Ejector heat pump
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Solution Overview
Problem
Ejector refrigeration systems face limitations in efficiently managing refrigerant flow and pressure ratios, leading to suboptimal refrigeration effects and evaporator performance, particularly in switching between cooling and heating modes.
Innovation Solution
The system incorporates two ejectors of different sizes and configurations, along with controllable valves, to manage refrigerant flow paths and heat exchanger roles, allowing for optimized operation in both cooling and heating modes by adjusting the flow paths and ejector sizes to maintain efficient refrigerant distribution and pressure recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single ejector is used in the refrigeration system, then the device complexity is reduced, but the refrigeration efficiency and evaporator performance deteriorate due to inability to optimize refrigerant flow and pressure ratios for different operating modes
Solution Approach 1:
The single ejector is divided into two separate ejectors (first ejector and second ejector), each optimized for specific operating conditions. The first ejector handles cooling mode with its motive nozzle and secondary flow inlet configured for cooling refrigerant flow, while the second ejector handles heating mode with different configuration. This segmentation allows each ejector to be optimized for its specific function, improving overall refrigeration efficiency without requiring one complex ejector to handle all modes.
Solution Approach 2:
The system achieves multi-functionality by having two ejectors that can operate independently or in combination to serve different modes (cooling and heating). The first heat exchanger and second heat exchanger can switch roles depending on which ejector is active, allowing the system to provide both cooling and heating functions using dedicated ejector configurations for each mode.
2Adaptability or versatility
If refrigerant flow direction is reversed in heat exchangers to switch between cooling and heating modes, then the system versatility is improved, but the heat transfer performance deteriorates due to flow direction changes
Solution Approach 1:
The heat exchangers are functionally segmented into first heat exchanger and second heat exchanger, where each has a dedicated role in specific modes. The first heat exchanger serves as the primary heat exchanger in cooling mode, while the second heat exchanger serves as the primary heat exchanger in heating mode. This functional segmentation allows each heat exchanger to maintain optimized flow directions for its specific function, preserving heat transfer performance while enabling mode switching through ejector selection rather than flow reversal.
3Device complexity
If the refrigerant flow path is simplified with fewer valves, then the device complexity is reduced, but the ability to optimize refrigerant distribution and pressure recovery deteriorates
Solution Approach 1:
The system employs dynamically controllable valves (first controllable valve and second controllable valve) that can adjust their opening positions to optimize refrigerant flow distribution. These valves are controlled by a controller that receives signals from sensors monitoring system conditions, allowing real-time adjustment of refrigerant flow paths and pressure ratios to match optimal conditions for the current operating mode, thereby maintaining high refrigerant distribution efficiency.
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 enhances refrigeration efficiency by reducing power consumption, improving evaporator performance, and allowing for flexible operation between cooling and heating modes without reversing refrigerant flow directions in heat exchangers, thus maintaining high heat transfer performance.
Implementation Method 1
a first ejector and a second ejector, wherein: the first ejector includes a first nozzle; the second ejector includes a second nozzle
Implementation Method 2
a first heat exchanger and a second heat exchanger
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A vapor compression system (200; 400; 600; 700; 800; 900; 1000) comprises a plurality of valves (260, 262, 264; 260) controllable to define a first mode flowpath and a second mode flowpath. The first mode flowpath is sequentially through: a compressor (22); a first heat exchanger (30); a first nozzle (228; 624); and a separator (48), and then branching into: a first branch returning to the compressor; and a second branch passing through an expansion device (70) and a second heat exchanger (64) to the rejoin the flowpath between the first heat exchanger and the separator. The second mode flowpath is sequentially through: the compressor; the second heat exchanger; a second nozzle (248; 625); and the separator, and then branching into: a first branch returning to the compressor; and a second branch passing through the expansion device and first heat exchanger to the rejoin the flowpath between the first heat exchanger and the separator.