System and method of ocean thermal energy conversion and mariculture

An integrated system of ocean thermal energy conversion and mariculture comprising:

• a lagoon located adjacent to a deep ocean region having warm seawater at the surface of the region and nutrient-rich cold seawater at a predetermined depth below the surface, the surface seawater in said region having an average minimum temperature of at least about 21.degree. C and the deep nutrient-rich seawater having an average maximum temperature of no more than about 10.degree. C, the lagoon being stocked with a preselected species of edible marine fauna;
• a passageway connecting the lagoon to the adjacent ocean region;
• a closed loop power generating plant located adjacent to the lagoon, said closed loop containing a working fluid capable of operating in a Rankine cycle between the warm and cold seawater temperature, and said generating plant including
• a first heat exchanger connected in said loop and having a separate seawater side;
• means for delivering a stream of warm surface seawater from said ocean region to the seawater side of said first heat exchanger for evaporating the working fluid at a substantially constant first pressure;
• a second heat exchanger connected in said loop and having a separate seawater side;
• means for delivering a stream of cold nutrient-rich seawater from said predetermined depth of the ocean region to the seawater side of the second heat exchanger for condensing the working fluid at a substantially constant second pressure lower than said first pressure;
• pumping means connected in said loop between the second and first heat exchangers for pumping the working fluid as liquid from the second heat exchanger at said second pressure to the first heat exchanger at said first pressure;
• power generating means connected in said loop between the first and second heat exchangers for extracting useful work from the working fluid as a vapor expanding from said first pressure to said second pressure;
• and
• conduit means having an inlet connected to the seawater sides of the first and second heat exchangers and an outlet into the lagoon approximately opposite the passageway connecting the lagoon with the adjacent ocean region for mixing the streams of cooled surface seawater from the first heat exchanger and the warmed nutrient-rich deep seawater from the second heat exchanger and discharging the mixed streams into the lagoon at an optimum temperature for growth of said preselected marine fauna.