Ejector-Based Refrigeration System for Dual-Temperature Cooling
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Solution Overview
Problem
Conventional refrigeration systems are limited in their ability to provide cooling at multiple temperatures using a single compression device and ejector, as they often require multiple compression devices and complex configurations to achieve differing heat absorption pressures.
Innovation Solution
A refrigeration system incorporating two heat absorbing heat exchangers and an ejector with a branched flow path, where the first heat absorbing heat exchanger operates for air conditioning (15° C. to 30° C.) and the second for medium temperature applications (−25° C. to 8° C.), with differing expansion devices and a receiver to manage refrigerant flow and pressure, allowing for cooling at two distinct temperatures without additional compression devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple compression devices are used to provide cooling at multiple temperatures, then the cooling capacity at different temperatures is improved, but the device complexity increases
Solution Approach 1:
The single compression device performs multiple functions by compressing refrigerant for different temperature levels and the ejector serves dual purposes as both a compression assist device and a flow distribution mechanism, eliminating the need for multiple dedicated compression devices while achieving multi-temperature cooling capability
Solution Approach 2:
The ejector acts as an intermediary device that receives high-pressure refrigerant from the heat rejecting heat exchanger and uses it to drive the compression process for multiple temperature levels, mediating between the single compression device and the multiple heat absorbing heat exchangers operating at different temperatures
2Adaptability or versatility
If multiple heat absorbing heat exchangers are used to achieve different temperatures, then the temperature adaptability is improved, but the system complexity increases
Solution Approach 1:
The heat absorption process is segmented into multiple heat absorbing heat exchangers operating at different temperature levels, with each exchanger handling a specific temperature range, allowing independent optimization of heat transfer for each temperature level while maintaining overall system efficiency
Solution Approach 2:
The system incorporates dynamic flow distribution through the ejector and expansion devices that can adjust refrigerant flow rates to each heat absorbing heat exchanger based on cooling demands, enabling flexible adaptation to varying temperature requirements without fixed system configuration
3Device complexity
If a single compression device is used for multiple temperatures, then the device complexity is reduced, but the control difficulty increases
Solution Approach 1:
The system incorporates feedback mechanisms where the ejector responds to pressure and flow conditions from the heat rejecting heat exchanger and automatically adjusts the distribution of refrigerant to different heat absorbing heat exchangers, providing self-regulating control that reduces manual intervention while maintaining optimal performance across multiple temperature levels
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
Enables efficient cooling at two different temperatures using a single compression device and ejector, suitable for applications requiring both air conditioning and refrigerated storage, such as small retail establishments, with improved control and efficiency through the use of expansion devices and internal heat exchangers.
Implementation Method 1
an ejector having a high pressure inlet, a low pressure inlet, and an outlet, the ejector being arranged to receive refrigerant fluid from the heat rejecting heat exchanger at the high pressure inlet of the ejector
Implementation Method 2
a first expansion device and a second expansion device, fluid pathways extending from the outlet of the ejector and branching into a branched flow path in order to provide refrigerant from the outlet of the ejector to a first expansion device and a second expansion device
Implementation Method 3
a first heat absorbing heat exchanger that is arranged to receive refrigerant fluid from the first expansion device, and a second heat absorbing heat exchanger that is arranged to receive refrigerant fluid from the second expansion device
Implementation Method 4
a compression device having an inlet for receiving refrigerant fluid at a suction pressure and an outlet for providing compressed refrigerant fluid at a discharge pressure
Implementation Method 5
the cooling of the refrigerant fluid is done via a heat rejection heat exchanger rejecting heat to the atmosphere
Data Source
AI summary
Refrigeration systems are described. The systems include a compression device, a heat rejecting heat exchanger, an ejector, and first and second expansion devices with respective heat absorbing heat exchangers. The ejector is arranged to receive refrigerant fluid from the heat rejecting heat exchanger at a high pressure inlet of the ejector. Fluid pathways extend from an outlet of the ejector into a branched flow path to provide flows of refrigerant from the ejector to the first and second expansion devices. The first heat absorbing heat exchanger provides cooling at a first temperature and refrigerant fluid from the outlet of the first heat absorbing heat exchanger is directed to a low pressure inlet of the ejector. The second heat absorbing heat exchanger provides cooling at a second temperature and refrigerant fluid from the outlet of the second heat absorbing heat exchanger is directed to the inlet of the compression device.