Solar Desalination Research Articles

Research on the application of single effect evaporation regenerative solar seawater desalination device

Abstract In remote islands and brackish water areas, seawater desalination devices are needed, but existing product technologies are relatively complex and inflexible to use. In this paper, a single-effect evaporation regenerative solar seawater desalination device is introduced. In this device, a solar collector composed of a straight-through-all glass vacuum tube is used for heat collection, while single-effect evaporation is used for seawater desalination. Moreover, the latent heat generated during condensation is used to increase the temperature of seawater, which increases the operation efficiency. This device has a simple structure, low cost, and is suitable for water desalination in remote islands and brackish water areas.

Performance Enhancement of Solar Still Couples With Solar Water Heater by Using Different PCM's and Nanoparticle Combinations

ABSTRACTThe majority of the water on Earth roughly 97% is contaminated or salty, only 3% is fresh water, and only 1% of pure water is easily available for human use. In rural areas and remote locations suffering from pure drinking water scarcity.Water purification techniques are generally dependent on electricity, which relies on coal and gas plants, these poses a risk to the environment and society. Solar desalination is being recognized as the most practical way to deal with the scarcity of pure drinking water in all aspects of sustainable development. This paper describes the creation of a single slope solar still (SSSS) using opaque and crystal‐clear toughened glass with a thickness of 6 mm as a cover and also another setup of a single slope phase change material (PCM)‐based solar still (MSSSS). In this paper, a flat plate solar collector coupled with water heater is used to enhance the productivity of still. In this study, an experimental model has been developed to experimentally analyze exercise productivity performance of SSSS and MSSSS of MMIT Kushinagar, India on April 10, 2023 to April 15, 2023. Combination of stearic acid, lauric acid, and paraffin wax combined with CuO (nanoadditive) is used to enhance the solar still productivity. Also, basin temperature for different PCM's such as paraffin wax, lauric acid, and stearic acid are compared. Different combinations of PCM's and nanoadditives are compared to find the better productivity. It is observed that maximum output is obtained at 3:00 p.m. afternoon on experimental setup. Paraffin wax, stearic acid, and lauric acid still increases productivity by 38.8%, 20.3%, and 30.5%, respectively, when compared to simple solar still. On experimentation of various combinations, it is found that the use of PCM paraffin wax and nanoadditives CuO gives 55% better productivity compared to other combinations. This innovative system is suitable and ideal for desalinating water in isolated and rural locations with low traffic and limited demand.

Water, energy, and food nexus in a solar-powered brackish water desalination plant in Jordan

Abstract The growing demand for water in domestic, agricultural, and energy production applications poses a significant challenge for Jordan. This work assesses the role of brackish water desalination as an alternative to alleviate water scarcity in semi-arid regions. Desalination is still limited in its application in Jordan due to high electricity tariffs. Shifting to renewable sources such as solar energy, abundant in the country, is a feasible way to power technologies with a high energy demand. In this work, we study the brackish water desalination plant at the Hashemite University in Jordan that is powered by a photovoltaic (PV) solar system (the HU PV-BWRO). The plant’s performance was evaluated in the context of the water-energy nexus as a hybrid water supply solution. While this work integrates essential elements, such as water availability, technical options, economic viability, and agricultural management, the analysis primarily focuses on the technical and economic aspects related to water, energy, and food. Water assessment results indicate that the groundwater wells near the HU campus are at risk of quality degradation over time, as they have shown a slight increasing trend in salinization from 2015 to 2023. Energy assessment results show a promising performance from the HU PV-BWRO desalination plant, with a specific energy consumption (SEC) value of 1.2 kWh m−3 (140% to 400% less energy consumption compared with other Jordanian desalination plants of similar capacity). Unit price comparisons indicate that the energy cost of PV (0.042 USD/m3) is 5 times less than the cost of grid electricity (0.24 USD/m3). The operational cost of the solar desalination plant at full capacity, is USD 0.23/m3. This is about 260% less than the operation cost for local, grid-powered desalination plants. Finally, it is estimated that by operating the plant at 50% of its total capacity, the produced water could be sufficient to irrigate up to 80% of the HU campus to increase agricultural production. This study highlights the importance of decreasing reliance on energy for water and food production, and it shows that the use of solar powered desalination could be used as an example in semi-arid regions, particularly in terms of integrating renewable energy and energy efficiency.

