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The hemispherical solar still (HSS) is a simple device used to desalinate saline water, but it has low productivity. This study aimed to enhance the evaporation rate of a hemispherical solar still (HSS) through several design modifications. The main innovation involved integrating an upper absorber with hanging wick cords, creating a modified system called the cords wick hemispherical solar still (CWHSS). Additionally, electric heaters powered by photovoltaic panels were incorporated to further boost performance, along with the introduction of squared baffles inside the CWHSS. Experimental results showed that the highest efficiency was achieved with the CWHSS incorporating baffles, heaters, and a condenser (CWHSS-B), leading to a 258 % increase in distillate output and a 66.5 % thermal efficiency. Under optimal conditions, the distillation rates were 4000 mL/m²/day for the HSS and 14,300 mL/m²/day for the CWHSS-B with heaters. Furthermore, the cost of water treatment was calculated at $0.022 per liter for the HSS and $0.016 per liter for the CWHSS-B, indicating significant cost benefits with the modified design.

This review examines advancements in cords wick technology for optimizing water depth in solar stills, a crucial factor in enhancing desalination efficiency. Shallow water depths generally lead to increased productivity, and cords wick technology effectively reduces energy waste by drawing only evaporated saline water, minimizing hot water loss. Various modifications, such as reflectors, fans, and baffles combined with nano-enhanced PCM, have significantly improved the performance of cords wick solar stills. Notably, incorporating cords, reflectors, a fan, and square baffles resulted in a 264 % increase in distillate production. Additionally, these enhancements offer environmental benefits, with reported annual CO₂ emissions reductions of approximately 28.71 tons and water treatment costs ranging from $0.01 to $0.0185 per liter. The insights provided here contribute to the ongoing research on maximizing desalination efficiency using cords wick technology in solar stills.

Limited access to safe drinking water is a critical global issue, particularly in areas with inadequate infrastructure. Solar stills offer a promising alternative for such regions. This study investigates the influence of square baffles within a modified solar still design on its overall efficiency. Additionally, the integration of reflectors is explored to enhance both evaporation and condensation rates. Furthermore, the effectiveness of a paraffin wax phase change material (PCM) combined with silver nanoparticles is assessed within the modified still. Thermo-economic analyses are conducted to evaluate the economic feasibility of the proposed system. The findings demonstrate a significant improvement in distillation yield. The modified still with square baffles achieved a yield of 9800 mL/m2.day compared to 3550 mL/m2.day for the reference still, representing a 193 % increase. Moreover, incorporating the nano-PCM at an optimal configuration (25 cords) resulted in a further 265 % productivity increase for the modified still with both square baffles and reflectors. This configuration also achieved an efficiency of 63 %. Economic analysis revealed a minimal cost difference between the reference still (0.014 $/L) and the modified still with square baffles and nano-PCM (0.01 $/L). In terms of environmental impact, the modified still exhibited a lower annual CO2 emission of 28.8 tons.

This study investigates the enhancement of freshwater production using a modified cords wick tubular solar still (CWTSS) compared to a traditional tubular solar still (TSS). The CWTSS design increased freshwater yield by 102 % over the baseline TSS. Also, the impact of using baffles (CWTSS-B) was tested. Incorporating reflectors into the CWTSS (CWTSS-B-R) further improved performance, achieving a 201 % increase in production with reflectors and 160 % without reflectors, highlighting the significant role of reflectors in solar energy capture and distillation efficiency. Various wick cord numbers (12, 22, 32, and 42) were tested to identify the optimal configuration. The use of nanoparticle-enhanced Phase Change Material (PCM) in the CWTSS (CWTSS-PCM) resulted in a 240 % production increase compared to the TSS, demonstrating the effectiveness of PCM in thermal energy storage and management. The most significant improvement was observed in the CWTSS-fan configuration, which employed a fan and an external condenser, leading to a 256 % increase in water production, reaching 15,300 mL/m2 compared to 4300 mL/m2 for the TSS. The modified design's freshwater production cost was $0.01/L, a 50 % reduction from the conventional design's cost of $0.02/L.

