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Falling film on horizontal tube evaporators, of both Mechanical Vapor Compression (MVC) and the Multi-Effect Distillation (MED) desalination systems, plays an important role in the heat and mass transfer (evaporation) and accordingly the systems productivity. Falling film thickness is mainly influenced by the intertube space, circumferential angle and the film’s Reynolds number. This paper presents two-dimensional numerical study of falling film thickness around horizontal tube in MVC and MED evaporators. The study is based on computational fluid dynamics (CFD) using volume of fraction (VOF) as a multi-phase technique in ANSYS Fluent. The numerical model is developed in order to study the heat and mass transfer charactristics, the liquid falling film behaviour and thickness distribution around circular horizontal. Four CFD study cases are developed to simulate the falling film behaviour at circumferential angle range from 150 to 1650 with inter-tube spacing of 10 mm, 16 mm, 33 mm and 40 mm and for constant value of flow rate and at the same surrounding conditions. Simulations are conducted using a domain of only two tubes with 20 mm outer diameter.The results from the numerical models are compared with the published experimental correlations, showing a comparatively reasonable agreement. In addition, a parametric study is carried out to illustrate the effect of flow Reyonlds number (Re) and intertube space on the average circumferential film thickness and heat transfer rates.

This paper presents the productivity and operational performance of a newly developed integrated solar still - two effects humidification-dehumidification desalination system (SS-HDH). The influence of partial solar thermal energy storage and solar Concentration Ratios (CR) on the transient performance and daily productivity is investigated. Other design, operation and environmental conditions include solar still basin water heights (h) and phase change materials (PCM) without and with Nano-particles are investigated. A transient comprehensive mathematical model is developed using mass and energy balance equations for the different system elements. The model results are validated with the available experimental and numerical data. Results of consecutive days indicated that the system daily production and basin water temperature increase in the second and third day due the stored energy in the system. Furthermore, increasing CR linearly raises the daily productivity and increases basin maximum water temperature (above the CaCO3 scale deposits defined limit of 70 °C) due to the added energy. However, increasing the basin water height, h, reduces the productivity and basin maximum water temperature. Without PCM, the results show that the maximum water production is 11.6 L/m2 per day at h = 0.2 m and CR = 2. This is considered the optimum parameters for high water production while avoiding scale formation on the solar still basin surface. Adding PCM without or with Nano-particles has a slight effect on both the daily production and the maximum basin water temperature. However, at CR = 2, and h = 0.1 m, the maximum productivity is about 11 L/m2 per day using Glaubers salt with 10% volume fraction of Cuo-Nano particles. Besides, the basin water temperature is below 70 °C to avoid a potential scale formation. The proposed SS-HDH suits more a small scale (of up to 100 L/day) house roof distillation unit for direct water need of a family.

Alterations to the tidal inlets shoals, whether natural or anthropogenic, can dramatically influence the hydro-morphological balance of the inlet system in the short and long-term. Jettied inlets, despite typically supported by former technical design reports in curtailing the sedimentology stock, sometimes they require amendments. This paper provides an expository epitome for understanding the role of jetties in concerning the extent of their adequacy to economically and ecologically rationalize the internal siltation within both the western and the eastern tidal inlets of the Bardawil Lagoon, which is situated along the Mediterranean coastline of the Sinai Peninsula, Egypt. The main tool to characterize that role is the hydro-morphological modeling of the inlets system. We used a two-dimensional hydrodynamic circulation model consisting of two steering modules, CMS-Flow and CMS-Wave. In a five-year simulation process, this study emphasized that the sole use of jetties was noticeably insufficient to fulfill the satisfactory stabilization of the sedimentation processes inside the inlets. Consequently, the lake's ecosystem might entirely collapse in the short run due to the progressive deposits fashioning in the form of ebb/flood-tidal deltas. Accordingly, we proposed alternative solutions based on structural modulation scenarios in the vicinity of inlets domain encompassing jetties extension, flow-diverted wall (FDW), sediment trap (ST), random radial channels (RC) and lateral wide channel (LWC). Based upon the results of an optimization model using the Mamdani-type fuzzy inference system, the addition of a lined LWC alongside with jetties proved to be an effective solution over a longer period that rather meets the needs of the majority of stakeholders satisfactorily.

The shoreline trajectory of Damietta city, locates at the Northern coast of Egypt, is dramatically subjected to kinematic changes. These variations mainly occur based on the incessant duel hydrodynamic impacts of both wave action and coastal currents. Several types of coastal measures have been applied substantially along the coastal stretch of Damietta to protect shoreline such as detached breakwaters, Jetties, groins, and seawalls. This study is essentially focused on the assessment of shoreline kinematics response due to the existence of these structures during the period from 1990 to 2015. In addition, the future changes of the shoreline at 2020, 2025 and 2035 are predicted using satellite images, Geo-spatial tools and Digital Shoreline Analysis System (DSAS) by the meaning of End Point Rate (EPR) and Linear Regression Rate (LRR) methods. Four Landsat images at different periods; TM1990, TM 1999, ETM 2003 and ETM 2015 are used to detect shoreline changes. Three semi-automatic extraction techniques are initially tempted for Landsat ETM 2003 imagery namely; Iso cluster technique, threshold method, and onscreen digitizing method to select the optimal one. Iso cluster technique is used as the optimal technique which achieves the least errors with the corresponding field data in 2003 by value of 0.34. Furthermore, the extraction shoreline change for Damietta coast is extensively measured for three zones: zone (1) the western sector encompassing Damietta port with two jetties; zone (2) the central sector including detached breakwaters; zone (3) the eastern portion of Damietta estuary passing through a seawall. Verification analysis shows that the EPR is the optimum method for shoreline detection with a value of RMSE by 0.27. The results show that, for zone (1), the western shoreline of Damietta port is progressed by a rate of +10.0 m/year. On the other hand, the shoreline on the down drift side at zone (2) has retreated by a rate of -5.0 m/year. While the shoreline behind the detached breakwaters in the central sector has advanced by +12.0 m/year from 1999 to 2003, then decreased gradually until become stable in 2015. For zone (3), alongshore currents have derived the disassembled sandy soil from west to east leaving a highly eroded area by average rate of -78m/year. The results of this study give indication to shoreline trend of near future which should be under consideration in planning of Damietta coastal zone.

