Subsea Power Module Cooling via Corrugated Tank Wall Channels
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Solution Overview
Problem
Subsea electrical equipment cooled by natural convection is thermally limited, and existing methods to enhance cooling, such as external heat exchangers and cooling fins, are either expensive or difficult to manufacture and install, prompting the need for a more efficient and space-saving cooling solution.
Innovation Solution
A subsea power module with a tank featuring outwardly protruding corrugations and a duct system that uses a pump to circulate dielectric liquid through narrow gaps between the duct and the tank wall, enabling efficient forced-convection cooling without the need for external heat sinks or contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external heat exchangers are provided to enhance cooling, then cooling performance is improved, but construction cost and complexity increase due to marinization requirements and risk of damage during transport and installation
Solution Approach 1:
The invention merges the heat exchanger function directly into the tank wall by forming cooling channels within the wall structure itself. This integration eliminates the need for separate external heat exchanger components, thereby reducing construction complexity and eliminating damage risks during transport while maintaining effective cooling performance through the integrated channels.
Solution Approach 2:
The cooling channels are nested within the tank wall structure, with the heat exchanger function embedded inside the wall thickness. This nesting approach allows the cooling system to be housed within the existing tank structure without adding external protrusions, simplifying construction and reducing vulnerability to damage.
2Temperature
If cooling fins are extended from the tank wall to increase heat transfer area, then cooling efficiency is improved, but manufacturing difficulty increases due to contact resistance and bonding challenges
Solution Approach 1:
Instead of adding separate cooling fins that require bonding or clamping to the tank wall, the invention merges the heat transfer function directly into the tank wall by forming channels within the wall structure. This eliminates the manufacturing challenges of bonding high thermal conductivity materials to the tank wall and avoids contact resistance issues associated with clamped fins.
Solution Approach 2:
The invention extracts the heat transfer function from the concept of external fins and relocates it into the tank wall structure itself. By forming cooling channels within the wall, the system achieves extended heat transfer area without the manufacturing complexities of attaching external fin structures.
3Reliability
If natural convection cooling is used, then reliability is improved by eliminating mechanical pumps, but cooling performance becomes thermally limited
Solution Approach 1:
The dielectric liquid serves multiple functions: it provides electrical insulation, absorbs heat from power components, and circulates through the cooling channels in the tank wall. The system utilizes the liquid's own circulation properties, combining natural convection reliability with enhanced heat transfer through the integrated wall channels, achieving both reliability and improved cooling performance.
4Temperature
If the tank wall is made thicker to accommodate cooling channels, then cooling functionality is improved, but the space available for power components is reduced
Solution Approach 1:
The cooling channels are formed locally within the tank wall structure rather than requiring uniform thickening of the entire tank. This localized approach allows effective cooling functionality to be integrated into the wall where needed, while minimizing the impact on the overall internal volume available for power components.
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
This solution achieves high dielectric liquid side heat transfer coefficients, up to 300 W/(m²K), while being space-efficient and avoiding the drawbacks of traditional cooling methods, such as contact resistance and manufacturing complexities.
Implementation Method 1
efficient forced-convection cooling is enabled by squeezing the dielectric liquid through the narrow gaps
Implementation Method 2
The dielectric liquid side heat transfer coefficient hdielectric-wall is inversely proportional to s
Implementation Method 3
enabling dielectric liquid that has been discharged through the at least one duct outlet into the chamber to be squeezed out from the chamber and the corrugation
Data Source
AI summary
A subsea power module including: a tank having a tank wall provided with an outwardly protruding corrugation, a power device arranged in the tank, a dielectric liquid which fills the tank, for cooling the power device, a pump configured to circulate the dielectric liquid in the tank, wherein the pump has a pump inlet and a pump outlet, a duct arranged in the corrugation such that a chamber is formed between a tip of the corrugation and the duct, wherein the duct has a duct inlet connected to the pump outlet, and wherein the duct is provided with at least one duct outlet opening into the chamber, and a distancing structure configured to space apart an outer surface of the duct facing the tank wall and the tank wall in the corrugation, whereby gaps are formed between the duct and the tank wall in the corrugation, enabling dielectric liquid that has been discharged through the at least one duct outlet into the chamber to be squeezed out from the chamber and the corrugation, and flow towards the pump inlet.