Solar Desalination Technologies Research Articles

Photothermal/magnetothermal coupled polyphenylene sulfide composite membranes for ultra-efficient and continuous seawater desalination

As the population continues to expand and industrialization gathers pace, the rate at which freshwater resources are dwindling is alarming. Solar desalination technology has shown encouraging results in generating clean water. However, solar-driven interfacial evaporation technology still faces a series of major challenges, specifically manifested in its low efficiency, poor chemical stability, and the tendency for salt crystallization to accumulate on the evaporation surface during operation. In this work, we proposed a novel magneto/photo-thermal coupled evaporator based on polyphenylene sulfide (PPS) fibrous membrane, which showed excellent high temperature and corrosion resistance. This non-contact responsive interfacial evaporator exhibited outstanding photothermal and magnetothermal conversion performance properties. Under one solar illumination, the evaporation rate of this evaporator could reach 1.52 kg m−2 h−1, corresponding to an evaporation efficiency of 91.84 %. In addition, under a magnetic field power of 2 kW m−2, the evaporator could achieve a remarkable evaporation rate of 4.2 kg m−2 h−1 under one solar illumination, with an evaporation efficiency of up to 93.77 %. Moreover, it also exhibited superb salt resistance, great mechanical properties, long-term operational stability, and outstanding dye purification property. Furthermore, by integrating the thermoelectric generator with the evaporator and utilizing the waste heat from the evaporation process to generate electricity, the efficiency of energy utilization has been improved. The interfacial evaporator opens up vast prospects for efficient and rapid clean water production, demonstrating significant potential and advantages.

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.

Salt Resistant PPy/MXene Flexible Waffle Type Fabric for Efficient Solar Evaporation and Water Purification Production.

In recent years, with the development of solar seawater desalination technology, many solar evaporators are affected by precipitated salts during the evaporation process, which can reduce efficiency. In this work, flexible fabrics made of polypyrrole (PPy)/MXene are obtained by impregnating the prepared PPy ink onto waffle like fabrics. The combination of PPy and fabric greatly improves the water absorption and evaporation performance of the fabric. The average evaporation rate of this structure is 1.43kg m-2 h-1, and the average evaporation efficiency under a single light source is 85.13%. After a 15-h testing cycle and a total of 8 cycles, lasting nearly 120 h, the performance of the device remained stable. The structural characteristics of waffle fabric, based on the Marangoni thermal effect, make it possible to suppress salt precipitation during evaporation, avoiding large salt particles covering the evaporation surface and reducing efficiency. This experiment successfully demonstrated long-term stable water evaporation, providing new ideas for the development of fabric evaporators.

EVALUATION OF ENHANCED SOLAR DESALINATION SYSTEM PROTOTYPE

Solar desalination technology has been one of the effective solutions to tackle the problem of water scarcity. A number of studies have been conducted at our water research group to determine which variable influences the quantity of distilled water produced by an independent solar desalination unit. Aims: This study was aimed to design and optimize a novel solar desalination unit and field-tested using the best variable from the previous studies. Methodology and results: Variables used from the previous studies were evaluated to obtain the best values for each parameter, those are: glass cover inclination, gap distance between water and glass cover, insulation thickness, water depth, and water mass flow rate. Those best values were then implemented in the optimized basin design, delivery mechanisms, evaporation techniques, and heat isolation methods. The optimized design can generate up to 2,778.2 mL/m2/8hrs of distilled water with an efficiency of 23.35% in preliminary test, and was field tested at Batukaras Beach, where it produced up to 902 mL/m2/8hrs with an efficiency of 13.56%. Conclusion, significance and impact study: Meteorological parameters and environmental conditions are important factors that greatly affect the performance and productivity of the desalination unit. The relative humidity is inversely proportional to the volume of distillate water, where the smaller the value, the greater the amount of distillate water that can be produced, and it has significant impact on the productivity of the prototype. The quality of the distillate water produced still needs improvement on the parameters of pH, turbidity, and total coliform.

A case study on single basin solar still augmented with wax filled metallic cylinders

This experimental study introduces a novel approach to enhancing solar still performance through the integration of wax-filled rods, marking a significant advancement in solar desalination technology. These rods, innovatively designed to absorb and store both sensible and latent heat during peak solar radiation hours, release this stored energy gradually, particularly during the evening and night. This unique mechanism results in a notable and consistent increase in water temperature within the modified solar still after 17:00, setting it apart from conventional models. The study's findings reveal that the modified solar still achieves a 12.8 % higher cumulative distillate yield and a 16.3 % increase in efficiency compared to traditional solar stills. Furthermore, this enhancement translates into a 6.3 % reduction in distillate production costs, underscoring the economic viability and superior performance of the modified design.