Theoretical investigation into saline optical properties for enhancing solar still performance: Mathematical modeling approach

This study investigates the dynamic optical properties of saline solutions, specifically transmissivity, absorptivity, and reflectivity, and their impact on the performance of solar stills. This research addresses the critical challenge of enhancing freshwater production through solar desalination, which is vital in water-scarce regions. Utilizing a validated mathematical model, the study examines how variations in saline depths (ranging from 5 mm to 40 mm), nanofluids, chemical additives, and dyes influence the optical properties and efficiency of solar stills. The results show that a depth of 20 mm emerges as optimal, providing a balance between high transmissivity, absorptivity, and low reflectivity, also a higher saline absorptivity, ranging from 0.014 to 0.021, significantly boosts solar still performance, while transmissivity, ranging from 0.26 to 0.95, affects instantaneous efficiency. The study reveals that the production of distilled water decreases from 6.77 to 4.87 L/m2 as the refractive index increases from 1.2 to 2.6, while higher extinction coefficients enhance production, reaching up to 6.96 L/m2 at 300 m−1. These findings demonstrate the importance of optimizing saline optical properties to improve solar still efficiency. The novelty of this work lies in its comprehensive analysis of the dynamic nature of saline optical properties and their practical application in enhancing solar desalination technology, going beyond previous efforts that assumed constant optical properties. This advanced understanding significantly contributes to the development of more efficient and effective solar desalination systems.

Experimental analysis of tubular solar still with custard apple seeds a bio-waste material: An energy, exergy, economic, environmental and sustainability analysis

Solar desalination is emerging as a sustainable solution for addressing water scarcity and the lack of access to fresh drinking water in various regions worldwide. This experimental study has employed custard apple seeds (CAS) a biowaste substance in Tubular Solar Still (TSS) to attain maximum water yield, and improved energy and exergy efficiency, thereby addressing water scarcity issues. Furthermore, the research examines the economic feasibility, environmental impact, and sustainability of utilizing CAS biowaste medium in the TSS. Two separate TSS were used in the experimental work in which one TSS is provided with CAS, which is named as Enhanced Tubular Solar Still (ETSS). The other TSS is utilized without inclusion of biowaste substance and is named as Normal Tubular Solar Still (NTSS). The results indicated that ETSS system, using 600 g of CAS, has a water yield of 3.73 kg/m2/day while for NTSS without any biowaste materials, the yield is obtained as 2.45 kg/m2/day. The ETSS model demonstrates a significant improvement of 52.51 % compared to the NTSS model. Additionally, the thermal and exergy efficiencies of ETSS are achieved as 38.22 % and 1.96 %, respectively, whereas for NTSS, both are evaluated to be 23.78 % and 1.04 %, respectively. The energy and exergy efficiencies for ETSS show enhancements of 60.69 % and 87.37 % in comparison to the NTSS system. Moreover, economic investigation reveals that the Cost Per Liter (CPL) for NTSS and ETSS models is $0.024/L and $0.016/L, respectively, indicating a 33.33 % improvement in the ETSS model over the NTSS model. The Economic Payback Time (PBT) for NTSS and ETSS is 141.3 and 95.57 days, respectively. Environmental analysis indicates that the mitigation of CO2 in NTSS and ETSS is evaluated as 66.7 kg/year and 101.66 kg/year, respectively. Additionally, the Net Carbon Emission Mitigation (NCEM) for both models is 8 and 12.42 tons for the 10-year lifetime of both NTSS and ETSS, respectively. Carbon credits gained amount is $87.22 and $135.4 for NTSS and ETSS models, respectively.

