Solar Distillation Research Articles

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%.

Identifying enhancement of double slope solar still performance by adding water cooling to walls

The object of this research is a double-slope solar still with the addition of water cooling on the wall (DSSS.WCW). The issue with solar stills is that the temperature of the cover glass is quite high, which consequently reduces the rate of evaporation. Methods to reduce the cover glass temperature involve water cooling, by flowing water and spraying it onto the cover glass. Both of these methods have been shown to reduce the temperature of the cover glass, but they still require additional energy and can decrease the solar radiation energy received by the absorber plate. This research proposes using a water cooling method on the wall that does not require additional energy and can prevent a reduction in the solar radiation energy received by the absorber plate. Experimental and theoretical research was conducted to study the effect of using DSSS.WCW. The results showed a 13.48 % reduction in the cover glass temperature, consequently increasing the temperature difference between the fins and the cover glass by 9.82 °C. The increase in temperature difference resulted in a 13.82 % increase in freshwater productivity theoretically by 2.80 kg/hour and a 13.10 % increase experimentally for the DSSS.WCW by 2.58 kg/hour. In addition, there was a theoretical increase in energy efficiency of 22.29 % and an experimental increase of 22.82 %, along with an increase in exergy efficiency of 15.71 %. The implementation of water cooling on the wall has been shown to enhance the efficiency of the double-slope solar still. In addition, the water cooling method on the wall does not reduce the solar radiation energy that can be received by the absorber plate and does not require additional energy. The results of this research can be applied in remote islands in Indonesia, particularly during the dry season

Brackish Water Phytodesalination by the Euhalophyte Sesuvium portulacastrum

In the Middle East and North Africa as well as in numerous countries in South America and Southeast Asia, water scarcity is a real concern. Therefore, water desalination has become a key solution and an important source of freshwater production. Solar stills are used for water desalination but they require low depth of sea or brackish water and sufficient solar radiation to evaporate water. In this investigation, a phytodesalinator is presented for the first time. The halophyte used in this work is Sesuvium portulacastrum L., a heat-tolerant euhalophyte. The presented phytodesalinator can replace basic solar stills during cold seasons if there is sufficient sunlight to ensure the transpiration process in the plant. The euhalophyte S. portulacastrum was tested for its ability to desalinate reject brine as grown for two subsequent phytodesalination cycles. Several factors were found to affect the productivity of the phytodesalinator, in particular, solar radiation, phytodesalination duration, and plant density. Nevertheless, it exhibited an average productivity of 2.44 kg/m2/d and showed several advantages in comparison with basic solar stills.

Experimental and computational modeling analysis of double slope solar still with a trapezoidal channel for preheating

In specific locations in India, water scarcity is an important issue, therefore several efforts are made to produce treated water so that rural and urban areas have access to safe and sustainable drinking water. The solar still method is the most affordable water purification option available in these hot areas. This research aims to enhance the performance of passive double-slope solar stills by analyzing the effects of preheated water on evaporation and yield rates. A new method was adopted to maintain the lowest water depth in the basin of a solar still by using a channel attachment to move the feed water. Additionally, the study investigates the impact of a trapezoidal channel attachment within the solar still, a first-time innovation, on its efficiency and yield rate. Computational fluid dynamics and experimental data collected on February 10, 2024, in Kattankulathur was analyzed to assess temperature variations and yield rates. A three-dimensional full-scale simulation was carried out using Ansys Fluent with a two-phase (evaporation and condensation) model, where the flow in the channels of the rate varied from 0.87 × 10-4 to 5.21 × 10-4 Ls−1 and the highest yield is achieved at flow rate of 1.74 × 10-4 Ls−1. The accuracy of the simulation technique was evaluated by comparing it to experimental data, and found a good match. The results demonstrated that solar still with trapezoidal channels significantly increased the overall yield rate. Optimal performance was achieved under specific environmental conditions, with a cumulative yield of 2.45 Lm−2 at a basin water depth of 10 mm, marking a 37.64 % increase over the conventional solar still. Economic analysis indicated a reduction in the payback period to 299 days, affirming the system’s cost-effectiveness. The trapezoidal channel design is limited to a cross-section of 10 mm2, and positioned at a 17° angle on the middle sidewall to minimize the shadow formation on the basin of still and maintain high yield and evaporation–condensation rates. The novelty of this work is to integrate trapezoidal channels on the double slope solar still and to optimize its design and flow rate to maximize the overall production.

