The Direct Use of Ocean Thermal Gradients for Freshwater Production

This is a scheme to utilize the low grade energy represented by the temperature difference between the deep and surface water of the oceans. If appropriate atmospheric and oceanic conditions prevail, this system can be used to condense fresh water directly from the atmosphere in quantities large enough to be used as a potable water source by coastal residents. Cold deep sea water is used as a heat sink for a condenser which extracts part of the atmospheric water vapor burden. The required size of the condenser is minimized by utilizing a spray chamber. Model experiments have been performed and are summarized. The basic thermodynamic constraints on the system are explored. The results of these investigations demonstrate a low cost, low technology alternative to conventional desalination plants.