Solar Desalination System Research Articles

Solar Desalination with Monolithic Foams Containing a Combination of Graphite and SnSe Featured with a Hierarchical Structure and Bimodal Pores for Spontaneous Salt Rejection

The increasing interest in solar water evaporation technology is due to its potential to replace conventional desalination systems. In this study, we suggest a new solar desalination system that has a hierarchical photothermal structure and is structurally monolithic. The overall membrane is made up of a macroscale porous melamine foam frame that acts as a porous insulator and a mass transfer layer. The mass transfer layer is designed with a bimodal porous structure of melamine foam, with large pores coated with a composite of graphite and SnSe (G-SnSe) and small pores. This simple structure provides many benefits. First, it combines two photothermal mechanisms, thermal vibration in graphite and non-radiative relaxation in SnSe, to achieve synergies in the conversion of light to heat energy. Second, compared to the single materials, graphite or SnSe alone, the nanocomposite of G-SnSe has a higher effective surface area, resulting in increased solar absorption. Finally, the melamine foam structure with bimodal pores enhances seawater wicking and has a high salt rejection capacity due to its volumetric porosity bimodal configuration of up to 35%. The monolithic melamine foam with a hierarchical photothermal structure minimizes interference with water transport due to the resistance-free presence of a continuous interfacial layer.The monolithic structure evaporaters (MSE) achieved a high evaporation rate of 1.303 kg m-2h-1 under 1 sun condition due to increased capillarity by the small-scale pores in the photothermal layer. Furthermore, spontaneous salt rejection was observed during solar desalination, attributed to the presence of intrinsic large-scale pores in melamine foam for draining the concentrated salt water from the surface. The feasibility of outdoor solar desalination was established, with a high evaporation rate of 1.259 kg m-2h-1. The mechanical stability of MSE was achieved by incorporating a small amount of binder (less than 3% of total photothermal materials), maintaining efficient performance for up to 30 days without degradation. The proposed strategy in the simple monolithic structure with bimodal porosity provides a general toolkit for designing high-performance solar desalination devices due to high evaporation rate and spontaneous salt rejection capability.In summary, the solar water evaporation technology is becoming increasingly popular as a possible replacement for traditional desalination systems. We propose a novel monolithic solar desalination system with a hierarchical photothermal structure, which is composed of a macroscale porous melamine foam as a skeleton which has both roles : an insulator and a mass transfer layer. The bimodal porous structure of melamine foam with large pores coated with a composite of graphite and SnSe provides many benefits, including increased solar absorption and a high salt rejection capacity. The MSE structure achieves a high evaporation rate and spontaneous salt rejection, making it a feasible option for outdoor solar desalination. The proposed strategy provides a general toolkit for designing high-performance solar desalination devices.

Seasonal dynamic modeling and simulation of solar thermal membrane desalination system for sustainable freshwater production: a case study of Tanta, Egypt

AbstractMembrane distillation (MD) is an effective process for desalinating seawater, combining the merits of both thermal and membrane distillation. In this context, the sizing methodologies and optimization strategies are developed from the balance of the system’s energy demand. Therefore, accurate numerical modeling of the heat transfer and thermodynamic behavior of the MD systems is crucial for the optimal design of solar-based MD systems. The interest in utilizing solar thermal heating techniques for feed water heating in MD systems is increasing worldwide for sustainable freshwater production and lowering energy consumption. Hence, in this research, a coupled analytical modeling based on heat transfer, mass transport, and thermodynamic analysis is created to dynamically simulate a solar direct contact membrane distillation system (SDCMDS) driven by vacuumed tubes solar collectors (VTSCs) to analyze its performance, under real weather of Tanta, Egypt. The influences of the solar collecting area on the performances of the proposed SDCMDS for augmenting the freshwater production of the SDCMDS are studied. Four cases of the proposed SDCMDS are investigated: two identical VTSCs of 1.80 m2 each unit in summer (Case I), two identical VTSCs in winter (Case II), four identical VTSCs in summer (Case III), and four identical VTSCs in winter (Case IV). The results show that the utilization of four VTSCs connected in series significantly improved the feed seawater temperature range from 30.0 to 70.5 °C compared to a feed temperature range of 30.0–49.5 was achievable by utilizing only two VTSCs. Moreover, the daily averaged permeate flux were 2.21, 1.29, 3.41, and 2.07 L/day per m2 of solar harvesting area with daily cumulative distilled water yield of 7.48, 4.60, 23.04, and 14.78 L/day for Cases I, II, III, and IV, respectively, at a saline flowrate of 0.20 kg/s. The daily average total efficiency of the SDCMDS was obtained to be 14.70%, 12.50%, 24.95%, and 22.50% for Cases I, II, III, and IV, respectively.

