing component count and control complexity.
2Device complexity
If a single throttling element model is selected, then the system structure is simplified, but it is difficult to operate while crossing two pressure difference intervals so far away from each other (0.5-1 bar in ejector mode vs. 15-20 bar in standard mode)
Solution Approach 1:
The patent applies a variable area throttling element whose effective flow area can dynamically adjust based on operating conditions. This dynamic adjustment capability allows the single throttling element to adapt to widely different pressure differences between ejector mode (0.5-1 bar) and standard mode (15-20 bar), eliminating the need for multiple fixed-model throttling elements while maintaining operational effectiveness across both modes.
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 approach enables reliable and efficient mode switching with reduced pressure differences across throttling elements and simplified control logic, improving system reliability and ease of operation.
Implementation Method 1
an ejector having a main flow inlet connected to the heat-extraction heat exchanger, and further having a secondary flow inlet and an ejector outlet
Implementation Method 2
a three-way valve connected to an outlet of the heat-absorption heat exchanger, the secondary flow inlet of the ejector, and the gas inlet of the compressor respectively
Implementation Method 3
a first throttling element, and a heat-absorption heat exchanger that are connected through pipelines
Data Source
Figure 1
Figure 2
AI summary
An ejector refrigeration system, comprising: a compressor, a heat-extraction heat exchanger, an ejector, a separator, a first throttling element, and a heat-absorption heat exchanger that are connected through pipelines, the ejector having a main flow inlet connected to the heat-extraction heat exchanger, and further having a secondary flow inlet and an ejector outlet; the separator having a separator inlet connected to the ejector outlet, a separator liquid outlet connected to the first throttling element, and a separator gas outlet connected to a gas inlet of the compressor, wherein turn-on and turn-off of a first flow path connecting the heat-absorption heat exchanger and the secondary flow inlet of the ejector and a second flow path connecting the heat-absorption heat exchanger and the gas inlet of the compressor are controllable.