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 pre- vail, 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.