Solar Distillation Research Articles

4E assessment of pyramid distiller performance utilizing V-corrugated wick material and TiO2 nanoparticles with hybrid solar heating

This study aims to increase freshwater productivity and thermal performance while improving the economic determinant of the traditional square pyramid distiller. The study was conducted on four modified pyramid distillation systems and their impact on 4E (Energy, Exergy, Economic, and Environmental). The V-corrugated wick material was combined with the water basin in the first configuration (AHPSS-1). The second system uses the same components but integrates a Solar Air Heater (SAH) to raise the water temperature (AHPSS-2). In the third proposed system, a hybrid solar heating system was used by combining a PV-powered electric heater with the previous system (AHPSS-3). The fourth configuration was similar to the third but with the addition of titanium oxide nanoparticles in the water to augment heat transfer performance (AHPSS-4). Thermal analysis of the proposed systems was performed to evaluate their thermal performance in various aspects of energy and exergy efficiency relative to the Conventional Pyramid Distiller (CPSS). In addition, an economic and environmental analysis was conducted for each case of the proposed systems. The outcomes showed an apparent enhancement in thermal and economic analyses versus the CPSS for the four proposed systems. Moreover, there was an improvement in productivity by 27.6, 102.5, 147.8 and 161.5 % for AHPSS-1, AHPSS-2, AHPSS-3, and AHPSS-4 severally. Consequently, the performance of the fourth proposed system was optimum compared to other cases, where the total freshwater yield of the conventional and novel pyramid solar distiller reached 3.9 and 10.2 L/m2. In addition, the daily thermal efficiency and the cost of one liter reached 69.8% and 0.011 USD. Furthermore, the annual CO2 emissions for the modified configuration were estimated at 9.44 and 19.75 tons/year versus 7.48 tons/year for CPSS. Also, the enviroeconomic parameters ranged from 136.81 to 286.35 USD/year.

Design and implementation of an IoT monitoring system for the optimization of solar stills for water desalination

The project "Design and Implementation of an IoT Monitoring System for the Optimization of Solar Distillers in Water Desalination" sought to improve the efficiency of desalination in La Guajira, a region with critical water scarcity. The objective was to develop an IoT system to optimize solar stills, offering a sustainable solution. A prototype solar still with IoT monitoring was built. The study included the creation of circuits to integrate sensors and an HTML dashboard to visualize real-time variables, such as internal and external temperatures, humidity, and water level in the basin, facilitating the calculation of efficiency. The IoT monitoring system proved to be effective in increasing efficiency and providing valuable data for design decisions, marking a step towards water autonomy.

Performance enhancement of solar distillers integrated with new green composite thermal insulations: Experimental and economic approach

This work aims to improve water productivity in solar stills by reducing heat loss through green composite insulators to ensure storage of the absorbed thermal energy. Two green composite materials were proposed and presented. The first is made of date palm fiber and mortar (PFM), and the second is made of date palm fiber and gypsum (PFG). Three identical solar distillers were designed and tested under the same meteorological conditions of El Oued, Algeria. The first is the reference case (RSW distiller) where a 5 cm thick wooden box is used as insulation. The second (MSD-PFM distiller) is insulated with a 2.5 cm thick PFM composite material and then installed inside a 2.5 cm thick wooden box. The third (MSD-PFG distiller) is insulated with a 2.5 cm thick PFG composite material and then installed inside a 2.5 cm thick wooden box. The thermal conductivity of the proposed composite insulators was first determined experimentally and then used as insulators. Results showed that the accumulated water production from the MSD-PFG (4100 mlm-2day-1) is higher than that of the MSD-PFM (3400 mlm-2day-1) and RSW solar distillers (2800 mlm-2day-1) by 21.5 % and 46.43 %, respectively. The improvement in thermal efficiency of the proposed MSD-PFG and MSD-PFM were 45.77 % and 21.14 %, respectively. The economic analysis showed that the improvement in the production cost by MSD-PFG (0.011 $/liter) and MSD-PFM (0.0153 $/liter) were 31.68 % and 4.97 %, respectively. The sustainability, eco-friendliness, and cost-effectiveness of composite date palm make it an attractive option for insulation applications in solar distillers.