Comparative thermoeconomic assessment of renewable-driven hybrid-cooled sustainable greenhouses for subtropical regions

The rapid population growth in subtropical regions and heavy reliance on food imports have led to many countries facing food insecurity. In subtropical regions, the combination of high ambient temperatures, intense solar radiation, lack of fertile soil, and limited freshwater resources create an inadequate environment for agriculture production. Without sustainable and innovative solutions, cultivation in subtropical regions will become energy-intensive, expensive, and susceptible, if not entirely unattainable. Therefore, this research work delves into assessing the thermoeconomic performance of 10 renewable-driven hybrid-cooled greenhouse integrated systems based on different solar power generation technologies, cooling cycles, and desalination systems. Four greenhouse configurations are simulated: Closed greenhouse, shaded greenhouse, buried greenhouse, and buried and shaded greenhouse. Firstly, passive cooling techniques' potential to reduce active-cooled greenhouse cooling demand and water usage was investigated, taking into account the need to provide crops with adequate environmental temperature, solar irradiation, and ventilation. Secondly, a detailed thermodynamic analysis was conducted to obtain the overall energy and exergy efficiencies of the investigated greenhouse integrated systems. Thirdly, a comparison of solar panels area requirement for the greenhouse integrated systems was performed. Finally, a comprehensive life cycle cost analysis of the examined integrated systems for the hybrid-cooled greenhouses was done to compare their economic performance. The results showed that the adopted passive cooling methods reduced yearly cooling load by 34.2–58.1%, evapotranspiration during maximum cooling load day by 17.4–34.1%, solar panels area by 8.5–32.1%, and integrated systems' life cycle cost by 5.6–28.6%. Greenhouse integrated systems powered by photovoltaic panels obtained the lowest life cycle cost, while greenhouse integrated system-4 driven by concentrating photovoltaic thermal panels was found superior in terms of panels area.

Novel solar still design using transparent waste bottles

With increasing pressure on the global climate under the high worm gases emissions of fossil fuel, the necessity of using renewable energy is rapidly increasing. This study proposed a new solar water desalination system using waste transparent bottles for freshwater production. Two concentric transparent bottles were used. The inner bottle was cut longitudinally and horizontally placed with upward cut direction and filled with black cotton wick saturated by saline water. The outer transparent tube was cut radially to insert the inner smaller bottle inside and then reassembled using a transparent tap. The proposed device was exposed to the sunrays that reached the black wick and the energy absorbed and transferred to the saline water. After a short time, the water evaporation appears and started to condensate on the inner surface of the outer transparent bottle and collected at the bottom of the bottle by gravity. The proposed device showed moderate performance with 30.28% thermal efficiency and 2.95 L/m2day freshwater productivity under August climatic conditions of Cairo city in Egypt. The proposed device reduced the freshwater cost per liter by almost 66.2%, reaching a very competitive level of $0.0042/L. The proposed device can cover the essential freshwater needs for one person/year with not only a reduction of 21.3 tons/year of CO2 emissions but also with a reuse of 117 kg/year of plastic waste bottles.

