Refrigeration device with improved single ejector refrigeration cycle and related refrigeration method
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Solution Overview
Problem
Single Ejector Refrigeration Systems (SERS) face efficiency losses due to the lack of regulation in ejectors, which are unable to maintain nominal operation when faced with fluctuating or intermittent heat sources, such as solar thermal energy, leading to unstable cold production.
Innovation Solution
Incorporating reversible compression members on the mixing and driving branches of the refrigeration cycle to regulate the conditions at the ejector outlet and inlet, allowing for operation closer to nominal speed and adapting to variations in heat source conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ejector refrigeration system is used without regulation components, then the device complexity is reduced and manufacturing cost is lowered, but the system cannot maintain efficient operation when heat source conditions fluctuate, leading to sharp COP decrease
Solution Approach 1:
The patent introduces a reversible compression member that can dynamically adjust its operation mode (compression or expansion) based on real-time heat source conditions. This dynamic adjustment capability allows the ejector to maintain optimal pressure ratios and operating conditions despite fluctuations in heat source temperature, resolving the contradiction between simple structure and operational adaptability.
Solution Approach 2:
The reversible compression member changes the operating parameters (pressure, flow rate) of the working fluid based on heat source conditions. By adjusting these parameters dynamically, the system maintains efficient ejector operation across varying thermal conditions, preventing the sharp COP decrease that would otherwise occur with fixed-parameter simple ejector systems.
2Reliability
If reversible compression members are added to regulate ejector conditions, then the COP and operation stability are improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The reversible compression member is designed to perform multiple functions: it can operate in compression mode to increase working fluid pressure when heat source temperature is low, and in expansion mode to decrease pressure when heat source temperature is high. This multi-functionality allows a single component to handle various operating conditions, improving reliability without requiring multiple separate regulation devices.
Solution Approach 2:
The reversible compression member is controlled to automatically switch between compression and expansion modes based on real-time monitoring of heat source conditions. This self-regulating capability reduces the need for external control systems and manual intervention, making the added complexity self-justifying through automated adaptation that maintains stable cold production.
3Ease of operation
If the ejector operates without regulation components, then the ease of operation is improved, but the productivity and cold production efficiency decrease when heat source conditions vary
Solution Approach 1:
The system incorporates sensors and control logic that continuously monitor heat source temperature and automatically adjust the reversible compression member's operation mode. This feedback mechanism maintains optimal ejector performance across varying conditions without requiring manual intervention, thus preserving ease of operation while significantly improving cold production efficiency compared to unregulated simple ejector systems.
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 enables stable and continuous cold production by maintaining efficient operation of the SERS cycle, even with fluctuating heat sources, by precisely controlling the pressure and flow conditions, thus enhancing the Coefficient of Performance (COP).
Implementation Method 1
an ejector ensuring a mixing of a working fluid coming from the generator and a working fluid coming from the evaporator
Implementation Method 2
a condenser ensuring an exchange of heat between an intermediate source and the mixed working fluid coming from the ejector
Implementation Method 3
a first reversible compression member arranged on the mixing branch downstream of the ejector and upstream of the condenser
Implementation Method 4
a generator ensuring an exchange of heat between a heat source and the working fluid
Implementation Method 5
an evaporator ensuring an extraction of heat from a source to be cooled
Data Source
Figure 1~2
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Figure 5~6
AI summary
The invention relates to a refrigeration device comprising a refrigeration cycle with an ejector, including a working fluid circulation circuit with three parallel branches: a drive branch on which a pump (101) and a generator (102) are arranged, a refrigeration branch on which an expansion valve (103) and an evaporator (104) are arranged, and a mixing branch on which an ejector (200) and a condenser (105) are arranged, characterized in that it includes a first reversible compression element (300) arranged on the mixing branch downstream of the ejector (200) and upstream of the condenser (105). The invention will find particular application in refrigeration devices operating from a low-temperature heat source, for example, in the range of 80°C to 150°C, which may be fluctuating or even intermittent.