Micro-particle-clay aided microporous support for removal of hydrocarbon toxicity from petroleum refinery wastewater in single-slope solar distillation

The removal of toxic hydrocarbon pollutants is not sustainable via conventional treatment technology. This research investigates the feasibility of a solar distillation (SSD) system to eliminate soluble hydrocarbon salts, stubborn organics, and separation of oil emulsion from petroleum refinery wastewater (PRW). The PRW collected from the petroleum refinery facility and hydrophilic micro-particle clay (MP-clay) samples were characterized following the ASTM and SEM techniques. The treatment process for the removal of total dissolved salts (TDS), biological oxygen demand (BOD), and separation of oil emulsion was monitored in the SSD still using MP-clay aided microporous filter support, at varying MP-clay concentrations (0.5–3.5 mg/L), pH (6.6–7.3), temperature (27–80 0C), and exposure time (1–18hrs) respectively. The results showed MP-clay as self-assembled monolayers on microporous support with a 98 % reduction in BOD concentration under optimum conditions: pH of 7.3, contact time of 9 hours, and MP-clay concentration of 3.2 mg/L. The TDS concentration decreased by 94 % at the optimal exposure time (15hrs) and temperature (48 0C) in SSD still. The investigation also examined the recyclability of MP-clay for oil content accumulation and water separation. The findings demonstrated MP-clay on reuse retained 90.5 % of its activity in water separation and established MP-clay can be operated to the optimum of 3 cycles, each lasting 60 minutes. After this period, reactivity loss becomes severe owing to lipase leakage and substrate obstruction. The research findings will help harness solar energy for environmentally friendly and cost-effective PRW remediation.

Evaluating the performance of spherical, hemispherical, and tubular solar stills with various configurations - A detailed review

Solving global water shortages has become an urgent challenge, hindering sustainable development. Therefore, comparing different solar still designs from application and economic perspectives is necessary. Solar distillation is considered a major innovation in the alternative energy sector for purifying brackish or brine water into clean water. Despite the extensive literature on improved solar stills, determining the most efficient designs for residential and industrial applications remains difficult. This review compares the productivity of spherical, hemispherical, and tubular solar still designs. The aim is to study the factors that influence the efficiency of each type and to analyze recent research and results obtained under different conditions. The results show that innovations in solar distillation design can take many forms to improve efficiency and productivity. For example, adding parabolic mirrors can increase productivity in spherical, hemispherical, and tubular stills by 35 to 70%. Likewise, innovative designs such as rotating spheres and changing bowl shapes significantly increased the productivity of spherical and hemispherical stills. Likewise, retrofitting a still with vacuum generation technology can significantly increase yields by 50 to 70%. In addition, using nanomaterials, especially nanophase change materials (NPCM), has increased the efficiency of the spherical and tubular stills by 116.5%, producing 7.62 kg/m2 per day. Therefore, the NPCM-equipped model was still the most efficient option among the three designs.

A data-driven method to construct prediction model of solar stills

The interdisciplinary field between solar desalination and machine learning is the subject of a cutting-edge study. Generally, the studies treat data acquisition and model construction as independent processes, leading to problems such as insufficient dataset size or resource wastage. This study proposes a data-driven method that integrates data acquisition with model construction processes. By using the Bayesian optimization algorithm, the method accelerates the convergence of model accuracy. By comparing the results of 100 pairs of simulations, it is found that the models using the data-driven method are more accurate than traditional expert-driven methods in 70 % of compared results. Additionally, when it makes a model with the mean absolute percentage error as 5 %, the proposed data-driven method requires 220 additional data on average, compared to 258 with the traditional expert-driven method, representing a 14.7 % reduction. This work offers new ways and a broad application of the interdiscipline between solar desalination and machine learning.