Thermo-economic evaluation of a solar desalination equipped with Phase change material and spraying unit

Solar desalination is a suitable and cost-effective system for producing fresh water from salt water. The main goal of this study is improving the thermal performance of a solar desalination with latent thermal storage system and the spraying unit. The heat loss of the solar collector increases due to the fluctuations in the intensity of solar radiation. Using phase change materials is a suitable solution for storing energy during peak hours and releasing it when the solar radiation intensity is reduced or in cloudy times. Moreover, due to the effective area of the spraying mechanism the desalination efficiency enhanced. Thermal performance of the collector was analyzed at three spraying rates of 0.25, 0.5 and 1 l/min with and without phase change material in consecutive days from 10: 00 to 14: 00. The results showed that the presented solar desalination system equipped with paraffin (as PCM) wax had the highest thermal efficiency at the spraying rate of 1 l/min and the lowest with a flow rate of 0.25 l/min. With integration PCM and spraying mechanism the amount of produced fresh water during 4 h was 1840 ml/m2 and it significantly reduced the hardness of the produced water. The solar collector simulated by Anysy and the simulated results showed a good correlation between the predicted and experimental data with reasonable accuracy (R2 > 0.97).

Analysis of solar water desalination using hybrid nanofluids: An experimental study

The performance characteristics of a novel solar water desalination system has been inves-tigated experimentally. The desalination unit consisted of a square basin-pyramid solar still coupled with a solar heater. Different DI water based mono and hybrid nanofluids were pre-pared using CuO and GO nanoparticles following the two-step method. DI water when em-ployed as the heat transfer fluid in the system, improved the distillate water yield by about 28.80% relative to the conventional solar still. Out of all the considered CuO mono-nano-fluids, the 1.0 wt.% concentration resulted in the maximum increment of about 78.80% in the distillate water yield followed by 1.5 wt.% (62.05%) and 0.5 wt.% (53.30%) respectively. Utilizing the CuO+GO hybrid nanofluid, resulted in maximum increment of about 127.46% at 25:75 nanoparticle proportion followed by, 50:50 (101.33%) and 75:25 (89.30%) respectively, while employing the 1.0 wt.% GO mono-nanofluid, resulted in an increment of about 54.93% in the distillate water yield. The pumping power of the prepared nanofluids was found to be the function of their concentration. Hence, the performance index was evaluated for all the tested heat transfer fluids followed by an economic analysis of all the considered cases. The pu-rity of the produced distilled water was also assessed by comparing with the Bureau of Indian Standards. Finally, the study proposed the best suitable heat transfer fluid for the investigated system and suggested the possible futuristic research objectives.

Experimental and theoretical investigation of thermal efficiency and productivity of single slope basin type solar distillation system using honey-comb

The aim of current research was to improve water quality by constructing a single slope basin type solar water distillation system with honeycomb, as well as to increase distilled water pro-ductivity. In this investigation, honeycomb structure of 2.25 cm and a diameter of 6 mm in a square section (100 cm ×100 cm) have been proposed to enhance the efficiency of the solar still. An experimental analysis was done to investigate the performance of the honeycomb structure. Thermal efficiency of the standard solar distillation system was obtained approxi-mately 18.48%, while the thermal efficiency and productivity of the solar distillation system with honeycomb was obtained 25.45% and 749.58 ml/m2 respectively. It was concluded that, the solar distillation system with honeycomb structure was more efficient that a simple con-ventional solar distillation system. The addition of honeycomb structure in simple solar de-salination system increased the productivity and efficiency by 35.36% and 37.71% respectively.

Investigations on a solar humidification dehumidification desalination system equipped with various packing materials and multi-stage bubble column dehumidifier.

This work presents the theoretical and experimental investigation of a solar-powered humidification dehumidification desalination (HDD) system with different humidifier packing materials and a two-stage bubble column dehumidifier (BCD). Naturally available coconut shells (CS) and coconut shells with drilled holes (CSH) on the surface to improve water permeability were used as packing materials in the humidifier, and their performance was compared with that of commercial-type pall ring (PR) and raschig ring (RR) packings. An in-house developed numerical model of the HDD system in conjunction with a flat plate solar water collector was used in this study. Steady-state experimental results showed that CSH packing exhibited the highest volumetric mass transfer coefficient (0.00852kg/s), resulting in maximum humidifier efficiency (96%) and freshwater yield (2.16kg/hr), followed by PR (0.00841kg/s, 94%, and 2.137kg/hr), CS (0.00831kg/s, 90%, and 2.127kg/hr), and RR (0.0081kg/s, 81%, and 2.087kg/hr) at feedwater mass flow rate of 1.5kg/min and humidifier inlet temperature of 75 [Formula: see text]. Furthermore, transient outdoor test results showed that using a two-stage configuration in a BCD increased the daily average effectiveness to 0.93, as against 0.79 for a single-stage BCD. Employing CSH instead of PR and RR packings in the humidifier reduced freshwater costs by 6.2% and 7.6%, respectively.

