Development of a salinity gradient power: upwelling tests using FLIP

A series of upwelling experiments were conducted onboard the research platform FLIP in May 2004 off San Diego, California. The objective was to test the relationship between pipe length and seawater entrainment or exit velocity towards development of a salinity gradient power source. Tubes with a diameter of 45 cm and lengths of 30 m to 60 m were attached to the hull of FLIP and suspended vertically in the water column. Freshwater was injected into the base of the vertical tubes at rates varying from 3.2 times 10^-2 to 6.3 times 10^-2 m³/s. A strong linear response to fresh water input was observed. However, no differences in entrainment ratios were noted directly among the three tube lengths over the conditions of the experiment. The data will be used, in collaboration with a municipal sanitation district, to develop a 20 kW hydrocratic pilot plant that will utilize the effluent stream from a wastewater treatment facility