Functional and financial analysis of an inclined step solar desalination using phase change nanomaterials.

Recent decades have seen a shortage of water, which has led scientists to concentrate on solar desalination technologies. The present study examines the solar water desalination system with inclined steps, while considering various phase change materials (PCMs). The findings suggest that the incorporation of PCM generally enhances the productivity of the solar desalination system. Additionally, the combination of nanoparticles has been used to PCM, which is a popular technique utilized nowadays to improve the efficiency of these systems. The current investigation involves the transient modeling of a solar water desalination system, utilizing energy conservation equations. The equations were solved using the Runge-Kutta technique of the ODE23s order. The temperatures of the salt water, the absorbent plate of the glass cover, and the PCM were calculated at each time. Without a phase changer, the rate at which fresh water is produced is around 5.15 kg/m2·h. The corresponding mass flow rates of paraffin, n-PCM I, n-PCM III, n-PCM II, and stearic acid are 22.9, 28.9, 5.9, 11.9, and 73 kg/m2·h. PCMs, with the exception of stearic acid, exhibit similar energy efficiency up to an ambient temperature of around 29°. However, at temperatures over 29°, n-PCM II outperforms other PCM.

Developing Salt-Rejecting Evaporators for Solar Desalination: A Critical Review.

Solar desalination, a green, low-cost, and sustainable technology, offers a promising way to get clean water from seawater without relying on electricity and complex infrastructures. However, the main challenge faced in solar desalination is salt accumulation, either on the surface of or inside the solar evaporator, which can impair solar-to-vapor efficiency and even lead to the failure of the evaporator itself. While many ideas have been tried to address this ″salt accumulation″, scientists have not had a clear system for understanding what works best for the enhancement of salt-rejecting ability. Therein, for the first time, we classified the state-of-the-art salt-rejecting designs into isolation strategy (isolating the solar evaporator from brine), dilution strategy (diluting the concentrated brine), and crystallization strategy (regulating the crystallization site into a tiny area). Through the specific equations presented, we have identified key parameters for each strategy and highlighted the corresponding improvements in the solar desalination performance. This Review provides a semiquantitative perspective on salt-rejecting designs and critical parameters for enhancing the salt-rejecting ability of dilution-based, isolation-based, and crystallization-based solar evaporators. Ultimately, this knowledge can help us create reliable solar desalination solutions to provide clean water from even the saltiest sources.

Performance Evaluation of an Enhanced Solar Still Using Simulink

This study focuses on enhancing the efficiency of solar desalination, particularly for small communities facing water scarcity. Despite the economic viability of solar desalination, the method encounters a technical challenge related to low solar yield. The research proposes innovative solutions, notably the integration of a Compound Parabolic Collector (CPC) and Thermal Energy Storage (TES). The CPC system addresses low solar yield by minimizing losses through reflection, significantly improving the capture efficiency of solar radiation. Additionally, TES serves as a strategic storage component, storing solar energy and providing high energy when needed, thereby enhancing water evaporation rates. Using the SIMULINK platform for evaluation, the study demonstrates that the solar still, enhanced with TES and CPC, consistently produces an average of 15 liters of clean water. This positive outcome underscores the effectiveness of the proposed enhancements and suggests avenues for further refinement. The research not only addresses technical challenges but also establishes a foundation for ongoing improvements in solar desalination technology, offering potential solutions for water-scarce communities.

Applications of different types of heat pipes in solar desalinations: A comprehensive review.

Desalination processes are energy consuming and it is required to apply clean energy sources for supplying them to prevent environmental issues. Solar energy is one of the attractive clean energy sources for desalination. In solar thermal desalination systems, different thermal components could be used for heat transfer purpose. In solar desalination technologies, heat pipe as efficient heat transfer mediums could be employed to transfer absorbed and/or stored thermal energy. The objective of this study is to review applications of heat pipes in solar energy desalination systems. Regarding the performance dependency of these thermal systems on the variety of factors, scholars have investigated these systems by consideration of the effect of different influential factors. Based on the results, it is concluded that use of heat pipes could lead to proper performance of solar desalination systems. Aside from direct transfer of absorbed heat from solar radiation, heat pipes can be applied in the storage units of solar desalination systems to keep the systems active in night-hours or low solar irradiation conditions. The overall performance of the solar desalinations systems with heat pipes can be influenced by some factors such as filling ratio and operating fluid that affect the performance of heat pipes.