Colloidal Plasmonic TiN Nanoparticles for Efficient Solar Seawater Desalination.

Transferring traditional plasmonic noble metal nanomaterials from the laboratory to industrial production has remained challenging due to the high price of noble metals. The development of cost-effective non-noble-metal alternatives with outstanding plasmonic properties has therefore become essential. Herein, we report on the gram-scale production of differently shaped TiN nanoparticles with strong plasmon-enabled broadband light absorption, including differently sized TiN nanospheres, nanobipyramids, and nanorod arrays. The TiN nanospheres and nanobipyramids are further coembedded in highly porous poly(vinyl alcohol) films to function as a photothermal material for solar seawater desalination. A seawater evaporation rate of 3.8 kg m-2 h-1 is achieved, which marks the record performance among all plasmonic solar seawater desalination systems reported so far. The removal percentage of phenol reaches 98.3%, which is attributed to the joint action of the excellent photocatalytic ability and the superhydrophilicity of the porous TiN-based composite film.

An effective solar assisted semi-cylindrical saline water desalination system with direct atomizer and energy storage materials for domestic use: an experimental investigation.

Solar still is the easiest method to purifying the saline water for domestic usage, but this method needs much improvement for better performance since it has lower productivity. In this paper, an experimental investigation is completed to analyse the semi cylindrical solar productivity still. The semi-cylindrical still is incorporated with direct atomizer and scrap used as an energy storage medium. Experiments are carried out during March 2020 in Kovilpatti, the southern part of India, with a depth of 2 and 4 cm saline water. Comparative performance analysis is made for conventional semi-cylindrical still, semi-cylindrical still with an atomizer, and semi-cylindrical still with atomizer and storage materials. The experimental study shows that the productivity of still increases while decreasing the water depth. Compared with 2-cm and 4-cm depth, solar still with 2-cm depth gives promising distillate productivity. The solar productivity still having 4-cm depth of water without atomizer gives only 2670 ml; on the other side, 2-cm water depth without atomizer gives 3100-ml productivity. The maximum productivity of solar still is found on a semi-cylindrical solar still combined with atomizer and energy storage medium having 2-cm water depth. Results revealed a higher freshwater production rate of 3610 ml found while incorporating atomizer and energy storage with the solar still. The system efficiency improved up to 35.20% compared to conventional semi-cylindrical still with 4 cm of saline water depth.

Energy, Exergy, Economic, Environmental, Exergoenvironmental, Exergoeconomic, and Enviroeconomic Analysis of Photovoltaic/Thermal System with Double‐Fan Arrangement for Effective Condensation and Evaporation: An Experimental Approach

Water is one of the basic needs for all living and nonliving things. It is important to sustain the available water resources effectively for future generations. A lot of studies are employed already to improve the performance of solar desalination systems rather than conventional methods. Subsequently, an experimental approach is proposed with energy, exergy, economic, environmental, exergoenvironmental, exergoeconomic, and enviroeconomic performance of photovoltaic/Thermal (PV/T) solar distillation system using two methods to enhance the fresh water yield production at feasible cost. First is the conventional solar still (CSS) with PV and second is PV with double fan solar still (DFSS) with optimized running time of the double fan, which increases the productivity of the solar distillation system. The results show that average daily energy and exergy efficiency of the system improve with DFSS (19.98%, 1.36%) than CSS (11.74%, 0.36%). The daily yield productivity of CSS is 1.618 L m−2 and is increased as 2.482 L m−2 with DFSS. Average cost of water yield production is also reduced with DFSS and estimated as 0.018$, 0.016$, and 0.015$ for the lifetime of 15, 20, and 30 years for CSS and 0.014, 0.013, and 0.012$ for DFSS. Overall, the proposed methodology shows promising results than the conventional approach.

