Salinity gradient solar ponds : theoretical modelling and integration with desalination

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.EThOS - Electronic Theses Online ServiceGBUnited Kingdo