Standardization of deep sea cold water pipe configuration for desalination plants in Lakshadweep islands

Low temperature thermal desalination plants that use the ocean thermal gradient between surface water and that at about 400 m depth were established at Kavaratti, Agatti and Minicoy islands in the Union Territory of Lakshadweep by National Institute of Ocean Technology. Agatti desalination plant has been commissioned in 2011. One of the major components of the plant is the 850 m, long 0.65 m diameter cold water pipe that supplies the 12°C cold water from about 400m water depth. Issues such as pipe surfacing in the deep water portion due to current reversal in the Lakshadweep Sea, required revisiting the analysis. The complexity in the design and installation of deep sea cold water pipe is that the bare pipe is always exposed to waves and current in the breaking and shoaling zone. The paper presents the standardization of cold water pipe design for various island bathymetry conditions that required analyzing the lengths for shallow water and deep water portions by global analysis.