Extraction of Fresh Water from Marine Air Using a Seawater Heat Sink

The concept of condensing fresh water from warm, moist air using cool seawater as a heat sink is investigated. A location in the Virgin Islands is considered where the condensator is operated in parallel with a 10 MW OTEC plant. The slight temperature increase in cold seawater within the OTEC system is more than compensated by the reduction in capital costs of a larger intake pipe. Minimum fresh water production rates of 1.5 MGD are examined with extended capabilities to over 3 MGD. 1.5 MGD can be produced by a simple open condenser system with a power load of only 1.3 MW. A spray-cooled system is also investigated and is found to have significantly greater energy costs. The condensator would produce more than 14 million CFM of cool air (51 deg. F) suitable for local air conditioning. The system appears to offer advantages of simplicity, reliability and low cost.