Effects of Utilizing Black Glass Balls, Phase Change Material, and Fins on the Performance of the Single-Slope and Single-Basin Solar Water Distiller under Climate Conditions of Mosul City: An Experimental Study

The present investigation involves an experimental examination of incorporating rectangular fins, black glass balls as porous media, and phase change material (PCM) above the absorber surface to improve the effectiveness of the single-slope and single-basin solar water distiller system, known as MSS-FPPCM. Data was gathered in November and December 2023 in Mosul City, Iraq. The performance was evaluated with and without the addition of porous media at varying water depths. The results indicated that the highest basin water temperature, PCM temperature, productivity, and efficiency were achieved when utilizing fins, black glass balls, and PCM. The maximum temperatures recorded for water basin and PCM, productivity, and efficiency were 55°C, 55.4°C, 1.01 kg/m2, and 30.83%, respectively, at a water depth of 3cm. The results highlight the significant impact of porous media, phase change material, fins, and water depth on heat exchange, evaporation, and heat transfer rates.

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.

Optimization and experimental study on the effect of graphite bars on the productivity of conical solar distiller: Exergo-economic approach

This work aims to enhance productivity and reduce the production cost of conical solar distillers using green and inexpensive materials. Conical solar stills are characterized by their cover is always exposed to the same solar radiation in all locations and do not create shading. Different graphite bars are installed at various distances in the still basin, acting as corrugated surfaces and energy storage materials to increase the interface area, reduce energy losses, and enhance the overall performance. Three conical stills were designed and tested to investigate the effect of changing the distances (0 to 30 mm) between the graphite rods on the production rate at the same climatic conditions of El Oued, Algeria. Furthermore, energy, exergy, economic, and exergoeconomic approaches were conducted to assess the viability of the proposed distillers. Results showed that reducing the distances between graphite bars increases the production rate due to the increased interfacial space with basin water and the storage of excess heat absorbed during the day. The energy and exergy efficiencies of the proposed conical solar distillers incorporated with graphite bars improved by 46.23–90.46 % and 181–321 % respectively, compared with the traditional conical still. Based on the exergo-economic approach, the annual energy and exergy outlets improved by 45.65–90.46 % and 187.5–439 % respectively, compared to the traditional conical still. The cost of the yield and payback period decreased by 40.41–74.91 % and 28.8–42.8 % respectively, compared to the traditional conical still. Finally, incorporated graphite rods with conical solar stills represent a good option for obtaining high performance with economic benefit.

Natural and sustainable thermal storage solution for solar distillation system using sensible fiber material and latent PCM: Enhanced energy storage application

AbstractThe current research work involves the design and performance assessment of a solar still, which is a conventional single‐slope basin‐type solar still (CSSBTSS) and a modified single‐slope basin‐type solar still (MSSBTSS) under the meteorological conditions of Solan city, Himachal Pradesh, India (30.90° N, 77.09° E). The individual and the combined effect of different sample quantities of sensible Himalayan Rambaan fibers (HRFs) and mass of latent paraffin wax (PW) A48 on the performance of MSSBTSS is evaluated and compared with CSSBTSS. The use of HRF material enhanced the evaporation rate significantly and improved the daytime distillates. Besides, different masses of latent PW filled inside the aluminum tubes improved the nocturnal distillates. For the analysis, three cases have been considered which are, namely: Case 1, solar still with sensible HRFs (MSSBTSS‐HRF); Case 2, solar still with latent PW A48 (MSSBTSS‐PW); and Case 3, solar still with sensible and latent material (MSSBTSS‐HRF‐PW). The results showed that the maximum thermal efficiency for Cases 1 and 2 was improved by 30.02% and 42.41% with five sample quantities of HRF material and 5000 g of PW. For Case 3, the maximum energy efficiency was 90.71% with a gain of 45.16% over CSSBTSS. The economic analysis concluded that the cost per liter of distillate yield produced using MSSBTSS‐HRF‐PW and CSSBTSS is ₹1.5 and ₹1.6, respectively. These outcomes showed the great potential of MSSBTSS‐HRF‐PW approach towards enhancing the overall performance and cost‐effectiveness of solar still.

