Offshore Cable Pipe Cooling Without Freezing or Expansion Tanks
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Solution Overview
Problem
Offshore power cables face cooling challenges at above-sea level ends, where they are not adequately cooled, potentially leading to damage from freezing or the need for additional expansion systems due to thermal expansion during power transmission.
Innovation Solution
A method involving a pipe with a temperature-dependent cooling liquid distribution, where the liquid fills only the underwater portion at lower temperatures and expands into the above-sea portion during heating, eliminating the risk of freezing and the need for additional expansion tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water is filled into the pipes to cool the power cables, then the cooling effect is improved, but the risk of freezing and the need for expansion tanks increases
Solution Approach 1:
The pipe is divided into a first portion (underwater) and a second portion (above sea level). The cooling liquid is contained only in the first portion, while the second portion remains free of cooling liquid. This segmentation allows the cooling system to avoid freezing risks in the above-water portion while maintaining cooling effectiveness in the underwater portion.
Solution Approach 2:
Different portions of the pipe have different functional requirements. The first portion (underwater) requires cooling liquid for cable cooling, while the second portion (above water) should remain free of cooling liquid to avoid freezing. The invention applies local quality by providing cooling liquid only where it is needed and safe to do so.
2Temperature
If expansion tanks are added to accommodate heated cooling liquid, then thermal expansion is managed, but device complexity and cost increase
Solution Approach 1:
The invention merges the cooling function with the pipe structure itself. The first portion of the pipe serves dual purposes: it acts as both the cable conduit and the cooling liquid containment vessel. This eliminates the need for separate expansion tanks, as the pipe's own structure accommodates the cooling liquid and its thermal expansion.
Solution Approach 2:
The pipe structure is given multiple functions: it serves as the cable conduit, the cooling liquid containment vessel, and the expansion accommodation space. By making the pipe multi-functional, the invention eliminates the need for additional dedicated expansion tanks, reducing device complexity and cost.
3Temperature
If cooling liquid is placed in the above-sea level portion of the pipe, then cooling coverage is improved, but the risk of freezing increases
Solution Approach 1:
The pipe is segmented into a first portion (underwater) and a second portion (above sea level). The cooling liquid is confined to the first portion where the ambient water temperature prevents freezing, while the second portion remains free of cooling liquid, eliminating freezing risk in the above-water section.
Solution Approach 2:
The invention applies local quality by providing cooling liquid only in the first portion (underwater) where the ambient temperature conditions prevent freezing. The second portion (above water) is deliberately kept free of cooling liquid to avoid exposure to freezing temperatures, thus eliminating the harmful freezing effect in that 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
This solution ensures the power cables are protected from freezing and thermal expansion without additional infrastructure, maintaining efficient operation and reducing costs by using the pipe's structure to manage cooling liquid volume.
Implementation Method 1
when the cooling liquid cools the electrical cable and, therefore, has a second temperature higher than the first temperature, it is expanded from the first portion into the second portion
Implementation Method 2
the cooling liquid cools the electrical cable
Data Source
AI summary
A method for installing an offshore installation is provided, the method including: a) providing a pipe for connecting the offshore installation with another offshore installation or an onshore installation; b) arranging an electrical cable inside the pipe; c) determining a level at or above the seabed, wherein the pipe includes a first portion arranged below the determined level and a second portion arranged above the determined level, and wherein the electrical cable is arranged inside the pipe so as to form a gap with an inner wall of the pipe along the first and second portion; d) determining an amount of cooling liquid such that, when the cooling liquid has a first temperature, the cooling liquid fills the gap along the first portion of the pipe, wherein the second portion of the pipe is free of the cooling liquid, and when the cooling liquid cools the electrical cable.