This study explored methods to enhance the performance of a coiled solar still (COSS). One technique involved adding a vertical wick distiller (VWSS) with built-in reflectors positioned after the COSS. Additionally, the research examined the impact of incorporating a fan and a separate condenser on the COSS's distillate output. Finally, the investigation assessed the potential advantages of incorporating paraffin wax infused with nanomaterial beneath the COSS base. The key findings revealed significant improvements in distillate production with the COSS modifications. Compared to a standard solar still (CSS), the COSS alone demonstrated a 76 % increase in daily output. Integrating a heating coil and internal reflectors with the COSS further boosted productivity by an impressive 92 %. The most significant advancements were achieved by combining the COSS with a VWSS and additional features. The MCOSS (COSS with VWSS and internal reflectors) exhibited a remarkable 209 % increase in distillate production compared to the CSS. This value increased to a staggering 269 % when incorporating a heating coil, VWSS, and an external condenser. Adding a fan to the MCOSS further enhanced efficiency to 68 %. Notably, incorporating nanomaterial-infused paraffin wax (PCM-Ag) with the MCOSS with VWSS resulted in a 246 % increase in productivity compared to the standard design. The research also revealed a significant decrease in freshwater production costs. The cost per liter of freshwater was determined to be $0.024 for the CSS and a considerably lower $0.0126 for the MCOSS with a fan.

This study aims at improving the desalination process of hemispherical solar still (HSS). A modified HSS (MHSS) design was developed, incorporating a 35 cm radius hemispherical absorber to heighten vaporization area and sun exposure. The influence of various factors on the MHSS performance was evaluated: wick material (jute cloth vs. cotton wick), rear reflectors for concentrated solar radiation, fan integration for enhanced heat transfer, and a phase change material (PCM) with silver nanoparticles (Ag) positioned beneath the liner. The MHSS design itself achieved a 96 % gain in productivity over HSS. Jute cloth proved to be a more effective wick material than cotton. The MHSS equipped with external reflectors exhibited a significant 120 % improvement in productivity. Furthermore, fan integration within the MHSS resulted in a 172 % productivity increase (11150 mL/m2⋅day compared to 4100 mL/m2⋅day for the HSS). Besides, the enhancement (152 %) was observed with the MHSS incorporating both a fan and a PCM-Ag composite, yielding a total daily freshwater production of 10500 mL compared to 4150 mL for the HSS. These findings suggest that the MHSS design with optimized features, particularly the use of a fan and PCM-Ag composite, offers a promising approach to significantly improve solar desalination performance.

Freshwater scarcity is a growing concern due to population expansion and industrial development. Solar stills offer a solution for generating potable water, although production volumes are limited. This research aims to address this challenge by improving the yield, thermal efficiency, and cost-effectiveness of freshwater production in tubular solar stills (TSS). We propose a novel approach that incorporates wick materials within the TSS design. This method involves creating a specific number of cuts (cracks) in a secondary basin liner positioned 2.5 cm above the original liner within the still. The upper liner is extended with wick, and wicking cords are suspended from edges and openings of this liner. These cords continuously remove saltwater, ensuring a consistently moist wick surface. The design of the wick cords optimizes water utilization and minimizes energy waste. The cords extract precisely the amount of saline water needed for evaporation, eliminating the loss or overflow of hot water. This approach maximizes wick efficiency without sacrificing freshwater production. The study investigates the performance of the TSS using 32 wick cords in conjunction with jute wick material. This modification to the conventional TSS offers a simple and cost-effective method to enhance productivity. Additionally, the glass cover of the still is tilted at an angle to facilitate the collection of distilled water droplets. ICWTSS was used as a code name for the modified TSS. After that, three distinct inclination angles (2°, 4°, and 6°) were examined, and the effectiveness of ICWTSS at each angle was contrasted with that of CSS. With a 6° angle of inclination, the ICWTSS showed a 67 % thermal efficiency and a 257 % increase in production over CSS.