Optimization of Eucalyptus essential oil extraction by applying response surface methodology in traditional distillation and its adaption to solar thermal process

This work reports the utilization of solar thermal energy to generate Eucalyptus essential oil, reducing the dependence on conventional energy and minimizing the environmental impact. The study optimized oil extraction by traditional steam distillation using response surface methodology and applied the results to a Scheffler concentrator-driven solar steam distillation setup. The optimum factors included leaf size (0.02 m), extraction temperature (97.76 ℃), solid/solvent ratio (0.61), and extraction time (206 min), with temperature being crucial. The major oil components were 1–8 cineole (57.53–78.45%) and α-Pinene (15.27–27.83%). The outdoor experiments achieved an efficiency of 27% and produced 2 kg/h steam at an average solar insolation of 700 W/m2. Despite consistent processing temperatures favouring conventional steam distillation, the solar extraction process offers an eco-friendly alternative. In line with the sustainable development goals, this initiative is well-suited for sunny regions and small businesses targeting niche markets.

Band gap engineering of g-C3N4/CuS and its application in Solar Still

Interfacial solar steam generation is considered as economical and more effective implementation of Solar steam generation (SSG) where solar energy is concentrated at the liquid surface via the utilization of heat localization materials (HLM). Herein we report the fabrication of an HLM constituted of a nanocomposite absorber of graphitic carbon nitride (g-C3N4) and covellite copper sulfide (CuS) supported on a mixed cellulose ester membrane, with a substrate of air laid paper-wrapped polystyrene foam. This structure allowed for strong broad-spectrum absorbance, increased hydrophilic character and minimal thermal losses. The HLM system absorbed 98% of the material and had an evaporation rate of 2.58 kgs per square meter per hour. This is twice the evaporation rate of water tested under the same conditions. Moreover, as fabricated HLM was also incorporated in a solar still in order to assess its practical performance in solar distillation. Initial studies proved that HLM modified solar still was more effective than conventional solar stills.

Computational Fluid Dynamics Analysis of Temperature Distribution in Solar Distillation Panel with Various Flat Plate Materials

As the world population continues to grow, the demand for clean water is increasing daily, making it a crucial resource to access. However, there are ways to harness abundant resources like solar energy and seawater to produce clean water. The present studies have conducted experimental investigations to convert seawater into freshwater using solar stills, where solar energy is utilized as the primary heat source for evaporation. The temperature distribution inside the solar stills was analyzed using a flat plate made of three different materials: copper, stainless steel, and aluminum. To examine the temperature distribution and performance of the solar stills, researchers employed computational fluid dynamics simulations (Ansys R15.0). The results showed variations in temperature distribution among the three plate materials. Copper flat plates achieved the highest temperature, approximately 44.5 Celsius, followed by aluminum at 43.91 Celsius, while stainless steel exhibited the lowest temperature at around 42.01 Celsius. The average heat flux across the three materials was approximately 581 W/m2. Additionally, observations indicated that the amount of convection occurring in copper flat plates was 121.108 Watts; in aluminum, it was 118.517 Watts; and in stainless steel, it was 105.05 Watts. The radiation energy for stainless steel flat plates was 29.93 W; for copper, 16.14 W; and for aluminum, 13.49 W.

Artificial intelligence vision technology application in sustainability evaluation of solar-driven distillation device

The process of transforming brackish water into freshwater utilizing solar thermal energy is referred to as solar-driven distillation device, or solar still. Such device without fossil fuel provides significant environmental and health benefits by reducing air pollutants and remedying brackish water. The yield of purified water from conventional solar stills remains insufficient, prompting the necessity for research to enhance it by understanding the coupling effect between steam flow, heat transfer, and mass transfer. As such, computer-aided brackish water treatment comparison of the hemispherical solar still and other multi-slope solar stills is conducted in this paper, and an automatic steam&heat flow detection algorithm is developed to solve the problem of difficult data acquisition for gas-liquid transport processes. Firstly, double slope, four slope, and hemispherical solar stills are exposed to the sun in outdoor experiments, therefore the solar thermal performance of each still is analyzed through pairwise comparisons. Secondly, a large amount of experimental image data is input into neural network for training, and by continuously adjusting network parameters, the network can accurately recognize different types of images. Finally, the image to be recognized is input into the trained neural network, which outputs the category labels of the image to achieve automatic image recognition. Based on the data above, the best structure of solar-driven device is hemispherical structure, due to that the hemispherical solar still possesses the best performance in terms of distilled water yield, energy efficiency, exergy efficiency and energy payback.

