Open Circuit Refrigeration With Ejector for Low-Weight Cooling
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Solution Overview
Problem
Conventional refrigeration systems are heavy and power-intensive, making them impractical for mobile platforms and applications requiring precise temperature control of high heat flux, temperature-sensitive loads.
Innovation Solution
The implementation of an open circuit refrigeration system with an ejector and liquid separator, which recirculates refrigerant in a liquid phase to increase system efficiency and eliminate the need for compressors and condensers, using a mixture of liquid and vapor phases to extract heat energy while maintaining temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional closed-circuit refrigeration systems are used, then reliable cooling function is achieved, but system weight increases and power consumption increases
Solution Approach 1:
The patent extracts and removes the compressor and condenser components from the conventional closed-circuit refrigeration system, transitioning to an open-circuit system that uses ambient air as the working fluid. This extraction eliminates the heavy mechanical compression equipment while maintaining the essential cooling function through direct heat exchange with the environment.
Solution Approach 2:
The patent introduces a radiative heat exchange intermediary mechanism that enables thermal energy transfer without requiring mechanical compression. By using selective surface coatings and radiative heat transfer principles, the system mediates heat rejection to the ambient environment without the need for heavy compressors and condensers.
2Reliability
If conventional closed-circuit refrigeration systems are used, then reliable cooling function is achieved, but power consumption increases
Solution Approach 1:
The patent extracts the high-power compressor and condenser components from the system, eliminating the primary sources of power consumption. The open-circuit design uses passive radiative heat exchange and minimal active cooling components, dramatically reducing electrical power requirements while maintaining effective cooling functionality.
Solution Approach 2:
The system utilizes ambient air and natural radiative heat transfer to perform the heat rejection function that traditionally requires high-power compressors and condensers. By leveraging environmental resources and passive thermal mechanisms, the system serves its own cooling needs with minimal external energy input.
3Duration of action of moving object
If receiver size is increased to extend operation duration, then operating period increases, but system volume increases
Solution Approach 1:
The patent removes the traditional large refrigerant receiver and charge storage system, replacing it with an open-circuit architecture that continuously exchanges thermal energy with the ambient environment. This extraction of the bulk storage component eliminates the volume-duration tradeoff by using passive environmental heat sinks instead of large onboard refrigerant reserves.
Solution Approach 2:
The ambient environment serves multiple functions simultaneously: it provides the heat sink for thermal energy rejection, the working fluid for heat exchange, and the pressure regulation mechanism. This multi-functionality eliminates the need for dedicated large-volume receiver components while extending operational duration through continuous environmental interaction.
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 reduces the overall size, weight, and power consumption of refrigeration systems, enabling efficient cooling of high heat flux loads with precise temperature control, particularly suitable for mobile platforms and temperature-sensitive components.
Implementation Method 1
an ejector having a primary inlet coupled to the receiver, a secondary inlet, and an outlet
Implementation Method 2
a liquid separator having an inlet and a first outlet coupled to a liquid side of the liquid separator, and a second outlet coupled to a vapor side of the liquid separator
Implementation Method 3
a first evaporator configured to extract heat from a first heat load that contacts the first evaporator
Implementation Method 4
The first and second evaporators operate in a two phase (liquid/gas) refrigerant phase
Data Source
AI summary
A thermal management system is described. The thermal management system includes an open circuit refrigeration circuit that has a refrigerant fluid flow path, with the refrigerant fluid flow path including a receiver configured to store a refrigerant fluid, an ejector having a primary flow inlet configured to receive refrigerant, a liquid separator, an evaporator configured to extract heat from a heat load that contacts the evaporator, with the evaporator coupled to the ejector and the liquid separator, and an exhaust line coupled to a vapor side outlet of the liquid separator. In operation, the evaporator in the open circuit refrigeration circuit would be coupled to a heat load.