Thermal energy storage using phase change material for solar thermal technologies: A sustainable and efficient approach

Over-exploitation of fossil-based energy sources is majorly responsible for greenhouse gas emissions which causes global warming and climate change. To mitigate these challenges renewable energy sources, especially solar thermal technologies, can play a decisive role. United Nations also proposes steps to attenuate the adverse effects of fossil-based energy and climate change through Sustainable Development Goals (SDG7 and SDG8). Solar thermal technologies have seen a huge capacity expansion around the globe in previous decades because of their inherent advantages. However, solar energy faces crucial limitations of fluctuating intensity and time-dependent availability. This decreases solar thermal system performance and makes solar thermal technologies time-dependent. To overcome these challenges, integrating phase change material (PCM) in solar thermal technologies makes a sustainable approach to enhance the efficacy, productivity, and utilization rate of solar thermal technologies. In this manuscript, the sustainable approach of integrating PCM in solar thermal technologies was reviewed. This includes literature on PCMs which covers classification, properties, importance, and limitation. Comprehensive data on the integration of PCM with solar thermal technologies such as solar water heating, solar desalination, solar cooking, solar dryers, solar PV/T, solar ponds, solar chimneys, and solar power plants were reported explicitly in terms of the type of PCM, efficiency and their productivity. In addition, the effect of PCMs integration in solar thermal technologies was analyzed in terms of mitigation of CO2 emissions and economic analysis at different locations around the World.

Carbon nanodots-based interfacial nanofluid for high-performance solar-driven water evaporation

Solar steam generation through volumetric heating using nanofluids is a promising approach for wastewater treatment and desalination. However, low evaporation rate and slow response time to the change in solar intensity seriously affect their cumulative evaporation performance in practice. Here, we propose an interfacial nanofluid structure for high-performance solar-driven water evaporation using carbon nanodot (CDs) nanofluid and airlaid paper. CDs nanofluid transferred down through the paper from a source water tank to form an interfacial evaporation structure and ensure continuous water supply for evaporation. The solar conversion heat was only localized on a small amount of nanofluid on the paper resulting in low heat loss to the bulk nanofluid and a fast response time of within 2 min to reach a steady evaporation rate. In addition, the flowing nanofluid on the paper can absorb environmental energy to achieve high-rate evaporation of 1.93 kg m−2 h−1 under one sun irradiation. This study provides an effective strategy to improve the performance of volumetric heating systems for solar wastewater treatment and desalination.

Construction of bilayer cellulose-based aerogel with salt-resistant design for efficient solar desalination and wastewater purification

Solar-driven interfacial evaporation (SDIE) technology, which utilizes green and renewable solar energy to produce clean water, has shown great potential in alleviating global water scarcity. However, practical applications still face numerous challenges, including salt crystallization precipitation and accumulation, low energy utilization, and complex preparation processes. Hence, We designed a vertically ordered porous bilayer aerogel based on nanofibrillated cellulose (NFC)/polyethyleneimine (PEI) with excellent salt resistance, light absorption and local thermal effects to achieve efficient solar steam generation. Specifically, the photothermal conversion layer (PCL) at the top had excellent light absorption and photothermal conversion efficiency by introducing graphene oxide (GO) as a highly efficient photothermal material. The water transport layer (WTL) at the bottom ensured a stable water supply to the evaporation layer by virtue of the vertical water transfer path and inherent hydrophilicity, and effectively prevented formation of salts in the evaporation area. In addition, the designed aerogel had a low thermal conductivity, which achieved effective thermal insulation and further enhanced the localized heating effect. This superhydrophilic bilayer aerogel achieved a high evaporation rate of 1.9596 kg m−2 h−1 and an energy conversion efficiency of 92.28% under one solar irradiation. It is noteworthy that evaporation process exhibited excellent stability during 8 h of continuous evaporation in 20 wt% brine and no salt accumulation was observed on the evaporated surface. In addition, the bilayer aerogel demonstrated excellent long-term stability and self-cleaning. Meanwhile, its excellent anti-contamination and wastewater treatment capabilities give SDIE technology a stable and continuous operation in practical applications, thus demonstrating significant application potential.