Full tea waste-based photothermal aerogel with vertical water transport channels for steady solar desalination

Interfacial solar desalination technology holds immense promise in combatting global freshwater scarcity. However, salt accumulation on solar evaporators poses a significant hurdle in sustaining desalination performance. Therefore, the development of salt-resistance solar evaporators remains a formidable challenge. Herein, we have exploited a full tea waste-based photothermal aerogel (TWPA) to achieve steady desalination performance. This TWPA is fabricated with carbonized tea waste (TWC) and tea waste fiber (TWF) with a simple crosslinking method and liquid nitrogen freeze-drying. The TWPA efficiently absorbs 97% of sunlight, which results in an exceptional evaporation rate of 1.63 kg m–2 h–1 under 1-solar intensity. Moreover, the vertical water transport channels and large pore structure within TWPA expedite solution transport and salt ion backflow diffusion, ensuring stable desalination of 10 wt% brine at a rate of 1.37 kg m–2 h–1. Long-term indoor and outdoor experiments demonstrate that TWPA is durable. Notably, a 1 m2 TWPA can generate about 6.34 kg freshwater per day from 10 wt% brine. This simple waste-to-treasure approach not only demonstrates a sustainable solution but also promises to drive the development of waste-based solar evaporators, addressing freshwater scarcity while mitigating environmental pollution.

Synergizing environmental and technological advances: Discarded transmission oil and paraffin wax as a phase change material for energy storage in solar distillation as a step towards sustainability

The increasing demand for water desalination technologies in coastal areas with high seawater levels but limited freshwater resources calls for innovative solutions. This research delves into the effectiveness of a new double-slope solar still with bottom fins (DSSS-BF) and a groundbreaking Composite Energy Storage Material (CESM). This study addresses productivity challenges in traditional solar stills, focusing on cost-effectiveness and adaptability. This investigation also aligns with the Sustainable Development Goals (SDGs) and utilizes eco-friendly materials such as discarded transmission oil, presenting a unique waste-to-energy approach. This research offers a sustainable and efficient energy storage material by repurposing discarded automotive transmission oil as an energy storage medium by mixing various volume proportions in paraffin wax. Experimental findings demonstrate that the CESM composed of 80 % wax and 20 % oil shows a striking 35.34 % boost in thermal conductivity compared to pure paraffin wax. Moreover, incorporating a finned absorber basin into the energy storage material significantly improves heat transfer, water evaporation, and production of safe drinking water, outperforming traditional solar stills. The DSSS-BF-CESM shows a significant increase in water and absorber temperatures compared to CSS, leading to high productivity. The DSSS-BF-CESM displays an impressive 46.57 % increase in productivity over conventional solar stills, directly contributing towards Sustainable Development Goals (SDGs) 6 and 7. Moreover, a careful examination of the economics reveals that the DSSS-BF-CESM had a 16.67 % decrease in CPL and a 15.38 % decrease in the payback period compared to CSS. This extensive research further promotes the development of solar desalination technology and highlights its viability in addressing both water scarcity and sustainability concerns.

Pengaruh Kaca Penutup Double Slope dengan Piramida Menggunakan Pelat Penyerap Sirip terhadap Kinerja Solar Still

Solar desalination technology is a technology that utilizes sunlight as the main energy resource to produce clean water through the process of heating seawater. This study compared solar stills using a double slope cover glass model with a pyramid model. The study used an experimental method to compare the cover glass of the double slope model and the pyramid model. The data taken are temperature, solar radiation intensity and water productivity. The thickness of the water above the basin is 1 cm. The study resulted in the highest productivity and efficiency of solar stills using the highest double slope model cover glass of 2,780 liters and an efficiency of 37.79% compared to solar stills using pyramid model cover glass with a productivity of 2,580 liters and an efficiency of 35.16%.

Scalable Carbon Black‐Enabled Membranes for Sustainable Solar Membrane Desalination

AbstractSolar energy is used worldwide for generating electricity or desalting seawater. Photothermal membrane distillation (PMD), an emerging thermal‐driven process for seawater desalination, combines interfacial heating with membrane distillation (MD) technology to address the energy consumption issues of conventional MD. However, it is still a great challenge to develop a cost‐effective and scalable membrane, which hampers the practical use of PMD. Herein, a dual‐layer carbon black (CB)/PVDF membrane is prepared via direct electrospraying on a commercial PVDF membrane. With the introduction of a functional layer, a photothermal effect is imparted to the bare membrane, thus significantly increasing the water production rate and solar utilization efficiency (SUE) during exposure to artificial sunlight (≈57% enhancement and 72% SUE under 1 sun). In addition to the outstanding photothermal properties, this functional layer also served as a passivation coating to synergistically reduce the crystallization rate and physical binding of inorganic salts on the modified membrane without adding hazardous chemicals or using laborious steps. This multifunctional coated membrane and fast‐growing solar desalination technology provides a promising solution to the water crisis, especially in off‐grid areas where energy and resources are both relatively insufficient.

