Counter-Flow Flat-Tube Cooling Loop for Low-Pressure Server Racks
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Solution Overview
Problem
Cooling systems for data centers face challenges in efficiently managing the increasing heat loads from high-density computer servers, with existing solutions experiencing pressure drops and compromised performance due to high temperature differences and leakage concerns.
Innovation Solution
A single-phase fluid cooling system utilizing fluoroketone (FK) fluid with micro-encapsulated phase change material, coupled with multi-row counter-flow heat exchangers and extruded aluminum tubes, which operates under low pressure and is safer than water-based systems, providing efficient heat transfer and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling systems are used to handle increasing heat loads, then cooling capacity is improved, but pressure drops and leakage risks increase
Solution Approach 1:
The patent changes the physical parameters of the cooling fluid by using fluoroketone-based refrigerant with specific thermodynamic properties (low specific heat, high temperature difference capability) instead of conventional cooling fluids. This parameter change allows efficient heat transfer at lower pressures, reducing leakage risks while maintaining cooling capacity
Solution Approach 2:
The patent utilizes phase change material micro-encapsulated within the fluoroketone fluid. During cooling operation, these micro-encapsulated phase change materials absorb and release latent heat, enhancing the cooling effect and temperature regulation capability without requiring high pressure systems
2Use of energy by moving object
If high temperature difference is used to improve heat transfer efficiency, then energy efficiency is improved, but system reliability deteriorates due to leakage concerns
Solution Approach 1:
The system operates with optimized temperature differences by leveraging the unique thermodynamic properties of fluoroketone refrigerant. The low specific heat of the refrigerant allows for efficient heat absorption with moderate temperature differences, while the inherent chemical stability and low pressure operation of the fluoroketone system maintain reliability even at elevated temperature differentials
3Use of energy by moving object
If water-based cooling systems are used, then heat transfer efficiency is improved, but safety and environmental impact worsen
Solution Approach 1:
The patent replaces water-based cooling systems with fluoroketone-based refrigerant systems. The fluoroketone refrigerant has favorable safety characteristics (non-flammable, low toxicity) and environmental properties (low GWP) while maintaining efficient heat transfer capabilities through its specific thermodynamic parameters including low specific heat and appropriate operating pressure ranges
Solution Approach 2:
The cooling system uses a composite fluid formulation combining fluoroketone base refrigerant with micro-encapsulated phase change materials. This composite approach provides both efficient heat transfer properties and enhanced safety/environmental performance, eliminating the harmful aspects of water-based systems while maintaining thermal efficiency
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 high energy efficiency, reduced leakage risk, and increased 'free cooling' hours by leveraging the low specific heat and high temperature difference of FK fluid, while maintaining robust operation and minimizing environmental impact.
Implementation Method 1
The single-phase fluid circuit circulates a single-phase fluid through the heat exchanger from the first flat tube to the second flat tube
Implementation Method 2
The FK fluid includes micro-encapsulated, phase change material
Implementation Method 3
The fan moves air from the hot aisle through the heat exchanger from the second row to the first row
Data Source
AI summary
A cooling system includes a heat exchanger having one or more rows of multiple flat tubes, louvered fins disposed between pairs of flat tubes, and special header tube connections to form a counter flow heat exchanger. Heat exchangers having multiple rows may be placed near or close to the server racks and may be in fluid communication with an outdoor heat exchanger having one or more rows. A single-phase fluid is pumped through a fluid circuit or loop, which includes the heat exchangers at the server racks and the outdoor heat exchanger. The single-phase fluid circuit including the heat exchangers at the IT racks may alternatively be in thermal communication with a water circuit that includes an outdoor fluid cooler. The flat tubes can be formed tubes with one or more channels, or extruded tubes with multiple channels. The heat exchangers include header tubes/connections, which facilitate easy fabrication and connection between rows and inlet/outlet, and lower the pressure drop.