Fumed nano-silica modified PVA-chitosan composite hydrogel with Janus structure for solar-driven interfacial evaporation

Solar-driven interfacial evaporation (SIE) receives much attention nowadays. At present, efficient thermal management and salt resistance during operation are still the difficulties of SIE technology. In this work, a new composite hydrogel for SIE has been reported. This composite hydrogel uses polyvinyl acetate (PVA) and chitosan (CS) as the framework, carbon nanoparticles (CB) as the photothermal material, modified with hydrophilic/hydrophobic fumed nano-silica. The addition of fumed nano-silica reduces the thermal conductivity and effectively immobilizes heat energy on the evaporator’s top surface, which reduces heat loss and improves the evaporation rate. The CSPC (CB/Nano-silica PVA-CS) evaporator modified with hydrophobic nano-silica exhibits Janus structure with transition from a hydrophobic top to a hydrophilic bottom. The Janus-structured CSPC evaporator has the characteristics of excellent salt resistance, simple preparation process, low heat loss with self-floating property. The CSPC evaporator containing 0.5 g hydrophobic fumed nano-silica has a maximum evaporation rate of 1.58 kg/(m2·h), about 1.6 times higher than the evaporator without fumed nano-silica, which proves that the introduction of fumed nano-silica can effectively improve the evaporation performance of hydrogel. The overall efficiency of CSPC evaporator in simulated seawater is 88.63 %. The evaporation rate of CSPC evaporator has reached a high level in the evaporators using carbon black as photothermal material which was prepared by simple and low-cost method. It should be a promising category of material to be employed for solar desalination.

Possibility of Implementing Large-Scale Solar Desalination System in the Republic of South Africa

Possibility of Implementing Large-Scale Solar Desalination System in the Republic of South Africa

Optimizing Solar Desalination: Integrating Predictive Models with Thermal Energy Storage for Enhanced Efficiency and Sustainability

Optimizing Solar Desalination: Integrating Predictive Models with Thermal Energy Storage for Enhanced Efficiency and Sustainability

Bifunctional Janus Membranes for Multicomponent Contaminated Seawater Separation and Recovery.

Solar-driven interface desalination has emerged as a promising strategy to address the global freshwater shortage crisis. However, the separation and recovery of multicomponent oil-contaminated seawater remain a key challenge. This study reports a novel high-strength Janus photothermal membrane with a unique reverse wettability design. On one side, the membrane has hydrophilic and oleophobic properties, while on the other, it has hydrophobic and oleophilic characteristics. The Janus membrane demonstrates dual functionality: solar desalination and oil-water separation. This dual functionality enables efficient separation and recovery of four components from contaminated seawater: purified water, salt crystals, light oil, and heavy oil. As a result, the Janus membrane achieves an evaporation rate of 2.06 kg m-2 h-1 under 1.0 sun. The ion (Na+, K+, Ca2+, and Mg2+) removal rate approaches 100% with nearly complete recovery of salt crystals. Furthermore, various types of oils can be accurately separated, with separation efficiency approaching 100%. An integrated separation device successfully separates and recovers the four components. This research presents significant potential for efficient separation and recovery of complex components in oil-contaminated seawater.

Simultaneous Salt Rejection and Heat Localization Via Engineering Macrochannels in Morning Glory-Shaped 3D Evaporator.

Solar desalination is a promising solution for alleviating water scarcity due to its low-cost, environmentally friendly, and off-grid capabilities. However, simultaneous salt rejection and heat localization remain challenging, as the rapid salt convection often results in considerable heat loss. Herein, this challenge is overcome via a facile design: i) isolating high-temperature and high-salt zones by rationally designing morning glory-shaped wick structures and ii) bridging high-salt zones and bulk water with low-tortuosity macrochannels across low-temperature surfaces. The salinity gradient in the macrochannels passively triggers convective flow, facilitating the rapid transfer of salt ions from the high-salt zone to the bulk water. Meanwhile, the macrochannels are spatially isolated from the high-temperature zone, preventing heat loss during salt convection and thereby achieving a high evaporation rate (≈3kgm-2h-1) and superior salt rejection even in highly concentrated real seawater. This work provides new insights into salt rejection strategies and advances practical applications for sustainable seawater desalination.