Natural multiscale channeled salt resistant solar evaporator for efficient and long-term water desalination

Solar steam evaporation exhibits great potential in solving the global shortage of freshwater resources. However, salt accumulation at the top photothermal conversion surface has severely limited the desalination efficiency and stability of solar desalination systems. Herein, we demonstrated a nature-inspired salt resistant bilayered evaporator by using a slight delignificated tree root as bottom substrate and decorated graphene oxide layer as the top absorber surface. The naturally design of tree root inherently exists multilevel vertical channels interconnected porous microstructures. This distinctive structure of tree root allows ultra-high-speed water transport capability and rapid multi-directional salt exchange, enabling it to possess anti-salt-accumulation properties for solar steam generation. This designed tree root-based evaporator effectively prevented salt accumulation while maintaining a fast and stable evaporation rate, which exhibited an evaporation rate of 1.60 kg m−2 h−1 with excellent long-term stability in a high-salinity brine (21 wt%) under 1 sun irradiation. Taking the unparalleled advantages, our designed tree root-based evaporator obtained by a facile fabrication method represents a high-efficacy and stable fresh water production platform for practical applications in water purification.

Performance of a solar hybrid desalination plant integrated with photovoltaic-thermal collectors for remote regions: Experimental and modeling investigation

Energy and freshwater are the most prioritized needs for any nation nowadays, especially for arid areas. Giving attention to renewable energy sources like solar energy is a must towards a cleaner environment and a world with no need of temporary sources like fossil fuels. Also, a solution to lower the power requirements and costs of desalination hybrid systems should be investigated to overcome the water problem. The present study aims to design and build a novel hybrid desalination plant working with the highest productivity and lowest power consumption. This was done by incorporating a reverse osmosis desalination unit with the conventional solar distiller. The photovoltaic/thermal collectors were utilized to produce electricity as well as a heating unit in addition to the evacuated tube solar collectors, to preheat the hybrid desalination plant feed water. The results presented that the use of photovoltaic/thermal panels and evacuated tube solar collectors as preheating units improved water recovery by 46% and reduced power consumption by 38.34% for the small reverse osmosis unit but the salt rejection decreased by 4%. Cooling the photovoltaic panel increased its electricity production by 24.1% on average. Moreover, the combination of the solar distiller with the reverse osmosis unit on the feed line represents the best configuration which improves the solar distiller’s productivity by 98.32% as compared to separate solar distillers. The cost of freshwater produced is 0.719 $/m3 which is cost competitive compared to previous solar desalination systems.

Development of Thermal Energy Storage Material From Blends of Jatropha Biodiesel and Paraffin Wax for Augmenting Freshwater Generation Capacity in a Solar Desalination System

Abstract Enhancing nocturnal productivity holds promise for boosting the effectiveness of solar desalination setups. Current research concentrates on an innovative strategy: the integration of paraffin wax and Jatropha biodiesel as a composite energy storage material (CESM) to amplify distilled water output during nighttime. The composite material, comprising Jatropha biodiesel and paraffin wax in a 1:1 ratio by weight, is meticulously examined for its impact on productivity, juxtaposed against a conventional solar still (CSS). Results reveal a substantial improvement in thermal conductivity with CESM, exhibiting a noteworthy 20.37%% surge compared to pure paraffin wax. Furthermore, a solar still with biodiesel and phase change material (SSBDPCM) is pitted against a CSS, with continuous monitoring of water and absorber temperatures alongside distillate production. The findings illustrate that SSBDPCM achieves a 16% upsurge in water temperature and a 10% elevation in absorber temperature compared to CSS. Impressively, SSBDPCM achieves a staggering 63% increase in distillate production, yielding 3.6 l/m2 and 3.4 l/m2, in sharp contrast to CSS, which only manages 2.2 l/m2 and 2.1 l/m2 over a two-day test period. Furthermore, a comprehensive cost analysis showcases the economic superiority of SSBDPCM over CSS. SSBDPCM demonstrates a compelling 29.2% reduction in cost per liter and a significant 25.9% decrease in the payback period in comparison to CSS. These compelling outcomes underscore the substantial potential of the SSBDPCM approach in delivering heightened efficiency and cost-effectiveness, paving the way for a promising advancement in solar stills.

