Brackish Water for Condensation Irrigation

Advanced Cooling Technologies, Inc. will develop a low-cost, high-efficiency condensation irrigation system to desalinate brackish water and provide affordable freshwater for agricultural applications. Solar thermal energy or low grade waste heat will be used to vaporize water from brackish water and humidify air; the hot humid air will then be sent to buried perforated condensation pipes and condensed in the pipes to supply fresh water directly to the roots of the crops. To further improve the condensation efficiency and uniformity, a simple double pipe design is used to exchange the heat from hot humid air to cold brackish water. Meanwhile, the latent heat of condensation is recovered to pre-heat cold brackish water, so as to reduce required solar energy for desalination and therefore save the agricultural area needed for solar collection. By adopting the proposed system, it will make fresh water from the brackish water available for irrigation at a reasonable cost, while avoiding the degradation of farmland by brackish water. In summary, thisthermally enhanced condensation irrigation system has the following features:• Enable the use of brackish water and seawater for irrigation in areas lack of fresh water resources;• High solar energy utilization efficiency due to the heat recovery during condensation; and• Less solar area required, which leads to competitive price for irrigation with brackish water.