Phase-Change Liquid Cooling with Sub-Ambient Bypass Operation
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Solution Overview
Problem
Conventional cooling systems for power electronic devices require energy-intensive vapor compression circuits to maintain sub-ambient temperatures, which can be inefficient when ambient temperatures are below the device's operating environment.
Innovation Solution
A pumped liquid cooling system utilizing a refrigerant-to-refrigerant heat exchanger in series with a condenser, allowing for efficient cooling without activating the vapor compression circuit when ambient temperatures are below the device's environment, and switching to vapor compression when necessary, thereby optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a vapor compression circuit is used to cool power electronic devices, then sub-ambient temperatures can be achieved, but energy consumption increases significantly
Solution Approach 1:
The refrigerant-to-refrigerant heat exchanger serves multiple functions: it acts as a condenser for the first refrigerant circuit and an evaporator for the second refrigerant circuit simultaneously. This multi-functionality allows the system to achieve sub-ambient cooling without requiring a traditional vapor compression circuit with compressor, expansion valve, and separate evaporator, thereby significantly reducing energy consumption while maintaining the ability to cool to sub-ambient temperatures.
2Temperature
If the vapor compression circuit is always activated to maintain cooling, then temperature control is ensured, but energy efficiency decreases when ambient temperature is already below operating environment
Solution Approach 1:
The system dynamically switches between two operating modes based on ambient temperature conditions. When ambient temperature is below the desired operating environment, the system uses the refrigerant-to-refrigerant heat exchanger in a heat exchange mode without activating the vapor compression circuit. When ambient temperature rises above the desired operating environment, the system activates the vapor compression circuit through the control valve to provide active cooling. This dynamic adaptation optimizes energy efficiency while ensuring temperature control is maintained under varying ambient conditions.
3Use of energy by moving object
If a simple pumped liquid cooling system is used, then energy consumption is reduced, but the system cannot achieve sub-ambient cooling when ambient temperature is high
Solution Approach 1:
The refrigerant-to-refrigerant heat exchanger acts as an intermediary between two refrigerant circuits. The first circuit (pumped liquid cooling) provides efficient heat removal with low energy consumption, while the second circuit (vapor compression) provides sub-ambient cooling capability when needed. The heat exchanger mediates thermal energy transfer between these two circuits, allowing the system to achieve sub-ambient cooling by transferring heat from the first refrigerant to the second refrigerant, thereby combining the energy efficiency of pumped liquid cooling with the sub-ambient capability of vapor compression only when necessary.
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 effectively cools power electronic devices by reducing energy consumption and preventing refrigerant trapping, ensuring efficient operation across varying ambient temperature conditions.
Implementation Method 1
a refrigerant-to-refrigerant heat exchanger having first and second flow passages in heat exchange relationship
Implementation Method 2
at least one evaporator located in a first environment having a first ambient temperature
Implementation Method 3
whereby a first two-phase refrigerant can be circulated by the pump through the evaporator
Implementation Method 4
to the first condenser where the refrigerant is condensed and cooled
Implementation Method 5
a vapor compression circuit including an expansion valve, a second condenser, and a compressor
Data Source
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AI summary
Provided is a cooling system wherein a first two-phase refrigerant can be circulated by a pump through an evaporator, to a first condenser, to a refrigerant-to-refrigerant heat exchanger and back to the pump. By providing the refrigerant-to-refrigerant heat exchanger in series with the condenser, a first environment can be cooled without having to operate a vapor compression circuit when an ambient temperature outside the first environment is a predetermined amount below an ambient temperature in the first environment.