For many socio-economic and demographic issues, majority of the Egyptian population live near the Nile River for thousands of years. Shortage of freshwater resources at remote and rural areas is limiting population settlement and development. Therefore, it is necessary to find alternative solutions including saline water desalination processes to assist obtaining fresh water for domestic and industrial purposes in these remote areas. The energy needed for the desalination process represents another challenge due to the available fossil fuel limitation, increasing prices and their negative impacts on the environment. These challenges may be tackled by applying hybrid renewable energy (RE) resources such as solar and wind energies as the driving power for the desalination technologies. Many studies are conducted in Egypt, Middle East region and worldwide investigating the possibilities of different desalination systems driven by RE. This article presents a recent review of the global desalination processes with a focus on membrane desalination systems such as reverse osmosis (RO), membrane distillation (MD), hybrid desalination technologies and processes as well as advanced plasmonic nanomaterials for water distillation derived by RE suitable for remote and isolated areas. Some recent activities for coupling desalination systems with hybrid RE carried-out by the co-authors will be highlighted.

Industrial activities produce millions of tons of hazardous waste annually, which are eventually disposed of in landfills. In this study, the effect of saline industrial hazardous landfill leachate (SIHLL) on the geotechnical properties of natural and contaminated silty clay soil was investigated via laboratory-based experiments in order to assess the potential application of this soil as a barrier lining in a saline hazardous industrial waste landfill. Contaminated soil specimens were prepared by mixing natural soil with SIHLL at different concentrations (0%, 25%, 50%, 75%, and 100%). The results revealed that the permeability coefficient (k) and the total pore volume (TPV) of the SIHLL-contaminated soil decreased from 8.6 × 10−8 to 5.91 × 10−8 cm/s and from 10.24 × 10−2 to 7.65 × 10−2 cm3/g, respectively, as the SIHLL concentration was increased from 0 to 50%. These effects were mainly due to the high concentration of salts in the SIHLL. The addition of SIHLL reduced the optimum moisture content (OMC) of the soil from 18% for natural soil to 14% for 100% SIHLL-contaminated soil, and the maximum dry density (MDD) recorded (for 100% SIHLL-contaminated soil) was 17.95 kN/m3. The angle of internal friction (φ) of the soil dropped from 27.8° for 0% SIHLL-contaminated soil to 23.7° for 100% SIHLL-contaminated soil. Also, the cohesion (c) decreased as the SIHLL concentration increased. In addition, considerable lowering of the consistency limits was observed for the SIHLL-contaminated soils. Based on these findings, the studied silty clay soil would be suitable for use in the construction of a new hazardous solid-waste landfill liner due to its low permeability and widespread availability in Egypt.

Industrial activities annually produce millions of tons of hazardous waste which are disposed eventually on landfills. In this study, the effect of saline industrial hazardous landfill leachate (SIHLL) contamination on the engineering properties of natural and contaminated silty clay soil was investigated in a laboratory program to assess the potentials of using this soil as a barrier for the lining of the saline hazardous industrial waste landfill. The contaminated specimens were prepared by mixing the natural soil with SIHLL at different concentrations (0, 25, 50, 75, and 100%). The results revealed that the permeability coefficient (K) and total pore volume of soil contaminated with SIHLL decreased as the SIHLL concentration increased from 0 to 50%. This was mainly due to the presence of high concentration of salts in SIHLL. The angle of internal friction (φ) of SIHLL-contaminated soil dropped from 24.95° (for 0% SIHLL) to 20.24° for 100% SIHLL, whereas this was not the case for the cohesion (C), where the value increased from 1.161 t/m2 for 0% SIHLL to 3.705 t/m2 for 100% SIHLL. A considerable decrease in consistency limits was observed for the contaminated soil at different SIHLL concentrations. Based on these findings, the studied silty clay soil can be feasible for construction of new hazardous solid waste landfill liner thanks to its low permeability and widespread availability in Egypt. The study recommends to carefully line the landfill with fully impervious liner materials to protect the soil and the groundwater from the leachate hazards.

Water shortage, human population increase, and lack of food resources have directed societies towards sustainable energy and water resources, especially for agriculture. While open agriculture requires a massive amount of water and energy, the requirements of horticultural systems can be controlled to provide standard conditions for the plants to grow, with significant decrease in water consumption. A greenhouse is a transparent indoor environment used for horticulture, as it allows for reasonable control of the microclimate conditions (e.g., temperature, air velocity, rate of ventilation, and humidity). While such systems create a controlled environment for the plants, the greenhouses need ventilation to provide fresh air. In order to have a sustainable venting mechanism, a novel solution has been proposed in this study providing a naturally ventilating system required for the plants, while at the same time reducing the energy requirements for cooling or other forced ventilation techniques. Computational fluid dynamics (CFD) was used to analyse the ventilation requirements for different vent opening scenarios, showing the importance of inlet locations for the proposed sustainable greenhouse system.