Solar powered hybrid desalination system using a novel evaporative humidification tower: A numerical investigation

This research describes a hybrid solar desalination system that includes a humidification-dehumidification unit as well as a solar still unit. The current system is being studied numerically. A one-dimensional model of the important heat and mass exchanges, as well as the flow field, was built using the finite difference method. Freshwater productivity is calculated under various operating and weather conditions. The model has been modified to investigate the steady-state behavior of the system components. Four major parameters that have a significant impact on system water production are investigated: the feed flow rate of cooling water through the dehumidifier unit, the airflow rate, and the number and height of packing columns. According to the results, the proposed hybrid desalination system provides appropriate operational compatibility between HDH technology and solar energy. The system can provide a daily production of up to 35 liters per day. Increasing the number of packing columns results in a higher increase in fresh water productivity than increasing the height of the packing columns. The optimal air flow rate at a constant saline-water flow rate is obtained. For high airflow rates, the packing column height doesn't significantly affect the daily water production. System performance is investigated by four main parameters: gained output ratio (GOR), humidifier efficiency, exergy efficiency, and system efficiency. The system efficiency reached about 65% and the GOR reached 3.1. The humidifier’s efficiency varied between 50% and 75%. The maximum exergy efficiency reached about 5.2%.

A novel solar desalination system equipped with thermoelectric generator, reflectors and low-cost sensible energy-storage for co-production of power and drinking water

The present study aimed to improve the efficiency of the solar desalination unit by employing mirrors, waste material as a heat storage material, and thermoelectric generator by waste heat from the absorber sheet. Two mirrors were used to reflect the solar radiation into the absorber sheet and enhance the water temperature. The iron scraps painted in black color as a heat storage media were immersed to the basin of the solar still to raise the evaporation rate. Two thermoelectric generators (TEG) were attached under the basin to commute the loss of thermal energy of the absorber sheet to electrical power. The experiments were carried out for conventional solar desalination (CSS), solar still using TEG (SS-TEG), solar still using TEG and iron scraps (SS-TEG-WI), and solar still using TEG, iron scraps and mirrors (SS-TEG-WI-M). The results showed that the freshwater produced by CSS, SS-TEG, SS-TEG-WI, and SS-TEG-WI-M was 0.64 L/m2, 0.63 L/m2, 0.652 L/m2 and 0.796 L/m2, respectively. Also, the CO2 removal of the SS-TEG-WI-M improved by 24.5 %. Moreover, the daily power output of SS-TEG, SS-TEG-WI, and SS-TEG-WI-M was 2.13 W, 2.17 W, and 2.5 W, respectively. In addition, the SS-TEG configuration had the highest cost per liter (CPL) of 0.075 $/L.

Weather effect and cost analysis of solar adsorption desalination system using MIL-101(cr) – Graphite oxide composite material

Solar-powered adsorption desalination systems (ADSs) are a significant way to provide clean and fresh water using environmentally friendly adsorbent materials. This work presents an innovative investigation of solar-driven ADS's performance and cost analysis using a metal–organic framework MIL-101(cr) with and without a 2D graphite oxide (GO) material. The investigation is conducted over a complete year using lumped modeling by MATLAB and TRNSYS software. The production cost of desalinated water is evaluated using solar energy and waste heat sources. It is found that the effect of adding 2D-GO to MIL-101(cr) is positive on the isotherms and negative on the kinetics properties; hence the overall performance of MIL-101(cr) and MIL-101(cr) + GO was very close with an average difference of 2%. Optimum-specific daily water production and gain output ratio achieved at summer 24 m3/ton-day and 0.7, respectively, using MIL-101(cr). The cost is estimated to be 4.7 $/m3 using solar energy and 1.01 $/m3 using waste heat. The performance parameters indicate the effectiveness of MIL-101(cr) in solar/waste heat-driven ADS at a reasonable cost to remote areas.

