Open-Circuit Refrigeration With Vapor Pressure Control
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Solution Overview
Problem
Conventional closed-circuit refrigeration systems are heavy and power-intensive due to the need for large compressors and condensers, making them unsuitable for mobile or space-constrained applications, and struggle to maintain precise temperature control for high heat flux and temperature-sensitive loads.
Innovation Solution
An open-circuit refrigeration system with a vapor pump and back pressure regulator, which eliminates the need for condensers and allows for controlled refrigerant vapor discharge, using a compressor or vacuum pump to manage refrigerant pressure and temperature, and includes a controller system to regulate vapor quality and superheat conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional closed-circuit refrigeration systems are used, then reliable cooling function is provided, but system weight and power consumption increase significantly
Solution Approach 1:
The patent extracts and removes the condenser component from the conventional closed-circuit refrigeration system, transitioning to an open-circuit design where refrigerant vapor is discharged directly to the environment after absorbing heat in the evaporator. This elimination of the condenser significantly reduces system weight while maintaining the essential cooling function through the evaporator and refrigerant circulation components.
Solution Approach 2:
The refrigeration system is segmented into distinct functional components (receiver, evaporator, vapor pump device, back pressure regulator, exhaust line) that can operate independently. The open-circuit configuration segments the system so that refrigerant vapor is discharged separately rather than being recirculated through a condenser, reducing overall system mass while preserving cooling reliability.
2Productivity
If conventional closed-circuit refrigeration systems are used, then cooling capacity is provided, but power consumption increases due to large compressors and condensers
Solution Approach 1:
By removing the condenser from the system, the patent eliminates the energy-intensive compression and condensation process required in closed-circuit systems. The vapor pump device only needs to manage vapor discharge rather than compressing refrigerant through a full compression cycle, significantly reducing power consumption while maintaining cooling capacity through the evaporator.
Solution Approach 2:
The system changes the operating parameters of the vapor pump device to operate in vapor discharge mode rather than full compression mode. The back pressure regulator controls vapor discharge pressure, allowing the system to maintain cooling capacity with reduced energy input compared to conventional compression cycles.
3Loss of energy
If conventional closed-circuit refrigeration systems are used, then thermal energy is discharged into the environment, but system complexity and component count increase
Solution Approach 1:
The patent removes the condenser component, simplifying the system architecture. Thermal energy is still discharged into the environment through the exhaust line where refrigerant vapor is released, but the system complexity is reduced by eliminating the complex condensation and refrigerant recirculation infrastructure required in closed-circuit systems.
Solution Approach 2:
The system is segmented into simpler functional units with the open-circuit design. The exhaust line provides a direct path for thermal energy discharge without requiring the complex condenser assembly, reducing overall system complexity while maintaining the heat rejection function essential for cooling operation.
4Weight of moving object
If open-circuit configuration is used, then system weight and power consumption are reduced, but temperature control precision may be affected
Solution Approach 1:
The back pressure regulator provides feedback control for vapor discharge pressure, which indirectly controls evaporator temperature. By monitoring and regulating the pressure at which vapor is discharged, the system maintains precise temperature control in the evaporator despite the simplified open-circuit configuration and reduced system mass.
Solution Approach 2:
The system uses parameter changes in the back pressure regulator to control vapor discharge conditions, which in turn controls the evaporator temperature. This parameter-based control mechanism maintains temperature precision without requiring the heavier components of conventional systems.
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 system size and weight, consumes less power, and effectively stabilizes high heat flux load temperatures within a narrow range, while maintaining efficient heat transfer coefficients.
Implementation Method 1
an evaporator configured to receive the refrigerant fluid and to extract heat from a heat load that contacts the evaporator
Implementation Method 2
a vapor pump device having a vapor pump inlet that receives refrigerant vapor from the evaporator and having a vapor pump outlet that outputs compressed refrigerant vapor
Implementation Method 3
a back pressure regulator that receives at a back pressure regulator inlet, the compressed refrigerant vapor from the vapor pump outlet, the back pressure regulator configurable to discharge at a back pressure regulator outlet
Data Source
AI summary
A thermal management system includes an open-circuit refrigeration system having an open-circuit refrigerant fluid flow path. The open-circuit refrigeration system includes a receiver configured to store a refrigerant fluid, an evaporator configured to receive the refrigerant fluid at an evaporator inlet and to extract heat from a heat load that contacts the evaporator, and provide refrigerant vapor at an 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.