Egypt, as one of the countries in the MENA region, is facing water scarcity, which is one of the challenges affecting the productivity of agricultural crops. The integration of solar water desalination systems in greenhouses to overcome water shortages in some areas like Egypt is, therefore, one of the favored technologies in crop-growing areas. Crop growth control is done by adequately manipulating climatic variables of the environment as well as the quantity of water and fertilizers applied through irrigation. Numerous crops can be grown under greenhouse circumstances with water produced from desalinated units. Cucumbers, tomatoes, peppers, lettuce, strawberries, flowers, herbs anything that can be grown in traditional greenhouses, can also be grown in a greenhouse. This paper presents the state-of-the-art in the use of solar energy in water desalination to irrigate crops, the feasibility of greenhouse systems in agriculture, the feasibility of water desalination for agriculture in Arab countries and Egypt and the future outlook.

Solar-powered desalination is a sustainable solution for countries experiencing water scarcity. Several studies have presented different solutions to provide cleaner production in desalination systems. Parabolic trough collector (PTC) is one of these solutions that has proven to be superior among solar concentrators. Furthermore, a number of studies have investigated the use of PTC for distillation of saline water in response to water scarcity. In this study, a modified PTC model was developed, in which the heat exchanger was replaced by a condensation tube to reduce the energy consumption, and a black layer was introduced to the surface of the receiver to enhance its absorptance. As a reference case, the system productivity according to average solar intensities in Zagazig, located at 30°34′N 31°30′E in the North East of Egypt, is estimated. The results indicated that the maximum production rate that can be attained is 1.72 kg/h. Then, the structure of the system is evaluated with the aid of Computational Fluid Dynamics (CFD) modelling, in order to enhance its productivity. Many materials are examined and the results recognised copper as the most suitable material amongst marine grade metals (i.e., aluminium, galvanised steel and stainless steel) to construct the receiver tube. This is due to its superior thermal performance, satisfactory corrosion resistance, and acceptable cost. Afterwards, the selected receiver tube was employed to identify the optimal Concentration Ratio (CR). Consequently, a CR of 90.56 was determined to be the optimum value for Zagazig and regions with similar solar radiation. As a result, the system’s productivity was enhanced drastically, as it was estimated that a maximum production rate of 6.93 kg/h can be achieved.

Many countries in the MENA region (Middle East and North Africa) are facing water scarcity, which poses a great challenge to agricultural production. Furthermore, water scarcity is projected to increase due to climate change, particularly in arid and semi-arid regions. The integration of solar power and water desalination systems in greenhouses to overcome water shortages is one of the preferred technologies in crop-growing areas. Crop growth control is done through sufficient management of environmental climatic variables as well as the quantity and quality of water and applied fertilisers with irrigation. Numerous crops such as cucumbers, tomatoes, peppers, lettuces, strawberries, flowers, and herbs can be grown under greenhouse conditions using desalinated water. This paper displays the state of the art in (i) solar-driven saltwater desalination to irrigate crops, (ii) the feasibility of water desalination for agriculture in the MENA region, (iii) the economics and environmental impacts of the desalination process, (iv) the quality of desalinated water compared with other non-conventional water resources and (v) recommendations for the future in the MENA region.

The need for sustainable desalination arises from fast-occurring global warming and intensifying droughts due to increasing temperatures, particularly in the Middle East and North African (MENA) regions. Lack of water resources has meant that the countries in these regions have had to desalinate seawater through different sustainable technologies for food supplies and agricultural products. Greenhouses (GH) are used to protect crops from harsh climates, creating a controlled environment requiring less water. In order to have a sustainable resilient GH, a zero-liquid-discharge system (ZLD) was developed by using solar still (SS) desalination techniques, humidification-dehumidification (HDH), and rainwater harvesting. An experiment was designed and carried out by designing and manufacturing a wick type solar still, together with an HDH system, implemented into a GH. Using a pyrometer, the solar intensity was recorded, while the microclimate conditions (temperature and relative humidity) of the GH were also monitored. The GH model was tested in the UK and was shown to be a successful standalone model, providing its water requirements. In the UK, for one solar still with a surface area of 0.72 m2, maximum amount of 58 mL of distilled water was achieved per day. In Egypt, a maximum amount of 1090 mL water was collected per day, from each solar still. This difference is mainly due to the differences in the solar radiation intensity and duration in addition to the temperature variance. While dehumidification generated 7 L of distilled water, rainwater harvesting was added as another solution to the greenhouse in the UK, harvested a maximum of 7 L per day from one side (half the area of the greenhouse roof). This helped to compensate for the less distilled water from the solar stills. The results for the developed greenhouses showed how GHs in countries with different weather conditions could be standalone systems for their agricultural water requirement.

Cultivation in open fields mainly depends on the location and time of farming, which itself highly depends on the quality and quantity of water for irrigation, weather conditions and soil characteristics. Water resources are highly dependent on the limited freshwater resources from the groundwater system, or rainwater. Countries in MENA (the Middle East and North Africa) rely mostly on desalination technologies for agriculture, due to water scarcity. Therefore, greenhouse (GH) agriculture can be developed to succeed in dealing with the water scarcity and provide sufficient sources of agricultural products as a sustainable solution. These indoor agriculture facilities, which are enclosed by transparent covers, can produce different sources of fruits and vegetables, using a controlled amount of water. By reducing the exchange rate of air with the outside environment, which is known as the confinement effects, greenhouses generate a suitable environment for the plants to grow under transparent covers to trap the sunlight. This raises the inside temperature above the maximum threshold levels, especially within the warm season, due to the high solar radiation intensity, having an adverse influence on the microclimate conditions and consequently the crop growth. In order to sustain maximum agricultural yield, greenhouse ventilation is an important parameter in which its trends and emerging practices were reviewed in this study.

