Thermal management systems and methods for cooling a heat load with a refrigerant fluid managed with a closed-circuit cooling system
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Solution Overview
Problem
Conventional refrigeration systems are heavy and power-intensive, making them unsuitable for mobile platforms and applications requiring precise temperature control of high heat flux, temperature-sensitive loads due to their large size and weight, and inefficiencies in thermal energy management.
Innovation Solution
A thermal management system utilizing an open-circuit refrigeration system with a liquid refrigerant receiver and integrated cooling, which reduces the refrigerant flow rate and charge needed, incorporating a back-pressure regulator and ammonia as the refrigerant, to achieve compactness and efficiency in cooling high heat flux loads while maintaining precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional closed-circuit refrigeration systems are used, then significant thermal energy can be absorbed and discharged, but the system becomes heavy and consumes large amounts of power
Solution Approach 1:
The patent extracts the essential cooling function from the heavy closed-circuit system by using an open-circuit design where refrigerant is stored in a receiver and evaporated on-demand in an evaporator, eliminating the need for continuous operation of heavy components like compressors and condensers, thereby achieving significant weight reduction while maintaining thermal energy absorption capability
Solution Approach 2:
The system pre-cools the refrigerant in the receiver before it reaches the evaporator, and pre-charges the receiver with cooled refrigerant in advance, allowing the evaporator to immediately begin cooling the heat load without waiting for the refrigerant to reach operating temperature, thus maintaining efficient thermal energy absorption with reduced system mass
2Productivity
If conventional refrigeration systems are designed for large heat removal capacity, then cooling performance is improved, but system size and power consumption increase
Solution Approach 1:
The open-circuit system uses partial action by only evaporating the amount of refrigerant needed in the evaporator at any given time, rather than continuously circulating large amounts of refrigerant through the entire closed circuit. This on-demand evaporation approach maintains adequate cooling capacity while significantly reducing the power required to pump and compress refrigerant throughout the system
3Duration of action of moving object
If conventional systems are used for short-duration cooling, then cooling function is provided, but system weight and complexity remain high
Solution Approach 1:
The patent removes unnecessary components from the conventional closed-circuit system, retaining only the essential elements (receiver, evaporator, expansion device) needed for short-duration cooling applications. This extraction of essential functions eliminates complex control systems, large condensers, and continuous circulation mechanisms, thereby reducing overall system complexity while maintaining effective cooling for the required duration
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 a more compact and lightweight design with reduced power consumption, effectively managing thermal energy and maintaining precise temperature control for high heat flux, temperature-sensitive components, suitable for mobile applications.
Implementation Method 1
an evaporator configurable to receive refrigerant fluid from the receiver outlet and to extract heat from a heat load when the heat load contacts or is in proximity to the evaporator
Implementation Method 2
a liquid separator configurable to separate the refrigerant fluid from the evaporator and provide refrigerant vapor at the vapor side outlet of the liquid separator
Data Source
AI summary
A thermal management system includes an open-circuit refrigeration system including a cooling system configured to supply a cooling medium. The open-circuit refrigeration system includes a receiver having a receiver outlet, the receiver configurable to store a refrigerant fluid, the receiver configured to receive the cooling medium from the cooling system, an evaporator coupled to the receiver outlet, the evaporator configurable to receive liquid refrigerant fluid from the receiver outlet and to extract heat from a heat load when the heat load contacts or is proximate to the evaporator a control device configurable to control a temperature of the heat load and an exhaust line, with the receiver, the evaporator, and the exhaust line coupled to form an open-circuit refrigerant fluid flow path.