Design Of A Concrete Cold Water Pipe For Ocean Thermal Energy Conversion (OTEC) Systems

1979 ◽  
Author(s):  
W.J. Cichanski ◽  
R.F. Mast
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Cold Water ◽  
Water Pipe ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Current Developments in the Validation of Numerical Methods for Predicting the Responses of an Ocean Thermal Energy Conversion (OTEC) System Cold Water Pipe

2014 ◽  
Author(s):  
John Halkyard ◽  
Rizwan Sheikh ◽  
Thiago Marinho ◽  
Shan Shi ◽  
Matthew Ascari
Keyword(s):  
Numerical Methods ◽  
Energy Conversion ◽  
Thermal Energy ◽  
Cold Water ◽  
Oil Prices ◽  
Model Tests ◽  
Water Pipe ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Ocean Thermal Energy Conversion (OTEC) was a subject of intense research in the late 1970s and early 1980s in response to a historical jump in oil prices from the 1973 oil embargo. The principal author for this paper first met Prof. Paulling as a participant in a National Research Council (NRC) Panel to review OTEC Technology around 1982. Prof. Pauling had authored a frequency domain program to analyze the coupled response of a platform and OTEC pipe. The author was involved in model tests to validate the program. The United States (U.S.) Department of Energy (DoE) and National Oceanic and Atmospheric Administration (NOAA) had sponsored this work, along with the development of other numerical methods. Shortly after the NRC completed its review, oil prices fell and interest in renewable energy, including OTEC, evaporated. Fast forward to the 2000s, the price of oil skyrocketed again, and OTEC research saw a rebirth. Lockheed Martin and others have been working on new OTEC designs over the course of the last several years. As was the case thirty-five years ago, the cold water pipe remains a key technical challenge. A commercial scale OTEC plant requires a pipe diameter of about 10-meter (m) and a length of 1,000m to pump about half the average discharge of the Colorado River from the deep ocean to the surface and through heat exchangers. Because of the large effective mass of the CWP and entrained water, the dynamic response of the OTEC CWP and the platform can only be considered as a coupled system. This conclusion is not new, but is worth repeating and doubly important to consider when the supporting platform is a semi-submersible as opposed to a large water plane ship shaped vessel. A new generation of software is available to analyze the cold water pipe-platform responses, including the important effect of the fluid flow inside the pipe and the local effects at the connection of the pipe to the platform. The DoE and Lockheed Martin recently sponsored a 1:50 scale wave basin model test of a commercial OTEC platform with an elastically scaled model of a 10m pipe. The purpose of the test was to validate the use of current software for the large CWP diameters in the designs of a pilot or commercial systems in the near future. This paper will briefly review past work on the OTEC cold-water pipe and present the current state of the art in numerical modeling and the results of the model tests recently completed. It will include recommendations for further experimental and numerical work to be prepared for the future design of OTEC systems.

Design and Construction of an Ocean Thermal Energy Conversion Test Plant

1980 ◽  
Vol 102 (1) ◽  
pp. 41-46 ◽  
Author(s):  
L. C. Trimble ◽  
R. L. Potash
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Cold Water ◽  
Seawater Temperature ◽  
Test Plant ◽  
Deep Seawater ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Power Plant Control ◽  
Ocean Thermal Energy

Mini-OTEC, shown in Fig. 1, is the first at-sea, closed-loop Ocean Thermal Energy Conversion (OTEC) system using surface and deep seawater to generate electric power. The Mini-OTEC cycle is installed on a moored barge incorporating the cold water pipe (CWP) in the single anchor leg. The design seawater temperature difference (ΔT) of 36°F provides thermal resource for a gross power output of 50 kW. This paper presents an overview of the Mini-OTEC project, including a description of the power plant, control system, instrumentation, and CWP mooring system.

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