Ejector Refrigeration Flow Switching for Wide Pressure-Difference Modes
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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 for mode transitions.
Innovation Solution
The system includes controllable first and second flow paths connecting the heat-absorption heat exchanger to the ejector and compressor, allowing for simplified mode switching by turning on/off these paths, reducing the pressure difference burden on the first throttling element and using valves like three-way or solenoid valves for control.
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 in different operating modes, then the ejector can be turned on/off, but the control logic becomes extremely complex, thus reducing the reliability of the whole system
Solution Approach 1:
The patent extracts the mode switching function from complex multi-valve control logic and implements it through a single three-way electronic expansion valve. By taking out the switching control from the flow paths and concentrating it in one valve, the system achieves mode transition without requiring multiple solenoid valves or complex control logic, thus improving reliability while maintaining adaptability
Solution Approach 2:
The three-way electronic expansion valve performs multiple functions: it acts as both a flow control device and a mode switching device. This universal component replaces multiple specialized valves (solenoid valves, three-way valves) that would otherwise be needed for mode switching, simplifying the overall control system while maintaining the ability to operate in both standard and ejector modes
2Device complexity
If a single throttling element model is selected, then the device structure is simple, but it cannot 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 dynamics by making the throttling element adjustable rather than fixed. The electronic expansion valve can dynamically adjust its opening degree and flow characteristics based on operating conditions. In ejector mode, it operates with small pressure difference (0.5-1 bar), while in standard mode, it handles large pressure difference (15-20 bar), achieving adaptability across widely different pressure intervals through dynamic adjustment capability
Solution Approach 2:
The patent changes the operating parameters of the throttling element based on mode requirements. By adjusting the valve opening degree, flow area, and pressure differential across the valve, the same throttling element can accommodate both the low pressure difference of ejector mode and the high pressure difference of standard mode, eliminating the need for multiple specialized throttling elements
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 simplifies control logic, enhances system reliability, and reduces the pressure difference span across the first throttling element, facilitating smoother mode transitions and improved operational reliability.
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
Data Source
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.