Open-Circuit Refrigeration for Lightweight Precise Thermal Control
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Solution Overview
Problem
Conventional refrigeration systems are heavy and power-consuming due to the need for large compressors and condensers, making them unsuitable for mobile or space-based applications where size and weight constraints are significant, and they struggle to maintain precise temperature control for high heat flux and temperature-sensitive loads.
Innovation Solution
An open-circuit refrigeration system that uses a compressor or vacuum pump to manage refrigerant flow, eliminating the need for condensers and reducing power consumption by maintaining refrigerant fluid in a two-phase region, allowing for efficient heat extraction and precise temperature control through an expansion device and vapor quality regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional closed-circuit refrigeration systems are used, then reliable temperature control can be achieved, but the system becomes heavy and consumes large amounts of power due to compressors and condensers
Solution Approach 1:
The patent extracts and removes the condenser component from the conventional refrigeration cycle, transitioning to an open-circuit system where refrigerant vapor is discharged directly to the atmosphere after absorbing heat in the evaporator. This elimination of the condenser significantly reduces system weight while maintaining temperature control reliability through the open-circuit architecture.
Solution Approach 2:
The system changes the operational parameters by operating the evaporator at varying pressures and temperatures rather than maintaining constant high-pressure operation. The open-circuit design allows the evaporator to operate at lower pressures, reducing the need for heavy-duty compressors and condensers while maintaining effective heat absorption capabilities.
2Power
If conventional closed-circuit refrigeration systems are used, then sufficient cooling capacity can be provided, but the system consumes relatively large amounts of electrical power
Solution Approach 1:
By removing the condenser from the system, the patent eliminates the energy-intensive compression and condensation processes required in closed-circuit systems. The open-circuit design allows refrigerant to absorb heat in the evaporator and then discharge directly, significantly reducing electrical power consumption while maintaining adequate cooling capacity for the intended application.
Solution Approach 2:
The system uses a small amount of liquid refrigerant that evaporates completely in the evaporator, providing sufficient cooling capacity for the specific application without requiring the excessive cooling capacity and infrastructure of conventional systems. This partial action approach matches the cooling needs precisely without over-engineering.
3Power
If the amount of absorbed thermal energy is increased, then cooling capacity is improved, but the system becomes heavier and consumes more power
Solution Approach 1:
The patent removes the condenser and associated heavy infrastructure, allowing the system to achieve cooling capacity through a simplified open-circuit design. The cooling capacity is determined by the evaporation rate of the refrigerant in the evaporator, which can be controlled by adjusting the amount of liquid refrigerant supplied, without requiring additional heavy components.
Solution Approach 2:
The system uses just enough liquid refrigerant to achieve the required cooling capacity through evaporation, avoiding the excessive infrastructure needed in conventional systems. The open-circuit design allows flexible adjustment of cooling capacity by controlling refrigerant flow rate without proportionally increasing system weight.
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
The system achieves significant reduction in size and weight, improved power efficiency, and precise temperature control for high heat flux and temperature-sensitive loads, making it suitable for mobile and space-based applications.
Implementation Method 1
an evaporator having an evaporator inlet and an evaporator outlet, with 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
the evaporator configured to extract heat from a heat load that contacts the evaporator
Implementation Method 4
a liquid pump device having a liquid pump device inlet coupled to the liquid side outlet of the liquid separator and having a liquid pump device outlet
Implementation Method 5
a vapor pump device having a vapor pump device inlet and a vapor pump device outlet, with the vapor pump device inlet coupled to the vapor side outlet of the liquid separator, with the vapor pump device configured to receive refrigerant vapor from the vapor side outlet of the liquid separator, and pump the received refrigerant vapor to the vapor pump device outlet
Data Source
AI summary
A thermal management system that includes an open-circuit refrigeration system having an open-circuit refrigerant fluid flow path is described. The open-circuit refrigeration system includes a receiver configured to store a refrigerant fluid, an evaporator configured to receive the refrigerant fluid at a evaporator inlet and to extract heat from a heat load that contacts the evaporator, and provide refrigerant vapor at a evaporator outlet. The open-circuit refrigeration system also includes a vapor pump device having a vapor pump inlet that receives the refrigerant vapor and having a vapor pump outlet that outputs compressed refrigerant vapor to an exhaust line coupled to the vapor pump outlet, with the receiver, the evaporator, the vapor pump device, and the exhaust line connected in the open-circuit refrigerant fluid flow path.