Design of water distribution systems is commonly performed using design guidelines which often rely on designers' expertise. Determination of the required pumping power and the size and location of storage tanks, according to the network layout and the available diameters, is not a trivial task. The difficulty of optimizing such systems arises from applying non-uniform demand patterns along the one-day operation accompanied by the different constraints to satisfy the large fluctuations in pressure heads and flow velocities, the dilemma between choosing to reduce the cost of constructing and operating the network or to increase its resilience and the complex relationship between the pumping power and the size, bottom elevation and location of storage tanks. In this study, a general multi-objective optimization framework is developed to get the optimum diameters, pumping power and storage tank locations and bottom elevations to minimize the cost while maximizing the resilience using a combination of the Particle Swarm Optimization technique and EPANET software. The objective function of the optimization is obtained from combining the cost and resilience using a transformation function. The proposed framework is applied to Safi town network in Yemen and the results prove the success of performing the developed framework.

This paper presents an experimental study on the hydrodynamic performance of seawalls in terms of wave reflection coefficient (Kr), relative wave run-up (Rup/Hi), and relative wave run-down (Rdown/Hi). Various experiments were carried out under monochromatic waves to test five non-traditional seawall setups; plane wall (PW), rectangular serrated wall (RSW), triangular serrated wall (TSW), slotted wall (SLW), and triangular serrated-slotted wall (TSLW). A thin-parallel solid wall with a water chamber width (D) was used on the leeward side of SLW and TSLW in order to preclude the wave transmission. RSW was found hydrodynamically superior as compared with TSW. The blocks spacing of RSW and TSW were hydrodynamically optimized at a value of 2.5 times the width of the block. Nevertheless, the hydrodynamic behaviour of both SLW and TSLW was optimal when the slots ratio was about 0.33, whilst the chamber width was about 0.25 of the incident wavelength. New empirical formulas were developed for understanding the hydrodynamic behaviour of the proposed seawalls using nonlinear regression analysis. These formulas were calibrated using SPSS based on the experimental results. The formulas were used to predict the hydrodynamic behaviour of both RSW and TSLW for El-Tinah Plain Bay in the North-East coast of Egypt.

This paper introduces an appropriate visualization of the tidal inlets including the characterization of internal siltation and the remediation of associated non-affirmative consequences due to the existence of its protective jetties, such as down-side erosion and up-side accretion. Accordingly, the 2D hydrodynamic circulation models CMS-Flow and CMS-Wave have been initially set up to describe the morphodynamics situation inside the artificial western inlet (inlet (1)) of the Bardawil Lagoon, which is situated along the Mediterranean coastline of the Sinai Peninsula, in the presence and absence of the jetties. Simultaneously, the Littoral Processes and Coastline Kinetics (DHI-LITPACK) numerical model is essentially applied to predict the shoreline responses in the vicinity of inlet (1) to numerous different scenarios considering both hard (i.e., groins and detached breakwaters) and soft (i.e., sand nourishment and sand bypassing systems) measures during the period from 2010 to 2030. The study has revealed that the use of hard measures to the east of the inlet would induce exceedingly high recession rates of the shoreline. Nevertheless, the use of a one-time nourishment of 250,000 m3 in the areas between short groins (with lengths of 90 m and an interval of 400 m) during their construction would optimally reduce the expected area of erosion by approximately 91.85%. Meanwhile, a single groin with a length of 200 m and a westward drift distance of 450 m to the west of the inlet would be superior with regard to optimizing the sedimentary stock compared to an annual dredging rate of 100,000 m3/year. Finally, an optimization model has been constructed using a Mamdani-type fuzzy inference system to determine the cheapest and most efficient solution with the minimum impact on the sandy barrier zone of inlet (1).

This paper introduces an appropriate visualization of how to effectively digitize, quantify and predict shoreline kinematics changes. The method relies mainly on the coupling of Geographic Information System (GIS) with Digital Shoreline Analysis System (DSAS). The North Sinai coast in Egypt is selected as a case study. The proposed technique is applied over a quarter-centennial period of 27 years (1989–2016). However, the years 2025, 2035, and 2050 are used for prediction purpose. Histogram threshold of band 5, Histogram threshold of band ratio, and Tasselled Cap Transformation (TCT) are initially tempted as semi-automatic shoreline extraction techniques for Landsat ETM 2010 imagery. Among of them, the TCT is found superior as a digitizing technique that attains the least normalized root mean square errors with the corresponding field data in 2010. Meanwhile, the shoreline change rates in the form of erosion/accretion patterns are automatically quantified by four statistical parameters functioned in DSAS coding. Those, namely end point rate (EPR), net shoreline movement (NSM), linear regression rate (LRR), and least median of squares (LMS). On the basis of the LRR and EPR results, this study offers to the coastal managers a highly reliable decision-support-algorism that can dynamically assist in elaborating strategies to curtail the non-affirmative consequences due to the erosion/accretion of the shoreline.

This study focuses on the shoreline change detection along the North Sinai coast in Egypt using geographic information system and digital shoreline analysis system (DSAS) during the elapsed period ...

A new solar driven desalination system is developed using hybrid solar still/two effects humidification-dehumidification desalination system combined with solar concentrator and two thermally cooled photovoltaic panels. The system performance is investigated under different operating conditions including varying the basin water height, circulating air mass flow rate, and solar concentration ratio. A transient mathematical model based on the conservation of mass and energy equations for the system components is developed and the predicted results are validated using the available experimental and numerical data. The results indicated that the system productivity decreases with the increase of the basin height and the circulating air mass flow rate. Integrating the photovoltaic panels along with solar concentrator leads to a significant increase in the fresh water yield at high concentration ratio. The maximum temperature of photovoltaic panels, electrical output power and efficiency of both panels are presented. Accordingly, selection of the optimal operating conditions is developed within the allowable maximum basin water temperature (to avoid a potential scale formation) and the maximum photovoltaic panels' temperature.

