Vapor compression system and methods for its operation
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Solution Overview
Problem
Existing vapor compression refrigeration systems with ejectors face inefficiencies in controlling the flow through the motive nozzle, leading to potential energy losses and the need for additional valves, which complicates the system and reduces performance.
Innovation Solution
A vapor compression system with a motive nozzle featuring a control needle that can shift between conditions, allowing for precise control of the flow by adjusting the angle of the needle's tip and shoulder portions, eliminating the need for a separate solenoid valve and improving sealing and flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate solenoid valve is used to control flow through the motive nozzle, then flow control capability is improved, but device complexity increases
Solution Approach 1:
The control needle is integrated directly into the motive nozzle structure, merging the flow control function with the nozzle itself. This eliminates the need for a separate solenoid valve while maintaining precise flow control capability through the needle's position adjustment.
Solution Approach 2:
The control needle serves multiple functions: it controls the flow area of the motive nozzle, acts as a sealing element against the nozzle wall, and can be positioned to fully open or fully close the flow path. This multi-functionality replaces what would otherwise require separate valve components.
2Ease of operation
If traditional valve mechanisms are used for flow control, then flow regulation is achieved, but energy losses increase
Solution Approach 1:
The invention replaces traditional mechanical valve mechanisms with a streamlined control needle system that has minimal flow disturbance. The needle's geometry and movement mechanism are designed to reduce turbulence and pressure drops, thereby minimizing energy losses during flow regulation.
Solution Approach 2:
The control needle provides dynamic flow control with smooth, continuous adjustment capability. This dynamic control allows the system to optimize flow conditions in real-time, avoiding the energy losses associated with discrete valve positions and abrupt flow changes.
3Ease of manufacture
If the control needle has simple geometry, then manufacturing is easier, but sealing performance deteriorates
Solution Approach 1:
The control needle features localized geometric variations: the main body has simple cylindrical geometry for easy manufacturing, while the tip section has precise conical geometry with specific angles (15°-30°) to ensure proper sealing contact with the motive nozzle wall. This local quality differentiation achieves both manufacturability and sealing reliability.
Solution Approach 2:
The control needle employs asymmetric geometry with different angles for different sections: a larger angle (15°-30°) for the sealing portion that contacts the nozzle wall, and a smaller angle (5°-15°) for the flow control portion. This asymmetric design optimizes both sealing performance and flow characteristics while remaining manufacturable.
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 solution enhances the system's efficiency by reducing energy losses and simplifying the configuration by eliminating the need for additional valves, while maintaining effective refrigeration performance.
Implementation Method 1
The primary refrigerant flow enters the inlet and then passes into a convergent section of the motive nozzle. It then passes through a throat section and an expansion (divergent) section through an outlet (exit) of the motive nozzle. The motive nozzle accelerates the flow and decreases the pressure of the flow.
Implementation Method 2
The pressure reduction caused to the primary flow by the motive nozzle helps draw the secondary flow into the outer member.
Implementation Method 3
The resulting combined flow is a liquid/vapor mixture and decelerates and recovers pressure in the diffuser while remaining a mixture.
Data Source
Figure 1~2
Figure 3
Figure 4~4A
AI summary
An ejector has: a motive flow inlet (40); a secondary flow inlet (42); an outlet (44); a motive flow nozzle (242) having an outlet (110); a primary flowpath from the motive flow inlet through the motive flow nozzle to the ejector outlet; a secondary flowpath from the secondary flow inlet to the ejector outlet, merging with the primary flowpath at the motive nozzle outlet; a control needle (200; 300; 400) shiftable along a range of motion between a first condition and a second condition and seated against the motive nozzle in the second condition. The needle comprises: a main shaft (210); a tip (204); a first portion (220; 320) converging toward the tip; and a shoulder portion (214; 314; 422) between the first portion and the main shaft and seated against the motive nozzle in the second condition and converging toward the tip at a greater angle (?1; ?1 2) than an angle (?2; ?2 2) of the first portion.