Polymer‐based supporting materials and polymer‐encapsulated phase change materials for thermal energy storage: A review on the recent advances of materials, synthesis, and characterization techniques

AbstractPhase change materials (PCMs) can be classified as smart materials having its applications in varied fields like domestic and commercial refrigerators, solar absorption chillers, air conditioning, free and radiative cooling, solar air heaters, solar stills, solar absorption cooling, electric and electronic devices for cooling purposes and in textiles. Here, in this review, the various polymer‐based and encapsulated PCMs used for fulfilling the above applications are discussed along with their varied synthesis/fabrication methods. Furthermore, chemical characterization is discussed by FTIR for understanding the chemical structure along with functional groups present in the materials. The thermogravimetric analysis (TGA) is also critically discussed for understanding the thermal stability of the Polymer PCM or the phase change composites and the latent heat of PCM melting was also explored by differential scanning calorimetry (DSC) for various PCM which gives insight into the thermal energy storage capability and property. The inbuilt surface structure of the polymer PCM was also tried to be investigated by scanning electron microscopy (SEM) which when understood gives a clear picture about the structure–property relationship.Highlights Polymeric supporting materials and polymer encapsulation on PCM were reviewed. The materials used and the synthesis of polymeric PCM were studied in depth. Chemical characterization was reviewed for chemical structure. Thermal stability checks by TGA and latent heat prediction was done by DSC. Morphology was reviewed using SEM for the structure–property relationship.

Enhanced water production and improving solar water distillation efficiency of double-slope solar stills: Modeling and validation

Solar distillation is a promising technology for producing clean water using renewable energy, especially in regions with water scarcity and contamination. This study investigates the impact of design modifications on the efficiency of a double-slope solar still coupled with evacuated tubes and external reflectors. Using Matlab software analysis, key findings indicate that packing factors, temperature control, and solar radiation exposure all contribute to the system’s optimal performance. Solar radiation levels directly correlate with production rates, emphasizing the need for effective sunlight exposure. The system’s ability to rely on stored heat at night enhances its practicality. This study shows how to make solar stills more efficient at producing clean water. It is found that the best way to do this is to use PV cells with a packing factor of 0.25. A packing factor of 0.25 outperforms other factors, significantly increasing water production and system efficiency. With this optimal factor, the system achieved a remarkable thermal efficiency of 83.5 % and a maximum daily production of 19 L per square meter during peak solar radiation hours. The system’s overall efficiency is 94 % increased by 13 % over the highest value recorded in previous studies. Furthermore, the system’s productivity increased by 40 % from the highest value recorded in previous studies. The amount of electrical energy produced is directly proportional to the packing factor, by the power of 41.1 W-hours (Wh) at a PV cell with a packing factor of 0.25.

3E analysis of enhancing solar distillation performance through innovative wick convex stepped absorber, PCM, and evacuated tube solar water collector: Experimental investigation

Solar distillers have been developed to meet daily potable needs because they are simple to construct and easy to operate, especially in arid areas. Despite all this development, their efficiency and yield represent a challenge. Thus, the present study aims to improve the thermo-economic performance of stepped solar distillers via raising the rates of evaporation. This was achieved by shaping the absorber surface into the shape of a convex stepped absorber and incorporating it with the evacuated tube solar water collector as a first case, where different operating times were tested. After that, wick materials were added above the convex stepped absorber. Finally, in the third case, the reservoir of paraffin wax was added below the absorber as a latent storage medium. In all experiments, the performance indicators of the three cases are compared to those of classical solar distiller. As a result, incorporating all the proposed additives (third case) improved the productivity, thermal, and exergy efficiencies by 186.96 %, 44.52 %, and 171.15 %, respectively. In addition, all proposed additions reduced the cost of potable water per L by 16 %. The findings of this investigation demonstrated the sustainability, suitability, and economic viability of the suggested enhancements in the domain of solar distillation.