Emad M.S. El-Said

Development strategies and solar thermal energy utilization for water desalination systems in remote regions: a review

ABSTRACTThis paper reviews the current solar thermal desalination research activities with systems production in the range of 10–150 liter/day for remote or arid regions. A comparative study between different sustainable efforts in such solar thermal desalination systems as well as economics has been done. Throughout the review, the results indicated that most of the reviewed systems are in research stage and have not clear economical feasibility such as the price per cubic meter of water which may stimulates the decision-maker to direct these studies into the actual commercial applications. Also, the review showed that although many developed systems have several novel and valuable features, more efforts are required to further investigate more efficient, economical, and applicable solar thermal energy-driven desalination systems. Small production systems as solar stills and HDH can be used if fresh water demand is low and the land are available at low cost. The economical analyses carried out so far hav...

Solar-based atmospheric water generator utilisation of a fresh water recovery: A numerical study

In many regions in the world, the climate conditions are suitable for generating drinkable water; however, they have one or more types of water scarcity. An alternative method for fresh water recovery from atmosphere had been studied in this paper. The studied method is designed for Arabic Gulf countries or similar by using solar-based thermoelectric generator utilisation. The existence of solar energy and humid air gives a good chance for effective productivity. Nowadays, the mathematical model is able to give a good representation of the different cases. The use of recent numerical modelling is robust enough to give accurate results with cost and time saving. For simplification; the cases in this paper were supposed to be the fluid flow region, it means that the simulation will not be involved in the multi physics. The cases have been simulated in 3D using commercial CFD software called Star-CCM+. For the proposed system, four parameters were studied, which were the pressure drop over the flow bath, the water productivity per square metre as the goal parameter and the influence of ambient temperature as well as humidity. The ambient conditions were considered as the design parameters. The three different climatic regions are Red Sea, Arabic Gulf, and southern Europe (south Spain). Only summer climatic conditions are considered. It is found that the pumping power required for air fan did not exceed 9.1 W. Fresh water productivity of the unit was up to 3.9 L/h/m2.

Technological aspects of advancement in low-capacity solar thermal desalination units

Drinking water of acceptable quality has become a scarce commodity. The standard high-capacity desalination methods such as multi-stage flash evaporation and multi-effect evaporation, vapour compression and reverse osmosis are reliable in the range of about 100–500,000 m3/day fresh-water productions. However, the wide-scale implementations of these methods face numerous technological, economic and political barriers and these methods are not used in decentralised regions with a poor infrastructure due to their permanent need of qualified maintenance and electricity supply. In this paper, various low-capacity solar thermal desalination systems, with fresh-water output production in the range of 10–150 l/day for the use in rural areas, are reviewed and classified based on five technological aspects such as the development of the technology of the systems, the applicability of high-capacity thermal desalination technologies, the enhancement of solar heat collectors, the hybridisation of thermal desalination technologies and heat recovery processes. Most of the reviewed systems are in the research stage and have not cleared economic feasibility such as the price per cubic metre of water that may stimulate the decision-maker to direct these studies into the actual commercial applications to find a solution to the water scarcity problem in isolated and remote areas. Although many of the developed systems have several novel and valuable features, more efforts are required for further investigating more efficient, economic and applicable solar energy-driven low-capacity desalination systems.

Thermal solar water heater with H2O-Al2O3 nano-fluid in forced convection: experimental investigation

This paper describes laboratory experiments with a thermal solar water heater consisting of a flat-plate solar collector and helical coil heat exchanger using Al2O3 nano-particles dispersed in water as a working. The experiments were carried out for various nano-particle concentrations, from 0% to 3% (by volume), through forced convection cooling. The experiments were carried out under the climatic conditions of Tanta University, Egypt. The laboratory work has been carried out in actual thermal environment in August 2013. The experiments have an emphasis on the main parameters with impact on the water production temperature. These parameters include the solar radiation, the feed water mass flow rate and the nano-particle volume fraction. The main conclusion is that considerable improvement in the daily solar collector efficiency is obtained with increasing the nano-particle concentration up to 11% for concentration 3% with; this increase in efficiency is bounded by ±10% uncertainty. The outlet water temperature is increased with increasing of nano-particle concentration by 5.46% for concentration 2%. The helical heat exchanger effectiveness is increased by 4.25% for a concentration of 1% with ±13% uncertainty. The helical heat exchanger effectiveness and solar collector efficiency are increased with decreasing the working fluid mass flow rate.