Researcher Adi Kazim Jaber's doctoral dissertation was discussed at the College of Engineering, Department of Mechanical Engineering, University of Basra, entitled MODELING THE DISTILLATION OF HEAVY SEWAGE WATER USING SOLAR ENERGY FOR THE CLIMATE OF SOUTHERN IRAQ
Water scarcity and pollution of the available sources of water are among the most important environmental and economic issues that developing countries, particularly, in the rural, remote, areas like southern Iraq face. Since the capital costs and the clear reliance on fossil fuels are high and the conventional desalination units rely on fossil fuels, it means that the shift towards renewable energy technologies is a high value-added and sustainable alternative. In this connection, solar energy is highly considered as the most prospective renewable energy source in terms of desalination systems, because with solar energy, both heat and electricity can be generated, which makes this resource especially good at competing with other sources of fuel. Currently, Solar-powered desalination plants provide about two-thirds of all the worldwide sources of renewable energy-powered desalination plants.
In this thesis, the concept of designing and constructing a simplified solar distillation plant coupled with a parabolic dish collector (PDC) is used to enhance fresh water productivity. Solar still with a basin area of 1 m2 is used as the system and has a sloping glass lid inclined at 31° to the horizon to facilitate vapor condensation and fitted with insulating panels to minimize thermal losses. The solar radiation is focused in a parabolic dish collector having a reflector surface area of 2m2, which heats water in a closed circuit that passes through heat exchanger and therefore indirectly transfers the incident heat to the water in the basin. The water flow rate of the heating remained at 0.03 kg/s.
A comprehensive experimental work was carried out in the city of Al-Shatrah in Thi-QarProvince (latitude 31.409°N and longitude 46.1727°E) which had representative climatic conditions and had both summer and winter climatic conditions. Data gathering was conducted during the normal working hours in the daily operation, that is 7:00am to 8:00pm. At the same-time, theoretical models were used to measure the heat transfer coefficients and system productivity as all the mathematical computations, simulations, and statistical analysis were carried out in MATLAB R2022a. As part of the experimental procedure, the values of temperatures of the sewage water, the surface of the glass cover and the surface of basin temperatures were constantly measured and the intensity of the solar-radiation and the wind speed recorded to clarify their corresponding effects on the performance.
The results of the current research support the high level of agreement between theoretically derived and on-site recorded experimental values hence affirming the validity of the models presented as well as the soundness of the system. Also, the findings show that incorporation of a parabolic dish collector significantly increases the water temperature in a basin and consequently increases the evaporation rate. The daily productivity improvement reached about 41% at a basin water depth of 2cm and exceeded 90% at a depth of 4cm. The optimum daily productivity, which was estimated to be 4.1 kg/m2day, was when the parabolic dish collector was on, as compared to using a solar collector without it, which resulted in a productivity of 2.9 kg/m2day, all of which were recorded in August when the basin depth is 2cm.These results are very acceptable when compared with the existing literature.