Solar stills are acknowledged as an environmentally friendly desalination method that addresses water scarcity issues in remote areas; however, they contend with a productivity challenge. This work presents a combination of novel arrangements for the spherical solar distiller (RBSD) to augment its productivity. Rotational sphere was anticipated. The influence of speed for RBSD (0, 0.5, 1, 1.5, and 2 rpm) with and without wick was tested. Also, the effect of utilizing a preheater to supply the RBSD with hot feed water under various preheating temperatures, specifically 45, 50, 55, 60, 65, and 70 °C with and without condenser was investigated. Results revealed that the optimized speed is 0.5 rpm and 1 rpm for the RBSD with and without wick, respectively, where the productivity rise reached 62 % and 45 %, respectively. Also, the best preheating temperature that provided the highest performance for RBSD was 65 °C, where the CSD produced 3250 mL/m2.day, while, at 0.5 rpm and 65 °C, the RBSD with a preheater produced 6200 mL/m2.day with an increase in productivity by 91 %. When integrating the external condenser to RBSD with wick and preheater, the productivity of RBSD (6800 mL/m2.day) was augmented by 116 % over that of the CSD (3150 mL/m2.day). Also, the thermal efficiency of CSD and RBSD with wick, preheater and condenser was 32 % and 62 %, respectively. Finally, the cost of distilled water for CSD, RBSD with wick, RBSD with wick and preheater, and RBSD with wick, preheater, and condenser was found to be 0.220$/L, 0.075$/L, 0.055$/L, and 0.030$/L, respectively.

The development of sustainable water resources is an issue of great interest globally. To meet the demand for freshwater, Humidification-Dehumidification (HDH) technology has been successfully used. The effectiveness of this strategy has been improved by the implementation of numerous research investigations. To get purified water, the HDH system involves getting vapor content from the saline into a carrier air stream. HDH cycle is discussed in various forms in this paper, along with a thorough overview of important recent technological developments. Utilizing bubbles in evaporators and condensers of HDH, fogging techniques (ultrasonic and nozzles), and various packing materials are also discussed. A detailed comparison of the HDH performance factors such as the productivity, gained output ratio, and costs has been conducted.

Abstract Nowadays, the whole world is moving very quickly into the field of seawater desalination. This is because the world suffers from a lack of potable water. Water and energy are adjoining linked fields. The present work aims at investigating the performance of a reverse osmosis (RO) plant integrated with Pelton Wheel under various operating conditions. The main reason for using Pelton turbine instead of the pressure exchanger (PX) is the low cost of Pelton compared to that of PX. The RO system integrated with the Pelton Wheel was tested under various operating pressures of 650, 700, 750, 800, and 850 kPa. Changing the feed water pressure affects the pressure of the reject entering the Pelton wheel and this, in turn, affects the velocity of the water jet. Also, the impact of varying the feed water salinity (total dissolved solids (TDS) = 400, 500, 600, 700, and 850 ppm) and temperature (20–39 °C) on the permeate and reject of RO was tested. In addition, a theoretical modeling was built to predict the performance of the RO system. The permeate flow rate was increased by raising the RO operating pressures. The permeate flow rate was augmented from 2.5 to 4.3 L min−1 when increasing the operating pressure from 650 to 850 kPa, respectively. Therefore, the permeate flow rate is enhanced by around 72% when increasing the operating pressure by only 30%. Besides, increasing the pressure by 30% (from 650 to 860 kPa) decreased the generated power of the Pelton Wheel by approximately 72% (from 960 to 270 W, respectively). Also, increasing the feed water salinity leads to raise the salinity of RO permeate, and vice versa. The RO permeate salinity is raised from 165 to 285 ppm when increasing the operating pressure from 650 to 850 kPa, respectively. As well, the more the increase in feed water temperature, the more improve in the permeate flux and salinity. The permeate TDS was decreased from 140 ppm at feed-water temperature 20 °C to 56 ppm at feed water temperature 39 °C. In this study, the Arduino program circuit was used to supply the required emergency loads by controlling the pressure values of high-pressure pump due to easy and open code program. Finally, the theoretical modelling results are in good correspondence with the experimental results. The average deviation among the theoretical and experimental results was 3.5%.

