Water is essential for food security, industrial output, ecological sustainability, and a country’s socioeconomic progress. Water scarcity and environmental concerns have increased globally in recent years as a result of the ever-increasing population, rapid industrialization and urbanization, and poor water resource management. Even though there are sufficient water resources, their uneven circulation leads to shortages and the requirement for portable fresh water. More than two billion people live in water-stressed areas. Hence, the present study covers all of the research based on water extraction from atmospheric air, including theoretical and practical (different experimental methods) research. A comparison between different results is made. The calculated efficiency of the systems used to extract water from atmospheric air by simulating the governing equations is discussed. The effects of different limitations, which affect and enhance the collectors’ efficiency, are studied. This research article will be very useful to society and will support further research on the extraction of water in arid zones.

The purpose of this paper is to estimate the quantity and quality of the useful energy that could be converted to work, this analysis was carried out based on the energy and exergy analysis by using the first and second laws of thermodynamics. This paper study the effect of varying the ambient temperature on the performance of the turbine. Results showed increasing in exergy destruction in the turbine solely and in each of its three components(Air compressor, Combustion chambers and the gas turbine) with increasing in ambient temperature. Also results showed by keeping the load unchanged, the exergy destruction are bigger in higher ambient temperatures than in lower ones. The exergy destruction concentrated in the combustion chambers, where the percent of exergy destruction in the combustion chambers to the total exergy destruction in the plant was(87%) followed by the air compressor(9%) and the lower exergy destruction was in the gas turbine(4%).

Heat transfer enhancement employing an elliptical tube inside a circular tube to increase the heat transfer rate without increasing in pressure drop is investigated. The flow rate inside the narrow is in the range of Reynolds number 10,000 to 100,000. Commercial software is used to solve the governing equations (continuity, momentum, and energy) by adopting a finite volume method (FVM). The electrical heater is connected around the circular tube to apply uniform heat flux (3000 W/m2) as a boundary condition. The volume concentrations are in the range of 0.25% to 1% with different TiO2 nanoparticle diameters in the range of 27 nm to 50 nm dispersed in water. The results indicate that the elliptical annulus tube can enhance heat transfer and friction factor by approximately 19% and 6% than the circular tube respectively. Results show that the heat transfer enhancement is significantly increasing as the volume concentrations increase and the nanoparticles size diameter decrease.

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