Heat Pump Ejector with Controllable Needle for Multi-Mode Operation
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Solution Overview
Problem
Vapor compression systems with ejectors face inefficiencies in switching between cooling and heating modes, particularly at varying temperature differences between indoor and outdoor environments, as existing systems either overuse or underutilize the ejector, leading to suboptimal performance.
Innovation Solution
A controllable ejector system with a needle that can shift between closed and open positions, combined with a controller to switch between cooling, first heating, and second heating modes based on sensed outdoor temperatures, utilizing a single four-way switching valve and check valves to manage refrigerant flowpaths effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an ejector is used as an expansion device in vapor compression systems, then efficiency is improved where there is a large temperature difference between indoor and outdoor environments, but performance becomes suboptimal when temperature differences are small
Solution Approach 1:
The ejector is designed with a movable needle that can shift between closed and open positions, allowing the system to dynamically adjust the ejector's operation based on temperature conditions. This dynamic control enables the system to optimize efficiency in large temperature difference conditions while maintaining adaptability in smaller temperature difference scenarios.
Solution Approach 2:
The system changes the operational parameters of the ejector by controlling the needle position, which alters the flow characteristics and pressure ratios. This parameter adjustment allows the system to adapt to varying temperature differences between indoor and outdoor environments, resolving the contradiction between efficiency and adaptability.
2Productivity
If the ejector is always enabled, then efficiency is maximized in large temperature difference conditions, but energy use increases and performance decreases in small temperature difference conditions
Solution Approach 1:
The needle within the ejector creates local flow control by selectively opening or closing specific passages based on operating conditions. This local quality adjustment allows the system to enable ejector functionality only when beneficial (large temperature differences), reducing energy consumption when the ejector would not provide efficiency benefits.
Solution Approach 2:
The controllable needle position enables dynamic switching of the ejector's operational state, allowing the system to adapt energy consumption to actual temperature difference conditions rather than operating at constant high energy usage.
3Use of energy by moving object
If the ejector is always disabled, then energy use is reduced in small temperature difference conditions, but efficiency is lost in large temperature difference conditions
Solution Approach 1:
The needle provides localized flow control within the ejector, enabling selective activation of the ejector's expansion function. This allows the system to maintain low energy consumption by keeping the ejector disabled when not needed, while enabling efficient operation when large temperature differences exist.
Solution Approach 2:
The dynamic control mechanism allows the system to switch between enabled and disabled states based on real-time temperature conditions, ensuring energy efficiency is optimized without sacrificing productivity when the ejector's capabilities are actually beneficial.
4Adaptability or versatility
If multiple heating modes are implemented with a controllable ejector, then adaptability to different temperature conditions is improved, but device complexity increases
Solution Approach 1:
The controllable ejector with its movable needle serves multiple functions across different heating modes (first heating mode with ejector enabled, second heating mode with ejector disabled). This multi-functionality allows a single component to adapt to various temperature conditions without requiring entirely separate systems for each mode.
Solution Approach 2:
The dynamic needle control mechanism provides a unified way to manage multiple heating modes, reducing the need for separate complex control systems for each mode. The single controllable ejector handles adaptability across conditions, simplifying overall system architecture compared to having dedicated components for each heating scenario.
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 configuration allows for efficient operation across different temperature conditions by enabling or disabling the ejector as needed, optimizing energy use and performance by selecting the appropriate heating mode based on ambient temperature, thereby enhancing the system's overall efficiency and adaptability.
Implementation Method 1
The motive nozzle accelerates the flow and decreases the pressure of the flow. The pressure reduction caused to the primary flow by the motive nozzle helps draw a suction flow or secondary flow into the outer member through the suction port.
Implementation Method 2
The motive nozzle accelerates the flow and decreases the pressure of the flow.
Implementation Method 3
The resulting combined flow is a liquid/vapor mixture and decelerates and recovers pressure in the diffuser while remaining a mixture.
Implementation Method 4
The resulting combined flow is a liquid/vapor mixture and decelerates and recovers pressure in the diffuser while remaining a mixture.
Implementation Method 5
As the motive flow exits the motive nozzle outlet, it begins to mix with the suction flow with further mixing occurring through the mixing section which provides a mixing zone.
Data Source
AI summary
A system (20; 300) has: a compressor (22) having a suction port (40) and a discharge port (42); an ejector (32) having a motive flow inlet (50), a suction flow inlet (52), and an outlet (54); a separator (34) having an inlet (72), a vapor outlet (74), and a liquid outlet (76); a first heat exchanger (24); an expansion device (28); and a second heat exchanger (26; 302). Conduits and valves are positioned to provide alternative operation in: a cooling mode; a first heating mode; and a second heating mode. In the cooling mode and second heating mode, a needle (60) of the ejector is closed.