Open-Circuit Refrigeration System for Extended Low-Power Cooling
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Solution Overview
Problem
Conventional refrigeration systems are heavy and power-intensive, making them unsuitable for applications with size and weight constraints, such as mobile platforms, and struggle to maintain precise temperature control for high heat flux, temperature-sensitive loads due to the temperature increase of refrigerant fluids during heat absorption.
Innovation Solution
The implementation of an open circuit refrigeration system using a two-phase refrigerant fluid flow path with a recuperative heat exchanger and control devices to manage vapor quality and pressure, reducing the refrigerant mass transfer rate and extending operational time by utilizing a gas receiver to maintain pressure and control temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional closed-circuit refrigeration systems are used, then cooling capacity is sufficient, but weight and power consumption increase significantly
Solution Approach 1:
The patent extracts and removes the compressor and condenser components from the refrigeration system, transitioning from a closed-circuit to an open-circuit design. This extraction eliminates the heavy mechanical compression equipment while maintaining cooling functionality through direct refrigerant evaporation in the evaporator, thereby reducing system weight without sacrificing cooling capacity.
Solution Approach 2:
The patent replaces the mechanical compression system with a thermodynamic approach where refrigerant is directly evaporated in the evaporator to provide cooling. The mechanical compressor is substituted by utilizing the phase change properties of refrigerant and controlling evaporation through heat exchange, eliminating heavy mechanical parts while maintaining cooling effectiveness.
2Temperature
If conventional closed-circuit refrigeration systems are used, then cooling capacity is sufficient, but power consumption increases significantly
Solution Approach 1:
The patent extracts the power-intensive compressor and condenser components from the system, eliminating the need for mechanical compression and heat rejection cycles. This extraction removes the primary sources of power consumption while maintaining cooling capacity through direct evaporative cooling in the evaporator using ambient or process air.
Solution Approach 2:
The patent replaces the energy-consuming mechanical compression system with a passive thermodynamic system where refrigerant evaporation provides cooling directly. The mechanical work input required for compression is substituted by utilizing natural heat transfer processes and refrigerant phase change, dramatically reducing power consumption while maintaining cooling effectiveness.
3Duration of action of moving object
If receiver size is increased to extend operational time, then operation duration increases, but system weight and volume increase
Solution Approach 1:
The patent implements continuous operational capability by integrating multiple receivers (first receiver for gas, second receiver for liquid refrigerant) that work in sequence. The system maintains continuous cooling by transitioning from gas phase to liquid phase refrigerant storage, ensuring uninterrupted refrigerant supply to the evaporator without requiring a single oversized receiver, thereby extending operational time while controlling weight.
Solution Approach 2:
The patent utilizes parameter changes in refrigerant phase (from gas to liquid) to extend operational time. By incorporating a first receiver for gas-phase refrigerant and a second receiver for liquid-phase refrigerant, the system adapts to changing operational requirements and extends duration without proportionally increasing weight, as the phase transition allows more efficient use of refrigerant mass.
4Duration of action of moving object
If receiver size is increased to extend operational time, then operation duration increases, but system volume increases
Solution Approach 1:
The patent ensures continuous operational capability by using multiple receivers with different refrigerant phases (gas and liquid) that supplement each other. This approach extends operational time without requiring a single large-volume receiver, as the phased refrigerant storage system maintains compact dimensions while ensuring prolonged operation through sequential refrigerant supply.
Solution Approach 2:
The patent employs parameter changes in refrigerant phase to optimize the volume-time relationship. By using a first receiver for gas-phase refrigerant and a second receiver for liquid-phase refrigerant, the system extends operational duration while maintaining compact volume, as the phase transition allows more refrigerant mass to be stored in smaller volumes compared to single-phase storage.
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 reduces the size, weight, and power consumption of refrigeration systems, enabling efficient cooling of high heat flux loads while maintaining temperature stability within a narrow range, extending operational time and reducing refrigerant usage.
Implementation Method 1
an evaporator coupled to the second receiver and configured to extract heat from a heat load that contacts the evaporator
Implementation Method 2
a recuperative heat exchanger that has a first fluid path that receives the refrigerant fluid from the second receiver and a second fluid path that provides thermal contact between the refrigerant leaving the receiver and refrigerant vapor passed into the recuperative heat exchanger
Data Source
AI summary
Thermal management systems include an open circuit refrigeration system featuring a first receiver configured to store a gas, a second receiver configured to store a liquid refrigerant fluid, an evaporator configured to extract heat from a heat load that contacts the evaporator, and an exhaust line, where the first receiver, the second receiver, the evaporator, and the exhaust line are connected to provide a refrigerant fluid flow path.