Thermosiphon Evaporator Flow Restriction for Compact Rack Cooling
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Solution Overview
Problem
The limited space in server racks poses a challenge for thermosiphon systems designed to remove heat from electronic devices, and existing systems often suffer from inefficiencies in heat transfer, leading to potential device failure due to overheating.
Innovation Solution
The thermosiphon system incorporates a condenser with multiple vertical chambers and undulations on internal surfaces, along with a flow restrictor in the evaporator to create a thin liquid layer, reducing thermal resistance and enhancing heat transfer efficiency, while also optimizing the design to fit within the constrained space of server racks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thermosiphon system is designed to fit within limited server rack space, then the system compactness is improved, but the heat transfer efficiency deteriorates due to reduced space for heat exchange surfaces
Solution Approach 1:
The condenser chambers are nested vertically within the evaporator housing, with multiple condensation surfaces arranged in a compact vertical configuration. This nesting approach allows extensive heat exchange surfaces to be contained within a reduced overall system volume, resolving the contradiction between compactness and heat transfer efficiency.
Solution Approach 2:
The patent transitions from horizontal heat exchange surface arrangement to vertical stacking of condenser chambers. By utilizing the vertical dimension within the evaporator housing, the system achieves increased heat transfer surface area without proportionally increasing the system's footprint, thereby maintaining heat transfer efficiency while improving compactness.
2Reliability
If the condenser is designed with multiple vertical chambers to increase heat transfer surface area, then the heat transfer efficiency is improved, but the device complexity increases
Solution Approach 1:
Multiple condenser chambers are merged into a single integrated condenser assembly that fits within the evaporator housing. The chambers share common structural elements and are fluidly connected through a unified design, reducing the overall complexity compared to separate independent chambers while maintaining increased heat transfer surface area.
Solution Approach 2:
The evaporator housing serves multiple functions: it contains the evaporator components, provides structural support, and houses the nested condenser chambers. This multi-functionality reduces the need for additional separate components, thereby decreasing device complexity while maintaining the benefits of multiple vertical condenser chambers.
3Volume of moving object
If the condenser lacks a top header to reduce vertical space, then the system compactness is improved, but the fluid flow management becomes more difficult
Solution Approach 1:
Instead of having condenser chambers connect to a top header and drain downward, the chambers are configured to drain upward or laterally to a condensate collection point. This inverted drainage approach eliminates the need for a top header while maintaining effective fluid flow management through gravity-assisted condensate return.
Solution Approach 2:
A condensate collection chamber or intermediate drainage structure is introduced within the evaporator housing to collect and redirect condensate from the vertical chambers. This intermediary structure simplifies fluid flow management by centralizing condensate collection and return, eliminating the need for a complex top header configuration.
4Reliability
If undulations are added to the condenser internal surfaces to reduce thermal resistance, then the heat transfer efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
Undulated or curved internal surfaces are formed on the condenser chambers using molding or forming techniques during manufacturing. These curved surfaces promote thinner and more uniform condensate film distribution, reducing thermal resistance. The curvature is integrated into the manufacturing process rather than requiring post-processing, thereby limiting the increase in manufacturing complexity.
5Reliability
If a flow restrictor is used in the evaporator to create a thin liquid layer and reduce thermal resistance, then the heat transfer efficiency is improved, but the device complexity increases
Solution Approach 1:
The flow restrictor creates a thin liquid layer specifically in the region where the evaporator contacts the electronic device, which is the critical heat transfer zone. By applying the thin liquid layer locally rather than uniformly throughout the evaporator, the system achieves improved heat transfer efficiency with minimal additional complexity, as the restrictor geometry is tailored to the specific thermal requirements of the contact region.
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 reduces thermal resistance in both the evaporator and condenser, improving heat transfer efficiency and reducing the likelihood of flooding, thus preventing device failure and enhancing overall cooling performance within the limited server rack environment.
Implementation Method 1
a wick located in the housing and in communication with the opening to the condensate line
Implementation Method 2
a flow restrictor located in the housing configured to restrict flow of a working fluid from the condensate line onto a portion of the wick
Implementation Method 3
A liquid form of the fluid is vaporized in an evaporator, and heat is carried by the vapor form of the fluid from the evaporator to a condenser
Implementation Method 4
In the condenser, the vapor condenses, and the liquid form of the fluid is then returned via gravity to the evaporator
Implementation Method 5
heat is carried by the vapor form of the fluid from the evaporator to a condenser
Implementation Method 6
the liquid form of the fluid is then returned via gravity to the evaporator
Implementation Method 7
The inner surfaces of the condenser can include undulations that reduce thermal resistance across the liquid film in the condenser
Data Source
AI summary
A thermosiphon system includes a condenser and an evaporator fluidly coupled to the condenser by a condensate line. The evaporator includes a housing having an opening to the condensate line, a wick located in the housing, and a flow restrictor located in the housing configured to restrict flow of a working fluid from the condensate line onto a portion of the wick.