This research paper presents a comprehensive review and comparative analysis aimed at enhancing the performance of tubular solar stills for water purification. As the global demand for clean and potable water rises, harnessing solar energy for water desalination has gained considerable attention. Tubular solar stills offer a promising solution, utilizing solar radiation to drive the purification process to produce a moderate productivity of 6–10 L/m2.day. This paper systematically reviews existing methodologies and materials employed in the design and construction of tubular solar stills, evaluating their impact on overall performance. The review encompasses various aspects, including the geometry of tubular solar stills, heat-absorbing materials, condensation surfaces, and innovative enhancements applied to improve efficiency. Comparative analyses are conducted to assess the strengths and limitations of different approaches, providing insights into the factors influencing distillation rates, energy efficiency, and cost-effectiveness such as using nanofluids, phase change materials and thermal storing materials, glass cooling, water preheating, rotating cylinders, various absorber shapes … etc. Furthermore, the paper discusses recent advancements in nanotechnology and novel materials that hold promise for optimizing tubular solar still performance to have such productivity of 11 L/m2.day and efficiency of 80 %. The findings of this research aim to guide researchers, engineers, and policymakers in selecting optimal design parameters and materials for tubular solar stills, ultimately contributing to the development of more efficient and sustainable water purification systems. The holistic approach presented in this paper seeks to address the existing challenges and promote the widespread adoption of tubular solar stills as a viable solution for decentralized water purification in regions facing water scarcity.

The objective of this study was to enhance the performance of hemispherical solar stills (HSS) through experimental investigations utilizing various types of sand beds as thermal storage materials. The research examined the influence of sand type (yellow and black) and sand bed heights (1, 2, and 3 cm) on the efficacy of HSS. Additionally, the study explored the effects of external reflectors and a vapor extraction fan on the performance of sand-based HSS. The experimental results indicated that HSS using black sand demonstrated superior performance compared to other operating conditions in terms of both productivity and efficiency. Particularly, the most significant improvement in performance for the black sand hemispherical solar still (BSHSS) was observed when employing reflectors and a fan with a sand bed height of 1 cm, resulting in a substantial 154% increase in production, where the production for hemispherical SS and BSHSS + fan and reflectors was 4100 and 10400 mL/m2.day, respectively. Under these optimized conditions, the thermal efficiency of BSHSS + R + F reached 56%. In conclusion, an economic analysis was conducted, revealing that the cost for water treatment was $0.022 per liter for the conventional hemispherical solar still (HSS) and $0.012 per liter for the BSHSS equipped with reflectors and a condenser. These findings represent a significant advancement in enhancing the feasibility and efficiency of solar distillation systems, thereby addressing the global challenges of water scarcity and environmental sustainability.

In order to maintain access to freshwater resources in water-stressed regions, it is important to improve the performance of solar-powered desalination systems with lower cost units like solar stills (SS). However, the SS produces low productivity especially through the rainy or cloudy days due to the indirect diffused beams. Therefore, the main aim of this study is to increase the yield from brackish/seawater via a solar still operating with renewable energy sources. The water depth was lowered, and thermal storage materials with different sand beds trays solar still (TSS) are used to augment the amount of yield from a SS. The effects of sandy bed height, and sand type (black and yellow) on the performance of TSS were investigated. Also, the effect of internal reflectors on the sand TSS performance was investigated. Experimental results revealed that the sandy layer (storage beds) improves the TSS production. The maximum increase in accumulated production of sandy TSS with internal reflectors was reached at sand beds height of 1 cm and black sand. In this case, the freshwater was heightened by 105 % over CSS.