The River Nile is one of the world’s longest rivers. The Damietta branch in Egypt is important as a major source of irrigation and navigation path from Cairo to the Mediterranean Sea. Morphological changes in this branch of the Nile occurred following construction of the Aswan High Dam, which affected sedimentation and erosive flow, especially at bends in the river. In this study, morphometric temporal changes were investigated for the forced bends using Remote Sensing (RS) and Geographical Information System (GIS) techniques for a study period between 1987 and 2015. In addition, a comparative study was performed among three image classification techniques; onscreen digitizing, maximum likelihood classification and histogram thresholding techniques. A field map of the river banks for the year 2000 was used to verify morphometric behaviorof the forced bends extracted from the satellite images. The study showed that the maximum likelihood classification technique showed good performance in shoreline detection, with percentage error of only 0.42 % compared with observed data. Results show significant morphometric changes of the bank status for the forced bends studied. The forced bend named Sherpas was found to have the highest average annual rate of erosion, with a value of 1.62 m a-1. The maximum average annual rate of sedimentation was located at the inner bank of Sawalem forced bend, with a value of 1.0 m a-1. The maximum erosion and sedimentation rates achieved the greatest values within the period 1987 to 1998.

The performance of the mechanical vapor compression desalination system is limited due to the required vacuum pressure and associated high temperature scaling problem. Thus, a new solar driven mechanical vapor compression desalination plant with nano-filtration pretreatment operating at atmospheric pressure is developed for a production of 500 m3/day. The electrical and thermal energies of the new system are generated using the integration of solar photovoltaic modules and parabolic trough collectors. To evaluate the performance of the new system, energy/exergy analysis is performed by employing a MATLAB package and a Graphical User Interface (GUI) tool. Also, an economic evaluation for the plant's direct, indirect, and unit product costs ($/m3) is presented. The predicted results are validated with the available measurements. The effects of different design parameters such as feed water temperature, distilled and brine water temperature difference, salt rejection and recovery ratio on plant performance are investigated. The proposed plant's exergy efficiency is found to vary from 14.59 to 20% consistently with design parameters. The enhancement in exergy efficiency is estimated to be 153.7%, 56.3%, 32.63% and 27% compared with Multi-Effect evaporation mechanical and conventional vapor compression, forward feed multi-effect mechanical vapor compression and reverse osmosis systems, respectively. The salt rejection and recovery ratio are found to be the most significant parameters to enhance the plant exergy efficiency. Furthermore, the photovoltaic unit has a significant effect on exergy destruction of the plant with a percentage of 85.79%. The parabolic trough collectors also have high exergy destruction of about 69.53%. The economic analysis reveals that the unit water price for the proposed plant is equal to 1.54 $/m3. Therefore, the developed solar-NF-MVC system suits small scale units for remote communities.

This study is an analytical investigation for the performance of a new stand-alone agriculture Green House (GH) integrated with on-roof Transparent Solar Stills (TSS) to be a self-sufficient of irrigation requirements. This system utilizes the surplus solar energy via direct solar desalination in TSS and Humidification-Dehumidification (HDH) process as two sources for water production. The effect of using the on-roof TSS on the GH performance, the power required for heating and fans operation at different climate conditions is discussed. The paper investigates the effect of the fresh air ratio and the bypass ratio for the condenser of the cooling system on the internal micro-climatic conditions of the GH. For different climatic conditions of Borg-Elarab, Egypt, controlling both the condenser bypass and fresh air ratios can be used to satisfy the required micro-climate conditions and water requirements for plant growth and minimize the power consumption for cooling system. The results show that the daily average temperature inside the GH can be increased during winter. Furthermore, the system can produce a sufficient amount of fresh water during summer. The system can only produce a maximum amount of water of 2.44 L/m2⋅day during the coldest day which indicates the need for additional solar stills to be installed if a higher amount of water is required. In general, recovering the extra solar radiation to either produce fresh water via on-roof TSS or reduce the power consumption by cooling, heating and ventilation systems is the main advantage of the new proposed GH system. This work is a good applied example for food, water, energy and climate change Nexus which covers the main elements of Sustainable Development Goals (SDGs).

In Egyptian desert, growing plants is difficult due to harsh climate (hot at the daytime and cold at the night), infertile soil, low average rainfall and lack of fresh water for irrigation purposes. A set of simple transparent solar stills are integrated with a new solar driven agriculture greenhouse (GH). The stills are placed at the GH roof to use the extra solar radiation (above that required for plant photosynthesis process) for water desalination. In addition to water desalination concept the solar still units even reduce the cooling load during the daytime. A net of aluminum metal coated with black colour is placed on the base of the solar still units to raise the water temperature (enhance desalination process) and provide partially shading for the GH. Using aluminum net decreases also the number of solar still units required to produce the required amount of GH fresh water leading to a significant cost reduction.The main objectives of this work are sizing of the aluminum net, spacing between solar still units to obtain the threshold of plant requirements. Also fresh water production and greenhouse climatic conditions that plant needs (temperature, relative humidity, air velocity and amount of oxygen) are simulated.Numerical simulation was carried out for the hottest day of Borg Elarab, Alexandria (Egypt).

