Controllable Ejector Heat Pump for Multi-Mode Temperature Switching
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Solution Overview
Problem
Conventional heat pumps face inefficiencies in operating modes, particularly when temperature differences between indoor and outdoor environments are low, as ejectors lose efficiency and require alternative expansion devices, 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, utilizing a single ejector and expansion device, and a 4-way switching valve to manage refrigerant flowpaths effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional expansion device is used in heat pump operation, then the system can operate in high ambient temperature conditions, but the system loses efficiency in low ambient temperature conditions where ejectors would be more effective
Solution Approach 1:
The system dynamically switches between conventional expansion device mode and ejector mode based on ambient temperature conditions. The controllable ejector can be activated or deactivated to optimize system performance for different operating conditions, transforming a static system into a dynamic one that adapts to environmental changes.
Solution Approach 2:
The system changes its operational parameters by switching between different expansion mechanisms. When ambient temperature is low, the ejector is activated to utilize the temperature difference between indoor and outdoor environments for efficient refrigerant expansion. When ambient temperature is high, the system reverts to conventional expansion device operation.
2Productivity
If a controllable ejector with needle positioning is used, then the system can optimize performance across different temperature ranges, but the device complexity increases
Solution Approach 1:
The needle within the ejector is made controllable and positionable, allowing dynamic adjustment of the ejector's operation. This enables the system to optimize refrigerant expansion efficiency by adjusting the needle position based on operating conditions, while the controller automates this adjustment to manage the added complexity.
Solution Approach 2:
The controller monitors system operating conditions and automatically adjusts the needle position in the ejector to optimize performance. This feedback mechanism allows the system to maintain high efficiency across varying temperature conditions while removing the need for manual intervention, thereby managing the complexity through automation.
3Loss of energy
If the ejector is disabled in high ambient temperature conditions, then the system operates efficiently with conventional expansion devices, but the adaptability to utilize ejector benefits in all conditions is lost
Solution Approach 1:
The system changes its operational mode based on ambient temperature parameters. In high ambient temperature conditions, the ejector is disabled and conventional expansion devices are used. In low ambient temperature conditions, the system transitions to ejector mode to utilize the temperature difference for efficient refrigerant expansion, thereby adapting to different thermal environments.
Solution Approach 2:
The system dynamically switches between operational modes (ejector mode and conventional expansion mode) based on environmental conditions. This dynamic switching allows the system to maintain optimal efficiency across different temperature ranges while preserving the adaptability to utilize the most appropriate expansion mechanism for each condition.
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 system optimizes performance across different temperature ranges by enabling efficient operation in both low and high ambient temperature conditions, enhancing the controllability and efficiency of heat pump systems by selectively enabling or disabling the ejector based on temperature differences.
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 resulting combined flow is a liquid/vapor mixture and decelerates and recovers pressure in the diffuser while remaining a mixture.
Data Source
AI summary
A system (20; 300) comprises: 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.