The problem of freshwater shortage is increasing a day after day. Solar distillers are suitable devices to overcome this problem for remote areas and small families. However, these devices suffer from their low productivities. Here, two different modified designs for the distillers of rotating wick types were tested. One distiller contained a rotating wick belt with a path of “L” character shape (l-RWSS), and the other with a path of “LC” shape (LC-RWSS). In addition, the wick type was investigated for black jute and cotton wicks. Moreover, the effect of belt-rotation direction (clockwise and counterclockwise) on the still performance has been studied. The period of wick belt rotation was tested (ON = 5 min and OFF = zero, 10, 20, 30, 40, 50, and 60 min). Also, the impact of using graphene quantum dots nanofluid on the distiller performance was investigated. Experimental results obtained that the jute wick obtained more distillate than the cotton cloth. Furthermore, the productivity of LC-RWSS with counterclockwise movement of wick belt was always larger than that with clockwise direction under all different OFF times. Also, the LC-RWSS (jute wick-counterclockwise-0.1 rpm) increased the freshwater productivity by about 17 % over l-RWSS. Besides, the LC-RWSS provided higher accumulated daily productivity than l-RWSS by 19 % and 17 % with and without nanofluid, respectively. Also, the cost of freshwater obtained is 0.018 and 0.021 $/L for LC-RWSS with and without nanofluids, respectively.

Introduction: Nanofluids, hybrid nanofluid possesses thermophysical features that boost the fluid performance. This research work is motivated by the utilization of water solar collectors that incorporate non-Newtonian, power-law hybrid nanofluid in a three-dimensional model, considering the two-phase model.Method: The primary objective of this study is to transform the governing equations of the flow model into a set of ordinary differential equations by employing the three-parameters group technique. Based on the innovative discoveries, two models incorporating new associated functions have been successfully developed for two distinct scenarios characterized by the power-law index, n. The impact of physical factors on the velocity profile, temperature distribution, concentration field, and entropy output of the system is clearly illustrated through a variety of graphs.Results: The results indicated that the inclination angle of 20° had the best thermal characteristics compared to other inclinations. The entropy generation reached its maximum value at temperature difference of 13 K due to irreversibility of the system, which indicates that the system is more efficient.Discussion: Furthermore, the increasing percentage in Nusselt number is predicted to be 28.18% when the Prandtl number is taken a range. The Sherwood number enhanced up to 18.61% with a range of Brownian motion. A quantitative comparison is conducted between the present results and the literature in order to validate the superior efficiency of the used method.

Solar stills are famous techniques of solar desalination methods, but they suffer from the low daily water production. In this work, an experimental study was conducted to enhance the trays solar still (TSS) performance. The heat transfer rate between the saline water and absorber of TSS has been improved. So, the performance of TSSs with flat and finned absorbers shapes was studied. The tested SSs were conventional solar still (CSS), TSS, and finned TSS (FTSS). Jute wick materials were utilized to cover the finned absorbers, where the wick feed water flows slowly to upward through the porous material. The influence of installing reflecting mirrors on the internal sides of TSS was studied. For further enhancement of TSS performance, phase change materials mixed with copper oxide-nanoparticles has been utilized to test the FTSS performance. In addition, 3 electric heaters have been utilized to heat the water basin. The photovoltaic cell was added beside the back wall of the FTSS thereby using the same FTSS space and used as a power source for the electric heaters. Results indicated that the FTSS productivity was enhanced by 166 and 136% when utilizing the heaters and phase change materials with nanoparticles compared to that of the CSS, respectively. Also, the daily water productivity of the FTSS was enhanced by 196% over the CSS when using both the electrical heaters and phase change materials with nanoparticles at the same time.

Solar stills are considered one of the most thermally eco-friendly and promising solutions for producing potable water in sunny and arid regions. However, they suffer from a disadvantage in terms of their low productivity. Therefore, this study aims to investigate the performance of cylindrical sector solar stills and compare them with double-slope solar stills. The study also presents the enhanced performance of a thermo-economic system by integrating cost-effective and readily available materials. The experiments were conducted in Egyptian climate conditions, with a water depth of 2 cm in the stills basin, using different materials. Under the same operating conditions, the results showed that the accumulated productivities of the cylindrical sector solar stills (CSSS) and double slope solar stills (DSSS), using black fiber and black dye, were 3514 ml/m2 and 3029 ml/m2, respectively, representing an increase of 16.01%. Furthermore, the daily thermal efficiency of the CSSS and DSSS, using black fiber and black dye, were 30.42% and 26.32%, respectively, showing an increase of 15.58%. The cost per liter (CPL) of potable water produced by CSSS, using black dye with black natural-fiber, was approximately 0.0119 US$/L, while it was 0.0137 US$/L for DSSS. Additionally, the payback periods for CSSS and DSSS were 92 days and 106 days, respectively. In all scenarios studied, the daily accumulated productivities and thermal efficiency of CSSS were greater than those of DSSS.

