Modelling the Thermal Potential and Operation of Salinity Gradient Solar Ponds PDF Download
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Author: Sirajadien Alzin
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Access to freshwater is crucial for socio-economic development. In Libya, the demand for freshwater is soaring, but the supply is limited. Freshwater is intrinsically linked to energy where the paramount consideration for its sustainability is the amount of energy required to guarantee sufficient supplies of freshwater through seawater-desalination. This emphasises two paramount needs that should be promptly sought as a national priority, first stringent water conservation, and second the employment of sustainable energy sources to power desalination. Salinity Gradient Solar Pond (SGSP) can be one of a mix of technologies leading to a future based on sustainable energy. This study models the potential and operation of SGSPs as a source of thermal energy in Libya. The study makes an original contribution to knowledge by explaining the essence (when, how,and where) of the SGSP operational instability. It also investigates the optimum zone thicknesses ratio of the three different salinity zones constituting the SGSP; Upper Convective Zone (UCZ), middle Non-Convective Zone (NCZ), and Lower Convective Zone (LCZ) while implementing the double-diffusive convection (DDC) phenomenon. One-dimensional and two-dimensional numerical studies are conducted. The results indicate that SGSP has the potential to provide hot saline-water at a temperature exceeding 70°C for multi-effect desalination thermal vapour compression units which require a minimum top brine temperature of 60 - 65°C. At a SGSP thermal output of 55 W m−2, 46.8 m2 of land is required for the production of 1 m3 per day of distillate. The two-dimensional study explains the nature of the operational instability where the occurrence and expansion of convective cells at the interfaces of the NCZ due to DDC leads to instability. This study also gathered evidence on the effect of buoyancy ratio. Salt concentration differences separating the UCZ and the LCZ should be sustained at 300 kg m−3 to maintain stability. The optimum zone thicknesses for an average SGSP of 2 m height are 0.4, 1.2, and 0.4 meters for the UCZ, the NCZ, and the LCZ, respectively.
Author: Sirajadien Alzin
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Access to freshwater is crucial for socio-economic development. In Libya, the demand for freshwater is soaring, but the supply is limited. Freshwater is intrinsically linked to energy where the paramount consideration for its sustainability is the amount of energy required to guarantee sufficient supplies of freshwater through seawater-desalination. This emphasises two paramount needs that should be promptly sought as a national priority, first stringent water conservation, and second the employment of sustainable energy sources to power desalination. Salinity Gradient Solar Pond (SGSP) can be one of a mix of technologies leading to a future based on sustainable energy. This study models the potential and operation of SGSPs as a source of thermal energy in Libya. The study makes an original contribution to knowledge by explaining the essence (when, how,and where) of the SGSP operational instability. It also investigates the optimum zone thicknesses ratio of the three different salinity zones constituting the SGSP; Upper Convective Zone (UCZ), middle Non-Convective Zone (NCZ), and Lower Convective Zone (LCZ) while implementing the double-diffusive convection (DDC) phenomenon. One-dimensional and two-dimensional numerical studies are conducted. The results indicate that SGSP has the potential to provide hot saline-water at a temperature exceeding 70°C for multi-effect desalination thermal vapour compression units which require a minimum top brine temperature of 60 - 65°C. At a SGSP thermal output of 55 W m−2, 46.8 m2 of land is required for the production of 1 m3 per day of distillate. The two-dimensional study explains the nature of the operational instability where the occurrence and expansion of convective cells at the interfaces of the NCZ due to DDC leads to instability. This study also gathered evidence on the effect of buoyancy ratio. Salt concentration differences separating the UCZ and the LCZ should be sustained at 300 kg m−3 to maintain stability. The optimum zone thicknesses for an average SGSP of 2 m height are 0.4, 1.2, and 0.4 meters for the UCZ, the NCZ, and the LCZ, respectively.
Author: John R. Hull
Publisher: Springer
ISBN:
Category : Mathematics
Languages : en
Pages : 304
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Book Description
Despite a dearth of both water and love, the family discovers, through sorrow and fear, the green kiss of the Kappa Child, a mythical creature who blesses those who can imagine its magic -- back cover.