Agricultural greenhouse (GH) systems provides suitable microclimatic environment for maximum plant growth (quality and quantity) and protect plants from adverse atmospheric agents using appropriate technology. This will influence and ultimately modifies the crop microclimate, thereby improving the plants growing condition, improving their quality and permitting high yields; thus, lengthening the market availability of the products. This paper describes the basic operation of a sustainable agricultural greenhouse suitable for the mild winter climate of the Mediterranean region for air heating, solar energy utilization, water desalination and plant production. The numerical analysis of the dynamic model for determination of various GH performance was done for a typical winter day of December of Borg El-Arab, Alexandria Egypt. A GH heating control strategy based on MATLAB and CFD simulations for energy saving, suitable microclimate maintenance and better performance of the GH systems were studied. The GH transient performance and uncertain microclimate conditions depend on air temperature, relative humidity, carbon dioxide concentration and solar radiation. A mathematical model was developed using MATLAB/Simulink to compute the transmitted hourly solar radiation, air cooling by the outlet condenser, air and wall temperatures, water production from TSS and condenser and air recirculation ratios. Computed air and wall temperatures were then introduced to ANSYS computational fluid dynamics (CFD) to evaluate the microclimatic conditions of the GH cavity. Flow vectors, relative humidity and temperatures stream lines are presented for the whole GH. Results shows that the south wall receive the greater amount of solar radiation in the winter periods. The results also predicted over 4 L/m2.day of water to be produced, with inside air temperature average of 18 °C.

This paper was specially written to complement the first part series published by (Nassar et al., 2019), to investigate the impact of anthropogenic changes around tidal entrances on sedimentary mass stocks in response to the successive pressures of decision-makers due to the sensitivity of the issue. The CMS package was therefore used to model coastal processes at the Bardawil Lagoon Western inlet1 and to forecast sediment-logical stocks each year such that the accumulation of sediments within the inlet can be mitigated by impeding the navigation of this inlet and by allowing water movement between sea and lake. The CMS package is based on a finite-volume approach. A CMS-Flow and CMS-Wave two steering modules have been introduced. In this analysis, unorthodox structural scenarios inside the tidal inlets were evaluated: extension of the jetties, flow-diverted wall (FDW), current deflector wall (CDW), sediment trap (ST), radial channels (RC) and lateral wide channel (LWC). Following the current posture of inlet 1, the use of CDW, ST or RC was considered to be reasonable compensation for the current dredging operation. This is mostly attributed to a lower infilling pace as well as the fewer dredging at year-end. Whereas the benefits generated from maintenance dredging can be perceived to be slightly costly, the long-term benefits of that expenditure can justify it.

This study investigates, analytically, the design of a new stand-alone agriculture Green House (GH) designed to be a self-sufficient of energy and irrigation requirements. This design uses Transparent Photo Voltaic (TPV) for electrical power generation and humidification-Dehumidification process for water production. The paper investigates the effect of the location of the condenser(s) for the cooling system, the condenser bypass and fresh air ratios on the internal micro-climatic conditions of the GH. For the hot climatic conditions of Abu Dhabi, UAE, controlling both the condenser bypass and fresh air ratios can be used to satisfy the required micro-climate conditions for plant growth, minimize the power consumption for refrigeration cycle and maximize the water production. According to the operating conditions, water production ranges between 8.3 and 13 L/m2 day which is sufficient for plant needs while the generated electrical power of the TPV is about 10% of the electrical energy requirements which indicates the need for additional PV panels to be installed with the GH system.

The main objective of this article is to present a new and practical correlation associating the effectiveness (e) with its number of transfer unit (NTU) and vice versa of the humidification process. This correlation is featured by its simplicity in use and has non-iterative procedure to implement as the traditional published correlations in the literature. The new correlation can predict the thermal performance/design of the humidifier at different Lewis numbers (both unit and non-unit) with a reasonable accuracy. General integral equation, which is similar to that of Merkel equation, is developed and used in the present humidifier simulation model. The validity of the new correlations was tested against the available experimental and numerical data reported in literature for an industrial air humidifier. In addition, the comparison was conducted with the traditional numerical model at different Lewis numbers. The simulated results of the present correlation show a good agreement with those obtained from the experimental work within 10% accuracy. The main benefits of this new correlation are: (1) its simplicity to be implemented through simple calculations of input parameters and (2) it provides helpful guidelines for developing of humidification-dehumidification HDH desalination cycle simulation program.

Integrating cooling systems with photovoltaic (PV) modules represents a very important aspect of keeping modules within acceptable operating temperatures. The objective of this study is to analyse the performance of each series-connected PV cell in photovoltaic thermal (PVT) modules. The importance of this analysis is due to the consideration of the variable operating temperature values of the PV cells, resulting in a different performance of each PV cell. The PVT modules are cooled with water serving as both a heat sink and a solar heat collector. This enhances the electrical efficiency value of the PVT modules by preventing them from elevated temperature values, while the recovered thermal energy can be utilised to increase the overall PV effectiveness. The new consideration in this study over the existing ones is the temperature distribution of each PV cell is applied for the calculation of the current voltage characteristics of the PV modules, which makes the analysis more accurate. The variance in the temperature values is a result of the temperature gradient of the fluid flowing through the pipes where the heat exchange differs in the flow direction. The potential of this study becomes more important for countries of high ambient temperatures and high solar intensity.

