Underwater OTEC Condenser Design for Pipe Reliability
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Solution Overview
Problem
Conventional ocean thermal energy conversion (OTEC) plants face low thermal efficiency and high manufacturing costs due to the large diameter of sea water pipes required for transporting deep sea water, which are prone to damage from harsh marine conditions.
Innovation Solution
The OTEC system locates a condenser underwater between 50-100 meters below the sea surface, allowing direct suction of deep sea water and reducing the need for large diameter pipes, with the condenser connected to a working fluid pump and turbine, and using a smaller diameter deep sea water suction pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large diameter sea water pipe is used to transport deep sea water, then the power generation capacity is sufficient, but the manufacturing cost increases and reliability decreases
Solution Approach 1:
The invention changes the spatial dimension by submerging the condenser underwater (50-100 meters below sea surface) instead of keeping it on land. This dimensional change allows the system to access cold deep sea water directly at the condenser location, eliminating the need for large diameter pipes to transport cold water from great depths, thus resolving the contradiction between power generation capacity and pipe reliability
Solution Approach 2:
The invention extracts the condenser from the land-based plant structure and places it independently underwater. This separation allows the cold water suction pipe to be positioned directly in the cold water source, eliminating the need for long-distance transport of large volumes of cold water through vulnerable large diameter pipes, thereby improving reliability while maintaining power generation capacity
2Productivity
If a large diameter sea water pipe is used to transport deep sea water, then the power generation capacity is sufficient, but the manufacturing cost increases
Solution Approach 1:
By submerging the condenser underwater, the system accesses cold deep sea water in situ, eliminating the need for expensive large diameter pipes (which account for about 20% of manufacturing cost) while maintaining sufficient power generation capacity through direct heat exchange at the underwater location
3Ease of operation
If the condenser is located on land, then the plant operation is easier, but large diameter pipes are required which are prone to damage
Solution Approach 1:
The condenser is extracted from the land-based operation and placed underwater, directly in the cold water source. This eliminates the need for large diameter pipes that are vulnerable to marine environment damage (bending stress, shear force, vibration, warping) while the plant can still be operated from land through remote control and monitoring systems
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 configuration enhances thermal efficiency and reduces manufacturing costs by minimizing pipe diameter and improving reliability, while maintaining power generation capacity.
Implementation Method 1
the working fluid in turn has to release thermal energy to the deep sea water through a condenser
Implementation Method 2
the working fluid in turn has to release thermal energy to the deep sea water through a condenser
Implementation Method 3
the surface sea water has to transfer thermal energy to a working fluid through an evaporator
Implementation Method 4
the surface sea water has to transfer thermal energy to a working fluid through an evaporator
Implementation Method 5
employs Rankine cycle power system to convert the temperature thermal energy (a temperature difference) between warm surface sea water and cold deep sea water into rotational kinetic energy by a turbine
Implementation Method 6
The working fluid flows between the working fluid pump, the evaporator, the turbine, and the condenser under the driven of the working fluid pump
Data Source
AI summary
An ocean thermal energy conversion (OTEC) system includes a working fluid pump, an evaporator, a turbine, a condenser, and a working fluid. The evaporator is connected to the working fluid pump. The turbine is connected to the evaporator. The condenser is respectively connected to the turbine and the working fluid pump, and located in a sea area below sea surface. The condenser includes a condenser main body and a deep sea water pipe. The condenser main body is respectively connected to the turbine and the working fluid pump. The deep sea water pipe is connected to the condenser main body, and has an inlet end and an outlet end. The deep sea water pipe is connected to the condenser main body via the outlet end. The working fluid flows between the working fluid pump, the evaporator, the turbine, and the condenser under the driven of the working fluid pump.