Author: Ibrahim Alenezi
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Solar thermal energy generated by a salinity gradient solar pond (SGSP) is one of the most promising techniques for providing heat for desalination and other applications. A solar pond is a unique, free-energy-source system for collecting, converting and storing solar energy. Saudi Arabia is one of the most solar-radiation abundant countries on the planet, but the region also has limited water resources. Studying the thermal behaviour of a SGSP under Saudi Arabian conditions for heat generation for a thermal desalination application is the aim of this study. An empirical equation is developed and a Matlab script is programmed to calculate hourly-averaged daily solar radiation (from sunrise to sunset). The results are validated through NASA's 22-year-average data for solar radiation. Mathematical models are developed to describe and simulate the thermal behaviour of a SGSP. The results are compared with a SGSP in Kuwait; the results of the steady state model are sufficiently close to the measurements. The efficiency of a solar pond depends on the salt gradient stability in the middle non-convecting zone, and the diffusion and erosion of these salt layers are considered in this study. The proposed SGSP in Riyadh, Saudi Arabia, has an area of 100 x 100m2, and the predicted temperature of the storage zone is about 100De. Higher temperatures can be reached through improved insulation and covering the surface. Additionally, an SGSP in a cold climate is suggested to compare with and test our model. The University of Surrey SGSP exceeded 80De. This renewable and sustainable heat source can be employed in desalination; the energy cost of desalinated water constitutes over 50% of operating costs. The heat removal process from the solar pond is investigated, and coupling the proposed solar pond with a Multi-Effect Evaporator (MEE) is described; the effects of various factors on the SGSP-MEE coupling are studied.
Author: Ibrahim Dincer
Publisher: Springer Nature
ISBN: 303145457X
Category : Technology & Engineering
Languages : en
Pages : 253
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Book Description
This book is about solar ponds for energy storage from various perspectives, including fundamentals, efficiencies, system designs, local applications and details about what have been done in the world in the field of solar ponds for generating energy and storage it for useful purposes.
Author: Aurora Alcaraz Segura
Publisher:
ISBN:
Category :
Languages : en
Pages : 130
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Book Description
The energy model in the last decades has been dominated by the consumption of fossil fuels assuming a high environmental cost. Global warming and the destruction of the ozone layer are two examples of the deterioration that is being suffered due to the use of these energy sources. Increasingly, the use of renewable energy one of the alternatives in building a sustainable economic model. Among renewables, solar energy is presented as an inexhaustible and accessible source of energy. The solar pond is a technology that meets all requirements to be considered an energy storage device. It can store solar energy, charging during the months of high solar incidence (Spring-Summer), storing the energy through the time and making possible its use when it is requested. A salt gradient solar pond is a body of saline water with long term thermal storage capacity. The aim and scope of this PhD thesis is divided in two parts. First, the improvement of the efficiency of the solar pond technology through experimental evaluation the heat extraction and heat supply processes under different weather conditions. These experiments were carried out in a 50 m2 solar pond pilot plant located in Martorell (Catalonia). Heat extraction experiments were performed using both heat exchangers installed (lateral and bottom) individually or both at the same time. The results demonstrated that the efficiency of the pond increases when the heat is removed from the lateral heat exchanger compared to either using the bottom heat exchanger or using both heat exchangers simultaneously. On the other hand, the use of solar collectors as an external source of heat were conducted together with heat extraction process under two different seasonal temperature conditions: winter and summer. The results indicated that the use of solar collectors allowed a 50% increase in daily efficiency during the cold season tests. The second part was focused on the design, construction and operation of a 500 m2 solar pond in Solvay Minerales facilities (Granada). The solar pond was designed to supply the heat required to preheat the water (> 60 °C) and the reagents in the mineral flotation unit at the mineral processing facility. The overall efficiencies obtained after the first and second operation periods are 9.7 and 12.3%, respectively, with maximum values of 28 and 24% obtained during the first months of operation. Regarding the economic savings, reductions of 52 and 68% were obtained in the first and second periods compared with the traditional system without solar pond. Also, the environmental impact is clearly reduced considering the reduction of CO2 emissions. The experience of the Granada solar pond proves that the main advantage of a solar pond is the capacity to store energy in the months with the highest solar radiation to provide a flux of heat to an external system during the whole year even under strong weather conditions, as observed during the January 2015 snowfall.
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1294
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Author:
Publisher:
ISBN:
Category : Fuel
Languages : en
Pages : 356
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Author:
Publisher:
ISBN:
Category : Solar air conditioning
Languages : en
Pages : 560
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Author:
Publisher:
ISBN:
Category : Solar energy
Languages : en
Pages : 236
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Author:
Publisher:
ISBN:
Category : Solar air conditioning
Languages : en
Pages : 566
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