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, weight, and power constraints, such as cooling high heat flux loads in mobile platforms, where precise temperature control is required for temperature-sensitive components.
Innovation Solution
The development of open circuit refrigeration systems that utilize a refrigerant fluid flow path with a gas receiver and a liquid receiver, controlled by multiple devices to regulate vapor pressure and vapor quality, allowing for efficient heat extraction and temperature stabilization without the need for compressors and condensers, using ammonia as the refrigerant fluid and inert gases like nitrogen, argon, or xenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
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 removes the compressor and condenser from the refrigeration system, extracting these heavy components to reduce overall system weight. The open-circuit design eliminates the need for these components by using direct expansion of refrigerant gas in the evaporator, while still maintaining sufficient cooling capacity through optimized refrigerant flow control and heat exchanger design.
2Quantity of substance
If conventional closed-circuit refrigeration systems are used, then cooling capacity is sufficient, but power consumption increases significantly
Solution Approach 1:
The patent eliminates the compressor, which is the primary power-consuming component in conventional refrigeration systems. By using an open-circuit design where refrigerant gas expands directly in the evaporator, the system achieves cooling capacity without requiring mechanical compression, thereby dramatically reducing power consumption.
3Weight of moving object
If open circuit refrigeration systems are used to reduce weight, then system size and power consumption decrease, but operational duration is limited
Solution Approach 1:
The patent pre-charges the evaporator with a specific amount of refrigerant gas before operation begins. This preliminary charging ensures that the evaporator has sufficient refrigerant to maintain cooling operation for an extended duration without requiring a compressor to replenish refrigerant, thereby extending operational duration while maintaining the lightweight open-circuit design.
4Weight of moving object
If open circuit refrigeration systems are used to reduce system size, then weight and dimensions decrease, but temperature control precision deteriorates
Solution Approach 1:
The patent incorporates a control system that monitors temperature and refrigerant flow conditions in real-time, providing feedback to adjust refrigerant flow rates and maintain precise temperature control. This feedback mechanism compensates for the lack of a compressor by dynamically regulating the expansion process, ensuring stable and precise temperature control despite the simplified open-circuit architecture.
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 overall size, weight, and power consumption of the refrigeration system while maintaining precise temperature control for high heat flux loads, extending operational time by maintaining refrigerant fluid pressure and optimizing refrigerant usage, and allowing for cooling of multiple thermal loads with a single heat exchanger.
Implementation Method 1
an evaporator coupled to the second receiver, the evaporator configured to extract heat from a heat load that contacts the evaporator
Implementation Method 2
Refrigeration systems absorb thermal energy from the heat sources operating at temperatures below the temperature of the surrounding environment
Implementation Method 3
an evaporator coupled to the second receiver, the evaporator configured to extract heat from a heat load
Implementation Method 4
discharge thermal energy into the surrounding environment
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.