Multi stage flash (MSF) desalination has proven to be the most reliable desalination technology for the Gulf region. As part of the continual quest for more sustainable and environment-friendly desalination technologies, this study investigates a proposed novel method for improving the thermodynamic and economic efficiency of MSF desalination. The proposed method has been tentatively named “brine extraction”. The technique involves extracting a part of the cooling brine from the water boxes and re-injecting this extracted brine directly into the flashing chambers; i.e. the extracted brine will not pass through the brine heater or high-temperature flashing stages. Economically speaking, brine extraction is expected to reduce the surface area of condenser tubes at the brine heater and high temperature flashing stages, and shift the vapor condensation heat load to lower temperature flashing stages, where a cheaper condenser tube material is used. More importantly, brine extraction is expected to reduce both the heating steam and the specific electrical power consumption of the MSF process. A computer model of conventional MSF desalination was constructed and verified against the currently operational MSF plant “Ayoun Mousa” located in Egypt. After the computer model was validated, a model of a 16.2 MIGD brine recirculation MSF plant was constructed and its performance was studied with and without the novel configuration named “brine extraction”. Single-point brine extraction, where a single stream of brine is extracted, performed better than multiple-point brine extraction, where multiple streams are extracted at multiple points. Single-point brine extraction is also favored because it will cause minimal increase in complexity and reduction in the robustness of the MSF process, as only a single stream of brine will be redirected. At the optimum extraction ratio of 9%, single-point extraction yielded a 7.23% increase in gain output ratio (GOR), a 3.47% decrease in electrical consumption, and a 3.90% decrease in total cost. Although the reduction in the cost of water is marginal, the reduction in electrical consumption and improved GOR indicate that the implementation of brine extraction at high top brine temperature (TBT) could be a promising technology in the case of solar-powered MSF, where the high expense of supplying thermal and electrical energy has been the most prohibitive factor.

Solar stills, as a simple technology, have many advantages such as simple design; unsophisticated fabrication; low capital and operation costs and easily maintained. However, their low daily production has put constraints on their usage. A radical improvement in the performance of solar stills can be achieved by the partial recovery of the energy losses from the glass cover of the still. This paper simulates a direct solar distillation system of combined solar still with an air heating humidification–dehumidification (HDH) sub-system. The main objective of the Still-HDH system is to improve the productivity and thermal efficiency of the conventional solar still by partially recovering the still energy losses to the ambient for additional water production. Various procedures have been employed to improve the thermal performance of the integrated system by recovering heat losses from one component in another component of the system. Simulations have been carried out for the performance of the Still-HDH system under different weather conditions. A comparison has been held between the Still-HDH system and a conventional solar still of the same size and under the same operating conditions.

Humidification–dehumidification (HDH) desalination technology with the use of recovered photovoltaic (PV) thermal energy could be viable for the production of small-capacity sustainable water and improvement of PV electric power generation efficiency. This paper investigates the technical feasibility and environmental friendliness of an air-cooled PV system integrated with ambient seawater inflow into a HDH desalination system. The technical analysis of the PV-HDH desalination process was carried out through the modeling of the physical and thermodynamic properties involved in the recovery of PV thermal energy and determination of the effect of this recovery on water produced under the environmental conditions of Abu Dhabi, UAE. The results showed that the heat recovered from the PV resulted in the production of a daily average of 2.28 L of fresh water per m 2 of PV. On the other hand, the environmental impact assessment of this PV-HDH power and desalination technology was also carried out for the first time in order to determine its viability for small-scale sustainable water and energy production. The PV-HDH system resulted in 83.6% decrease in environmental impacts when compared with PV-Reverse Osmosis (PV-RO) system. In conclusion, the integrated PV-HDH desalination technology is promising and expected to play a key role in the field of water desalination.

In this study, an analysis is carried out to determine the optimal application of multiple renewable energy resources, namely wind and solar, to provide electricity requirements for green smart cities and environments. This was done to determine the potential of renewable energy to provide clean, economically viable energy for the case study of Zagazig, located at 30°34′ N 31°30′ E in the North East of Egypt. The relevant data surrounding the production of energy were collected, including the meteorological data from NASA, and specifications regarding renewable resources including solar panels, wind turbines, and storage batteries. Then a hybrid model was constructed consisting of Photovoltaics (PV) panels, wind turbines, a converter, and storage batteries. Once the model was constructed, meteorological data were added alongside average daily demand and cost of electricity per kWh. The optimal solution for Zagazig consisted of 181,000 kW of solar panels feeding directly into the grid. This system had the lowest Net Present Cost (NPC) of the simulations run of US$1,361,029,000 and a net reduction of 156,355 tonnes of CO2 per year.

This paper addresses the integration of vacuum multi effect membrane distillation (VMEMD) with adsorption (AD) unit to produce distilled water for many applications and cooling water to cool the buildings. Integration between VMEMD and AD systems aims to increase the water productivity with low power consumption. In this system, VMEMD is driven by hot seawater to produce fresh water, as the remind brine of VMEMD will discharge into the evaporator of AD cycle to produce other part as a fresh water. AD is a heat driven technology that can be used to generate distilled water and/or cooling water through adsorption/desorption of water vapour using porous metal organic framework (MOF) adsorbent materials. MOF is a new class of porous material with high surface area, superior adsorption characteristics and large porosity. The MOF such as, Aluminium Fumarate (Al-Fum), shows have water vapour adsorption characteristics superior to those of silica gel and zeolite. While, Nickel salts (CPO-27-Ni) was found to be more suitable for applications working at a low evaporation temperature (5 °C) and high temperature (≥90 °C), meanwhile Al-Fum showed a superior performance at a higher evaporation temperature (20 °C) and low regeneration temperature (70 °C). Both systems, VMEMD and AD, have ability to produce more distilled water with recovery ratio about 60%, in addition to produce cooling water.

This paper presents the simulation and modeling of the concentrated solar power (CSP) plant for multipurpose applications at Borg El Arab in Egypt. The plant produces 1 MWe and 250 m3 of distilled water using steam turbine and electric generator. The purpose of using different applications is to improve the overall efficiency and the coefficient of performance of the plant. The trnsys simulation platform was used for simulating the thermal performance of the solar power and desalination plant covering the parabolic trough concentrator (PTC), storage tank with an integrated steam generator, a backup unit, steam turbine, electric generator, and two effects desalination unit. The temperature and energy profiles of the plant were investigated for the PTC, steam generator and the electric generator. The results prove that the simulation could be used to support the operation of the CSP plant and for improving the performance of the cogeneration plant at Borg El Arab.