Proposing a novel solar adsorption desalination unit using conceptual design and AHP-TOPSIS

In response to the escalating issue of water scarcity, the United Nations has allocated Sustainable Development Goal 6 of ‘Clean Water and Sanitation’ to address the issue by providing clean water and improved sanitation. Solar stills are an attractive solution to water scarcity as they are simple, cost-effective, and convenient for communities with limited resources. However, they have shortcomings, such as limited production and nocturnal ineffectiveness. The present study proposes several alternatives to address these issues using the conceptual design technique. The customer requirements were met using the Quality Function Deployment (QFD) method targeted during the design stage. An integrated AHP-TOPSIS was used to evaluate the design of alternatives considering seven criteria. This proposed method includes many factors, including system efficiency, cost, and ease of operation and maintenance. The three alternatives combine solar stills with adsorption desalination units. Two weighting methods were used, consistency-based ranking index for decision making (CRITIC) and Entropy, to evaluate the results' reliability. The findings showed that the most favorable alternative with CRITIC value of 0.975 and entropy of 0.988, combines a pyramid solar still and an evacuated tube solar collector. The purpose of this investigation is to build on the body of knowledge of solar desalination and support decision-makers in the evaluation process of selecting an appropriate solar still system.

Enhanced water production in pyramid solar stills: Utilizing suspended trays, fogging system, and forced condensation

This work investigated how to improve the thermal efficiency of pyramid distiller (PSD). A modified PSD (MPSD) was constructed with suspended trays (4-cm width) on three vertical walls. The performance of the MPSD with and without a fogging system was evaluated. Additionally, the MPSD was integrated with an external condensation unit using a withdrawing fan operating at various speeds (1, 1.5, 2, 2.5, 3, & 3.5 rpm). The MPSD with suspended trays exhibited a significant improvement, achieving a 35 % increase in distillate yield compared to the PSD. The MPSD with a fogging system demonstrated a 160 % yield increase. The highest thermal performance for the MPSD with trays, fogger, and external condenser was attained at a fan speed of 2 rpm. At this setting, the MPSD's productivity increased by 194 % with a thermal efficiency of 62.4 %. Notably, the cost of water production decreased from 0.24$/L for the PSD to 0.18$/L for the MPSD. These findings suggest that the MPSD with suspended trays, fogging system, and external condenser offers a promising approach to enhance both the yield and efficiency of solar desalination.

Numerical analysis of evaporation process in the heating column of a solar water desalination plant under various geometries, ambient conditions, solar radiations, and time steps

Solar-powered desalination offers a promising and sustainable method for producing potable water. In this study, the heating column of a solar desalination powerplant is numerically investigated under different novel geometric/structure scenarios, various solar/ambient conditions and different seawater salinity through different time steps. The primary objective is to identify the optimal configuration that maximizes water evaporation within the heating cylinder which has not been carried out before. Initially, four distinct heating cylinder configurations are examined under a fixed time step. The most promising configuration is then selected and evaluated under a broader range of ambient conditions and the same time step. The influence of solar radiation throughout the day is also analyzed. Finally, the evaporation process is simulated for the selected geometrical and environmental conditions across different time steps ranging from 60 to 300 s. The findings reveal that incorporating fins alone, a glass cover alone, and a combination of both fins and a glass cover could enhance the volume fraction of vapor by approximately 8 %, 33.3 % and 10.6 %, respectively, compared to the baseline configuration without fins or a glass cover. However, the evaporation rate for the glass cover configuration increased with rising ambient air temperature. Additionally, the highest evaporation is observed at 15:00 p.m., corresponding to the peak solar radiation intensity. Under optimal conditions, the heating cylinder achieved a promising vapor volume fraction of approximately 78.2 % after 300 s. These findings offer valuable insights for optimizing solar desalination system design. By increasing the salinity of the water from 0 to 75 %, the value of steam volume fraction is reduced from 77 % to 60 % for a given time step.

Simulation of vacuum membrane desalination within an enhanced design of compact solar water heaters