The freshwater shortage problem is increasing day after day. Solar stills are suitable devices to overcome this problem for small families and remote areas. However, these devices suffer from their low productivity. Two different modified designs for spinning wick solar stills were tested here. One distiller contained a rotating wick belt with a path of “LC” character shape (LC-RWSS), and the other with a path of “L” shape (L-RWSS). Additionally, the wick type was studied for black cotton and jute wicks. Moreover, the influence of belt-rotation direction (counterclockwise and clockwise) on the performance of solar still has been investigated. The period of wick belt rotation was tested (ON = 5 min and different OFF times = zero, 10, 20, 30, 40, 50, and 60 min). Also, the impact of utilizing graphene quantum dots nanofluid on the performance of LC-RWSS was considered. In addition, the effects of external reflectors and exhaust fan were examined. Results indicated that the jute wick provided more distillate than the cotton cloth. Furthermore, the productivity of LC-RWSS with counterclockwise movement of wick belt was always larger than that with clockwise direction under all different OFF times. In addition, the best output yield of LC-RWSS (at 0.1 rpm with jute wick-counterclockwise) was achieved when operating the wick belt under 30 min OFF and 5 min ON times, the LC still had a daily distillate more than L still by 17%. The thermal efficiency of L still and LC still was 82% and 86%, under 30 min OFF period of belt. With reflectors, exhaust fan and nano, the best output yield of LC-RWSS was provided when operating the belt under 10 min OFF and 5 min ON times. The LC still had a total yield more than that of the L still by 28% with 87% thermal efficiency. Also, the cost of freshwater obtained is 0.016 for LC still with reflectors, fan and nanofluids.

The countries suffer from the freshwater shortage. The solar still is one of the overcoming strategies, however its distillate production is limited. The present work introduces a different arrangement of modifying the pyramid solar still (PSS). This was conducted by changing the flat absorber to a pyramidal absorber to increase the vaporization surface area of distiller. Additionally, several wick materials made of jute cloth and cotton wick were placed over the pyramidal absorber under investigation. Besides, the performance of the modified pyramid solar still (MPSS) was studied when using external condenser and utilizing external mirrors to increase the input solar energy. Finally, a paraffin wax mixed with silver nanoparticles was used as a phase change material (PCM) under the pyramidal absorber of MPSS to be tested. The results revealed that using the modified absorber increased the evaporative surface area of MPSS by around 40%. Also, using the jute cloth material is suggested to be used instead of cotton cloth for the MPSS due to its better operation. Additionally, the best performance of MPSS was obtained with mirrors and condenser, where the productivity improvement and distiller efficiency were 142% and 52.5%.

The effect of tungsten, aluminum, and cobalt on the mechanical properties of iron-based composites prepared by powder technology was studied. Five samples with different contents of tungsten, aluminum, and cobalt were established. The five samples have the following chemical compositions: (I) full iron sample, (II) 5wt.% tungsten, (III) 5wt.% tungsten-4wt.% cobalt-1wt.% aluminum, (IV) 5wt.% tungsten-2.5wt.% cobalt-2.5wt.% aluminum, and (V) 5wt.% tungsten-1wt.% cobalt-4wt.% aluminum. The mixed composite powders were prepared by mechanical milling, in which 10:1 ball to powder ratio with 350 rpm for 20 h was cold compacted by a diaxial press under 80 bars, then sintered at temperatures ranging from 1050 °C to 1250 °C in an argon furnace. The samples were characterized mechanically and physically using XRD, SEM, a density measuring device, a hardness measuring device, a compression test device, and a tribological device for wear and friction tests. XRD results refer to the formation of different intermetallic compounds such as Fe7W6, Al5Co2, Fe2W2Co and Co7W6 with the main peaks of Fe. The good combination of tribological and mechanical properties was recorded for sample number five, which contained 5% W, 4% Al, 1% Co and Fe base, where it obtained the highest wear resistance, largest hardness, acceptable compressive strength, and lowest friction coefficient due to the good combination of hard and anti-friction intermetallic action compared with the other samples. This sample is a good candidate for applications which require high wear resistance and a moderate friction coefficient accompanied with high toughness, like bearing materials for both static and dynamic loading with superior mechanical and tribological properties.

