Submerged reverse osmosis system

A desalination and cooling system comprising a submerged offshore reverse osmosis desalination apparatus having:

• a) one or more submerged osmotic membranes each having an inlet surface supplied with seawater at least partially under hydrostatic pressure and an outlet surface that provides desalinated water to a submerged product water collector in fluid communication with the outlet surface(s),
• b) an at least partially submerged water discharge conduit in fluid communication with the collector and providing a pipeline that delivers the desalinated water to shore;
• and
• an onshore cooler or heat exchanger in fluid communication with the water discharge conduit,
• wherein the product water and onshore cooler or heat exchanger provide or improve the cooling of a Sea Water Air Conditioning (SWAC) system, power plant, data center, Ocean Thermal Energy Conversion (OTEC) system, or Rankine Cycle heat engine, and
• wherein the submerged apparatus includes an air supply for removing water from the collector via airlift, and an airflow valve that controls airflow into the collector or into the conduit so that the desalinated water is lifted by supplied air in an annular flow regime over 10% or more of the airlift depth.

A method for desalination and cooling, the method comprising operating a submerged reverse osmosis desalination apparatus having:

• a) one or more submerged osmotic membranes each having an inlet surface supplied with saltwater at least partially under hydrostatic pressure and an outlet surface that provides desalinated product water containing less than 0.5 parts per thousand (ppt) dissolved inorganic salts by weight to a submerged product water collector in fluid communication with the outlet surface(s),
• b) an at least partially submerged water discharge conduit in fluid communication with the collector and providing a pipeline that delivers the desalinated water to shore;
• and
• using the desalinated product water in an onshore heat exchanger in fluid communication with the water discharge conduit to provide or improve the cooling of an onshore Sea Water Air Conditioning (SWAC) system or data center.

A method for desalination and cooling, the method comprising operating a submerged reverse osmosis desalination apparatus having:

• a) one or more submerged osmotic membranes each having an inlet surface supplied with saltwater at least partially under hydrostatic pressure and an outlet surface that provides desalinated water to a submerged product water collector in fluid communication with the outlet surface(s),
• b) an at least partially submerged water discharge conduit in fluid communication with the collector and providing a pipeline that delivers the desalinated water to shore;
• and
• using the desalinated water in an onshore cooler or heat exchanger in fluid communication with the water discharge conduit to provide or improve the cooling of a Sea Water Air Conditioning (SWAC) system, power plant, data center, Ocean Thermal Energy Conversion (OTEC) system, or Rankine Cycle heat engine,
• wherein the submerged apparatus includes an air supply for removing water from the collector via airlift, and an airflow valve that controls airflow into the collector or into the conduit so that the desalinated water is lifted by supplied air in an annular flow regime over 10% or more of the airlift depth.