Femtosecond laser induced porous surface on polymethyl methacrylate for filmwise condensation to improve solar still productivity

The decline in freshwater availability has spurred research into employing solar desalination technology. Recent research has concentrated on investigating the use of surface modification to improve the productivity of solar still for desalination. This paper presents the use of femtosecond laser texturing to induce a porous surface on the polymethyl methacrylate (PMMA) cover of a solar still for producing filmwise condensation. Vertical lines 2.5 mm wide were fabricated on the PMMA surface using ultrafast laser texturing, and experiments were conducted using the modified cover on a solar still at a constant basin water temperature. Results show that the static water contact angle measured on the cleaned laser textured surface is hydrophobic. However, the formation of the porous structure leads to a change in wetting state from Cassie-Baxter to Wenzel upon exposure to water vapour. This change in wetting state enables the formation of filmwise condensation under the continuous presence of water vapours. The solar still productivity improves by 15.4 % and 23.1 % using both cleaned and uncleaned laser textured surfaces respectively. The modified surface is stable upon repeated exposure to water vapour, thus proving to be an excellent surface modification method for enhancing PMMA covered solar still performance.

Advancements in Solar Panel Technology in Civil Engineering for Revolutionizing Renewable Energy Solutions—A Review

Globally, solar energy has become a major contributor to the rapid adoption of renewable energy. Significant energy savings have resulted from the widespread utilization of solar energy in the industrial, residential, and commercial divisions. This review article comprises research conducted over the past 15 years (2008–2023), utilizing a comprehensive collection of 163 references. Significantly, a considerable focus is directed towards the period from 2020 to 2023, encompassing an extensive investigation into the latest developments in solar panel technology in civil engineering. The article examines the incorporation of solar panels into building designs and addresses installation-related structural considerations. In addition, the present review examines the applications of solar panels in terms of innovative infrastructure development applications of solar panels, such as photovoltaic parking lot canopies and photovoltaic noise barriers, which contribute to improved energy efficiency. It also emphasizes their role in water management systems, including water treatment plants, water pumping and irrigation systems, energy-efficient solar desalination technologies, and promoting sustainable water practices. In addition, this study examines how solar panels have been incorporated into urban planning, including smart cities and public parks, thereby transforming urban landscapes into greener alternatives. This study also examined the use of solar panels in building materials, such as façade systems and solar-powered building envelope solutions, demonstrating their versatility in the construction industry. This review explores the diverse applications of solar energy, which promotes sustainable practices in various industries. Owing to the ongoing research, solar energy holds great promise for a greener and cleaner future.

Efficient Solar Desalination of Seawater Using a Novel Carbon Nanotube-Based Composite Aerogel.

Solar desalination of seawater is an effective approach to address the scarcity of freshwater resources. For solar steam generation, it is critical to design biodegradable, sustainable, low-cost, and high-evaporation-rate technology. This study aims to develop a novel solar desalination technology by designing and fabricating a nanocomposite material with excellent light absorption and thermal conversion properties. We designed a double-layer aerogel structure, which uses naturally abundant carboxymethyl cellulose (CMC) as the basic skeleton to achieve sustainability and biodegradability, and uses carbon nanotubes as the photothermal material for efficient light absorption to prepare a ferric tannate/carbon nanotube/carboxymethyl cellulose composite aerogel (FT-CNT-CMC aerogel). Experimental results demonstrate that the FT-CNT-CMC aerogel exhibits a high light absorption rate of 96-98% within the spectral range of 250-2400 nm, showcasing remarkable photothermal conversion performance. Under a sun intensity of 1 kW·m-2, the FT-CNT-CMC aerogel achieves a significant evaporation rate of 1.942 kg·m-2·h-1 at room temperature. Moreover, the excellent performance of the FT-CNT-CMC aerogel is validated in practical seawater desalination and organic dye wastewater purification. The FT-CNT-CMC aerogel exhibits a retention rate exceeding 99% for Na+, Mg2+, K+, and Ca2+ ions in simulated seawater, while no characteristic absorption peaks are observed in methylene blue and rhodamine B dye solutions after purification. These findings highlight the promising potential of the FT-CNT-CMC aerogel in the field of novel solar desalination, providing a viable solution to obtain freshwater.