In recent years, industries in the suburb have retrofitted their power supply units with solar power supply systems. Using solar power supply systems for various applications, such as food processing, enables energy expense saving. A promising opportunity in the food industry is solar-powered Pulsed Electric Field (PEF) used in the treatment of fruits and their by-products. For this application, a converter is proposed in this paper with a combination of a passive switched inductor cell and a switched capacitor cell. Furthermore, the derived topology possesses an extendable feature. This topology generates high voltage repetitive pulses with a single semiconductor switch and a reduced component count. Dynamic study of the converter is also performed with the derivation of the transfer function. Cost effective, reliable, and simple circuitry are the critical features of this topology. The circuit topology can generate high voltage pulses by increasing the number of switched inductors and switched capacitor cells. A correlation study on the impact of the switched inductor/capacitor cell is also performed and analyzed, which is not usually performed. A 50 W prototype is designed and tested to validate the performance of the converter

Researches in many laboratories on solar still desalination are concerned with increasing efficiency using only solar energy. One of the techniques is the difference in the thickness of the glass cover of the distiller. In order to see the influence of this parameter on efficiency, three similar stills with three different glass coverings were investigated. The flow of heat goes through the cover, and higher glass temperature leads to solar still productivity becoming lower. This paper presents an optimization of glass thickness (Gt) of a conventional solar still (CSS) in El Oued climate, Algeria. Based on the experimental results, the distilled water production rate, energy, and energy efficiency of the CSS have been discussed. The results showed that the suitable Gt of the CSS was 3 mm. The distilled water of around 3.15, 2.02, and 1.13 kg was produced by the CSS at energy efficiency of 30.71, 19.02, and 11.44% with the Gt of 3, 5, and 6 mm, respectively. The daily average exergy efficiency of 2.46, 1.38, and 0.84% was calculated for the CSS at Gt of 3, 5, and 6 mm, respectively.

The difficulty of delivering electrical power to rural areas motivated the researchers to explore more accessible power sources. Hydropower is considered a desirable option due to its sustainability and lower costs. Pelton turbines have been widely used in hydropower plants because of their low installation and maintenance costs. This study provides a computational fluid dynamics (CFD) model for Pelton turbine performance under various flow conditions. The model is based on the conservation of mass principle, Newton’s second law, and the first law of thermodynamics. It is used to predict the torque produced by a turbine at different rotational speeds. Previously published experimental results for the same turbine geometry and flow parameters were used to validate the model’s predictions. Validation revealed that the model can reproduce the experimental results. This provides the required robustness for its use as a tool for turbine design and modification.

This study is intended to investigate and analyze the operational performances of the Conventional Tubular Solar Still (CTSS), Tubular Solar Still with Phase Change Material (TSS-PCM) and Tubular Solar Still with Nano Phase Change Material (TSS-NPCM). Paraffin wax and graphene plusparaffin wax were used in the CTSS to obtain the modified solar still models. The experimental study was carried out in the three stills to observe the operational parameters at a water depth of 1 cm. The experiment revealed that TSS-NPCM showed the best performance and the highest yield in comparison to other stills. The distillate yield from the CTSS, TSS-PCM and TSS-NPCM was noted to be 4.3, 6.0 and 7.9 kg, respectively, the daily energy efficiency of the stills was observed to be 31%, 46% and 59%, respectively, and the daily exergy efficiency of the stills was recorded to be 1.67%, 2.20% and 3.75%, respectively. As the performance of the TSS-NPCM was enhanced, the cost of freshwater yield obtained was also low in contrast to the other two types of stills.