Integrated vapor cycle and pumped two-phase cooling system with latent thermal storage of refrigerants for transient thermal management
Solution Overview
Problem
Current two-phase cooling systems for transient heat loads, such as laser diodes, are inefficient and bulky due to the need for external heat sinks and sequential thermal loops, which increase power consumption and size, especially when handling high heat fluxes.
Innovation Solution
A cooling system that integrates a subcooler/superheater in a single heat exchanger, eliminating the need for external heat sinks, and includes a compressor, condenser, and flash tank with variable speed components and adjustable expansion valves to manage refrigerant pressure and temperature, allowing for efficient heat removal and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a vapor cycle system with thermal storage is used to buffer maximum heat loads, then the size of the VCS can be reduced, but the system becomes heavy and bulky due to additional loops and components
Solution Approach 1:
The patent combines the thermal storage function directly within the flash tank, merging the storage loop with the cooling loop. This eliminates the need for separate hot/cold tanks and multiple piping loops, reducing system complexity while maintaining the ability to buffer heat loads.
Solution Approach 2:
The flash tank serves multiple functions: it acts as both the thermal storage device and the evaporator for the VCS. By making the flash tank multi-functional, the patent eliminates redundant components and simplifies the overall system structure while achieving both heat load buffering and refrigeration.
2Volume of stationary object
If pre-chilling coolant to a temperature below heat load is used to minimize storage tank size, then thermal storage capacity is improved, but power consumption for the VCS increases due to higher thermal lift
Solution Approach 1:
The patent changes the operating parameters of the VCS by using variable speed compressors and adjustable expansion valves to optimize the refrigerant pressure and temperature. This allows the system to achieve efficient cooling without requiring excessive thermal lift, thereby reducing power consumption while maintaining compact storage.
Solution Approach 2:
The system employs dynamic control through variable speed compressors and adjustable expansion valves that can adapt to different heat load conditions. This dynamic adjustment optimizes the balance between storage tank size and power consumption by matching the cooling capacity to the actual heat load requirements.
3Temperature
If sequential pull down of three thermal loops is used for cooling, then temperature control is achieved, but significant start-up time is required
Solution Approach 1:
The patent merges the thermal storage loop with the cooling loop by using the flash tank as both storage and evaporator. This single-loop integrated design eliminates the need for sequential operation of multiple loops, enabling simultaneous cooling and storage functions that dramatically reduce start-up time while maintaining precise temperature control.
4Productivity
If constant pressure in the condenser and flash tank is maintained, then heat removal capability is improved, but an external heat sink is required which defeats the purpose of the thermal lift loop
Solution Approach 1:
The system uses the flash tank's own phase change process to provide the necessary subcooling and pressure regulation. The refrigerant flashes from liquid to vapor in the flash tank, and this self-generated phase change provides the cooling effect without requiring an external heat sink, making the system self-sufficient while maintaining high heat removal capability.
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 provides robust cooling for both steady and transient heat loads, reducing system size and power consumption by maintaining constant refrigerant pressure and level in the flash tank, while ensuring adequate heat removal and precise temperature control.
Implementation Method 1
latent heat of vaporization of a recirculating refrigerant is used for cooling
Implementation Method 2
latent heat of vaporization of a recirculating refrigerant is used for cooling
Implementation Method 3
a subcooler/superheater downstream of the flash tank
Implementation Method 4
a compressor downstream of the subcooler/super-heater
Implementation Method 5
a condenser downstream of the compressor and upstream of the flash tank
Data Source
AI summary
A cooling system uses refrigerants for two-phase cooling and thermal energy storage for a transient heat source. The cooling system includes a flash tank downstream of a heat load to be cooled. A subcooler/super-heater is downstream of the flash tank. A compressor is downstream of the subcooler/super-heater. A condenser is downstream of the compressor and upstream of the flash tank.