The effect of adding layers of date stones on the profitability of brackish water solar desalination process

Lately, there has been a pronounced and alarming up tick in the global demand for fresh water, resulting in a limited availability of this precious resource. Solar desalination emerges as a promising solution, particularly for supplying the sparsely populated desert regions in the southern regions of Algeria, where plentiful solar energy and subterranean brackish water resources are present.The current paper seeks to optimize the performance of traditional solar stills and elevate the quality of distilled water by incorporating layers of blackened date stones as an additional heat storage medium. Date stones, typically discarded post-date consumption, undergo a process of washing and blackening before being introduced in two forms (stone and powder). They are then uniformly distributed across the horizontal surface of solar still’s absorber.Three solar stills of identical design featuring glass sides were designed, manufactured, and subjected to testing to compare their productivity with that of a control unit. Experimental trials conducted at Ouargla University reveal significant enhancements the inclusion of a single layer of date stones (approximately 2.210 kg/ (m2 of absorber area)) leads to a remarkable 45.66 % increase in yield. Conversely, an equivalent amount (≈ 504 g) of date stones in powder form results in a 29.42 % improvement in yield. Notably, the distillate quality is substantially enhanced in both cases contrasted with the conventional setup.

Assessment of thermoeconomic and thermoenvironmental impacts of a novel solar desalination system using a heat pump, evacuated tubes, cover cooling, and ultrasonic mist

Various desalination methods have been introduced to address the growing demand for freshwater. Among these methods, solar stills have emerged as one of the simplest approaches. However, their performance has been hindered by low reliability, particularly due to heavy reliance on solar energy year-round. Addressing this issue, this study presents a novel and reliable solar desalination unit incorporating an evacuated tube water solar heater as a heat collector and a 250 W heat pump unit for condensation. Additionally, ultrasonic atomizers are integrated to facilitate vapor generation and accelerate its separation from the hot water fed into the desalination unit. The research commences with the selection of the optimal number of atomizers, followed by a comprehensive analysis encompassing environmental, economic, exergy, and energy (4E) considerations for the system with the optimal atomizer configuration. Furthermore, cover cooling is implemented to enhance condensation rates. Results indicate that the system, equipped with a single atomizer, yields 19.565 L/m2 per day of distilled water, with daily energy and exergy efficiencies of 62.39 % and 6.04 %, respectively. Following cover cooling, the system achieves production of 20.95 L/m2 of distilled water per day, accompanied by energy and exergy efficiencies of 65.48 % and 6.67 %, respectively. These improvements represent enhancements in freshwater production, energy efficiency, and exergy efficiency by 431.7 %, 57.82 %, and 74.61 %, respectively. Additionally, the system demonstrates a cost reduction of 14.36 % and a decrease in carbon dioxide emissions by 11.17 tons CO2, underscoring its economic and environmental benefits.

Optimized distribution of black cylinder ceramic magnet with dual effects of magnetic field and thermal energy storage to enhance the productivity of conical solar distillers

Optimized distribution of black cylinder ceramic magnet with dual effects of magnetic field and thermal energy storage to enhance the productivity of conical solar distillers

Enhancement and evaluation of solar still performance using internal reflectors and woven wire mesh: An experimental approach

