Desalination, Vol.365, 250-260, 2015
The Bubble-Greenhouse: A holistic sustainable approach to small-scale water desalination in remote regions
The Bubble-Greenhouse system combines the well established Seawater Greenhouse concept with a novel humidification-dehumidification (HD) process, based on the large air/water interface generated by bubbling air through a water filled column. Multistage bubble evaporators and multistage bubble condensers allow for effective recovery and reuse of latent heat via a heating/cooling circuit throughout all column stages. The system can operate with salinities of 5000-35,000 ppm. Following the HD process, cooled vapour provides the tropical type greenhouse with a humid environment for selected crops. Additional condensation occurs along the greenhouse skin and is gravity-fed to drip line irrigation. Low grade energy options such as solar-thermal, photovoltaic, wind, geo-thermal and salinity-gradient solar ponds provide the energy for the Bubble-Greenhouse. Alternatively, waste heat from diesel power stations nearby can provide cogeneration of electricity and bubble evaporator heat and pressure requirements. Crops grown inside a greenhouse demonstrate a strongly reduced water demand and the closed environment protects crops from insects and diseases. As the technology is conceptually simple to implement, it holds great potential for community participation, empowerment, skills development and capacity building of local people in remote locations. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Bubble evaporation;Multi-stage bubble condenser;Thermal desalination;Greenhouse water desalination;Greenhouse food production;Remote community development