Study On Achieving Economic Combined Utilization Of Seawater By Solar Chimney Technology

Aiming at eliminating the shortages of solar chimney, solar desalination andenvironmental requirement being considered, combined systems utilizing seawater bysolar chimney technology were put forward. Solar greenhouse technology andchimney technology were used for enhancing water evaporation. Evaporated waterwas condensed through heat transferring and was collected as freshwater. Remainingcondensation heat or condensed water was respectively applied for wind power orhydraulic power generation.Preliminary theoretical analyses were firstly introduced to evaluate thefeasibilities of technology and economy. A large scale greenhouse of new materialswas set up and theoretically predicted to provide basic design data for combinedsystem without evaporation. Bulk air flow and evaporation being added, enhancedevaporation system using solar chimney technology was put up to investigate the airtemperature and saturation status. Compared systems of different heat storage style,different scale were established for finding the way to higher air temperature. Porousmaterials were added and optimized on its kinds, placed ways and amounts to higherair saturation status. Simple models were firstly established to analyze experimentaldata, while for the basic magnification rule, CFD method was used to detect themicroscopic mechanism of fluid flow, mass and heat transfer in different system.Condensation systems through indirect or direct heat exchanging ways were put uppartially for verifying related evaluated performance of combined system and partiallyfor detect heat transferring mechanism for system magnification.Performance evaluation results indicate that this combination way producefeasibilities of technology and economy simultaneously. High temperature differenceand heat storage performance in the large scale sealed greenhouse guarantee thereasonability of previous evaluation. It is revealed that with bulk air flow andevaporation added, air temperature decreases step by step. Also, experimental dataand analysis results show that different style or scale systems have differentheat-collector performance. It is also indicated that addition of porous materials canmake air saturated, but there is optimization on its material, amount and placementstyle. With transient data introduced, predicted results from CFD agree better withexperimental data. Large amount of non-condensable gases in saturated air is the mainresistance to heat or mass transfer during condensation. Simple models weredeveloped to analyze the specific mechanism through two different aspects.Attenuation factor or diffusion speed of vapor molecule was introduced tocharacterize the influence of non-condensable gases. It is believed that experimental,theoretical or simulated results in this paper will provide basic data or act as referencefor future large scale combined system. The application of this style combined systemwill blaze a way in realizing economical utilization of solar energy.