Vacuum Membrane Distillation stands out as a solar desalination method utilizing membrane pressure differentials to evaporate seawater and collect it as fresh water. On the other hand, the new design of compact (or integrated) solar water heaters can be very suitable for Vacuum Membrane Distillation use. In the new design of solar system, its upper part, which is under buoyancy pressure, can have a very suitable space for installing the Vacuum Membrane Distillation system. The purpose of this research is to simulate the proposed design and a dynamic time-domain model was developed for comprehensive simulation, encompassing absorber plate characteristics, collector dimensions, mass flow rate, vacuum pressure reduction, the influence of increasing membrane rows, and seawater concentration. Simulation results showcase the system’s potential, yielding 57.12kg/m2/day of freshwater daily with an average gain output ratio exceeding 1.1. The estimated water production cost is 0.039USD.L-1, along with the generation of 4.3kg.kg/m2/day of chlorine and 0.037g.kg/m2/day of bromine from Mediterranean seawater. For super saline water, the projections indicate a daily production of 104.46kg.kg/m2/day of freshwater with a production cost of less than 0.01 USD/L, a GOR of 1.7, and a daily production of 37.8kg.kg/m2/day of chlorine for a collector area of 6 m2. These outcomes underscore the efficiency and economic viability of the proposed design, positioning it as a promising solution for seawater desalination challenges.

Mapping the evolution of seawater desalination research (2000–2024): Bibliometric and co-word analysis of 11,000+ publications

Seawater desalination (SWD) can partially mitigate the increasing freshwater needs globally. Although, SWD is multifaceted and involves processes with environmental and economic challenges, research is often analyzed through Literature Reviews (LRs) in specific contexts that may miss general trends. Bibliometric Analyzes (BAs), however, provide researchers with an overview through Co-occurrence Networks (CNs), Strategic Diagrams (SDs), Thematic Subnetworks (TSs), and Thematic Evolution Diagrams (TEDs). Nevertheless, their use in SWD research has been limited, with minimal attention given to them. Thus, we created a bibliometric dataset, compared it with other BAs, and developed CNs, SDs, TSs, and a TED for SWD. Furthermore, key term searches (Energy, Solar, Reverse Osmosis, Modeling and Optimization, Membrane Distillation, Environmental, Economics, Fouling, Nanofiltration, and Ultrafiltration) and their literature are discussed. Geographical analysis shows China and the US lead SWD research, shifting from process design to membrane fabrication and solar energy. Furthermore, RO remains the leading technique despite high energy demands. Solar desalination shows promise but faces cost and scalability challenges. Environmental and economic concerns are discussed, as well as emerging solutions regarding, solar desalination, blue energy, “blue carbon”, and zero liquid discharge. Research gaps include fouling effects and pretreatment incorporation in optimizations are also highlighted.

Superhydrophobic photothermal evaporator based on MoS2 nanoflowers for efficient solar desalination

Solar desalination is a promising solution to address global water scarcity. In this study, a novel superhydrophobic photothermal evaporator based on MoS2 nanoflowers, known for their excellent photothermal conversion properties, was developed. The evaporator is coated with 1H, 1H, 2H, 2H-Perfluorodecyltriethoxysilane (PFDTES) to create superhydrophobic structures, which are then loaded onto a macroporous non-woven fabric (NWF) to facilitate efficient steam release. The hydrophobic PFDTES coating effectively prevents salt crystallization, ensuring long-term desalination. The developed device demonstrates an exceptional solar steam generation performance of 1.52 kg m−2 h−1 with an evaporation efficiency of up to 87.1 %. This evaporator offers a promising solution to water scarcity challenges due to its high evaporation efficiency, impressive durability, and low-cost.

Biomimetic hydrogel evaporator with excellent salt-rejection performance via edge-preferential crystallization and ion-transport effects

Solar steam generation has been considered a compellent desalination technology due to its environmental friendliness and sustainability, while interfacial salt crystallization and low freshwater yield are two serious issues that constrain its widespread application. In this work, inspired by lotus seedpod, a biomimetic evaporator containing conductive hydrogel was fabricated through 3D printing. The printed evaporator has excellent solar absorption, good mechanical properties, high water capture ability, and reduced vaporization enthalpy, which are exactly desired by good evaporators. Furthermore, the vertical micro-channels and networks inside hydrogel promote the transport of ions from the interface to bulk seawater, and the constructed edge petals drive salt ions to crystallize at the edges, both of these strategies suppress the salt crystallization and ensure long-term continuous operation of the evaporator in concentrated (25 wt%) seawater. Due to these positive effects, the evaporator can achieve 2.413 and 1.889 kg·m−2·h−1 steam yield under one sun in pure water and concentrated (25 wt%) seawater, which is much higher than the 2D evaporator and competitive among the reported evaporators. This work paves the road for the practical utilization of hydrogel in solar desalination.