In recent years, the urgency for harnessing solar energy for water desalination has grown significantly, driven by the escalating costs and the increasing scarcity of clean water sources. Numerous research efforts were dedicated to enhance the productivity of solar still, including the thermal energy storage materials, solar concentrators, nanofluid, and more. The main objective of this research is to improve the solar still performance by using wastes of workshops and factories so, their actual cost can be assumed to be zero. The experimental setup placed at faculty of Engineering Suez Canal University. Two solar still were included: one representing the conventional and the second one is modified with internal reflectors and woven wire mesh. The performance of the stills was assessed under identical climate conditions, considering water depths of 1, 2, 3 and 4 cm using both fresh and saline water with Total dissolved Solids of 18,562 and 35643 ppm. The obtained results indicated that the incorporation of internal reflectors and woven wire mesh led to a notable percentage increase in daily thermal efficiency and accumulative productivity ranged from 42.49 % to 45.04 % and from 43.0 % to 46.8 % respectively. The economic analysis demonstrated that the cost per liter for conventional and modified solar still was about 0.0018 and 0.0011$ per liter per m2 respectively. This study’s findings suggested that the integration of internal reflectors and woven wire mesh into solar stills to obtain high productivity potable water with low cost. These results align with and reinforce previous publications in this field, highlighting the potential of this approach for addressing the pressing challenges of affordable and efficient water desalination.

Experimental investigation on productivity enhancement of conical solar distillers using various sand bed types based on energy, exergy, and exergo-economic analysis

In this study, performance enhancement of conical distillers was investigated with various natural sand bed types. Four sand types with different colors (compositions and concentrations of chemical compounds) were tested and used as thermal storage materials to reduce heat loss, enhance evaporation process, and daily production. Three similar distillers were designed and investigated experimentally under the same climatic parameters over two consecutive days. Performance parameters of the proposed distillers, including yield, energy, exergy, and exergo-economic were analyzed and compared with those of reference distiller and other related studies. Results showed that the highest yield and performance values were achieved by the distiller combined with a golden sand bed. The utilization of golden sand bed achieves a daily production of 7.38 lm−2day−1 with enhancement of 10.31 %, 22.79 %, 35.91 %, and 60.43 % compared with yellow sand, red sand, white sand, and reference distillers, respectively. The daily energy and exergy efficiency of conical distillers combined with golden, yellow, red, and white sand beds 59.59 %, 44.84 %, 30.33 %, and 17.85 % and 143.52 %, 103.44 %, 64.73 %, and 36.39 %, respectively, higher than that of the reference distiller. Integrating golden, yellow, red, and white sand beds with conical distillers reduces the yield price and payback time by 60.43 %, 45.43 %, 30.65 %, and 18.04 %. The annual energy and exergy output of conical distillers combined with golden, yellow, red, and white sand beds were 130.54, 118.47, 106.60, 96.41, and 81.76 kWh/year and 6.08, 5.08, 4.00, 3.31, and 2.49 kWh/year, respectively.

Experimental Investigation of Single Slope Solar Still by Varying Water Depth and with External Reflector

Solar distillation converts salt water into drinkable water, requiring minimal maintenance and energy-saving. However, the desalination process has drawbacks because the system's slow evaporation and condensation rate leads to low freshwater output. Consequently, this method is not widely utilized due to its limited productivity. To address this issue, the study's primary aim was to enhance the productivity of the single-slope solar still. This was achieved by altering the water depth from 3 cm to 6 cm and incorporating an external reflector. The experiments were conducted in Coimbatore, Tamil Nadu, India (11.0168° N, 76.9558° E), with a condensing cover inclined at 11 degrees. The research occurred on varying days between October and November 2023, with water depths ranging from 3 to 6 cm. A comprehensive analysis investigated the influence of different factors on daily production, such as ambient temperature, solar intensity, and inner and outer glass temperatures. The experimental results indicate that the solar still with a single basin, operating at a water depth of 3 cm, achieved the highest water productivity (2.68 L/day) and displayed the best efficiency (30.52%) compared to 4, 5, and 6cm depths. Furthermore, incorporating an external reflector into the solar system still demonstrated a notable elevation in temperature, resulting in a significant boost in water productivity of 3.085 liters per day. This improvement also led to an increase in efficiency of 35.1%.