Superhydrophobic/Superhydrophilic Janus Evaporator for Extreme High Salt-Resistance Solar Desalination by an Integrated 3D Printing Method

The emerging solar desalination technology has incomparable advantages for providing a clean water solution. However, the issue of salt accumulation on the solar evaporator tops during the steam generation leads to a considerable decrease in the evaporation rate. Herein, we demonstrate a superhydrophobic/superhydrophilic Janus evaporator that enables a stable solar evaporation even in saturated brine. Our Janus solar evaporator with a superhydrophobic top and a superhydrophilic bottom has been manufactured integrally, allowing for a fast steam evaporation without the impediment of the accumulated salt residues. The superhydrophobic top changes the water passageway from the center toward the edges while it allows for the vertical transport of both solar thermo and evaporated steams. Salt residues would only be deposited at the edges of the superhydrophilic bottom, allowing for a long-term stability of the evaporator for a continuous (>50 h) solar evaporation in saturated brine, which is record-breaking for salt-resistant solar evaporators. With stable and efficient evaporation performance out of high-salinity brine, this work provides a fascinating avenue for the desalination of seawater in a salt-resistant and efficient manner.

Inventions, innovations, and new technologies: Solar Desalination

This article is a brief review of inventions, innovations, and commercialization aspects of solar desalination technology for clean water supply. It is estimated that by the year 2025, nearly two-thirds of the global population will be affected by clean water scarcity. Solar desalination is one of the most sustainable ways of facing this global challenge with emerging technological advancements. Highly efficient interfacial solar evaporation that localizes the heat on the evaporating surface has attracted tremendous research interest within the last few years. In addition, notable innovations can be found in adsorption desalination and energy-efficient freeze desalination. The mini review is followed by a list of notable recent patents and articles. However, the list is by no means exhaustive or complete, and quite possibly some important patents and articles are not cited. The mini review and the lists support the objective of this section: to draw attention to the topic of inventions, innovations and new technologies, which can be a major contributor to the global goal of net zero carbon emissions.

Reversed vapor generation with Janus fabric evaporator and comprehensive thermal management for efficient interfacial solar distillation

Interfacial solar steam generation, with high energy efficiency, promotes the solar desalination technology to a new era. However, the problem of low freshwater yield in enclosed distillation system owing to optical loss and insufficient condensation capability remains a challenge. In this work, a reversed interfacial solar distillation system is proposed by combining Janus fabric with comprehensive thermal management to significantly enhance the freshwater yield. Recycled cotton fabric is used to fabricate the low-cost Janus fabric with carbon black@silicone on the top side via a simple and scalable pre-wet coating method. The Janus fabric with high sunlight absorbance (98.0 %) and good sealing properties remarkably guarantees the downward vapor generation to eliminate the optical loss, resulting in the improved freshwater collection of the distiller. Comprehensive thermal management is designed for the distillation system to reduce the heat loss of the evaporator and enhance the condensation effect of the condenser. The optimal Janus fabric-based interfacial solar distiller achieves an outstanding water yield of 1.17 kg m−2h−1 and an efficiency of 78 % under one sun (1 kW m−2) illumination. This work presents a novel design of a high-performance interfacial solar distillation system, offering the potential for large-scale and low-cost industrial production.

A comprehensive review of solar thermal desalination technologies for freshwater production

<abstract> <p>This review is inspired by the increasing shortage of fresh water in areas of the world, and is written in response to the expanding demand for sustainable technologies due to the prevailing crisis of depleting natural water resources. It focuses on comprehending different solar energy-based technologies. Since the increasing population has resulted in the rising demand for freshwater, desalination installation volume is rapidly increasing globally. Conventional ways of desalination technologies involve the use of fossil fuels to extract thermal energy which imparts adverse impacts on the environment. To lessen the carbon footprint left by energy-intensive desalination processes, the emphasis has shifted to using renewable energy sources to drive desalination systems. The growing interest in combining solar energy with desalination with an emphasis on increasing energy efficiency has been sparked by the rapid advancements in solar energy technology, particularly solar thermal. This review paper aims to reflect various developments in solar thermal desalination technologies and presents prospects of solar energy-based desalination techniques. This paper reviews direct and indirect desalination techniques coupled with solar energy, and goes on to explain recent trends in technologies. This review also summarizes the emerging trends in the field of solar thermal desalination technologies. The use of nanoparticles and photo-thermal materials for localized heating in solar desalination systems has decreased energy consumption and enhanced the efficiency of the system. Solar power combined with emerging processes like membrane distillation (MD) has also a recent resurgence.</p> </abstract>