Assessing the performance, sustainability, and economic viability of a photovoltaic-based solar desalination system for water scarce regions

Solar desalination is gaining increasing attention as a sustainable solution to address water scarcity in many regions. This study presents a comprehensive analysis of various aspects of solar desalination systems, including distillate quality, cost estimation, efficiency, and performance comparison. The research involved developing a photovoltaic-based solar desalination system and investigating its distillate quantity and quality, demonstrating its improvement over the conventional system (solar still which comprises a basin and a glass cover) and similar research. A pretreatment system was incorporated to produce a cleaner distillate over conventional solar stills. The results showed an improvement in distillate quantity from 4.7 L/m2 day to 19.7 L/m2 day, for the conventional and modified systems respectively. The pretreatment system enhances the distillate quality with a range of 10–55% in certain parameters. Cost estimation analysis revealed the distillate cost for the traditional and improved systems are 0.041 and 0.091 $/L respectively. A comparison with other studies highlighted the remarkable efficiency of the present study with an average improvement of 30%. It is recommended that future research should be focused on integrating pre-treatment systems, optimizing distillate cost, improving the performance of the conventional system, exploring efficiency enhancements, conducting comparative studies, performing techno-economic analysis, and scaling up. In conclusion, this work contributes to the understanding of desalination systems that use solar energy, their performance, and cost-effectiveness.

The solar-driven redox seawater desalination based on the stable and environmentally friendly WO3/BiVO4 photoanode

Nowadays, stable photoelectrochemical seawater desalination is a challenge. In this work, an environmentally friendly WO3/BiVO4 photoanode is reported to achieve stable solar-driven redox desalination. The WO3/BiVO4 photoanode was prepared by the hydrothermal method and drop-casting and the cathode is the activated carbon coated on graphite paper. Within the desalination system, the I−/I3− redox species are recycled between anode/cathode chambers. In the short-circuit state, with illumination as the driving force, the salt removal rate of 65.03 μg/(cm2·min) is obtained without the electric consumption. During the desalination process, the energy output process can be implemented with a salt removal rate of 29.8 μg/(cm2·min) with constant current discharge. Importantly, the solar desalination system based on WO3/BiVO4 photoanode is quite stable. Within the five cycles, the variation of the salt removal rate is within 3.32 μg/(cm2·min). As the practical application, the seawater is desalted to the freshwater standard using the current system, in which the conductivity decreases to 0.96 mS/cm from 53 mS/cm. This work provides a feasible approach to developing stable and efficient solar-driven seawater desalination for long-term usage.

Performance Investigation on a Double-Slope Passive Solar Desalination System Targeting towards Sustainable Development of Oman

In recent times, academicians and scientists have developed many methods for purifying saline water into pure water that is suitable for drinking, as well as other suitable applications. Fortunately, solar desalination has been a very popular technique, which uses eco-friendly solar energy. In this work, a passive-type double-slope solar still was designed and fabricated according to the Global Positioning System (GPS) coordinates of Nizwa city in Oman. Economically and readily available materials, such as acrylic, glass, and foam insulation materials, were used in the construction of the double-slope solar still in addition to the conventional materials used for the supporting structure of the solar still. The climatic factors (such as the solar radiation and ambient temperature), design factors (such as the exposure surface area, inclination, insulation material and thickness, and glazing material), and operating parameters (such as the glass temperature, feed water temperature and yield) obtained were considered in the study to estimate the performance of the solar still. DHT 11 sensors with Arduino programming were used in the experiment to record the temperatures at specific locations on the solar still daily with regular time intervals for a period of 3 to 4 weeks. The solar still was designed to operate from February to March 2023. The temperatures were recorded every two hours daily, whereas the yield was recorded at the end of the day of operation. The quality of the yield was estimated through the measurement of pH and TDS (Total Dissolved Solids) values. The energy and exergy analysis of the desalination unit was carried out to estimate the thermal performance of the system. A significant effect of solar intensity and ambient temperature was observed on the thermal performance of the system and on the quality of the drinking water. An energy efficiency ranging between 30 to 45% and exergy efficiency ranging between 2 to 3.5% was obtained in the system, which was reasonably better for a thermal system involving a renewable source of energy.