The aim of this work was the development of a numerical methodology to simulate and study the dynamic behavior of vacuum membrane distillation (VMD) system. A time-dependent one-dimensional finite difference numerical model is developed to study the flow as well as thermal regimes and the dynamic operational performance of VMD under stepped flow disturbance function in the hot channel. The study simulates the process parameters including mass flow rates, temperatures, vapor pressures, and concentration distributions for the hot feed channels along the flat-plate membrane length with transmembrane flux. The developed dynamic tool predicts the hydrodynamic behaviors and thermal characteristics of the very thin channels of VMD module. A rectangular pulse disturbance function is applied to rise up the inlet hot mass flow rate from steady state (SS) value of 1 to 1.34 kg/s for 60 s. The model ran for 3 min, which included the 60 s of applied dynamic disturbance; it started at the 10th s and finished at...

This work presents a novel integrated MSF–MED thermal desalination technology and its techno-economics as compared to conventional systems such as MSF-BR, MED-TVC, MSF-OT-LT and plain MED. The new integrated MSF–MED benefits from (i) high top brine temperature (TBT) of natural dilution seawater feed of the once through (MSF-OT), (ii) lower pumping power of long tube MSF-LT, and (iii) the low heating steam quality and cost of MED. The process calculation showed that the pumping power of the integrated MSF–MED is 58% lower than that of the traditional MSF-BR while it is 16%, lower than that of MED-TVC. The cost analysis showed that at subsidized oil price of 12 $/bbl, the unit water cost of the integrated MSF–MED is 32% lower than that of MSF-BR and 21% lower than that of MED-TVC. The unit water cost of the integrated MSF–MED is the lowest value when the oil price is lower than 40 $/bbl. This result showed the superiority of the integrated MSF–MED configuration for GCC countries since the oil price is generally subsidized. It also has a chance to utilize a diverse available energy such as waste heat and steam from backpressure or condensing turbine.

Egypt’s hot climate, high solar radiation, and lack of irrigating water are limiting factors for successful farmland, and makes growing crops an expensive and resource-intensive endeavor. In addition, Egypt is composed of 95% desert land which makes growing plants in open fields difficult due to infertile soil, low average rainfall, and lack of freshwater for irrigation purposes. These difficulties can be overcome by using Greenhouses (GHs) for agricultural purposes which can provide the proper environment for plants growth in all seasons.

This paper presents the Computational Fluid Dynamics (CFD) analysis of the vapor flow inside the Evaporation Chamber (EC) of a two-effect Multi-Effect Distillation (MED) unit. The study is part of the EU–Egypt funded project Multipurpose Applications by Thermodynamics Solar. The numerical analysis investigates the effect of velocity variations on the EC’s carryover factor and demister pressure drop for different separation baffle configurations. The trajectory of liquid droplets was calculated using Lagrange approach. The computational model was verified by comparing the predicated results (vapor pressure drop through the demister and separation efficiency) with those obtained from published data, with good agreement. At the design inlet vapor velocity of 3.3 m/s, a new baffle configuration is presented and is characterized by the best performance among the other configurations. This new baffle configuration shows a minimum carryover factor of 0.097 with a reasonable demister pressure drop less th...

Renewable energy technologies, in particular concentrating solar power (CSP), are becoming more and more interesting for powering water desalination system. Moving from a European Community funded project called MATS, Multipurpose Applications by Thermodynamics Solar, which is in an advanced phase of detailed engineering, the authors have further developed an alternative scheme by a proper integration of CSP with multi-effect distillation (MED) and reverse osmoses (RO) desalination processes. According to the proposed scheme MED is powered by the low temperature exhaust steam delivered from the back pressure steam turbine while the RO is powered by the electricity produced by the same steam turbine in addition to that generated by a conventional gas turbine integrated as a thermal backup system. The effective match of the alternative solar thermal and electricity into such hybrid power-desalination scheme is discussed in details. An economical analysis together with a developed comprehensive model is provided where power availability, water production rates and environmental benefits have been implemented. Desalination using the CSP system through such hybrid integration allows also for a continuous operation and can be an effective way to lower the total water production costs not only for large-scale plants.

Solar thermal power cycles assisted multi-stage flash brine recycle (MSF-BR) distillation process are thermo-economically analyzed and evaluated. In this work, the analyses are compared according to three different configurations via two techniques of solar thermal power cycles. The first technique is considered for only desalination process; however, the second is considered for desalination and electric power generation via organic Rankine cycle. Solar parabolic trough concentrator (PTC) field is considered to dominate sufficient thermal power for MSF plant. Water steam working fluid is used for a direct vapor generation (DVG); however, Therminol-VP1 working substance is used for an indirect vapor generation (IDVG) through the PTC field. Moreover, the optimized configuration from the first technique is compared with the power generation and desalination (the second technique). The comparisons are proceeding for the MSF-BR desalination plant with total productivity in the range of 5,000m3/d which...

Multistage flash (MSF) is a widely used technology in large capacity salted water desalination plants. The enhancement in the thermal performance of this technology is still prospective and promising. In this research, vapor flow through the flash chamber (FC) was studied. Flow development in 2D simulation model of a real FC was investigated. Trajectory of liquid droplets was calculated using Lagrange approach. The continuity and Navier–Stokes equations for the continuous phase “vapor” were solved simultaneously with the particle equation using two equations k–ϵ turbulence model. The computational model was verified by comparing the predicated results (vapor pressure drop through the FC demister and moist separation efficiency) with those obtained from the published experimental data. The comparison showed a good agreement between both results with maximum deviation of less than −19.16%, however, most of the disagreement between both results is fewer than 10%. Four different demister locations wer...